{"collection":"scripture-revelation","full_text_available":true,"graph_url":"https://unchartedknowledge.5gfusion.net/v2/api/page/gutenberg_66406/graph","html_url":"https://unchartedknowledge.5gfusion.net/v2/page/gutenberg_66406","id":"gutenberg_66406","license":"Public Domain (US)","rights_basis":"gutenberg_metadata_copyright_false","source":"gutenberg","source_url":"https://www.gutenberg.org/ebooks/66406","summary":null,"tags":["Astronomy","Category: Philosophy & Ethics","Category: Religion/Spirituality","Category: Science - Physics","Cosmic physics","Natural theology"],"text":"TRANSCRIBER\u2019S NOTE\n\n  Italic text is denoted by _underscores_.\n\n  Footnote anchors are denoted by [number], and the footnotes have been\n  placed at the end of the book.\n\n  Some minor changes to the text are noted at the end of the book.\n\n\n\n\n                        BRIDGEWATER TREATISES.\n\n\n                        CAREY, LEA & BLANCHARD\n\n                            HAVE PUBLISHED,\n\n\nASTRONOMY AND GENERAL PHYSICS, considered with reference to Natural\nTheology, by the Rev. WILLIAM WHEWELL, M. A., Fellow and Tutor\nof Trinity College, Cambridge; being the _Third Part_ of the\nBridgewater Treatises on the Power, Wisdom, and Goodness of God, as\nmanifested in the Creation.\n\n  The series of Treatises, of which the present is one, is\n  published under the following circumstances:--\n\n  The Right Honourable and Rev. FRANCIS HENRY, Earl of Bridgewater,\n  died in the month of February, 1825; he directed certain\n  trustees therein named, to invest in the public funds, the sum\n  of eight thousand pounds sterling; this sum, with the accruing\n  dividends thereon, to be held at the disposal of the President,\n  for the time being, of the Royal Society of London, to be paid\n  to the person or persons nominated by him. The Testator farther\n  directed, that the person or persons selected by the said\n  President, should be appointed to write, print and publish one\n  thousand copies of a work, on the Power, Wisdom, and Goodness\n  of God, as manifested in the Creation; illustrating such work,\n  by all reasonable arguments, as, for instance, the variety and\n  formation of God\u2019s creatures in the Animal, Vegetable, and\n  Mineral Kingdoms; the effect of digestion, and, thereby, of\n  conversion; the construction of the hand of man, and an infinite\n  variety of other arguments; as also by discoveries, ancient and\n  modern, in arts, sciences, and the whole extent of literature.\n\n  He desired, moreover, that the profits arising from the sale of\n  the works so published, should be paid to the authors of the\n  works.\n\n  The late President of the Royal Society, DAVIES GILBERT, Esq.,\n  requested the assistance of his Grace, the Archbishop of\n  Canterbury, and of the Bishop of London, in determining upon\n  the best mode of carrying into effect, the intentions of the\n  Testator. Acting with their advice, and with the concurrence of\n  a nobleman immediately connected with the deceased, Mr. Davies\n  Gilbert appointed the following eight gentlemen to write separate\n  Treatises in the different branches of the subjects here stated:--\n\n  I. The Adaptation of External Nature to the Moral and\n  Intellectual Constitution of Man, by the Rev. THOMAS CHALMERS, D.\n  D., Professor of Divinity in the University of Edinburgh.\n\n  II. The Adaptation of External Nature to the Physical Condition\n  of Man, by JOHN KIDD, M. D., F. R. S., Regius Professor of\n  Medicine in the University of Oxford.\n\n  III. Astronomy and General Physics, considered with reference to\n  Natural Theology, by the Rev. WILLIAM WHEWELL, M. A., F. R. S.,\n  Fellow of Trinity College, Cambridge.\n\n  IV. The Hand: its Mechanism and Vital Endowments as evincing\n  Design, by Sir CHARLES BELL, K. H., F. R. S.\n\n  V. Animal and Vegetable Physiology, by PETER MARK ROGET, M. D.,\n  Fellow of and Secretary to the Royal Society.\n\n  VI. Geology and Mineralogy, by the Rev. WILLIAM BUCKLAND, D. D.,\n  F. R. S., Canon of Christ Church, and Professor of Geology in the\n  University of Oxford.\n\n  VII. The History, Habits, and Instincts of Animals, by the Rev.\n  WILLIAM KIRBY, M. A., F. R. S.\n\n  VIII. Chemistry, Meteorology, and the Function of Digestion, by\n  WILLIAM PROUT, M. D., F. R. S.\n\n  _The whole of these Treatises are nearly finished, and will be\n  put to press as soon as received, and published in a cheap and\n  handsome form._\n\n\nTHE PRINCIPLES OF CHRISTIAN PHILOSOPHY; containing the Doctrines,\nDuties, Admonitions, and Consolations of the Christian Religion, by\nJOHN BURNS, M. D., F. R. S. From the fourth London edition. In the\npress.\n\n\nCONVERSATIONS WITH LORD BYRON ON THE SUBJECT OF RELIGION. By J.\nKENNEDY, M. D. 12mo.\n\n\nGLEANINGS IN NATURAL HISTORY, WITH LOCAL RECOLLECTIONS. By EDWARD\nJESSE, Esq. To which are added, Maxims and Hints for Anglers. From\nthe second London edition, in one volume, being a Companion to the\nJournal of a Naturalist.\n\n  We have occasionally selected a paragraph from a very pretty\n  volume, by Mr. Jesse, published under the above title. The\n  author lives in the neighbourhood of Kew, and like Mr. White\n  of Selborne,--who made a small village of Hampshire one of the\n  most interesting spots to the lover of nature, by his ample\n  descriptions of the natural objects which he saw around him,--Mr.\n  Jesse has rendered his walks a vehicle for much instruction and\n  amusement to himself and to others. He principally confines\n  his attention to zoology--the most generally attractive of the\n  departments of natural history; and he looks upon the animal\n  world with so much practical wisdom, being disposed to be happy\n  himself, and to see every creature around him happy, that there\n  are few persons who will not read his slight sketches with\n  improvement to their hearts and understandings.--_Penny Magazine._\n\n\nTHE MECHANISM OF THE HEAVENS. By Mrs. SOMERVILLE. In 18mo.\n\n  Is it asking too much of Mrs. Somerville to express a hope that\n  she will allow this beautiful preliminary Dissertation to be\n  printed separately for the delight and instruction of thousands\n  of readers, young and old, who cannot understand, or are too\n  indolent to apply themselves to the more elaborate parts of the\n  work? If she will do this, we hereby promise to exert our best\n  endeavours to make its merits known.--_Literary Gazette._\n\n\nSALMONIA; OR, DAYS OF FLY FISHING. By Sir H. DAVY.\n\n  We are surprised in meeting with an American reprint of this\n  delightful volume, that a work so universally popular has not\n  been before republished in this country.--_N. Y. American._\n\n  One of the most delightful labours of leisure ever seen; not a\n  few of the most beautiful phenomena of nature are here lucidly\n  explained.--_Gent. Magazine._\n\n\nTHE NATURAL HISTORY OF SELBORNE. By the late Rev. GILBERT WHITE,\nA. M., Fellow of the Oriel College, Oxford; with additions by Sir\nWILLIAM JARDINE, Bart. F. R. S., E. F. L. S., M. W. S., author of\n\u201cIllustrations of Ornithology.\u201d\n\n  White\u2019s History of Selborne, the most fascinating piece of rural\n  writing and sound English philosophy that has ever issued from\n  the press.--_Athen\u00e6um._\n\n\nJOURNAL OF A NATURALIST. With Plates.\n\n      ----Plants, trees, and stones we note;\n      Birds, insects, beasts and rural things.\n\n  We again most strongly recommend this little unpretending volume\n  to the attention of every lover of nature, and more particularly\n  of our country readers. It will induce them, we are sure, to\n  examine more closely than they have been accustomed to do, into\n  the objects of animated nature, and such examination will prove\n  one of the most innocent, and the most satisfactory sources of\n  gratification and amusement. It is a book that ought to find its\n  way into every rural drawing-room in the kingdom, and one that\n  may safely be placed in every lady\u2019s boudoir, be her rank and\n  station in life what they may.--_Quart. Review_, No. LXXVIII.\n\n  This is a most delightful book on the most delightful of all\n  studies. We are acquainted with no previous work which bears\n  any resemblance to this, except \u201cWhite\u2019s History of Selborne,\u201d\n  the most fascinating piece of rural writing and sound English\n  philosophy that ever issued from the press.--_Athen\u00e6um._\n\n\nTHE FAMILY CABINET ATLAS, constructed upon an original plan: being\na Companion to the Encyclop\u00e6dia Americana, Cabinet Cyclop\u00e6dia,\nFamily Library, Cabinet Library, &c.\n\n[This Atlas comprises, in a volume of the Family Library size,\nnearly one hundred Maps and Tables, which present equal to _fifty\nthousand names of places_; a body of information three times as\nextensive as that supplied by the generality of _Quarto Atlases_.]\n\n  This beautiful and most useful little volume, says the Literary\n  Gazette, is a perfect picture of elegance, containing a vast sum\n  of geographical information. A more instructive little present,\n  or a gift better calculated to be long preserved and often\n  referred to, could not be offered to favoured youth of either\n  sex. Its cheapness, we must add, is another recommendation; for,\n  although this elegant publication contains one hundred beautiful\n  engravings, it is issued at a price that can be no obstacle to\n  its being procured by every parent and friend to youth.\n\n  This Atlas far surpasses any thing of the kind which we have\n  seen, and is made to suit the popular libraries which Dr.\n  Lardner and Mr. Murray are now sending into every family in the\n  empire.--_Monthly Review._\n\n  Its very ingenious method of arrangement secures to the\n  geographical student the information for which hitherto\n  he has been obliged to resort to works of the largest\n  dimensions.--_Athen\u00e6um._\n\n\nTHE RECTORY OF VALEHEAD. By the Rev. ROBERT WILSON EVANS, M. A.\n\n  Universally and cordially do we recommend this delightful volume.\n  Impressed with the genuine spirit of Christianity; a diary, as it\n  were, of the feelings, hopes, and sorrows of a family,--it comes\n  home to all, either in sympathy or example. It is a beautiful\n  picture of a religious household, influencing to excellence all\n  within its sphere. We believe no person could read this work, and\n  not be better for its pious touching lessons.--_Literary Gaz._\n\n  We fearlessly pronounce this delightful little volume to be\n  not only one of the most faultless, but every way valuable\n  works it has ever fallen to our lot to recommend to public\n  perusal.--_Stamford Herald._\n\n  The Rectory of Valehead is a beautiful model of domestic life\n  in the Christian home of a well-regulated family, and combines\n  literary amusement with the most refined and intellectual\n  improvement.--_Scotsman._\n\n\nA GENERAL VIEW OF THE PROGRESS OF ETHICAL PHILOSOPHY, chiefly\nduring the Seventeenth and Eighteenth Centuries. By Sir JAMES\nMACKINTOSH, M. P. In 8vo.\n\n  The best offspring of the pen of an author who in philosophical\n  spirit, knowledge and reflection, richness of moral sentiment,\n  and elegance of style, has altogether no superior--perhaps no\n  equal--among his contemporaries. Some time ago we made copious\n  extracts from the beautiful work. We could not recommend the\n  whole too earnestly.--_National Gazette._\n\n\nTHE BOOK OF THE SEASONS; OR THE CALENDAR OF NATURE. By WILLIAM\nHOWITT. In one volume, 12mo.\n\n\n\n\n                      THE BRIDGEWATER TREATISES\n\n              ON THE POWER, WISDOM, AND GOODNESS OF GOD\n                    AS MANIFESTED IN THE CREATION.\n\n\n                            TREATISE III.\n\n                   ON ASTRONOMY AND GENERAL PHYSICS.\n\n                        BY THE REV. W. WHEWELL.\n\n\n\n\n  ET H\u00c6C DE DEO, DE QUO UTIQUE EX PH\u00c6NOMENIS DISSERERE AD\n  PHILOSOPHIAM NATURALEM PERTINET.\n\n                        NEWTON, CONCLUSION OF THE PRINCIPIA.\n\n\n\n\n                     ASTRONOMY AND GENERAL PHYSICS\n\n                      CONSIDERED WITH REFERENCE TO\n\n                           NATURAL THEOLOGY.\n\n\n                                BY THE\n\n                       REV. WILLIAM WHEWELL, M. A.\n                  FELLOW AND TUTOR OF TRINITY COLLEGE,\n                               CAMBRIDGE.\n\n\n                             Philadelphia:\n                        CAREY, LEA & BLANCHARD,\n                            CHESTNUT STREET.\n\n                                1833.\n\n\n\n\n                               TO THE\n\n                  RIGHT HONOURABLE AND RIGHT REVEREND\n\n                           CHARLES JAMES,\n\n                       LORD BISHOP OF LONDON.\n\n\n  MY LORD--\n\nI owe it to you that I was selected for the task attempted in the\nfollowing pages, a distinction which I feel to be honourable;\nand on this account alone I should have a peculiar pleasure in\ndedicating the work to your lordship. I do so with additional\ngratification on another account: the Treatise has been written\nwithin the walls of the College of which your lordship was formerly\na resident member, and its merits, if it have any, are mainly\ndue to the spirit and habits of the place. The society is always\npleased and proud to recollect that a person of the eminent talents\nand high character of your lordship is one of its members; and I\nam persuaded that any effort in the cause of letters and religion\ncoming from that quarter, will have for you an interest beyond what\nit would otherwise possess.\n\nThe subject proposed to me was limited: my prescribed object is to\nlead the friends of religion to look with confidence and pleasure\non the progress of the physical sciences, by showing how admirably\nevery advance in our knowledge of the universe harmonizes with\nthe belief of a most wise and good God. To do this effectually\nmay be, I trust, a useful labour. Yet, I feel most deeply, what\nI would take this occasion to express, that this, and all that\nthe speculator concerning Natural Theology can do, is utterly\ninsufficient for the great ends of Religion; namely, for the\npurpose of reforming men\u2019s lives, of purifying and elevating their\ncharacters, of preparing them for a more exalted state of being. It\nis the need of something fitted to do this, which gives to religion\nits vast and incomparable importance; and this can, I well know, be\nachieved only by that Revealed Religion of which we are ministers,\nbut on which the plan of the present work did not allow me to dwell.\n\nThat Divine Providence may prosper the labours of your lordship,\nand of all who are joined with you in the task of maintaining and\npromoting _this_ Religion, is, my lord, the earnest wish and prayer\nof\n\n                                       Your very faithful\n                                       And much obliged servant,\n\n                                       WILLIAM WHEWELL.\n\n  Trinity College, Cambridge,\n  Feb. 25, 1833.\n\n\n\n\nNOTICE.\n\n\nThe series of Treatises, of which the present is one, is published\nunder the following circumstances:\n\n  The RIGHT HONOURABLE and REVEREND FRANCIS HENRY, EARL OF\n  BRIDGEWATER, died in the month of February, 1829; and by his last\n  Will and Testament, bearing date the 25th of February, 1825, he\n  directed certain Trustees therein named to invest in the public\n  funds the sum of Eight thousand pounds sterling; this sum, with\n  the accruing dividends thereon, to be held at the disposal of the\n  President, for the time being, of the Royal Society of London, to\n  be paid to the person or persons nominated by him. The Testator\n  further directed, that the person or persons selected by the said\n  President should be appointed to write, print, and publish one\n  thousand copies of a work _On the Power, Wisdom, and Goodness of\n  God, as manifested in the Creation; illustrating such work by all\n  reasonable arguments, as for instance the variety and formation\n  of God\u2019s creatures in the animal, vegetable, and mineral\n  kingdoms; the effect of digestion, and thereby of conversion;\n  the construction of the hand of man, and an infinite variety of\n  other arguments; as also by discoveries ancient and modern, in\n  arts, sciences, and the whole extent of literature_. He desired,\n  moreover, that the profits arising from the sale of the works so\n  published should be paid to the authors of the works.\n\n  The late President of the Royal Society, Davies Gilbert,\n  Esq. requested the assistance of his Grace the Archbishop of\n  Canterbury and of the Bishop of London, in determining upon\n  the best mode of carrying into effect the intentions of the\n  Testator. Acting with their advice, and with the concurrence of\n  a nobleman immediately connected with the deceased, Mr. Davies\n  Gilbert appointed the following eight gentlemen to write separate\n  Treatises on the different branches of the subject as here stated:\n\n\n  THE REV. THOMAS CHALMERS, D. D.\n\n  Professor of Divinity in the University of Edinburgh.\n\n  ON THE ADAPTATION OF EXTERNAL NATURE TO THE MORAL AND\n  INTELLECTUAL CONSTITUTION OF MAN.\n\n\n  JOHN KID, M. D. F. R. S.\n\n  Regius Professor of Medicine in the University of Oxford.\n\n  ON THE ADAPTATION OF EXTERNAL NATURE TO THE PHYSICAL\n  CONDITION OF MAN.\n\n\n  THE REV. WILLIAM WHEWELL, M. A. F. R. S.\n\n  Fellow of Trinity College, Cambridge.\n\n  ON ASTRONOMY AND GENERAL PHYSICS.\n\n\n  SIR CHARLES BELL, K. H. F. R. S,\n\n  THE HAND: ITS MECHANISM AND VITAL ENDOWMENTS AS EVINCING\n  DESIGN.\n\n\n  PETER MARK ROGET, M. D.\n\n  Fellow of and Secretary to the Royal Society.\n\n  ON ANIMAL AND VEGETABLE PHYSIOLOGY.\n\n\n  THE REV. WILLIAM BUCKLAND, D. D. F. R. S.\n\n  Canon of Christ Church, and Professor of Geology in the University of Oxford.\n\n  ON GEOLOGY AND MINERALOGY.\n\n\n  THE REV. WILLIAM KIRBY, M. A. F. R. S.\n\n  ON THE HISTORY, HABITS, AND INSTINCTS OF ANIMALS.\n\n\n  WILLIAM PROUT, M. D. F. R. S.\n\n  ON CHEMISTRY, METEOROLOGY, AND THE FUNCTION OF DIGESTION.\n\n  HIS ROYAL HIGHNESS THE DUKE OF SUSSEX, President of the Royal\n  Society, having desired that no unnecessary delay should take\n  place in the publication of the above mentioned treatises, they\n  will appear at short intervals, as they are ready for publication.\n\n\n\n\nCONTENTS.\n\n[Within the last year or two, several works have been published in\nthis country on subjects more or less closely approaching to that\nhere treated. It may, therefore, be not superfluous to say that the\nauthor of the following pages believes that he has not borrowed\nany of his views or illustrations from recent English writers on\nNatural Theology.]\n\n\n                                                                 Page.\n  INTRODUCTION.\n    CHAPTER I. Object of the Present Treatise                      13\n           II. On Laws of Nature                                   17\n          III. Mutual Adaptation of Laws of Nature                 20\n           IV. Division of the Subject                             23\n\n  BOOK I. TERRESTRIAL ADAPTATIONS                                  25\n    CHAPTER I. The Length of the Year                              28\n           II. The Length of the Day                               37\n          III. The Mass of the Earth                               43\n           IV. The Magnitude of the Ocean                          50\n            V. The Magnitude of the Atmosphere                     51\n           VI. The Constancy and Variety of Climates               52\n          VII. The Variety of Organization corresponding\n                 to the Variety of Climate                         57\n         VIII. The Constituents of Climate                         66\n               The Laws of Heat with respect to the Earth          67\n           IX. The Laws of Heat with respect to Water              70\n            X. The Laws of Heat with respect to Air                81\n           XI. The Laws of Electricity                             91\n          XII. The Laws of Magnetism                               93\n         XIII. The Properties of Light with regard to\n                 Vegetation                                        94\n          XIV. Sound                                               96\n           XV. The Atmosphere                                     102\n          XVI. Light                                              104\n         XVII. The Ether                                          111\n        XVIII. Recapitulation                                     113\n\n  BOOK II. COSMICAL ARRANGEMENTS                                  119\n    CHAPTER I. The Structure of the Solar System                  121\n           II. The Circular Orbits of the Planets round the Sun   123\n          III. The Stability of the Solar System                  127\n           IV. The Sun in the Centre                              134\n            V. The Satellites                                     137\n           VI. The Stability of the Ocean                         140\n          VII. The Nebular Hypothesis                             143\n         VIII. The Existence of a Resisting Medium in the\n                 Solar System                                     150\n           IX. Mechanical Laws                                    163\n            X. The Law of Gravitation                             166\n           XI. The Laws of Motion                                 178\n          XII. Friction                                           183\n\n  BOOK III. RELIGIOUS VIEWS                                       193\n    CHAPTER I. The Creator of the Physical World is the\n                 Governor of the Moral World                      195\n           II. On the Vastness of the Universe                    205\n          III. On Man\u2019s Place in the Universe                     212\n           IV. On the Impression produced by the Contemplation\n                 of Laws of Nature; or, on the Conviction\n                 that Law implies Mind                            223\n            V. On Inductive Habits; or, on the impression\n                 produced on Men\u2019s Minds by discovering\n                 Laws of Nature                                   230\n           VI. On Deductive Habits; or, on the Impression\n                 produced on Men\u2019s Minds by tracing\n                 the Consequences of ascertained Laws             243\n          VII. On Final Causes                                    257\n         VIII. On the Physical Agency of the Deity                267\n           IX. On the Impression produced by considering\n                 the Nature and Prospects of Science;\n                 or, on the Impossibility of the Progress\n                 of our Knowledge ever enabling us to\n                 comprehend the Nature of the Deity               273\n\n\n\n\nON\n\nASTRONOMY\n\nAND\n\nGENERAL PHYSICS.\n\n\n\n\nINTRODUCTION.\n\n\n\n\nCHAPTER I.\n\n_Object of the Present Treatise._\n\n\nThe examination of the material world brings before us a number\nof things and relations of things which suggest to most minds\nthe belief of a creating and presiding Intelligence. And this\nimpression, which arises with the most vague and superficial\nconsideration of the objects by which we are surrounded, is, we\nconceive, confirmed and expanded by a more exact and profound study\nof external nature. Many works have been written at different\ntimes with the view of showing how our knowledge of the elements\nand their operation, of plants and animals and their construction,\nmay serve to nourish and unfold our idea of a Creator and Governor\nof the world. But though this is the case, a new work on the same\nsubject may still have its use. Our views of the Creator and\nGovernor of the world, as collected from or combined with our\nviews of the world itself, undergo modifications, as we are led by\nnew discoveries, new generalizations, to regard nature in a new\nlight. The conceptions concerning the Deity, his mode of effecting\nhis purposes, the scheme of his government, which are suggested\nby one stage of our knowledge of natural objects and operations,\nmay become manifestly imperfect or incongruous, if adhered to and\napplied at a later period, when our acquaintance with the immediate\ncauses of natural events has been greatly extended. On this account\nit may be interesting, after such an advance, to show how the views\nof the creation, preservation, and government of the universe,\nwhich natural science opens to us, harmonize with our belief in\na Creator, Governor, and Preserver of the world. To do this with\nrespect to certain departments of Natural Philosophy is the object\nof the following pages; and the author will deem himself fortunate,\nif he succeeds in removing any of the difficulties and obscurities\nwhich prevail in men\u2019s minds, from the want of a clear mutual\nunderstanding between the religious and the scientific speculator.\nIt is needless here to remark the necessarily imperfect and scanty\ncharacter of Natural Religion; for most persons will allow that,\nhowever imperfect may be the knowledge of a Supreme Intelligence\nwhich we gather from the contemplation of the natural world, it\nis still of most essential use and value. And our purpose on this\noccasion is, not to show that Natural Theology is a perfect and\nsatisfactory scheme, but to bring up our Natural Theology to the\npoint of view in which it may be contemplated by the aid of our\nNatural Philosophy.\n\nNow the peculiar point of view which at present belongs to Natural\nPhilosophy, and especially to the departments of it which have been\nmost successfully cultivated, is, that nature, so far as it is an\nobject of scientific research, is a collection of facts governed by\n_laws_: our knowledge of nature is our knowledge of laws; of laws\nof operation and connexion, of laws of succession and co-existence,\namong the various elements and appearances around us. And it must\ntherefore here be our aim to show how this view of the universe\nfalls in with our conception of the Divine Author, by whom we hold\nthe universe to be made and governed.\n\n_Nature acts by general laws_; that is, the occurrences of the\nworld in which we find ourselves, result from causes which operate\naccording to fixed and constant rules. The succession of days,\nand seasons, and years, is produced by the motions of the earth;\nand these again are governed by the attraction of the sun, a\nforce which acts with undeviating steadiness and regularity. The\nchanges of winds and skies, seemingly so capricious and casual,\nare produced by the operation of the sun\u2019s heat upon air and\nmoisture, land and sea; and though in this case we cannot trace\nthe particular events to their general causes, as we can trace\nthe motions of the sun and moon, no philosophical mind will doubt\nthe generality and fixity of the rules by which these causes act.\nThe variety of the effects takes place, because the circumstances\nin different cases vary; and not because the action of material\ncauses leaves anything to chance in the result. And again, though\nthe vital movements which go on in the frame of vegetables and\nanimals depend on agencies still less known, and probably still\nmore complex, than those which rule the weather, each of the powers\non which such movements depend has its peculiar laws of action,\nand these are as universal and as invariable as the law by which a\nstone falls to the earth when not supported.\n\nThe world then is governed by general laws; and in order to\ncollect from the world itself a judgment concerning the nature\nand character of its government, we must consider the import and\ntendency of such laws, so far as they come under our knowledge. If\nthere be, in the administration of the universe, intelligence and\nbenevolence, superintendence and foresight, grounds for love and\nhope, such qualities may be expected to appear in the constitution\nand combination of those fundamental regulations by which the\ncourse of nature is brought about, and made to be what it is.\n\nIf a man were, by some extraordinary event, to find himself in a\nremote and unknown country, so entirely strange to him that he\ndid not know whether there existed in it any law or government at\nall; he might in no long time ascertain whether the inhabitants\nwere controlled by any superintending authority; and with a little\nattention he might determine also whether such authority were\nexercised with a prudent care for the happiness and well-being\nof its subjects, or without any regard and fitness to such ends;\nwhether the country were governed by laws at all, and whether the\nlaws were good. And according to the laws which he thus found\nprevailing, he would judge of the sagacity, and the purposes of the\nlegislative power.\n\nBy observing the laws of the material universe and their operation,\nwe may hope, in a somewhat similar manner, to be able to direct\nour judgment concerning the government of the universe: concerning\nthe mode in which the elements are regulated and controlled, their\neffects combined and balanced. And the general tendency of the\nresults thus produced may discover to us something of the character\nof the power which has legislated for the material world.\n\nWe are not to push too far the analogy thus suggested. There is\nundoubtedly a wide difference between the circumstances of man\nlegislating for man, and God legislating for matter. Still we\nshall, it will appear, find abundant reason to admire the wisdom\nand the goodness which have established _the Laws of Nature_,\nhowever rigorously we may scrutinize the import of this expression.\n\n\n\n\nCHAPTER II.\n\n_On Laws of Nature._\n\n\nWhen we speak of material nature as being governed by _laws_, it\nis sufficiently evident that we use the term in a manner somewhat\nmetaphorical. The laws to which man\u2019s attention is primarily\ndirected are _moral_ laws; rules laid down for his actions; rules\nfor the conscious actions of a person; rules which, as a matter\nof possibility, he may obey or may transgress; the latter event\nbeing combined, not with an impossibility, but with a penalty. But\nthe _Laws of Nature_ are something different from this; they are\nrules for that which _things_ are to do and suffer; and this by\nno consciousness or will of theirs. They are rules describing the\nmode in which things _do_ act; they are invariably obeyed; their\ntransgression is not punished, it is excluded. The language of a\nmoral law is, man _shall_ not kill; the language of a Law of Nature\nis, a stone _will_ fall to the earth.\n\nThese two kinds of laws direct the actions of persons and of\nthings, by the sort of control of which persons and things are\nrespectively susceptible; so that the metaphor is very simple; but\nit is proper for us to recollect that it is a metaphor, in order\nthat we may clearly apprehend what is implied in speaking of the\nLaws of Nature.\n\nIn this phrase are included all properties of the portions of\nthe material world; all modes of action and rules of causation,\naccording to which they operate on each other. The whole course of\nthe visible universe therefore is but the collective result of such\nlaws; its movements are only the aggregate of _their_ working. All\nnatural occurrences, in the skies and on the earth, in the organic\nand in the inorganic world, are determined by the relations of the\nelements and the actions of the forces of which the rules are thus\nprescribed.\n\nThe relations and rules by which these occurrences are thus\ndetermined necessarily depend on measures of time and space,\nmotion and force; on quantities which are subject to numerical\nmeasurement, and capable of being connected by mathematical\nproperties. And thus all things are ordered by number and weight\nand measure. \u201cGod,\u201d as was said by the ancients, \u201cworks by\ngeometry:\u201d the legislation of the material universe is necessarily\ndelivered in the language of mathematics; the stars in their\ncourses are regulated by the properties of conic sections, and\nthe winds depend on arithmetical and geometrical progressions of\nelasticity and pressure.\n\nThe constitution of the universe, so far as it can be clearly\napprehended by our intellect, thus assumes a shape involving an\nassemblage of mathematical propositions: certain algebraical\nformul\u00e6, and the knowledge when and how to apply them, constitute\nthe last step of the physical science to which we can attain.\nThe labour and the endowments of ages have been employed in\nbringing such science into the condition in which it now exists;\nand an exact and extensive discipline in mathematics, followed\nby a practical and profound study of the researches of natural\nphilosophers, can alone put any one in possession of the knowledge\nconcerning the course of the material world, which is at present\nopen to man. The general impression, however, which arises from\nthe view thus obtained of the universe, the results which we\ncollect from the most careful scrutiny of its administration, may,\nwe trust, be rendered intelligible without this technical and\nlaborious study, and to do this is our present object.\n\nIt will be our business to show that the laws which really prevail\nin nature are, by their _form_, that is, by the nature of the\nconnexion which they establish among the quantities and properties\nwhich they regulate, remarkably adapted to the office which is\nassigned them; and thus offer evidence of selection, design, and\ngoodness, in the power by which they were established. But these\ncharacters of the legislation of the universe may also be seen, in\nmany instances, in a manner somewhat different from the selection\nof the law. The _nature of the connexion_ remaining the same, the\nquantities which it regulates may also in their _magnitude_ bear\nmarks of selection and purpose. For the law may be the same while\nthe quantities to which it applies are different. The law of the\ngravity which acts to the earth and to Jupiter, is the same; but\nthe intensity of the force at the surfaces of the two planets is\ndifferent. The law which regulates the density of the air at any\npoint, with reference to the height from the earth\u2019s surface,\nwould be the same, if the atmosphere were ten times as large, or\nonly one-tenth as large as it is; if the barometer at the earth\u2019s\nsurface stood at three inches only, or if it showed a pressure of\nthirty feet of mercury.\n\nNow this being understood, the adaptation of a law to its purpose,\nor to other laws, may appear in two ways:--either in the form of\nthe law, or in the amount of the magnitudes which it regulates,\nwhich are sometimes called _arbitrary magnitudes_.\n\nIf the attraction of the sun upon the planets did not vary\ninversely as the square of the distance, the _form_ of the law\nof gravitation would be changed; if this attraction were, at the\nearth\u2019s orbit, of a different _value_ from its present one, the\narbitrary magnitude would be changed; and it will appear, in a\nsubsequent part of this work, that either change would, so far as\nwe can trace its consequences, be detrimental. The form of the law\ndetermines in what manner the facts shall take place; the arbitrary\nmagnitude determines how fast, how far, how soon; the one gives a\nmodel, the other a measure of the phenomenon; the one draws the\nplan, the other gives the scale on which it is to be executed; the\none gives the rule, the other the rate. If either were wrongly\ntaken, the result would be wrong too.\n\n\n\n\nCHAPTER III.\n\n_Mutual Adaptation in the Laws of Nature._\n\n\nTo ascertain such laws of nature as we have been describing, is\nthe peculiar business of science. It is only with regard to a very\nsmall portion of the appearances of the universe, that science, in\nany strict application of the term, exists. In very few departments\nof research have men been able to trace a multitude of known facts\nto causes which appear to be the ultimate material causes, or to\ndiscern the laws which seem to be the most general laws. Yet, in\none or two instances, they have done this, or something approaching\nto this; and most especially in the instance of that part of\nnature, which it is the object of this treatise more peculiarly to\nconsider.\n\nThe apparent motions of the sun, moon, and stars have been more\ncompletely reduced to their causes and laws than any other class of\nphenomena. Astronomy, the science which treats of these, is already\na wonderful example of the degree of such knowledge which man may\nattain. The forms of its most important laws may be conceived to\nbe certainly known; and hundreds of observers in all parts of the\nworld are daily employed in determining, with additional accuracy,\nthe arbitrary magnitudes which these laws involve.\n\nThe inquiries in which the mutual effects of heat, moisture,\nair, and the like elements are treated of, including, among\nother subjects, all that we know of the causes of the weather\n(meteorology) is a far more imperfect science than astronomy. Yet,\nwith regard to these agents, a great number of laws of nature have\nbeen discovered, though, undoubtedly, a far greater number remain\nstill unknown.\n\nSo far, therefore, as our knowledge goes, astronomy and meteorology\nare parts of natural philosophy in which we may study the order\nof nature with such views as we have suggested; in which we may\nhope to make out the adaptations and aims which exist in the laws\nof nature; and thus to obtain some light on the tendency of this\npart of the legislation of the universe, and on the character and\ndisposition of the Legislator.\n\nThe number and variety of the laws which we find established in\nthe universe is so great, that it would be idle to endeavour\nto enumerate them. In their operation they are combined and\nintermixed in incalculable and endless perplexity, influencing\nand modifying each other\u2019s effects in every direction. If we\nattempt to comprehend at once the whole of this complex system,\nwe find ourselves utterly baffled and overwhelmed by its extent\nand multiplicity. Yet, in so far as we consider the bearing of\none part upon another, we receive an impression of adaptation, of\nmutual fitness, of conspiring means, of preparation and completion,\nof purpose and provision. This impression is suggested by the\ncontemplation of every part of nature; but the grounds of it, from\nthe very circumstances of the case, cannot be conveyed in a few\nwords. It can only be fully educed by leading the reader through\nseveral views and details, and must grow out of the combined\ninfluence of these on a sober and reflecting frame of mind. However\nstrong and solemn be the conviction which may be derived from a\ncontemplation of nature, concerning the existence, the power, the\nwisdom, the goodness of our Divine Governor, we cannot expect that\nthis conviction, as resulting from the extremely complex spectacle\nof the material world, should be capable of being irresistibly\nconveyed by a few steps of reasoning, like the conclusion of\na geometrical proposition, or the result of an arithmetical\ncalculation.\n\nWe shall, therefore, endeavour to point out cases and circumstances\nin which the different parts of the universe exhibit this mutual\nadaptation, and thus to bring before the mind of the reader the\nevidence of wisdom and providence, which the external world\naffords. When we have illustrated the correspondencies which\nexist in every province of nature, between the qualities of brute\nmatter and the constitution of living things, between the tendency\nto derangement and the conservative influences by which such a\ntendency is counteracted, between the office of the minutest speck\nand of the most general laws; it will, we trust, be difficult or\nimpossible to exclude from our conception of this wonderful system,\nthe idea of a harmonizing, a preserving, a contriving, an intending\nMind; of a Wisdom, Power, and Goodness far exceeding the limits of\nour thoughts.\n\n\n\n\nCHAPTER IV.\n\n_Division of the Subject._\n\n\nIn making a survey of the universe, for the purpose of pointing\nout such correspondencies and adaptations as we have mentioned, we\nshall suppose the general leading facts of the course of nature\nto be known, and the explanations of their causes now generally\nestablished among astronomers and natural philosophers to be\nconceded. We shall assume therefore that the earth is a solid\nglobe of ascertained magnitude, which travels round the sun, in\nan orbit nearly circular, in a period of about three hundred and\nsixty-five days and a quarter, and in the mean time revolves, in an\ninclined position, upon its own axis in about twenty-four hours,\nthus producing the succession of appearances and effects which\nconstitute seasons and climates, day and night;--that this globe\nhas its surface furrowed and ridged with various inequalities,\nthe waters of the ocean occupying the depressed parts:--that it\nis surrounded by an atmosphere, or spherical covering of air;\nand that various other physical agents, moisture, electricity,\nmagnetism, light, operate at the surface of the earth, according to\ntheir peculiar laws. This surface is, as we know, clothed with a\ncovering of plants, and inhabited by the various tribes of animals,\nwith all their variety of sensations, wants, and enjoyments. The\nrelations and connexions of the larger portions of the world, the\nsun, the planets, and the stars, the _cosmical_ arrangements of\nthe system, as they are sometimes called, determine the course\nof events among these bodies; and the more remarkable features\nof these arrangements are therefore some of the subjects for our\nconsideration. These cosmical arrangements, in their consequences,\naffect also the physical agencies which are at work at the surface\nof the earth, and hence come in contact with _terrestrial_\noccurrences. They thus influence the functions of plants and\nanimals. The circumstances in the cosmical system of the universe,\nand in the organic system of the earth, which have thus a bearing\non each other, form another of the subjects of which we shall\ntreat. The former class of considerations attends principally to\nthe stability and other apparent perfections of the solar system;\nthe latter to the well-being of the system of organic life by which\nthe earth is occupied. The two portions of the subject may be\ntreated as Cosmical Arrangements and Terrestrial Adaptations.\n\nWe shall begin with the latter class of adaptations, because in\ntreating of these the facts are more familiar and tangible, and the\nreasonings less abstract and technical, than in the other division\nof the subject. Moreover, in this case men have no difficulty\nin recognizing as desirable the end which is answered by such\nadaptations, and they therefore the more readily consider it _as\nan end_. The nourishment, the enjoyment, the diffusion of living\nthings, are willingly acknowledged to be a suitable object for\ncontrivance; the simplicity, the permanence, of an inert mechanical\ncombination might not so readily be allowed to be a manifestly\nworthy aim of a Creating Wisdom. The former branch of our argument\nmay therefore be best suited to introduce to us the Deity as the\ninstitutor of Laws of Nature, though the latter may afterwards give\nus a wider view and a clearer insight into one province of his\nlegislation.\n\n\n\n\nBOOK I.\n\nTERRESTRIAL ADAPTATIONS.\n\n\nWe proceed in this book to point out relations which subsist\nbetween the laws of the inorganic world, that is, the general facts\nof astronomy and meteorology; and the laws which prevail in the\norganic world, the properties of plants and animals.\n\nWith regard to the first kind of laws, they are in the highest\ndegree various and unlike each other. The intensity and activity\nof natural influences follow in different cases the most different\nrules. In some instances they are _periodical_, increasing and\ndiminishing alternately, in a perpetual succession of equal\nintervals of time. This is the case with the heat at the earth\u2019s\nsurface, which has a period of a year; with the light, which has a\nperiod of a day. Other qualities are _constant_, thus the force of\ngravity at the same place is always the same. In some cases, a very\nsimple cause produces very complicated effects; thus the globular\nform of the earth, and the inclination of its axis during its\nannual motion, give rise to all the variety of climates. In other\ncases a very complex and variable system of causes produces effects\ncomparatively steady and uniform; thus solar and terrestrial heat,\nair, moisture, and probably many other apparently conflicting\nagents, join to produce our weather, which never deviates very far\nfrom a certain average standard.\n\nNow a general fact, which we shall endeavour to exemplify in the\nfollowing chapters, is this:--That those properties of plants and\nanimals which have reference to agencies of a periodical character,\nhave also by their nature a periodical mode of working; while\nthose properties which refer to agencies of constant intensity,\nare adjusted to this constant intensity: and again, there are\npeculiarities in the nature of organized beings which have\nreference to a variety in the conditions of the external world,\nas, for instance, the difference of the organized population of\ndifferent regions: and there are other peculiarities which have\na reference to the constancy of the average of such conditions,\nand the limited range of the deviations from that average; as for\nexample, that constitution by which each plant and animal is fitted\nto exist and prosper in its usual place in the world.\n\nAnd not only is there this general agreement between the nature of\nthe laws which govern the organic and inorganic world, but also\nthere is a coincidence between the _arbitrary magnitudes_ which\nsuch laws involve on the one hand and on the other. Plants and\nanimals have, in their construction, certain periodical functions,\nwhich have a reference to alternations of heat and cold; the\nlength of the period which belongs to these functions by their\nconstruction, appears to be that of the period which belongs to the\nactual alternations of heat and cold, namely, a year. Plants and\nanimals have again in their construction certain other periodical\nfunctions, which have a reference to alternations of light and\ndarkness; the length of the period of such functions appears to\ncoincide with the natural day. In like manner the other arbitrary\nmagnitudes which enter into the laws of gravity, of the effects of\nair and moisture, and of other causes of permanence, and of change,\nby which the influences of the elements operate, are the same\narbitrary magnitudes to which the members of the organic world are\nadapted by the various peculiarities of their construction.\n\nThe illustration of this view will be pursued in the succeeding\nchapters; and when the coincidence here spoken of is distinctly\nbrought before the reader, it will, we trust, be found to convey\nthe conviction of a wise and benevolent design, which has been\nexercised in producing such an agreement between the internal\nconstitution and the external circumstances of organized beings.\nWe shall adduce cases where there is an apparent relation between\nthe course of operation of the elements and the course of vital\nfunctions; between some fixed measure of time or space, traced\nin the lifeless and in the living world; where creatures are\nconstructed on a certain plan, or a certain scale, and this plan\nor this scale is exactly the single one which is suited to their\nplace on the earth; where it was necessary for the Creator (if we\nmay use such a mode of speaking) _to take account_ of the weight\nof the earth, or the density of the air, or the measure of the\nocean, and where these quantities are rightly taken account of in\nthe arrangements of creation. In such cases we conceive that we\ntrace a Creator, who, in producing one part of his work, was not\nforgetful or careless of another part; who did not cast his living\ncreatures into the world to prosper or perish as they might find it\nsuited to them or not; but fitted together, with the nicest skill,\nthe world and the constitution which he gave to its inhabitants;\nso fashioning it and them, that light and darkness, sun and air,\nmoist and dry, should become their ministers and benefactors, the\nunwearied and unfailing causes of their well-being.\n\nWe have spoken of the mutual adaptation of the organic and the\ninorganic world. If we were to conceive the contrivance of the\nworld as taking place in an order of time in the contriving mind,\nwe might also have to conceive this adaptation as taking place\nin one of two ways: we might either suppose the laws of inert\nnature to be accommodated to the foreseen wants of living things,\nor the organization of life to be accommodated to the previously\nestablished laws of nature. But we are not forced upon any such\nmode of conception, or upon any decision between such suppositions:\nsince, for the purpose of our argument, the consequence of either\nview is the same. There is an adaptation somewhere or other,\non either supposition. There is account taken of one part of\nthe system in framing the other: and the mind which took such\naccount can be no other than that of the Intelligent Author of the\nuniverse. When indeed we come to see the vast number, the variety,\nthe extent, the interweaving, the reconciling of such adaptations,\nwe shall readily allow, that all things are so moulded upon and\nlocked into each other, connected by such subtilty and profundity\nof design, that we may well abandon the idle attempt to trace the\n_order_ of thought in the mind of the Supreme Ordainer.\n\n\n\n\nCHAPTER I.\n\n_The Length of the Year._\n\n\nA year is the most important and obvious of the periods which occur\nin the organic, and especially in the vegetable world. In this\ninterval of time the cycle of most of the external influences which\noperate upon plants is completed. There is also in plants a cycle\nof internal functions, corresponding to this succession of external\ncauses. The length of either of these periods might have been\ndifferent from what it is, according to any grounds of necessity\nwhich we can perceive. But a certain length is selected in both\ninstances, and in both instances the same. The length of the year\nis so determined as to be adapted to the constitution of most\nvegetables; or the construction of vegetables is so adjusted as to\nbe suited to the length which the year really has, and unsuited\nto a duration longer or shorter by any considerable portion. The\nvegetable clock-work is so set as to go for a year.\n\nThe length of the year or interval of recurrence of the seasons is\ndetermined by the time which the earth employs in performing its\nrevolution round the sun: and we can very easily conceive the solar\nsystem so adjusted that the year should be longer or shorter than\nit actually is. We can imagine the earth to revolve round the sun\nat a distance greater or less than that which it at present has,\nall the forces of the system remaining unaltered. If the earth were\nremoved towards the centre by about one-eighth of its distance, the\nyear would be diminished by about a month; and in the same manner\nit would be increased by a month on increasing the distance by\none-eighth. We can suppose the earth at a distance of eighty-four\nor a hundred and eight millions of miles, just as easily as at its\npresent distance of ninety-six millions: we can suppose the earth\nwith its present stock of animals and vegetables placed where Mars\nor where Venus is, and revolving in an orbit like one of theirs: on\nthe former supposition our year would become twenty-three, on the\nlatter seven of our present months. Or we can conceive the present\ndistances of the parts of the system to continue what they are,\nand the size, or the density of the central mass, the sun, to be\nincreased or diminished in any proportion; and in this way the time\nof the earth\u2019s revolution might have been increased or diminished\nin any degree; a greater velocity, and consequently a diminished\nperiod, being requisite in order to balance an augmented central\nattraction. In any of these ways the length of the earth\u2019s natural\nyear might have been different from what it now is: in the last\nway without any necessary alteration, so far as we can see, of\ntemperature.\n\nNow, if any change of this kind were to take place, the working\nof the botanical world would be thrown into utter disorder, the\nfunctions of plants would be entirely deranged, and the whole\nvegetable kingdom involved in instant decay and rapid extinction.\n\nThat this would be the case, may be collected from innumerable\nindications. Most of our fruit trees, for example, require the year\nto be of its present length. If the summer and the autumn were\nmuch shorter, the fruit could not ripen; if these seasons were\nmuch longer, the tree would put forth a fresh suit of blossoms, to\nbe cut down by the winter. Or if the year were twice its present\nlength, a second crop of fruit would probably not be matured, for\nwant, among other things, of an intermediate season of rest and\nconsolidation, such as the winter is. Our forest trees in like\nmanner appear to need all the seasons of our present year for their\nperfection; the spring, summer, and autumn, for the developement of\ntheir leaves and consequent formation of their _proper juice_, and\nof wood from this; and the winter for the hardening and solidifying\nthe substance thus formed.\n\nMost plants, indeed, have some peculiar function adapted to each\nperiod of the year, that is of the now existing year. The sap\nascends with extraordinary copiousness at two seasons, in the\nspring and in the autumn, especially the former. The opening of\nthe leaves and the opening of the flowers of the same plants are\nso constant to their times, (their _appointed_ times, as we are\nnaturally led to call them,) that such occurrences might be taken\nas indications of the times of the year. It has been proposed in\nthis way to select a series of botanical facts which should form a\ncalendar; and this has been termed a _calendar of Flora_. Thus, if\nwe consider the time of putting forth leaves,[1] the honeysuckle\nprotrudes them in the month of January; the gooseberry, currant,\nand elder in the end of February, or beginning of March; the\nwillow, elm, and lime-tree in April; the oak and ash, which are\nalways the latest among trees, in the beginning or towards the\nmiddle of May. In the same manner the flowering has its regular\ntime: the mezereon and snowdrop push forth their flowers in\nFebruary; the primrose in the month of March; the cowslip in April;\nthe great mass of plants in May and June; many in July, August,\nand September; some, not till the month of October, as the meadow\nsaffron; and some not till the approach and arrival of winter, as\nthe laurustinus and arbutus.\n\nThe fact which we have here to notice, is the recurrence of these\nstages in the developement of plants, at intervals precisely or\nvery nearly of twelve months. Undoubtedly, this result is in part\noccasioned by the action of external stimulants upon the plant,\nespecially heat, and by the recurrence of the intensity of such\nagents. Accordingly, there are slight differences in the times of\nsuch occurrences, according to the backwardness or forwardness of\nthe season, and according as the climate is genial or otherwise.\nGardeners use artifices which will, to a certain extent, accelerate\nor retard the time of developement of a plant. But there are\nvarious circumstances which show that this recurrence of the same\nevents and equal intervals is not entirely owing to external\ncauses, and that it depends also upon something in the internal\nstructure of vegetables. Alpine plants do not wait for the stimulus\nof the sun\u2019s heat, but exert such a struggle to blossom, that their\nflowers are seen among the yet unmelted snow. And this is still\nmore remarkable in the naturalization of plants from one hemisphere\nto the other. When we transplant our fruit trees to the temperate\nregions south of the equator, they continue for some years to\nflourish at the period which corresponds to our spring. The reverse\nof this obtains, with certain trees of the southern hemisphere.\nPlants from the Cape of Good Hope, and from Australia, countries\nwhose summer is simultaneous with our winter, exhibit their\nflowers in the coldest part of the year, as the heaths.\n\nThis view of the subject agrees with that maintained by the best\nbotanical writers. Thus Decandolle observes that after making\nallowance for all meteorological causes, which determine the epoch\nof flowering, we must reckon as another cause the peculiar nature\nof each species. The flowering once determined, appears to be\nsubject to a law of _periodicity_ and habit.[2]\n\nIt appears then that the functions of plants have by their nature a\nperiodical character; and the length of the period thus belonging\nto vegetables is a result of their organization. Warmth and light,\nsoil and moisture, may in some degree modify, and hasten or retard\nthe stages of this period; but when the constraint is removed\nthe natural period is again resumed. Such stimulants as we have\nmentioned are not the _causes_ of this periodicity. They do not\nproduce the varied functions of the plant, and could not occasion\ntheir performance at regular intervals, except the plant possessed\na suitable construction. They could not alter the length of the\ncycle of vegetable functions, except within certain very narrow\nlimits. The processes of the rising of the sap, of the formation of\nproper juices, of the unfolding of leaves, the opening of flowers,\nthe fecundation of the fruit, the ripening of the seed, its proper\ndeposition in order for the reproduction of a new plant;--all these\noperations require a certain portion of time, and could not be\ncompressed into a space less than a year, or at least could not be\nabbreviated in any very great degree. And on the other hand, if the\nwinter were greatly longer than it now is, many seeds would not\ngerminate at the return of spring. Seeds which have been kept too\nlong require stimulants to make them fertile.\n\nIf therefore the duration of the seasons were much to change,\nthe processes of vegetable life would be interrupted, deranged,\ndistempered. What, for instance, would become of our calendar of\nFlora, if the year were lengthened or shortened by six months? Some\nof the dates would never arrive in the one case, and the vegetable\nprocesses which mark them would be superseded; some seasons would\nbe without dates in the other case, and these periods would be\nemployed in a way harmful to the plants, and no doubt speedily\ndestructive. We should have not only _a year of confusion_, but, if\nit were repeated and continued, a year of death.\n\nBut in the existing state of things, the duration of the earth\u2019s\nrevolution round the sun, and the duration of the revolution of the\nvegetable functions of most plants are equal. These two periods are\n_adjusted_ to each other. The stimulants which the elements apply\ncome at such intervals and continue for such times, that the plant\nis supported in health and vigour, and enabled to reproduce its\nkind. Just such a portion of time is measured out for the vegetable\npowers to execute their task, as enables them to do so in the best\nmanner.\n\nNow such an adjustment must surely be accepted as a proof of\ndesign, exercised in the formation of the world. Why should the\nsolar year be so long and no longer? or, this being of such a\nlength, why should the vegetable cycle be exactly of the same\nlength? Can this be chance? And this occurs, it is to be observed,\nnot in one, or in a few species of plants, but in thousands. Take a\nsmall portion only of known species, as the most obviously endowed\nwith this adjustment, and say ten thousand. How should all these\norganized bodies be constructed for the same period of a year? How\nshould all these machines be wound up so as to go for the same\ntime? Even allowing that they could bear a year of a month longer\nor shorter, how do they all come within such limits? No chance\ncould produce such a result. And if not by chance, how otherwise\ncould such a coincidence occur, than by an intentional adjustment\nof these two things to one another? by a selection of such an\norganization in plants, as would fit them to the earth on which\nthey were to grow; by an adaptation of construction to conditions;\nof the scale of the construction to the scale of the conditions.\n\nIt cannot be accepted as an explanation of this fact in the\neconomy of plants, that it is necessary to their existence; that\nno plants could possibly have subsisted, and come down to us,\nexcept those which were thus suited to their place on earth.\nThis is true; but this does not at all remove the necessity of\nrecurring to design as the origin of the construction by which\nthe existence and continuance of plants is made possible. A watch\ncould not go, except there were the most exact adjustment in the\nforms and positions of its wheels; yet no one would accept it as\nan explanation of the origin of such forms and positions, that\nthe watch would not go if these were other than they are. If the\nobjector were to suppose that plants were originally fitted to\nyears of various lengths, and that such only have survived to the\npresent time, as had a cycle of a length equal to our present\nyear, or one which could be accommodated to it; we should reply,\nthat the assumption is too gratuitous and extravagant to require\nmuch consideration; but that, moreover, it does not remove the\ndifficulty. How came the functions of plants to be _periodical_ at\nall? Here is, in the first instance, an agreement in the form of\nthe laws that prevail in the organic and in the inorganic world,\nwhich appears to us a clear evidence of design in their Author.\nAnd the same kind of reply might be made to any similar objection\nto our argument. Any supposition that the universe has gradually\napproximated to that state of harmony among the operations of its\ndifferent parts, of which we have one instance in the coincidence\nnow under consideration, would make it necessary for the objector\nto assume a previous state of things preparatory to this perfect\ncorrespondence. And in this preparatory condition we should still\nbe able to trace the rudiments of that harmony, for which it was\nproposed to account: so that even the most unbounded license of\nhypothesis would not enable the opponent to obliterate the traces\nof an intentional adaptation of one part of nature to another.\n\nNor would it at all affect the argument, if these periodical\noccurrences could be traced to some proximate cause: if for\ninstance it could be shown, that the budding or flowering of\nplants is brought about at particular intervals, by the nutriment\naccumulated in their vessels during the preceding months. For the\nquestion would still remain, how their functions were so adjusted,\nthat the accumulation of the nutriment necessary for budding and\nflowering, together with the operation itself, comes to occupy\nexactly a year, instead of a month only, or ten years. There must\nbe in their structure some reference to time: how did such a\nreference occur? how was it i determined to the particular time of\nthe earth\u2019s revolution round the sun? This could be no otherwise,\nas we conceive, than by design and appointment.\n\nWe are left therefore with this manifest adjustment before us, of\ntwo parts of the universe, at first sight so remote; the dimensions\nof the solar system and the powers of vegetable life. These two\nthings are so related, that one has been made to fit the other. The\nrelation is as clear as that of a watch to a sundial. If a person\nwere to compare the watch with the dial, hour after hour, and day\nafter day, it would be impossible for him not to believe that the\nwatch had been _contrived_ to accommodate itself to the solar day.\nWe have at least ten thousand kinds of vegetable watches of the\nmost various forms, which are all accommodated to the solar year;\nand the evidence of contrivance seems to be no more capable of\nbeing eluded in this case than in the other.\n\nThe same kind of argument might be applied to the animal creation.\nThe pairing, nesting, hatching, fledging, and flight of birds,\nfor instance, occupy each its peculiar time of the year; and,\ntogether with a proper period of rest, fill up the twelve months.\nThe transformations of most insects have a similar reference to the\nseasons, their progress and duration. \u201cIn every species,\u201d (except\nman,) says a writer[3] on animals, \u201cthere is a peculiar period of\nthe year in which the reproductive system exercises its energies.\nAnd the season of love and the period of gestation are so arranged\nthat the young ones are produced at the time wherein the conditions\nof temperature are most suited to the commencement of life.\u201d It is\nnot our business here to consider the details of such provisions,\nbeautiful and striking as they are. But the prevalence of the great\nlaw of periodicity in the vital functions of organized beings\nwill be allowed to have a claim to be considered in its reference\nto astronomy, when it is seen that their periodical constitution\nderives its use from the periodical nature of the motions of the\nplanets round the sun; and that the duration of such cycles in the\nexistence of plants and animals has a reference to the arbitrary\nelements of the solar system: a reference which, we maintain, is\ninexplicable and unintelligible, except by admitting into our\nconceptions; an Intelligent Author, alike of the organic and\ninorganic universe.\n\n\n\n\nCHAPTER II.\n\n_The Length of the Day._\n\n\nWe shall now consider another astronomical element, the time of\nthe revolution of the earth on its axis; and we shall find here\nalso that the structure of organized bodies are suited to this\nelement;--that the cosmical and physiological arrangements are\nadapted to each other.\n\nWe can very easily conceive the earth to revolve on her axis faster\nor slower than she does, and thus the days to be longer or shorter\nthan they are, without supposing any other change to take place.\nThere is no apparent reason why this globe should turn on its axis\njust three hundred and sixty-six times while it describes its orbit\nround the sun. The revolutions of the other planets, so far as\nwe know them, do not appear to follow any rule by which they are\nconnected with the distance from the sun. Mercury, Venus, and Mars\nhave days nearly the length of ours. Jupiter and Saturn revolve\nin about ten hours each. For any thing we can discover, the earth\nmight have revolved in this or any other smaller period; or we\nmight have had, without mechanical inconvenience, much longer days\nthan we have.\n\nBut the terrestrial day, and consequently the length of the cycle\nof light and darkness, being what it is, we find various parts\nof the constitution both of animals and vegetables, which have\na periodical character in their functions, corresponding to the\ndiurnal succession of external conditions; and we find that the\nlength of the period, as it exists in their constitution, coincides\nwith the length of the natural day.\n\nThe alternation of processes which takes place in plants by day\nand by night is less obvious, and less obviously essential to\ntheir well-being, than the annual series of changes. But there are\nabundance of facts which serve to show that such an alternation is\npart of the vegetable economy.\n\nIn the same manner in which Linn\u00e6us proposed a Calendar of Flora,\nhe also proposed a _Dial of Flora_, or Flower-Clock; and this\nwas to consist, as will readily be supposed, of plants, which\nmark certain hours of the day, by opening and shutting their\nflowers. Thus the day-lily (_hemerocallis fulva_) opens at five\nin the morning; the _leontodon taraxacum_, or common dandelion,\nat five or six; the _hieracium latifolium_ (hawkweed), at seven;\nthe _hieracium pilosella_, at eight; the _calendula arvensis_, or\nmarigold, at nine; the _mesembryanthemum neapolitanum_, at ten or\neleven; and the closing of these and other flowers in the latter\npart of the day offers a similar system of hour marks.\n\nSome of these plants are thus expanded in consequence of the\nstimulating action of the light and heat of the day, as appears by\ntheir changing their time, when these influences are changed; but\nothers appear to be constant to the same hours, and independent\nof the impulse of such external circumstances. Other flowers by\ntheir opening and shutting prognosticate the weather. Plants of\nthe latter kind are called by Linn\u00e6us _meteoric_ flowers, as\nbeing regulated by atmospheric causes: those which change their\nhour of opening and shutting with the length of the day, he terms\n_tropical_; and the hours which they measure are, he observes, like\nTurkish hours, of varying length at different seasons. But there\nare other plants which he terms _equinoctial_; their vegetable\ndays, like the days of the equator, being always of equal length;\nand these open, and generally close, at a fixed and positive\nhour of the day. Such plants clearly prove that the periodical\ncharacter, and the period of the motions above described, do not\ndepend altogether on external circumstances.\n\nSome curious experiments on this subject were made by Decandolle.\nHe kept certain plants in two cellars, one warmed by a stove\nand dark, the other lighted by lamps. On some of the plants the\nartificial light appeared to have no influence, (_convolvulus\narvensis_, _convolvulus cneorum_, _silene fruticosa_) and they\nstill followed the clock hours in their opening and closing. The\nnight-blowing plants appeared somewhat disturbed, both by perpetual\nlight and perpetual darkness. In either condition they accelerated\ntheir _going_ so much, that in three days they had gained half a\nday, and thus exchanged night for day as their time of opening.\nOther flowers _went slower_ in the artificial light (_convolvulus\npurpureus_.) In like manner those plants which fold and unfold\ntheir leaves were variously affected by this mode of treatment.\nThe _oxalis stricta_ and _oxalis incarnata_ kept their habits,\nwithout regarding either artificial light or heat. The _mimosa\nleucocephala_ folded and unfolded at the usual times, whether in\nlight or in darkness, but the folding up was not so complete as\nin the open air. The _mimosa pudica_ (sensitive plant,) kept in\ndarkness during the day time, and illuminated during the night, had\nin three days accommodated herself to the artificial state, opening\nin the evening, and closing in the morning; restored to the open\nair, she recovered her usual habits.\n\nTropical plants in general, as is remarked by our gardeners, suffer\nfrom the length of our summer daylight; and it has been found\nnecessary to shade them during a certain part of the day.\n\nIt is clear from these facts, that there is a diurnal period\nbelonging to the constitution of vegetables; though the succession\nof functions depends in part on external stimulants, as light and\nheat, their periodical character is a result of the structure of\nthe plant; and this structure is such, that the length of the\nperiod, under the common influences to which plants are exposed,\ncoincides with the astronomical day. The power of accommodation\nwhich vegetables possess in this respect, is far from being such\nas either to leave the existence of this periodical constitution\ndoubtful, or to entitle us to suppose that the day might be\nconsiderably lengthened or shortened without injury to the\nvegetable kingdom.\n\nHere then we have an adaptation between the structure of plants,\nand the periodical order of light and darkness which arises from\nthe earth\u2019s rotation; and the arbitrary quantity, the length of the\ncycle of the physiological and of the astronomical fact, is the\nsame. Can this have occurred any otherwise than by an intentional\nadjustment?\n\nAny supposition that the astronomical cycle has occasioned the\nphysiological one, that the structure of plants has been brought\nto be what it is by the action of external causes, or that such\nplants as could not accommodate themselves to the existing day have\nperished, would be not only an arbitrary and baseless assumption,\nbut moreover useless for the purposes of explanation which it\nprofesses, as we have noticed of a similar supposition with respect\nto the annual cycle. How came plants to have periodicity at all in\nthose functions which have a relation to light and darkness? This\npart of their constitution was suited to organized things which\nwere to flourish on the earth, and it is accordingly bestowed on\nthem; it was necessary for this end that the period should be of\na certain length; it is of that length and no other. Surely this\nlooks like intentional provision.\n\nAnimals also have a period in their functions and habits; as in\nthe habits of waking, sleeping, eating, &c. and their well-being\nappears to depend on the coincidence of this period with the\nlength of the natural day. We see that in the day, as it now is,\nall animals find seasons for taking food and repose, which agree\nperfectly with their health and comfort. Some animals feed during\nthe day, as nearly all the ruminating animals and land birds;\nothers feed only in the twilight, as bats and owls, and are called\n_crepuscular;_ while many beasts of prey, aquatic birds, and\nothers, take their food during the night. Those animals which are\nnocturnal feeders are diurnal sleepers, while those which are\ncrepuscular, sleep partly in the night and partly in the day; but\nin all, the complete period of these functions is twenty-four\nhours. Man, in like manner, in all nations and ages, takes his\nprincipal rest once in twenty-four hours; and the regularity\nof this practice seems most suitable to his health, though the\nduration of the time allotted to repose is extremely different\nin different cases. So far as we can judge, this period is of a\nlength beneficial to the human frame, independently of the effect\nof external agents. In the voyages recently made into high northern\nlatitudes, where the sun did not rise for three months, the crews\nof the ships were made to adhere, with the utmost punctuality, to\nthe habit of retiring to rest at nine, and rising a quarter before\nsix; and they enjoyed, under circumstances apparently the most\ntrying, a state of salubrity quite remarkable. This shows, that\naccording to the common constitution of such men, the cycle of\ntwenty-four hours is very commodious, though not imposed on them by\nexternal circumstances.\n\nThe hours of food and repose are capable of such wide modifications\nin animals, and above all in man, by the influence of external\nstimulants and internal emotions, that it is not easy to\ndistinguish what portion of the tendency to such alternations\ndepends on original constitution. Yet no one can doubt that the\ninclination to food and sleep is periodical, or can maintain, with\nany plausibility, that the period may be lengthened or shortened\nwithout limit. We may be tolerably certain that a constantly\nrecurring period of forty-eight hours would be too long for one day\nof employment and one period of sleep, with our present faculties;\nand all, whose bodies and minds are tolerably active, will probably\nagree that, independently of habit, a perpetual alternation of\neight hours up and four in bed would employ the human powers less\nadvantageously and agreeably than an alternation of sixteen and\neight. A creature which could employ the full energies of his body\nand mind uninterruptedly for nine months, and then take a single\nsleep of three months, would not be a man.\n\nWhen, therefore, we have subtracted from the daily cycle of the\nemployments of men and animals, that which is to be set down to\nthe account of habits acquired, and that which is occasioned by\nextraneous causes, there still remains a periodical character;\nand a period of a certain length, which coincides with, or at any\nrate easily accommodates itself to, the duration of the earth\u2019s\nrevolution. The physiological analysis of this part of our\nconstitution is not necessary for our purpose. The succession of\nexertion and repose in the muscular system, of excited and dormant\nsensibility in the nervous, appear to be fundamentally connected\nwith the muscular and nervous powers, whatever the nature of these\nmay be. The necessity of these alternations is one of the measures\nof the intensity of those vital energies; and it would seem that\nwe cannot, without assuming the human powers to be altered,\nsuppose the intervals of tranquillity which they require to be\nmuch changed. This view agrees with the opinion of some of the\nmost eminent physiologists. Thus Cabanis[4] notices the periodical\nand isochronous character of the desire of sleep, as well as of\nother appetites. He states also that sleep is more easy and more\nsalutary, in proportion as we go to rest and rise every day at the\nsame hours; and observes that this periodicity seems to have a\nreference to the motions of the solar system.\n\nNow how should such a reference be at first established in the\nconstitution of man, animals, and plants, and transmitted from one\ngeneration of them to another? If we suppose a wise and benevolent\nCreator, by whom all the parts of nature were fitted to their uses\nand to each other, this is what we might expect and can understand.\nOn any other supposition such a fact appears altogether incredible\nand inconceivable.\n\n\n\n\nCHAPTER III.\n\n_The Mass of the Earth._\n\n\nWe shall now consider the adaptation which may, as we conceive, be\ntraced in the amount of some of the quantities which determine the\ncourse of events in the organic world; and especially in the amount\nof the _forces_ which are in action. The life of vegetables and\nanimals implies a constant motion of their fluid parts, and this\nmotion must be produced by forces which urge or draw the particles\nof the fluids. The positions of the parts of vegetables are also\nthe result of the flexibility and elasticity of their substance;\nthe voluntary motions of animals are produced by the tension of the\nmuscles. But in all those cases, the effect really produced depends\nupon the force of gravity also; and in order that the motions and\npositions may be such as answer their purpose, the forces which\nproduce them must have a due proportion to the force of gravity.\nIn human works, if, for instance, we have a fluid to raise, or\na weight to move, some calculation is requisite, in order to\ndetermine the power which we must use, relatively to the work which\nis to be done: we have a mechanical problem to solve, in order that\nwe may adjust the one to the other. And the same adjustment, the\nsame result of a comparison of quantities, manifests itself in the\nrelation which the forces of the organic world bear to the force of\ngravity.\n\nThe force of gravity might, so far as we can judge, have been\ndifferent from what it now is. It depends upon the mass of the\nearth; and this mass is one of the elements of the solar system,\nwhich is not determined by any cosmical necessity of which we are\naware. The masses of the several planets are very different, and\ndo not appear to follow any determinate rule, except that upon\nthe whole those nearer to the sun appear to be smaller, and those\nnearer the outskirts of the system to be larger. We cannot see any\nthing which would have prevented either the size or the density of\nthe earth from being different, to a very great extent, from what\nthey are.\n\nNow, it will be very obvious that if the intensity of gravity\nwere to be much increased, or much diminished, if every object\nwere to become twice as heavy or only half as heavy as it now is,\nall the forces, both of involuntary and voluntary motion which\nproduce the present orderly and suitable results by being properly\nproportioned to the resistance which they experience, would be\nthrown off their balance; they would produce motions too quick or\ntoo slow, wrong positions, jerks and stops, instead of steady,\nwell conducted movements. The universe would be like a machine ill\nregulated; every thing would go wrong; repeated collisions and a\nrapid disorganization must be the consequence. We will, however,\nattempt to illustrate one or two of the cases in which this would\ntake place, by pointing out forces which act in the organic world,\nand which are adjusted to the force of gravity.\n\n1. The first instance we shall take, is the force manifested by\nthe ascent of the sap in vegetables. It appears by a multitude\nof indisputable experiments, (among the rest, those of Hales,\nMirbel, and Dutrochet,) that all plants imbibe moisture by their\nroots, and _pump it up_, by some internal force, into every part\nof their frame, distributing it into every leaf. It will be easily\nconceived that this operation must require a very considerable\nmechanical force; for the fluid must be sustained as if it were a\nsingle column reaching to the top of the tree. The division into\nminute parts and distribution through small vessels does not at all\ndiminish the total force requisite to raise it. If, for instance,\nthe tree be thirty-three feet high, the pressure must be fifteen\npounds upon every square inch in the section of the vessels of\nthe bottom in order merely to support the sap. And it is not only\nsupported, but propelled upwards with great force, so as to supply\nthe constant evaporation of the leaves. The pumping power of the\ntree must, therefore, be very considerable.\n\nThat this power is great, has been confirmed by various curious\nexperiments, especially by those of Hales. He measured the force\nwith which the stems and branches of trees draw the fluid from\nbelow, and push it upwards. He found, for instance, that a vine in\nthe _bleeding_ season could push up its sap in a glass tube to the\nheight of twenty-one feet above the stump of an amputated branch.\n\nThe force which produces this effect is part of the economy of the\nvegetable world; and it is clear that the due operation of the\nforce depends upon its being rightly proportioned to the force of\ngravity. The weight of the fluid must be counterbalanced, and an\nexcess of force must exist to produce the motion upwards. In the\ncommon course of vegetable life, the rate of ascent of the sap is\nregulated, on the one hand, by the upward pressure of the vegetable\npower, and on the other, by the amount of the gravity of the fluid,\nalong with the other resistances, which are to be overcome. If,\ntherefore, we suppose gravity to increase, the rapidity of this\nvegetable circulation will diminish, and the rate at which this\nfunction proceeds, will not correspond either to the course of the\nseasons, or the other physiological processes with which this has\nto co-operate. We might easily conceive such an increase of gravity\nas would stop the vital movements of the plant in a very short\ntime. In like manner, a diminution of the gravity of the vegetable\njuices would accelerate the rising of the sap, and would, probably,\nhurry and overload the leaves and other organs, so as to interfere\nwith their due operation. Some injurious change, at least, would\ntake place.\n\nHere, then, we have the forces of the minutest parts of vegetables\nadjusted to the magnitude of the whole mass of the earth on which\nthey exist. There is no apparent connexion between the quantity of\nmatter of the earth, and the force of imbibition of the roots of a\nvine, or the force of propulsion of the vessels of its branches.\nYet, these things have such a proportion as the well being of the\nvine requires. How is this to be accounted for, but by supposing\nthat the circumstances under which the vine was to grow, were\nattended to in devising its structure?\n\nWe have not here pretended to decide whether this force of\npropulsion of vegetables is mechanical or not, because the argument\nis the same for our purpose on either supposition. Some very\ncurious experiments have recently been made, (by M. Dutrochet,)\nwhich are supposed to show that the force is mechanical; that when\ntwo different fluids are separated by a thin membrane, a force\nwhich M. Dutrochet calls _endosmose_ urges one fluid through the\nmembrane: and that the roots of plants are provided with small\nvesicles which act the part of such a membrane. M. Poisson has\nfurther attempted to show that this force of _endosmose_ may be\nconsidered as a particular modification of capillary action. If\nthese views be true, we have here two mechanical forces, capillary\naction and gravity, which are adjusted to each other in the manner\nprecisely suited to the welfare of vegetables.\n\n2. As another instance of adaptation between the force of gravity\nand forces which exist in the vegetable world, we may take the\npositions of flowers. Some flowers grow with the hollow of their\ncup upwards: others \u201chang the pensive head,\u201d and turn the opening\ndownwards. Now of these \u201cnodding flowers,\u201d as Linn\u00e6us calls\nthem, he observes that they are such as have their pistil longer\nthan the stamens; and, in consequence of this position, the dust\nfrom the anthers which are at the ends of the stamens can fall\nupon the stigma or extremity of the pistil; which process is\nrequisite for making the flower fertile. He gives as instances the\nflowers _campanula_, _leucoium_, _galanthus_, _fritillaria_. Other\nbotanists have remarked that the position changes at different\nperiods of the flower\u2019s progress. The pistil of the Euphorbia\n(which is a little globe or germen on a slender stalk) grows\nupright at first, and is taller than the stamens: at the period\nsuited to its fecundation, the stalk bends under the weight of\nthe ball at its extremity, so as to depress the germen below the\nstamens; after this it again becomes erect, the globe being now a\nfruit filled with fertile seeds.\n\nThe positions in all these cases depend upon the length and\nflexibility of the stalk which supports the flower, or in the\ncase of the Euphorbia, the germen. It is clear that a very slight\nalteration in the force of gravity, or in the stiffness of the\nstalk, would entirely alter the position of the flower cup, and\nthus make the continuation of the species impossible. We have\ntherefore here a little mechanical contrivance, which would have\nbeen frustrated if the proper intensity of gravity had not been\nassumed in the reckoning. An earth greater or smaller, denser or\nrarer than the one on which we live, would require a change in the\nstructure and strength of the footstalks of all the little flowers\nthat hang their heads under our hedges. There is something curious\nin thus considering the whole mass of the earth from pole to pole,\nand from circumference to centre, as employed in keeping a snowdrop\nin the position most suited to the promotion of its vegetable\nhealth.\n\nIt would be easy to mention many other parts of the economy of\nvegetable life, which depend for their use on their adaptation to\nthe force of gravity. Such are the forces and conditions which\ndetermine the positions of leaves and of branches. Such again\nthose parts of the vegetable constitution which have reference to\nthe pressure of the atmosphere; for differences in this pressure\nappear to exercise a powerful influence on the functions of plants,\nand to require differences of structure. But we pass over these\nconsiderations. The slightest attention to the relations of natural\nobjects will show that the subject is inexhaustible; and all that\nwe can or need do is to give a few examples, such as may show the\nnature of the impression which the examination of the universe\nproduces.\n\n3. Another instance of the adjustment of organic structure to the\nforce of gravity may be pointed out in the muscular powers of\nanimals. If the force of gravity were increased in any considerable\nproportion at the surface of the earth, it is manifest that all\nthe swiftness, and strength, and grace of animal motions must\ndisappear. If, for instance, the earth were as large as Jupiter,\ngravity would be eleven times what it is, the lightness of the\nfawn, the speed of the hare, the spring of the tiger, could no\nlonger exist with the existing muscular powers of those animals;\nfor man to lift himself upright, or to crawl from place to place,\nwould be a labour slower and more painful than the motions of the\nsloth. The density and pressure of the air too would be increased\nto an intolerable extent, and the operation of respiration, and\nothers, which depend upon these mechanical properties, would be\nrendered laborious, ineffectual, and probably impossible.\n\nIf, on the other hand, the force of gravity were much lessened,\ninconveniences of an opposite kind would occur. The air would be\ntoo thin to breathe; the weight of our bodies, and of all the\nsubstances surrounding us, would become too slight to resist the\nperpetually occurring causes of derangement and unsteadiness: we\nshould feel a want of ballast in our movements.\n\nIt has sometimes been maintained by fanciful theorists that the\nearth is merely a shell, and that the central parts are hollow.\nAll the reasons we can collect appear to be in favour of its being\na solid mass, considerably denser than any known rock. If this be\nso, and if we suppose the interior to be at any time scooped out,\nso as to leave only such a shell as the above mentioned speculators\nhave asserted, we should not be left in ignorance of the change,\nthough the appearance of the surface might remain the same. We\nshould discover the want of the usual force of gravity, by the\ninstability of all about us. Things would not lie where we placed\nthem, but would slide away with the slightest push. We should have\na difficulty in standing or walking, something like what we have\non ship-board when the deck is inclined; and we should stagger\nhelplessly through an atmosphere thinner than that which oppresses\nthe respiration of the traveller on the tops of the highest\nmountains.\n\nWe see therefore that those dark and unknown central portions of\nthe earth, which are placed far beyond the reach of the miner and\nthe geologist, and of which man will probably never know anything\ndirectly, are not to be considered as quite disconnected with us,\nas deposits of useless lumber without effect or purpose. We feel\ntheir influence on every step we take and on every breath we draw;\nand the powers we possess, and the comforts we enjoy would be\nunprofitable to us, if they had not been prepared with a reference\nto those as well as to the near and visible portions of the earth\u2019s\nmass.\n\nThe arbitrary quantity, therefore, of which we have been treating,\nthe intensity of the force of gravity, appears to have been taken\naccount of, in establishing the laws of those forces by which\nthe processes of vegetable and animal life are carried on. And\nthis leads us inevitably, we conceive, to the belief of a supreme\ncontriving mind, by which these laws were thus devised and thus\nestablished.\n\n\n\n\nCHAPTER IV.\n\n_The Magnitude of the Ocean._\n\n\nThere are several arbitrary quantities which contribute to\ndetermine the state of things at the earth\u2019s surface besides those\nalready mentioned. Some of these we shall briefly refer to, without\npursuing the subject into detail. We wish not only to show that\nthe properties and processes of vegetable and animal life must\nbe adjusted to each of these quantities in particular, but also\nto point out how numerous and complicated the conditions of the\nexistence of organized beings are; and we shall thus be led to\nthink less inadequately of the intelligence which has embraced at\nonce, and combined without confusion, all these conditions. We\nappear thus to be conducted to the conviction not only of design\nand intention, but of supreme knowledge and wisdom.\n\nOne of the quantities which enters into the constitution of the\nterrestrial system of things is the bulk of the waters of the\nocean. The mean depth of the sea, according to the calculations of\nLaplace, is four or five miles. On this supposition, the addition\nto the sea of one-fourth of the existing waters would drown the\nwhole of the globe, except a few chains of mountains. Whether this\nbe exact or no, we can easily conceive the quantity of water which\nlies in the cavities of our globe to be greater or less than it\nat present is. With every such addition or subtraction the form\nand magnitude of the dry land would vary, and if this change were\nconsiderable, many of the present relations of things would be\naltered. It may be sufficient to mention one effect of such a\nchange. The sources which water the earth, both clouds, rains,\nand rivers, are mainly fed by the aqueous vapour raised from the\nsea; and therefore if the sea were much diminished, and the land\nincreased, the mean quantity of moisture distributed upon the land\nmust be diminished, and the character of climates, as to wet and\ndry, must be materially affected. Similar, but opposite changes\nwould result from the increase of the surface of the ocean.\n\nIt appears then that the magnitude of the ocean is one of the\nconditions to which the structure of all organized beings which are\ndependent upon climate must be adapted.\n\n\n\n\nCHAPTER V.\n\n_The Magnitude of the Atmosphere._\n\n\nThe total quantity of air of which our atmosphere is composed is\nanother of the arbitrary magnitudes of our terrestrial system; and\nwe may apply to this subject considerations similar to those of the\nlast section. We can see no reason why the atmosphere might not\nhave been larger in comparison to the globe which it surrounds;\nthose of Mars and Jupiter appear to be so. But if the quantity of\nair were increased, the structure of organized beings would in many\nways cease to be adapted to their place. The atmospheric pressure,\nfor instance, would be increased, which, as we have already\nnoticed, would require an alteration in the structure of vegetables.\n\nAnother way in which an increase of the mass of the atmosphere\nwould produce inconvenience would be in the force of winds. If the\ncurrent of air in a strong gale were doubled or tripled, as might\nbe the case if the atmosphere were augmented, the destructive\neffects would be more than doubled or tripled. With such a change,\nnothing could stand against a storm. In general, houses and trees\nresist the violence of the wind; and except in extreme cases, as\nfor instance in occasional hurricanes in the West Indies, a few\nlarge trees in a forest are unusual trophies of the power of the\ntempest. The breezes which we commonly have are harmless messengers\nto bring about the salutary changes of the atmosphere, even the\nmotion which they communicate to vegetables tends to promote their\ngrowth, and is so advantageous, that it has been proposed to\nimitate it by artificial breezes in the hothouse. But with a stream\nof wind blowing against them, like three, or five, or ten, gales\ncompressed into the space of one, none of the existing trees could\nstand; and except they could either bend like rushes in a stream,\nor extend their roots far wider than their branches, they must be\ntorn up in whole groves. We have thus a manifest adaptation of the\npresent usual strength of the materials and of the workmanship of\nthe world to the stress of wind and weather which they have to\nsustain.\n\n\n\n\nCHAPTER VI.\n\n_The Constancy and Variety of Climates._\n\n\nIt is possible to conceive arrangements of our system, according\nto which all parts of the earth might have the same, or nearly\nthe same, climate. If, for example, we suppose the earth to be a\nflat disk, or flat ring, like the ring of Saturn, revolving in its\nown plane as that does, each part of both the flat surfaces would\nhave the same exposure to the sun, and the same temperature, so\nfar as the sun\u2019s effect is concerned. There is no obvious reason\nwhy a planet of such a form might not be occupied by animals and\nvegetables, as well as our present earth; and on this supposition\nthe climate would be every where the same, and the whole surface\nmight be covered with life, without the necessity of there being\nany difference in the kind of inhabitants belonging to different\nparts.\n\nAgain, it is possible to conceive arrangements according to which\nno part of our planet should have any steady climate. This may\nprobably be the case with a comet. If we suppose such a body,\nrevolving round the sun in a very oblong ellipse, to be of small\nsize and of a very high temperature, and therefore to cool rapidly;\nand if we suppose it also to be surrounded by a large atmosphere,\ncomposed of various gases; there would, on the surface of such a\nbody, be no average climate or seasons for each place. The years,\nif we give this name to the intervals of time occupied by its\nsuccessive revolutions, would be entirely unlike one another. The\ngreatest heat of one year might be cool compared with the greatest\ncold of a preceding one. The greatest heats and colds might succeed\neach other at intervals perpetually unequal. The atmosphere might\nbe perpetually changing its composition by the condensation of\nsome of its constituent gases. In the operations of the elements,\nall would be incessant and rapid change, without recurrence or\ncompensation. We cannot say that organized beings could not be\nfitted for such a habitation; but if they were, the adaptation must\nbe made by means of a constitution quite different from that of\nalmost all organized beings known to us.\n\nThe state of things upon the earth, in its present condition, is\nvery different from both these suppositions. The climate of the\nsame place, notwithstanding perpetual and apparently irregular\nchange, possesses a remarkable steadiness. And, though in different\nplaces the annual succession of appearances in the earth and\nheavens, is, in some of its main characters, the same, the result\nof these influences in the average climate is very different.\n\nNow, to this remarkable constitution of the earth as to climate,\nthe constitution of the animal and vegetable world is precisely\nadapted. The differences of different climates are provided for by\nthe existence of entirely different classes of plants and animals\nin different countries. The constancy of climate at the same place\nis a necessary condition of the prosperity of each species there\nfixed.\n\nWe shall illustrate, by a few details, these characteristics in the\nconstitution of inorganic and of organic nature, with the view of\nfixing the reader\u2019s attention upon the correspondence of the two.\n\n1. The succession and alternation, at any given place, of heat\nand cold, rain and sunshine, wind and calm, and other atmospheric\nchanges, appears at first sight to be extremely irregular, and not\nsubject to any law. It is, however, easy to see, with a little\nattention, that there is a certain degree of constancy in the\naverage weather and seasons of each place, though the particular\nfacts of which these generalities are made up seem to be out of the\nreach of fixed laws. And when we apply any numerical measure to\nthese particular occurrences, and take the average of the numbers\nthus observed, we generally find a remarkably close correspondence\nin the numbers belonging to the whole, or to analogous portions of\nsuccessive years. This will be found to apply to the measures given\nby the thermometer, the barometer, the hygrometer, the rain gauge,\nand similar instruments. Thus it is found that very hot summers,\nor very cold winters, raise or depress the mean annual temperature\nvery little above or below the general standard.\n\nThe heat may be expressed by degrees of the thermometer; the\ntemperature of the day is estimated by this measure taken at\na certain period of the day, which is found by experience to\ncorrespond with the daily average; and the mean annual temperature\nwill then be the average of all the heights of the thermometer for\nevery day in the year.\n\nThe mean annual temperature of London, thus measured, is about\n50 degrees 4-10ths. The frost of the year 1788 was so severe that\nthe Thames was passable on the ice; the mean temperature of that\nyear was 50 degrees 6-10ths, being within a small fraction a degree\nof the standard. In 1796, when the greatest cold ever observed in\nLondon occurred, the mean temperature of the year was 50 degrees\n1-10th, which is likewise within a fraction of a degree of the\nstandard. In the severe winter of 1813-14, when the Thames, Tyne,\nand other large rivers in England were completely frozen over, the\nmean temperature of the two years was 49 degrees, being little more\nthan a degree below the standard. And in the year 1808, when the\nsummer was so hot that the temperature in London was as high as 93\u00bd\ndegrees, the mean heat of the year was 50\u00bd, which is about that of\nthe standard.\n\nThe same numerical indications of the constancy of climate at the\nsame place might be collected from the records of other instruments\nof the kind above-mentioned.\n\nWe shall, hereafter, consider some of the very complex agencies by\nwhich this steadiness is produced; and shall endeavour to point\nout intentional adaptations to this object. But we may, in the\nmeantime, observe how this property of the atmospheric changes is\nmade subservient to a further object.\n\nTo this constancy of the climates of each place, the structure\nof plants is adapted; almost all vegetables require a particular\nmean temperature of the year, or of some season of the year; a\nparticular degree of moisture, and similar conditions. This will\nbe seen by observing that the range of most plants as to climate\nis very limited. A vegetable which flourishes where the mean\ntemperature is 55 degrees, would pine and wither when removed to a\nregion where the average is 50 degrees. If, therefore, the average\nat each place were to vary as much as this, our plants with their\npresent constitutions would suffer, languish, and soon die.\n\n2. It will be readily understood that the same mode of measurement\nby which we learn the constancy of climate at the same place,\nserves to show us the variety which belongs to different places.\nWhile the variations of the same region vanish when we take the\naverages even of moderate periods, those of distant countries are\nfixed and perpetual; and stand out more clear and distinct, the\nlonger is the interval for which we measure their operation.\n\nIn the way of measuring already described, the mean temperature\nof Petersburg is 39 degrees, of Rome 60, of Cairo 72. Such\nobservations as these, and others of the same kind, have been made\nat various places, collected and recorded; and in this way the\nsurface of the earth can be divided by boundary lines into various\nstrips, according to these physical differences. Thus, the zones\nwhich take in all the places having the same or nearly the same\nmean annual temperature, have been called _isothermal_ zones. These\nzones run nearly parallel to the equator, but not exactly, for,\nin Europe, they bend to the north in going eastward. In the same\nmanner, the lines passing through all places which have an equal\ntemperature for the summer or the winter half of the year, have\nbeen called respectively _isotheral_ and _isochimal_ lines. These\ndo not coincide with the isothermal lines, for a place may have\nthe same temperature as another, though its summer be hotter and\nits winter colder, as is the case of Pekin compared with London.\nIn the same way we might conceive lines drawn according to the\nconditions of clouds, rain, wind, and the like circumstances, if we\nhad observations enough to enable us to lay down such lines. The\ncourse of vegetation depends upon the combined influence of all\nsuch conditions; and the lines which bound the spread of particular\nvegetable productions do not, in most cases, coincide with any of\nthe separate meteorological boundaries above spoken of. Thus, the\nnorthern limit of vineyards runs through France, in a direction\nvery nearly north-east and south-west, while the line of equal\ntemperature is nearly east and west. And the spontaneous growth or\nadvantageous cultivation of other plants, is in like manner bounded\nby lines of which the course depends upon very complex causes, but\nof which the position is generally precise and fixed.\n\n\n\n\nCHAPTER VII.\n\n_The Variety of Organization corresponding to the Variety of\nClimate._\n\n\nThe organization of plants and animals is in different tribes\nformed upon schemes more or less different, but in all cases\nadjusted in a general way to the course and action of the elements.\nThe differences are connected with the different habits and manners\nof living which belong to different species; and at any one place\nthe various species, both of animals and plants, have a number of\nrelations and mutual dependences arising out of these differences.\nBut besides the differences of this kind, we find in the forms of\norganic life another set of differences, by which the animal and\nvegetable kingdom are fitted for that variety in the climates of\nthe earth, which we have been endeavouring to explain.\n\nThe existence of such differences is too obvious to require to be\ndwelt upon. The plants and animals which flourish and thrive in\ncountries remote from each other, offer to the eye of the traveller\na series of pictures, which, even to an ignorant and unreflective\nspectator, is full of a peculiar and fascinating interest in\nconsequence of the novelty and strangeness of the successive scenes.\n\nThose who describe the countries between the tropics, speak with\nadmiration of the luxuriant profusion and rich variety of the\nvegetable productions of those regions. Vegetable life seems there\nfar more vigorous and active, the circumstances under which it goes\non, far more favourable than in our latitudes. Now if we conceive\nan inhabitant of those regions, knowing, from the circumstances\nof the earth\u2019s form and motion, the difference of climates which\nmust prevail upon it, to guess, from what he saw about him, the\ncondition of other parts of the globe as to vegetable wealth, is\nnot likely that he would suppose that the extra-tropical climates\nmust be almost devoid of plants? We know that the ancients, living\nin the temperate zone, came to the conclusion that both the torrid\nand the frigid zones must be uninhabitable. In like manner the\nequatorial reasoner would probably conceive that vegetation must\ncease, or gradually die away, as he should proceed to places\nfurther and further removed from the genial influence of the sun.\nThe mean temperature of his year being about 80 degrees, he would\nhardly suppose that any plants could subsist through a year, where\nthe mean temperature was only 50, where the temperature of the\nsummer quarter was only 64, and where the mean temperature of a\nwhole quarter of the year was a very few degrees removed from that\nat which water becomes solid. He would suppose that scarcely any\ntree, shrub, or flower could exist in such a state of things, and\nso far as the plants of his own country are concerned, he would\njudge rightly.\n\nBut the countries further removed from the equator are not left\nthus unprovided. Instead of being scantily occupied by such of the\ntropical plants as could support a stunted and precarious life\nin ungenial climes, they are abundantly stocked with a multitude\nof vegetables which appear to be constructed expressly for them,\ninasmuch as these species can no more flourish at the equator than\nthe equatorial species can in these temperate regions. And such\nnew supplies thus adapted to new conditions, recur perpetually\nas we advance towards the apparently frozen and untenantable\nregions in the neighbourhood of the pole. Every zone has its\npeculiar vegetables; and as we miss some, we find others make their\nappearance, as if to replace those which are absent.\n\nIf we look at the indigenous plants of Asia and Europe, we find\nsuch a succession as we have here spoken of. At the equator we\nfind the natives of the Spice Islands, the clove and nutmeg trees,\npepper and mace. Cinnamon bushes clothe the surface of Ceylon; the\nodoriferous sandal wood, the ebony tree, the teak tree, the banyan,\ngrow in the East Indies. In the same latitudes in Arabia the Happy\nwe find balm, frankincense and myrrh, the coffee tree, and the\ntamarind. But in these countries, at least in the plains, the trees\nand shrubs which decorate our more northerly climes are wanting.\nAnd as we go northwards, at every step we change the vegetable\ngroup, both by addition and by subtraction. In the thickets to the\nwest of the Caspian Sea we have the apricot, citron, peach, walnut.\nIn the same latitude in Spain, Sicily, and Italy, we find the\ndwarf palm, the cypress, the chestnut, the cork tree: the orange\nand lemon tree perfume the air with their blossoms; the myrtle\nand pomegranate grow wild among the rocks. We cross the Alps, and\nwe find the vegetation which belongs to northern Europe, of which\nEngland is an instance. The oak, the beech, and the elm are natives\nof Great Britain: the elm tree seen in Scotland, and in the north\nof England, is the wych elm. As we travel still further to the\nnorth the forests again change their character. In the northern\nprovinces of the Russian empire are found forests of the various\nspecies of firs: the Scotch and spruce fir, and the larch. In the\nOrkney Islands no tree is found but the hazel, which occurs again\non the northern shores of the Baltic. As we proceed into colder\nregions we still find species which appear to have been made for\nthese situations. The hoary or cold elder makes its appearance\nnorth of Stockholm: the sycamore and mountain ash accompany us to\nthe head of the gulf of Bothnia: and as we leave this and traverse\nthe Dophrian range, we pass in succession the boundary lines of the\nspruce fir, the Scotch fir, and those minute shrubs which botanists\ndistinguish as the dwarf birch and dwarf willow. Here, near to or\nwithin the arctic circle, we yet find wild flowers of great beauty;\nthe mezereum, the yellow and white water lily, and the European\nglobe flower. And when these fail us, the reindeer moss still makes\nthe country habitable for animals and man.\n\nWe have thus a variety in the laws of vegetable organization\nremarkably adapted to the variety of climates; and by this\nadaptation the globe is clothed with vegetation and peopled with\nanimals from pole to pole, while without such an adaptation\nvegetable and animal life must have been confined almost, or\nentirely, to some narrow zone on the earth\u2019s surface. We conceive\nthat we see here the evidence of a wise and benevolent intention,\novercoming the varying difficulties, or employing the varying\nresources of the elements, with an inexhaustible fertility of\ncontrivance, a constant tendency to diffuse life and well being.\n\n2. One of the great uses to which the vegetable wealth of the earth\nis applied, is the support of man, whom it provides with food and\nclothing; and the adaptation of tribes of indigenous vegetables\nto every climate has, we cannot but believe, a reference to the\nintention that the human race should be diffused over the whole\nglobe. But this end is not answered by indigenous vegetables alone;\nand in the variety of vegetables capable of being _cultivated_ with\nadvantage in various countries, we conceive that we find evidence\nof an additional adaptation of the scheme of organic life to the\nsystem of the elements.\n\nThe cultivated vegetables, which form the necessaries or luxuries\nof human life, are each confined within limits, narrow, when\ncompared with the whole surface of the earth; yet almost every part\nof the earth\u2019s surface is capable of being abundantly covered with\none kind or other of these. When one class fails, another appears\nin its place. Thus corn, wine, and oil, have each its boundaries.\nWheat extends through the old Continent, from England to Thibet:\nbut it stops soon in going northwards, and is not found to succeed\nin the west of Scotland. Nor does it thrive better in the torrid\nzone than in the polar regions: within the tropics, wheat, barley\nand oats are not cultivated, excepting in situations considerably\nabove the level of the sea: the inhabitants of those countries have\nother species of grain, or other food. The cultivation of the vine\nsucceeds only in countries where the annual temperature is between\n50 and 63 degrees. In both hemispheres, the profitable culture\nof this plant ceases within 30 degrees of the equator, unless in\nelevated situations, or in islands, as Teneriffe. The limits of the\ncultivation of maize and of olives in France are parallel to those\nwhich bound the vine and corn in succession to the north. In the\nnorth of Italy, west of Milan, we first meet with the cultivation\nof rice; which extends over all the southern part of Asia, wherever\nthe land can be at pleasure covered with water. In great part of\nAfrica millet is one of the principal kinds of grain.\n\nCotton is cultivated to latitude 40 in the new world, but extends\nto Astrachan in latitude 46 in the old. The sugar cane, the\nplantain, the mulberry, the betel nut, the indigo tree, the tea\ntree, repay the labours of the cultivator in India and China;\nand several of these plants have been transferred, with success,\nto America and the West Indies. In equinoctial America a great\nnumber of inhabitants find abundant nourishment on a narrow space\ncultivated with plantain, cassava yams, and maize. The bread fruit\ntree begins to be cultivated in the Manillas, and extends through\nthe Pacific; the sago palm in the Moluccas, the cabbage tree in the\nPelew islands.\n\nIn this manner the various tribes of men are provided with\nvegetable food. Some however live on their cattle, and thus make\nthe produce of the earth only mediately subservient to their\nwants. Thus the Tartar tribes depend on their flocks and herds for\nfood: the taste for the flesh of the horse seems to belong to the\nMongols, Fins, and other descendants of the ancient Scythians: the\nlocust eaters are found now, as formerly, in Africa.\n\nMany of these differences depend upon custom, soil, and other\ncauses with which we do not here meddle; but many are connected\nwith climate: and the variety of the resources which man thus\npossesses, arises from the variety of constitution belonging to\ncultivable vegetables, through which one is fitted to one range of\nclimate, and another to another. We conceive that this variety and\nsuccession of fitness for cultivation, shows undoubted marks of a\nmost foreseeing and benevolent design in the Creator of man and of\nthe world.\n\n3. By differences in vegetables of the kind we have above\ndescribed, the sustentation and gratification of man\u2019s physical\nnature is copiously provided for. But there is another\ncircumstance, a result of the difference of the native products of\ndifferent regions, and therefore a consequence of that difference\nof climate on which the difference of native products depends,[5]\nwhich appears to be worthy our notice. The difference of the\nproductions of different countries has a bearing not only upon the\nphysical, but upon the social and moral condition of man.\n\nThe intercourse of nations in the way of discovery, colonization,\ncommerce; the study of the natural history, manners, institutions\nof foreign countries; lead to most numerous and important results.\nWithout dwelling upon this subject, it will probably be allowed\nthat such intercourse has a great influence upon the comforts, the\nprosperity, the arts, the literature, the power, of the nations\nwhich thus communicate. Now the variety of the productions of\ndifferent lands supplies both the stimulus to this intercourse, and\nthe instruments by which it produces its effects. The desire to\npossess the objects or the knowledge which foreign countries alone\ncan supply, urges the trader, the traveller, the discoverer to\ncompass land and sea; and the progress of the arts and advantages\nof civilization consists almost entirely in the cultivation, the\nuse, the improvement of that which has been received from other\ncountries.\n\nThis is the case to a much greater extent than might at first sight\nbe supposed. Where man is active as a cultivator, he scarcely ever\nbestows much of his care on those vegetables which the land would\nproduce in a state of nature. He does not select some of the plants\nof the soil and improve them by careful culture, but, for the most\npart, he expels the native possessors of the land, and introduces\ncolonies of strangers.\n\nThus, to take the condition of our own part of the globe as an\nexample; scarcely one of the plants which occupy our fields and\ngardens is indigenous to the country. The walnut and the peach\ncome to us from Persia; the apricot from Armenia: from Asia\nMinor, and Syria, we have the cherry tree, the fig, the pear, the\npomegranate, the olive, the plum, and the mulberry. The vine which\nis now cultivated is not a native of Europe; it is found wild on\nthe shores of the Caspian, in Armenia and Caramania. The most\nuseful species of plants, the _cereal_ vegetables, are certainly\nstrangers, though their birth place seems to be an impenetrable\nsecret. Some have fancied that barley is found wild on the banks\nof the Semara, in Tartary, rye in Crete, wheat at Baschkiros, in\nAsia; but this is held by the best botanists to be very doubtful.\nThe potatoe, which has been so widely diffused over the world in\nmodern times, and has added so much to the resources of life in\nmany countries, has been found equally difficult to trace back to\nits wild condition.\n\nThus widely are spread the traces of the connexion of the progress\nof civilization with national intercourse. In our own country a\nhigher state of the arts of life is marked by a more ready and\nextensive adoption of foreign productions. Our fields are covered\nwith herbs from Holland, and roots from Germany; with Flemish\nfarming and Swedish turnips; our hills with forests of the firs of\nNorway. The chestnut and poplar of the south of Europe adorn our\nlawns, and below them flourish shrubs and flowers from every clime\nin profusion. In the mean time Arabia improves our horses, China\nour pigs, North America our poultry, Spain our sheep, and almost\nevery country sends its dog. The products which are ingredients\nin our luxuries, and which we cannot naturalize at home, we raise\nin our colonies; the cotton, coffee, sugar of the east are thus\ntransplanted to the farthest west; and man lives in the middle of a\nrich and varied abundance which depends on the facility with which\nplants and animals and modes of culture can be transferred into\nlands far removed from those in which nature had placed them. And\nthis plenty and variety of material comforts is the companion and\nthe mark of advantages and improvements in social life, of progress\nin art and science, of activity of thought, of energy of purpose,\nand of ascendancy of character.\n\nThe differences in the productions of different countries which\nlead to the habitual intercourse of nations, and through this\nto the benefits which we have thus briefly noticed, do not all\ndepend upon the differences of temperature and climate alone. But\nthese differences are among the causes, and are some of the most\nimportant causes, or conditions, of the variety of products; and\nthus that arrangement of the earth\u2019s form and motion from which\nthe different climates of different places arises, is connected\nwith the social and moral welfare and advancement of man.\n\nWe conceive that this connexion, though there must be to our\napprehension much that is indefinite and uncertain in tracing\nits details, is yet a point where we may perceive the profound\nand comprehensive relations established by the counsel and\nforesight of a wise and good Creator of the world and of man, by\nwhom the progress and elevation of the human species was neither\nuncontemplated nor uncared for.\n\n4. We have traced, in the variety of organized beings, an\n_adaptation_ to the variety of climates, a _provision_ for the\nsustentation of man all over the globe, and an _instrument_ for\nthe promotion of civilization and many attendant benefits. We have\nnot considered this _variety_ as _itself_ a purpose which we can\nperceive or understand without reference to some ulterior end. Many\npersons, however, and especially those who are already in the habit\nof referring the world to its Creator, will probably see something\nadmirable in itself in this vast variety of created things.\nThere is indeed something well fitted to produce and confirm a\nreverential wonder, in these apparently inexhaustible stores of\nnew forms of being and modes of existence; the fixity of the laws\nof each class, its distinctness from all others, its relations to\nmany. Structures and habits and characters are exhibited, which are\nconnected and distinguished according to every conceivable degree\nof subordination and analogy, in their resemblances and in their\ndifferences. Every new country we explore presents us with new\ncombinations, where the possible cases seem to be exhausted; and\nwith new resemblances and differences, constructed as if to elude\nwhat conjecture might have hit upon, by proceeding from the old\nones. Most of those who have any large portion of nature brought\nunder their notice in this point of view, are led to feel that\nthere is, in such a creation, a harmony, a beauty, and a dignity,\nof which the impression is irresistible; which would have been\nwanting in any more uniform and limited system such as we might try\nto imagine; and which of itself gives to the arrangements by which\nsuch a variety on the earth\u2019s surface is produced, the character of\nwell devised means to a worthy end.\n\n\n\n\nCHAPTER VIII.\n\n_The Constituents of Climate._\n\n\nWe have spoken of the steady average of the climate at each place,\nof the difference of this average at different places, and of the\nadaptation of organized beings to this character in the laws of\nthe elements by which they are affected. But this steadiness in\nthe general effect of the elements, is the result of an extremely\ncomplex and extensive machinery. Climate, in its wider sense,\nis not one single agent, but is the aggregate result of a great\nnumber of different agents, governed by different laws, producing\neffects of various kinds. The steadiness of this compound agency is\nnot the steadiness of a permanent condition, like that of a body\nat rest; but it is the steadiness of a state of constant change\nand movement, succession and alternation, seeming accident and\nirregularity. It is a perpetual repose, combined with a perpetual\nmotion; an invariable average of most variable quantities. Now, the\nmanner in which such a state of things is produced, deserves, we\nconceive, a closer consideration. It may be useful to show how the\nparticular laws of the action of each of the elements of climate\nare so adjusted that they do not disturb this general constancy.\n\nThe principal constituents of climate are the following:--the\ntemperature of the earth, of the water, of the air:--the\ndistribution of the aqueous vapour contained in the\natmosphere:--the winds and rains by which the equilibrium of the\natmosphere is restored when it is in any degree disturbed. The\neffects of light, of electricity, probably of other causes also,\nare no doubt important in the economy of the vegetable world,\nbut these agencies have not been reduced by scientific inquirers\nto such laws as to admit of their being treated with the same\nexactness and certainty which we can obtain in the case of those\nfirst mentioned.\n\nWe shall proceed to trace some of the peculiarities in the laws of\nthe different physical agents which are in action at the earth\u2019s\nsurface, and the manner in which these peculiarities bear upon the\ngeneral result.\n\n\n_The Laws of Heat with respect to the Earth._\n\nOne of the main causes which determine the temperature of each\nclimate is the effect of the sun\u2019s rays on the solid mass of the\nearth. The laws of this operation have been recently made out with\nconsiderable exactness, experimentally by Leslie, theoretically by\nFourier, and by other inquirers. The theoretical inquiries have\nrequired the application of very complex and abstruse mathematical\ninvestigations; but the general character of the operation may,\nperhaps, be made easily intelligible.\n\nThe earth, like all solid bodies, transmits into its interior the\nimpressions of heat which it receives at the surface; and throws\noff the superfluous heat from its surface into the surrounding\nspace. These processes are called _conduction_ and _radiation_, and\nhave each their ascertained mathematical laws.\n\nBy the laws of conduction, the daily impressions of heat which the\nearth receives, follow each other into the interior of the mass,\nlike the waves which start from the edge of a canal;[6] and like\nthem, become more and more faint as they proceed, till they melt\ninto the general level of the internal temperature. The heat thus\ntransmitted is accumulated in the interior of the earth, as in a\nreservoir, and flows from one part to another of this reservoir.\nThe parts of the earth near the equator are more heated by the\nsun than other parts, and on this account there is a perpetual\ninternal conduction of heat from the equatorial to other parts\nof the sphere. And as all parts of the surface throw off heat by\nradiation, in the polar regions, where the surface receives little\nin return from the sun, a constant waste is produced. There is\nthus from the polar parts a perpetual dispersion of heat in the\nsurrounding space, which is supplied by a perpetual internal flow\nfrom the equator towards each pole.\n\nHere, then, is a kind of circulation of heat; and the quantity and\nrapidity of this circulation, determine the quantity of heat in the\nsolid part of the earth, and in each portion of it; and through\nthis, the _mean_ temperature belonging to each point on its surface.\n\nIf the earth _conducted_ heat more rapidly than it does, the\ninequalities of temperature would be more quickly balanced,\nand the temperature of the ground (below the reach of annual\nand diurnal variations) would differ less than it does. If the\nsurface _radiated_ more rapidly than it does, the flow of heat\nfrom the polar regions would increase, and the temperature of the\ninterior of the globe would find a lower level; the differences of\ntemperature in different latitudes would increase, but the mean\ntemperature of the globe would diminish.\n\nThere is nothing which, so far as we can perceive, determines\nnecessarily, either the conducting or the radiating power of\nthe earth to its present value. The measures of such powers, in\ndifferent substances, differ very widely. If the earth were a globe\nof pure iron, it would conduct heat, probably, twenty times as\nwell as it does; if its surface were polished iron, it would only\nradiate one-sixth as much as it does. Changes in the amount of the\nconduction and radiation far less than these, would, probably,\nsubvert the whole _thermal_ constitution of the earth, and make it\nuninhabitable by any of its present vegetable, or animal tenants.\n\nOne of the results of the laws of heat, as they exist in the globe,\nis, that, by their action, the thermal state tends to a limiting\ncondition, which, once reached, remains constant and steady, as it\nnow is. The oscillations or excursions from the mean condition,\nproduced by any temporary cause, are rapidly suppressed; the\ndeviations of seasons from their usual standard produce only a\nsmall and transient effect. The impression of an extremely hot\nday upon the ground melts almost immediately into the average\ninternal heat. The effect of a hot summer, in like manner, is soon\nlost in its progress through the globe. If this were otherwise,\nif the inequalities and oscillations of heat went on, through the\ninterior of the earth, retaining the same value, or becoming larger\nand larger, we might have the extreme heats or colds of one place\nmaking their appearance at another place after a long interval;\nlike a conflagration which creeps along a street and bursts out at\na point remote from its origin.\n\nIt appears, therefore, that both the present differences of\nclimate, and the steadiness of the average at each place, depend\nupon the form of the present laws of heat, and on the arbitrary\nmagnitudes which determine the rate of conduction and radiation.\nThe laws are such as to secure us from increasing and destructive\ninequalities of heat; the arbitrary magnitudes are elements to\nwhich the organic world is adjusted.\n\n\n\n\nCHAPTER IX.\n\n_The Laws of Heat with respect to Water._\n\n\nThe manner in which heat is transmitted through fluids is\naltogether different from the mode in which it passes through\nsolids; and hence the waters of the earth\u2019s surface produce\npeculiar effects upon its condition as to temperature. Moreover,\nwater is susceptible of evaporation in a degree depending upon the\nincrease of heat; and in consequence of this property it has most\nextensive and important functions to discharge in the economy of\nnature. We will consider some of the offices of this fluid.\n\n1. Heat is communicated through water, not by being _conducted_\nfrom one part of the fluid to another, as in solid bodies, but\n(at least principally) by being _carried_ with the parts of the\nfluid by means of an intestine motion. Water expands and becomes\nlighter by heat, and, therefore, if the upper parts be cooled\nbelow the subjacent temperature, this upper portion will become\nheavier than that below, bulk for bulk, and will descend through\nit, while the lower portion rises to take the upper place. In this\nmanner the colder parts descend, and the warmer parts ascend by\ncontrary currents, and by their interchange and mixture, reduce\nthe whole to a temperature at least as low as that of the surface.\nAnd this equalization of temperature by means of such currents,\nis an operation of a much more rapid nature than the slow motion\nof conduction by which heat creeps through a solid body. Hence,\nalternations of heat and cold, as day and night, summer and\nwinter, produce in water, inequalities of temperature much smaller\nthan those which occur in a solid body. The heat communicated is\nless, for transparent fluids imbibe heat very slowly; and the cold\nimpressed on the surface is soon diffused through the mass by\ninternal circulation.\n\nHence it follows that the ocean, which covers so large a portion\nof the earth, and affects the temperature of the whole surface\nby its influence, produces the effect of making the alternations\nof heat and cold much less violent than they would be if it were\nabsent. The different temperatures of its upper and lower parts\nproduce a current which draws the seas, and by means of the seas,\nthe air, towards the mean temperature. And this kind of circulation\nis produced, not only between the upper and lower parts, but also\nbetween distant tracts of the ocean. The great Gulf Stream which\nrushes out of the Gulf of Mexico, and runs across the Atlantic to\nthe western shores of Europe, carries with it a portion of the\ntropical heat into northern regions: and the returning current\nwhich descends along the coast of Africa, tends to cool the parts\nnearer the equator. Great as the difference of temperature is in\ndifferent climates, it would be still greater if there were not\nthis equalizing and moderating power exerted constantly over the\nwhole surface. Without this influence, it is probable that the two\npolar portions of the earth, which are locked in perpetual ice and\nsnow, and almost destitute of life, would be much increased.\n\nWe find an illustration of this effect of the ocean on temperature,\nin the peculiarities of the climates of maritime tracts and\nislands. The climate of such portions of the earth, corrected in\nsome measure by the temperature of the neighbouring sea, is more\nequable than that of places in the same latitudes differently\nsituated. London is cooler in summer and warmer in winter than\nParis.\n\n2. Water expands by heat and contracts by cold, as has been\nalready said; and in consequence of this property, the coldest\nportions of the fluid generally occupy the lower parts. The\ncontinued progress of cold produces congelation. If, therefore, the\nlaw just mentioned had been strictly true, the lower parts of water\nwould have been first frozen; and being once frozen, hardly any\nheat applied at the surface could have melted them, for the warm\nfluid could not have descended through the colder parts. This is\nso far the case, that in a vessel containing ice at the bottom and\nwater at the top, Rumford made the upper fluid boil without thawing\nthe congealed cake below.\n\nNow, a law of water with respect to heat operating in this manner,\nwould have been very inconvenient if it had obtained in our lakes\nand seas. They would all have had a bed of ice, increasing with\nevery occasion, till the whole was frozen. We could have had no\nbodies of water, except such pools on the surfaces of these icy\nreservoirs as the summer sun could thaw, to be again frozen to\nthe bottom with the first frosty night. The law of the regular\ncontraction of water by cold till it became ice, would, therefore,\nbe destructive of all the utility of our seas and lakes. How is\nthis inconvenience obviated?\n\nIt is obviated by a modification of the law which takes place when\nthe temperature approaches this limit. Water contracts by the\nincrease of cold, till we come _near_ the freezing temperature;\nbut then, by a further increase of cold, it contracts no more, but\nexpands till the point at which it becomes ice. It contracts in\ncooling down to 40 degrees of Fahrenheit\u2019s thermometer; in cooling\nfurther it expands, and when cooled to 32 degrees, it freezes.\nHence, the greatest density of the fluid is at 40 degrees, and\nwater of this temperature, or near it, will lie at the bottom\nwith cooler water or with ice floating above it. However much the\nsurface be cooled, water colder than 40 cannot descend to displace\nwater warmer than itself. Hence we can never have ice formed at\nthe bottom of deep water. In approaching the freezing point, the\ncoldest water will rise to the surface, and the congelation will\ntake place there; and the ice so formed will remain at the surface,\nexposed to the warmth of the sunbeams and the air, and will not\nsurvive any long continuance of such action.\n\nAnother peculiarity in the laws which regulate the action of cold\non water is, that in the very act of freezing a further sudden\nand considerable expansion takes place. Many persons will have\nknown instances of vessels burst by the freezing of water in them.\nThe consequence of this expansion is, that the specific gravity\nof ice is less than that of water of any temperature; and it\ntherefore always floats in the unfrozen fluid. If this expansion of\ncrystallization did not exist, ice would float in water which was\nbelow forty degrees, but would sink when the fluid was above that\ntemperature: as the case is, it floats under all circumstances. The\nicy remnants of the effects of winter, which the river carries down\nits stream, are visible on its surface till they melt away; and\nthe icebergs which are detached from the shores of the polar seas,\ndrift along, exposed to the sun and air, as well as to the water in\nwhich they are immersed.\n\nThese laws of the effect of temperature on water are truly\nremarkable in their adaptation to the beneficial course of things\nat the earth\u2019s surface. Water contracts by cold; it thus equalizes\nthe temperature of various times and places; but if its contraction\nwere continued all the way to the freezing point, it would bind a\ngreat part of the earth in fetters of ice. The contraction then\nis here replaced by expansion, in a manner which but slightly\nmodifies the former effects, while it completely obviates the bad\nconsequences. The further expansion which takes place at the point\nof freezing, still further facilitates the rapid removal of the\nicy chains, in which parts of the earth\u2019s surface are at certain\nseasons bound.\n\nWe do not know how far these laws of expansion are connected with\nand depend on more remote and general properties of this fluid, or\nof all fluids. But we have no reason to believe that, by whatever\nmeans they operate, they are not laws selected from among other\nlaws which might exist, as in fact for other fluids other laws do\nexist. And we have all the evidence, which the most remarkable\nfurtherance of important purposes can give us, that they _are_\nselected, and selected with a beneficial design.\n\n3. As water becomes ice by cold, it becomes steam by heat. In\ncommon language, steam is the name given to the vapour of _hot_\nwater; but in fact a vapour or steam rises from water at all\ntemperatures, however low, and even from ice. The expansive force\nof this vapour increases rapidly as the heat increases; so that\nwhen we reach the heat of boiling water, it operates in a far\nmore striking manner than when it is colder; but in all cases\nthe surface of water is covered with an atmosphere of aqueous\nvapour, the pressure or _tension_ of which is limited by the\ntemperature of the water. To each degree of pressure in steam there\nis a _constituent temperature_ corresponding. If the surface of\nwater is not pressed by vapour with the force thus corresponding\nto its temperature, an immediate _evaporation_ will supply the\ndeficiency. We can compare the tension of such vapour with that of\nour common atmosphere; the pressure of the latter is measured by\nthe barometrical column, about thirty inches of mercury; that of\nwatery vapour is equal to one inch of mercury at the constituent\ntemperature of 80 degrees, and to one-fifth of an inch, at the\ntemperature of 32 degrees.\n\nHence, if that part of the atmosphere which consists of common air\nwere annihilated, there would still remain an atmosphere of aqueous\nvapour, arising from the waters and moist parts of the earth; and\nin the existing state of things this vapour rises in the atmosphere\nof dry air. Its distribution and effects are materially influenced\nby the vehicle in which it is thus carried, as we shall hereafter\nnotice; but at present we have to observe the exceeding _utility_\nof water in this shape. We remark how suitable and indispensable to\nthe well-being of the creation it is, that the fluid should possess\nthe property of assuming such a form under such circumstances.\n\nThe _moisture_ which floats in the atmosphere is of most essential\nuse to vegetable life.[7] \u201cThe leaves of living plants appear to\nact upon this vapour in its elastic form, and to absorb it. Some\nvegetables increase in weight from this cause when suspended in the\natmosphere and unconnected with the soil, as the house-leek and the\naloe. In very intense heats, and when the soil is dry, the life\nof plants seems to be preserved by the absorbent power of their\nleaves.\u201d It follows from what has already been said, that, with an\nincreasing heat of the atmosphere, an increasing quantity of vapour\nwill rise into it, if supplied from any quarter. Hence it appears\nthat aqueous vapour is most abundant in the atmosphere when it is\nmost needed for the purposes of life; and that when other sources\nof moisture are cut off, this is most copious.\n\n4. _Clouds_ are produced by aqueous vapour when it returns to the\nstate of water. This process is _condensation_, the reverse of\nevaporation. When vapour exists in the atmosphere, if in any manner\nthe temperature becomes lower than the _constituent temperature_,\nrequisite for the maintenance of the vapoury state, some of the\nsteam will be condensed and will become water. It is in this manner\nthat the curl of steam from the spout of a boiling tea-kettle\nbecomes visible, being cooled down as it rushes to the air. The\nsteam condenses into a fine watery powder, which is carried about\nby the little aerial currents. Clouds are of the same nature with\nsuch curls, the condensation being generally produced when air,\ncharged with aqueous vapour, is mixed with a colder current, or has\nits temperature diminished in any other manner.\n\nClouds, while they retain that shape, are of the most essential\nuse to vegetable and animal life. They moderate the fervour of\nthe sun, in a manner agreeable, to a greater or less degree, in\nall climates, and grateful no less to vegetables than to animals.\nDuhamel says that plants grow more during a week of cloudy weather\nthan a month of dry and hot. It has been observed that vegetables\nare far more refreshed by being watered in cloudy than in clear\nweather. In the latter case, probably the supply of fluid is too\nrapidly carried off by evaporation. Clouds also moderate the\nalternations of temperature, by checking the radiation from the\nearth. The coldest nights are those which occur under a cloudless\nwinter sky.\n\nThe uses of clouds, therefore, in this stage of their history,\nare by no means inconsiderable, and seem to indicate to us that\nthe laws of their formation were constructed with a view to the\npurposes of organized life.\n\n5. Clouds produce _rain_. In the formation of a cloud the\nprecipitation of moisture probably forms a fine watery _powder_,\nwhich remains suspended in the air in consequence of the minuteness\nof its particles: but if from any cause the precipitation is\ncollected in larger portions, and becomes _drops_, these descend by\ntheir weight and produce a shower.\n\nHowever rain is formed, it is one of the consequences of the\ncapacity of evaporation and condensation which belongs to water,\nand its uses are the result of the laws of those processes. Its\nuses to plants are too obvious and too numerous to be described. It\nis evident that on its quantity and distribution depend in a great\nmeasure the prosperity of the vegetable kingdom: and different\nclimates are fitted for different productions, no less by the\nrelations of dry weather and showers, than by those of hot and cold.\n\n6. Returning back still further in the changes which cold can\nproduce on water, we come to _snow_ and _ice_: snow being\napparently frozen vapour, aggregated by a confused action of\ncrystalline laws; and ice being water in its fluid state,\nsolidified by the same crystalline forces. The impression of\nthese agents on the animal feelings is generally unpleasant,\nand we are in the habit of considering them as symptoms of the\npower of winter to interrupt that state of the elements in which\nthey are subservient to life. Yet, even in this form, they are\nnot without their uses.[8] \u201cSnow and ice are bad conductors of\ncold; and when the ground is covered with snow, or the surface\nof the soil or of water is frozen, the roots or bulbs of plants\nbeneath are protected by the congealed water from the influence\nof the atmosphere, the temperature of which, in northern winters,\nis usually very much below the freezing point; and this water\nbecomes the first nourishment of the plant in early spring. The\nexpansion of water during its congelation, at which time its volume\nincreases one-twelfth, and its contraction in bulk during a thaw,\ntend to pulverize the soil, to separate its parts from each other,\nand to make it more permeable to the influence of the air.\u201d In\nconsequence of the same slowness in the conduction of heat which\nsnow thus possesses, the arctic traveller finds his bed of snow\nof no intolerable coldness; the Esquimaux is sheltered from the\ninclemency of the season in his snow hut, and travels rapidly and\nagreeably over the frozen surface of the sea. The uses of those\narrangements, which at first appear productive only of pain and\ninconvenience, are well suited to give confidence and hope to our\nresearches for such usefulness in every part of the creation. They\nhave thus a peculiar value in adding connexion and universality to\nour perception of beneficial design.\n\n7. There is a peculiar circumstance still to be noticed in the\nchanges from ice to water and from water to steam. These changes\ntake place at a particular and invariable degree of heat; yet\nthey do not take place suddenly when we increase the heat to this\ndegree. This is a very curious arrangement. The temperature _makes\na stand_, as it were, at the point where thaw, and where boiling\ntake place. It is necessary to apply a considerable quantity of\nheat to produce these effects; all which heat disappears, or\nbecomes _latent_, as it is called. We cannot raise the temperature\nof a thawing mass of ice till we have thawed the whole. We cannot\nraise the temperature of boiling water, or of steam rising from it,\ntill we have converted all the water into steam. Any heat that we\napply while these changes are going on is absorbed in producing the\nchanges.\n\nThe consequences of this property of _latent heat_ are very\nimportant. It is on this account that the changes now spoken of\nnecessarily occupy a considerable time. Each part in succession\nmust have a proper degree of heat applied to it. If it were\notherwise, thaw and evaporation must be instantaneous: at the\nfirst touch of warmth, all the snow which lies on the roofs of our\nhouses would descend like a waterspout into the streets: all that\nwhich rests on the ground would rush like an inundation into the\nwater courses. The hut of the Esquimaux would vanish like a house\nin a pantomime: the icy floor of the river would be gone without\ngiving any warning to the skaiter or the traveller: and when, in\nheating our water, we reached the boiling point, the whole fluid\nwould \u201cflash into steam,\u201d (to use the expression of engineers,)\nand dissipate itself in the atmosphere, or settle in dew on the\nneighbouring objects.\n\nIt is obviously necessary for the purposes of human life, that\nthese changes should be of a more gradual and manageable kind\nthan such as we have now described. Yet this gradual progress of\nfreezing and thawing, of evaporation and condensation, is produced,\nso far as we can discover, by a particular contrivance. Like the\nfreezing of water from the top, or the floating of ice, the\nmoderation of the rate of these changes seems to be the result of\na _violation_ of a law: that is, the simple rule regarding the\neffects of change of temperature, which at first sight appears to\nbe the law, and which, from its simplicity, would seem to us the\nmost obvious laws for these as well as other cases, is modified\nat certain critical points, _so as to_ produce these advantageous\neffects:--why may we not say _in order to_ produce such effects?\n\n8. Another office of water which it discharges by means of its\nrelations to heat, is that of supplying our _springs_. There can be\nno doubt that the old hypotheses which represent springs as drawing\ntheir supplies from large subterranean reservoirs of water, or from\nthe sea by a process of subterraneous filtration, are erroneous\nand untenable. The quantity of evaporation from water and from wet\nground is found to be amply sufficient to supply the requisite\ndrain. Mr. Dalton calculated[9] that the quantity of rain which\nfalls in England is thirty-six inches a year. Of this he reckoned\nthat thirteen inches flow off to the sea by the rivers, and that\nthe remaining twenty-three inches are raised again from the ground\nby evaporation. The thirteen inches of water are of course supplied\nby evaporation from the sea, and are carried back to the land\nthrough the atmosphere. Vapour is perpetually rising from the\nocean, and is condensed in the hills and high lands, and through\ntheir pores and crevices descends, till it is deflected, collected,\nand conducted out to the bay, by some stratum or channel which is\nwatertight. The condensation which takes place in the higher parts\nof the country, may easily be recognised in the mists and rains\nwhich are the frequent occupants of such regions. The coldness of\nthe atmosphere and other causes precipitate the moisture in clouds\nand showers, and in the former as well as in the latter shape, it\nis condensed and absorbed by the cool ground. Thus a perpetual and\ncompound circulation of the waters is kept up; a narrower circle\nbetween the evaporation and precipitation of the land itself,\nthe rivers and streams only occasionally and partially forming a\nportion of the circuit; and a wider interchange between the sea and\nthe lands which feed the springs, the water ascending perpetually\nby a thousand currents through the air, and descending by the\ngradually converging branches of the rivers, till it is again\nreturned into the great reservoir of the ocean.\n\nIn every country, these two portions of the aqueous circulation\nhave their regular, and nearly constant, proportion. In this\nkingdom the relative quantities are, as we have said, twenty-three\nand thirteen. A due distribution of these circulating fluids in\neach country appears to be necessary to its organic health; to the\nhabits of vegetables, and of man. We have every reason to believe\nthat it is kept up from year to year as steadily as the circulation\nof the blood in the veins and arteries of man. It is maintained by\na machinery very different, indeed, from that of the human system,\nbut apparently as well, and, therefore, we may say as clearly, as\nthat, adapted to its purposes.\n\nBy this machinery, we have a connexion established between the\natmospheric changes of remote countries. Rains in England are often\nintroduced by a south-east wind. \u201cVapour brought to us by such\na wind, must have been generated in countries to the south and\neast of our island. It is, therefore, probably, in the extensive\nvalleys watered by the Meuse, the Moselle, and the Rhine, if not\nfrom the more distant Elbe, with the Oder and the Weser, that the\nwater rises, in the midst of sunshine, which is soon afterwards\nto form _our_ clouds, and pour down _our_ thunder-showers.\u201d\n\u201cDrought and sunshine in one part of Europe may be as necessary\nto the production of a wet season in another, as it is on the\ngreat scale of the continents of Africa and South America; where\nthe plains, during one-half the year, are burnt up, to feed\nthe springs of the mountain; which in their turn contribute to\ninundate the fertile valleys and prepare them for a luxuriant\nvegetation.\u201d[10] The properties of water which regard heat make one\nvast _watering-engine_ of the atmosphere.\n\n\n\n\nCHAPTER X.\n\n_The Laws of Heat with respect to Air._\n\n\nWe have seen in the preceding chapter how many and how important\nare the offices discharged by the aqueous part of the atmosphere.\nThe aqueous part is, however, a very small part only; it may\nvary, perhaps, from less than 1-100th to nearly as much as 1-20th\nin weight, of the whole aerial ocean. We have to offer some\nconsiderations with regard to the remainder of the mass.\n\n1. In the first place we may observe that the aerial atmosphere is\nnecessary as a vehicle for the aqueous vapour. Salutary as is the\noperation of this last element to the whole organized creation, it\nis a substance which would not have answered its purposes if it had\nbeen administered pure. It requires to be diluted and associated\nwith dry air, to make it serviceable. A little consideration will\nshow this.\n\nWe can suppose the earth with no atmosphere except the vapour\nwhich arises from its watery parts: and if we suppose also the\nequatorial parts of the globe to be hot, and the polar parts cold,\nwe may easily see what would be the consequence. The waters at\nthe equator, and near the equator, would produce steam of greater\nelasticity, rarity, and temperature, than that which occupies the\nregions further _polewards_; and such steam, as it came in contact\nwith the colder vapour of a higher latitude, would be precipitated\ninto the form of water. Hence there would be a perpetual current\nof steam from the equatorial parts towards each pole, which would\nbe condensed, would fall to the surface, and flow back to the\nequator in the form of fluid. We should have a circulation which\nmight be regarded as a species of regulated distillation.[11] On\na globe so constituted, the sky of the equatorial zone would be\nperpetually cloudless; but in all other latitudes we should have an\nuninterrupted shroud of clouds, fogs, rains, and, near the poles, a\ncontinual fall of snow. This would be balanced by a constant flow\nof the currents of the ocean from each pole towards the equator. We\nshould have an excessive circulation of moisture, but no sunshine,\nand probably only minute changes in the intensity and appearances\nof one eternal drizzle or shower.\n\nIt is plain that this state of things would but ill answer the ends\nof vegetable and animal life: so that even if the lungs of animals\nand the leaves of plants were so constructed as to breathe steam\ninstead of air, an atmosphere of unmixed steam would deprive those\ncreatures of most of the other external conditions of their well\nbeing.\n\nThe real state of things which we enjoy, the steam being mixed\nin our breath and in our sky in a moderate quantity, gives rise\nto results very different from those which have been described.\nThe machinery by which these results are produced is not a little\ncurious. It is in fact the machinery of the _weather_, and\ntherefore the reader will not be surprised to find it both complex\nand apparently uncertain in its working. At the same time some\nof the general principles which govern it seem now to be pretty\nwell made out, and they offer no small evidence of beneficent\narrangement.\n\nBesides our atmosphere of aqueous vapour, we have another and far\nlarger atmosphere of common air; a _permanently elastic_ fluid,\nthat is, one which is not condensed into a liquid form by pressure\nor cold, such as it is exposed to in the order of natural events.\nThe pressure of the dry air is about twenty-nine and a half inches\nof mercury; that of the watery vapour, perhaps, half an inch. Now\nif we had the earth quite dry, and covered with an atmosphere of\ndry air, we can trace in a great measure what would be the results,\nsupposing still the equatorial zone to be hot, and the temperature\nof the surface to decrease perpetually as we advance into higher\nlatitudes. The air at the equator would be rarefied by the heat,\nand would be perpetually displaced below by the denser portions\nwhich belonged to cooler latitudes. We should have a current of\nair from the equator to the poles in the higher regions of the\natmosphere, and at the surface a returning current setting towards\nthe equator to fill up the void so created. Such aerial currents,\ncombined with the rotatory motion of the earth, would produce\noblique winds; and we have in fact instances of winds so produced,\nin the trade winds, which between the tropics blow constantly from\nthe quarters between east and north, and are, we know, balanced\nby opposite currents in higher regions. The effect of a heated\nsurface of land would be the same as that of the heated zone of the\nequator, and would attract to it a sea breeze during the day time,\na phenomenon, as we also know, of perpetual occurrence.\n\nNow a mass of dry air of such a character as this, is by far the\ndominant part of our atmosphere; and hence carries with it in its\nmotions the thinner and smaller eddies of aqueous vapour. The\nlatter fluid may be considered as permeating and moving in the\ninterstices of the former, as a spring of water flows through a\nsand rock.[12] The lower current of air is, as has been said,\ndirected towards the equator, and hence it resists the motion of\nthe steam, the tendency of which is in the opposite direction; and\nprevents or much retards that continual flow of hot vapour into\ncolder regions, by which a constant precipitation would take place\nin the latter situations.\n\nIf, in this state of things, the flow of the current of air, which\nblows from any colder place into a warmer region, be retarded or\nstopped, the aqueous vapours will now be able to make their way\nto the colder point, where they will be precipitated in clouds or\nshowers.\n\nThus, in the lower part of the atmosphere, there are tendencies\nto a current of air in one direction, and a current of vapour in\nthe opposite; and these tendencies exist in the average weather\nof places situated at a moderate distance from the equator. The\nair tends from the colder to the warmer parts, the vapour from the\nwarmer to the colder.\n\nThe various distribution of land and sea, and many other causes\nmake these currents far from simple. But in general the air current\npredominates, and keeps the skies clear and the moisture dissolved.\nOccasional and irregular occurrences disturb this predominance;\nthe moisture is then precipitated, the skies are clouded, and the\nclouds may descend in copious rains.\n\nThese alternations of fair weather and showers, appear to be much\nmore favourable to vegetable and animal life than any uniform\ncourse of weather could have been. To produce this variety, we have\ntwo antagonist forces, by the struggle of which such changes occur.\nSteam and air, two transparent and elastic fluids, expansible by\nheat, are in many respects and properties very like each other.\nYet, the same heat similarly applied to the globe, produces at the\nsurface currents of these fluids, tending in opposite directions.\nAnd these currents mix and balance, conspire and interfere, so\nthat our trees and fields have alternately water and sunshine;\nour fruits and grain are successively developed and matured. Why\nshould such laws of heat and elastic fluids so obtain, and be so\ncombined? Is it not in order that they may be fit for such offices?\nThere is here an arrangement, which no chance could have produced.\nThe details of this apparatus may be beyond our power of tracing;\nits springs may be out of our sight. Such circumstances do not make\nit the less a curious and beautiful contrivance: they need not\nprevent our recognizing the skill and benevolence which we _can_\ndiscover.\n\n2. But we have not yet done with the machinery of the weather. In\nascending from the earth\u2019s surface through the atmosphere, we find\na remarkable difference in the heat and in the pressure of the air.\nIt becomes much colder, and much lighter; men\u2019s feelings tell them\nthis; and the thermometer and barometer confirm these indications.\nAnd here again we find something to remark.\n\nIn both the simple atmospheres of which we have spoken, the one of\nair and the one of steam, the property which we have mentioned must\nexist. In each of them, both the temperature and the tension would\ndiminish in ascending. But they would diminish at very different\nrates. The temperature, for instance, would decrease much more\nrapidly for the same height in dry air than in steam. If we begin\nwith a temperature of 80 degrees at the surface, on ascending five\nthousand feet the steam is still 76\u00bd degrees, the air is only 64\u00bd\ndegrees; at ten thousand feet, the steam is 73 degrees, the air\n48\u00bd degrees; at fifteen thousand feet, steam is at 70 degrees,\nair has fallen below the freezing point to 31\u00bd degrees. Hence\nthese two atmospheres cannot exist together without modifying one\nanother: one must heat or cool the other, so that the coincident\nparts may be of the same temperature. This accordingly does take\nplace, and this effect influences very greatly the constitution\nof the atmosphere. For the most part, the steam is compelled to\naccommodate itself to the temperature of the air, the latter being\nof much the greater bulk. But if the upper parts of the aqueous\nvapour be cooled down to the temperature of the air, they will not\nby any means exert on the lower parts of the same vapour so great a\npressure as the gaseous form of these could bear. Hence, there will\nbe a deficiency of moisture in the lower part of the atmosphere,\nand if water exist there, it will rise by evaporation, the surface\nfeeling an insufficient tension; and there will thus be a fresh\nsupply of vapour upwards. As, however, the upper regions already\ncontain as much as their temperature will support in the state of\ngas, a precipitation will now take place, and the fluid thus formed\nwill descend till it arrives in a lower region, where the tension\nand temperature are again adapted to its evaporation.\n\nThus, we can have no equilibrium in such an atmosphere, but a\nperpetual circulation of vapour between its upper and lower parts.\nThe currents of air which move about in different directions, at\ndifferent altitudes, will be differently charged with moisture, and\nas they touch and mingle, lines of cloud are formed, which grow and\njoin, and are spread out in floors, or rolled together in piles.\nThese, again, by an additional accession of humidity, are formed\ninto drops, and descend in showers into the lower regions, and if\nnot evaporated in their fall, reach the surface of the earth.\n\nThe varying occurrences thus produced, tend to multiply and extend\ntheir own variety. The ascending streams of vapour carry with them\nthat _latent heat_ belonging to their gaseous state, which, when\nthey are condensed, they give out as sensible heat. They thus\nraise the temperature of the upper regions of air, and occasion\nchanges in the pressure and motion of its currents. The clouds,\nagain, by shading the surface of the earth from the sun, diminish\nthe evaporation by which their own substance is supplied, and\nthe heating effects by which currents are caused. Even the mere\nmechanical effects of the currents of fluid on the distribution of\nits own pressure, and the dynamical conditions of its motion, are\nin a high degree abstruse in their principles and complex in their\nresults. It need not be wondered, therefore, if the study of this\nsubject is very difficult and entangled, and our knowledge, after\nall, very imperfect.\n\nIn the middle of all this apparent confusion, however, we can\nsee much that we can understand. And, among other things, we may\nnotice some of the consequences of the difference of the laws\nof temperature followed by steam and by air in going upwards.\nOne important result is that the atmosphere is much drier, near\nthe surface, than it would have been if the laws of density and\ntemperature had been the same for both gases. If this had been so,\nthe air would always have been _saturated_ with vapour. It would\nhave contained as much as the existing temperature could support,\nand the slightest cooling of any object would have covered it with\na watery film like dew. As it is, the air contains much less than\nits full quantity of vapour: we may often cool an object ten,\ntwenty, or thirty degrees without obtaining a deposition of water\nupon it, or reaching the _dew-point_, as it is called. To have had\nsuch a _dripping_ state of the atmosphere as the former arrangement\nwould have produced, would have been inconvenient, and so far\nas we can judge, unsuited to vegetables as well as animals. No\nevaporation from the surface of either could have taken place under\nsuch conditions.\n\nThe sizes and forms of clouds appear to depend on the same\ncircumstance, of the air not being saturated with moisture. And it\nis seemingly much better that clouds should be comparatively small\nand well defined, as they are, than that they should fill vast\ndepths of the atmosphere with a thin mist, which would have been\nthe consequence of the imaginary condition of things just mentioned.\n\nHere then we have another remarkable exhibition of two laws, in\ntwo nearly similar gaseous fluids, producing effects alike in kind,\nbut different in degree, and by the _play_ of their difference\ngiving rise to a new set of results, peculiar in their nature and\nbeneficial in their tendency. The _form_ of the laws of air and\nof steam with regard to heat might, so far as we can see, have\nbeen more similar, or more dissimilar, than it now is: the rate of\neach law might have had a different amount from its present one,\nso as quite to alter the relation of the two. By the laws having\nsuch forms and such rates as they have, effects are produced, some\nof which we can distinctly perceive to be beneficial. Perhaps\nmost persons will feel a strong persuasion, that if we understood\nthe operation of these laws more distinctly, we should see still\nmore clearly the beneficial tendency of these effects, and should\nprobably discover others, at present concealed in the apparent\nperplexity of the subject.\n\n3. From what has been said, we may see, in a general way, both the\ncauses and the effects of _winds_. They arise from any disturbance\nby temperature, motion, pressure, &c. of the equilibrium of the\natmosphere, and are the efforts of nature to restore the balance.\nTheir office in the economy of nature is to carry heat and moisture\nfrom one tract to another, and they are the great agents in the\ndistribution of temperature and the changes of weather. Other\npurposes might easily be ascribed to them in the business of the\nvegetable and animal kingdoms, and in the arts of human life, of\nwhich we shall not here treat. That character in which we now\nconsider them, that of the machinery of atmospheric changes, and\nthus, immediately or remotely, the instruments of atmospheric\ninfluences, cannot well be refused them by any person.\n\n4. There is still one reflexion which ought not to be omitted.\nAll the changes of the weather, even the most violent tempests\nand torrents of rain, may be considered as oscillations about the\nmean or average condition belonging to each place. All these\noscillations are limited and transient; the storm spends its fury,\nthe inundation passes off, the sky clears, the calmer course of\nnature succeeds. In the forces which produce this derangement,\nthere is a provision for making it short and moderate. The\noscillation stops of itself, like the rolling of a ship, when\nno longer impelled by the wind. Now, why should this be so? Why\nshould the oscillations, produced by the conflict of so many laws,\nseemingly quite unconnected with each other, be of this converging\nand subsiding character? Would it be so under all arrangements? Is\nit a matter of mechanical necessity that disturbance must end in\nthe restoration of the medium condition? By no means. There may\nbe an utter subversion of the equilibrium. The ship may roll too\nfar, and may _capsize_. The oscillations may go on, becoming larger\nand larger, till all trace of the original condition is lost; till\nnew forces of inequality and disturbance are brought into play;\nand disorder and irregularity may succeed, without apparent limit\nor check in its own nature, like the spread of a conflagration in\na city. This is a possibility in any combination of mechanical\nforces; why does it not happen in the one now before us? By what\ngood fortune are the powers of heat, of water, of steam, of air,\nthe effects of the earth\u2019s annual and diurnal motions, and probably\nother causes, so adjusted, that through all their struggles the\nelemental world goes on, upon the whole, so quietly and steadily?\nWhy is the whole fabric of the weather never utterly deranged, its\nbalance lost irrecoverably? Why is there not an eternal conflict,\nsuch as the poets imagine to take place in their chaos?\n\n      \u201cFor Hot, Cold, Moist, and Dry, four champions fierce,\n      Strive here for mastery, and to battle bring\n      Their embryon atoms:--\n                              to whom these most adhere,\n      He rules _a moment_: Chaos umpire sits,\n      And by decision more embroils the fray.\u201d--_Par. Lost._ b. ii.\n\nA state of things something like that which Milton here seems to\nhave imagined, is, so far as we know, not mechanically impossible.\nIt might have continued to obtain, if Hot and Cold, and Moist and\nDry had not been compelled to \u201crun into their places.\u201d It will be\nhereafter seen, that in the comparatively simple problem of the\nsolar system, a number of very peculiar adjustments were requisite,\nin order that the system might retain a permanent form, in order\nthat its motions might have their cycles, its perturbations their\nlimits and period. The problem of the continuation of such laws and\nmaterials as enter into the constitution of the atmosphere, is one\nmanifestly of much greater complexity, and indeed to us probably\nof insurmountable difficulty as a mechanical problem. But all that\ninvestigation and analogy teach us, tends to show that it will\nresemble the other problem in the nature of its result; and that\ncertain relations of its data, and of the laws of its elements,\nare necessary requisites, for securing the stability of its mean\ncondition, and for giving a small and periodical character to its\ndeviations from such a condition.\n\nIt would then be probable, from this reflection alone, that in\ndetermining the quantity and the law and intensity of the forces,\nof earth, water, air, and heat, the same regard has been shown to\nthe permanency and stability of the terrestrial system, which may\nbe traced in the adjustment of the masses, distances, positions,\nand motions of the bodies of the celestial machine.\n\nThis permanency appears to be, of itself, a suitable object of\ncontrivance. The purpose for which the world was made could be\nanswered only by its being preserved. But it has appeared, from\nthe preceding part of this and the former chapter, that this\npermanence is a permanence of a state of things adapted by the most\nremarkable and multiplied combinations to the well-being of man, of\nanimals, of vegetables. The adjustments and conditions therefore,\nbeyond the reach of our investigation as they are, by which its\npermanence is secured, must be conceived as fitted to add, in each\nof the instances above adduced, to the admiration which the several\nmanifestations of Intelligent Beneficence are calculated to excite.\n\n\n\n\nCHAPTER XI.\n\n_The Laws of Electricity._\n\n\nElectricity undoubtedly exists in the atmosphere in most states of\nthe air; but we know very imperfectly the laws of this agent, and\nare still more ignorant of its atmospheric operation. The present\nstate of science does not therefore enable us to perceive those\nadaptations of its laws to its uses, which we can discover in those\ncases where the laws and the uses are both of them more apparent.\n\nWe can, however, easily make out that electrical agency plays a\nvery considerable part among the clouds, in their usual conditions\nand changes. This may be easily shown by Franklin\u2019s experiment of\nthe electrical kite. The clouds are sometimes positively, sometimes\nnegatively, charged, and the rain which descends from them offers\nalso indications of one or other kind of electricity. The changes\nof wind and alterations of the form of the clouds are generally\naccompanied with changes in these electrical indications. Every one\nknows that a thunder-cloud is strongly charged with the electric\nfluid, (if it be a fluid,) and that the stroke of the lightning\nis an electrical discharge. We may add that it appears, by recent\nexperiments, that a transfer of electricity between plants and\nthe atmosphere is perpetually going on during the process of\nvegetation.\n\nWe cannot trace very exactly the precise circumstances, in the\noccurrences of the atmospheric regions, which depend on the\ninfluence of the laws of electricity: but we are tolerably certain,\nfrom what has been already noticed, that if these laws did not\nexist, or were very different from what they now are, the action of\nthe clouds and winds, and the course of vegetation, would also be\nother than it now is.\n\nIt is therefore at any rate very probable that electricity has its\nappointed and important purposes in the economy of the atmosphere.\nAnd this being so, we may see a use in the thunder-storm and the\nstroke of the lightning. These violent events are, with regard to\nthe electricity of the atmosphere, what winds are with regard to\nheat and moisture. They restore the equilibrium where it has been\ndissolved, and carry the fluid from places where it is superfluous,\nto others where it is deficient.\n\nWe are so constituted, however, that these crises impress almost\nevery one with a feeling of awe. The deep lowering gloom of the\nthunder-cloud, the overwhelming burst of the explosion, the flash\nfrom which the steadiest eye shrinks, and the irresistible arrow of\nthe lightning which no earthly substance can withstand, speak of\nsomething fearful, even independently of the personal danger which\nthey may whisper. They convey, far more than any other appearance\ndoes, the idea of a superior and mighty power, manifesting\ndispleasure and threatening punishment. Yet we find that this is\nnot the language which they speak to the physical inquirer: he sees\nthese formidable symptoms only as the means or the consequences\nof good. What office the thunderbolt and the whirlwind may have\nin the _moral_ world, we cannot here discuss: but certainly _he_\nmust speculate as far beyond the limits of philosophy as of piety,\nwho pretends to have learnt that there their work has more of evil\nthan of good. In the _natural_ world, these apparently destructive\nagents are, like all the other movements and appearances of the\natmosphere, parts of a great scheme, of which every discoverable\npurpose is marked with beneficence as well as wisdom.\n\n\n\n\nCHAPTER XII.\n\n_The Laws of Magnetism._\n\n\nMagnetism has no very obvious or apparently extensive office in\nthe mechanism of the atmosphere and the earth: but the mention of\nit may be introduced, because its ascertained relations to the\nother powers which exist in the system are well suited to show us\nthe connexion subsisting throughout the universe, and to check the\nsuspicion, if any such should arise, that any law of nature is\nwithout its use. The parts of creation when these uses are most\nobscure, are precisely those parts when the laws themselves are\nleast known.\n\nWhen indeed we consider the vast service of which magnetism is to\nman, by supplying him with that invaluable instrument the mariners\u2019\ncompass, many persons will require no further evidence of this\nproperty being introduced into the frame of things with a worthy\npurpose. As however, we have hitherto excluded _use in the arts_\nfrom our line of argument, we shall not here make an exception in\nfavour of navigation, and what we shall observe belongs to another\nview of the subject.\n\nMagnetism has been discovered in modern times to have so close\na connexion with galvanism, that they may be said to be almost\ndifferent aspects of the same agent. All the phenomena which we can\nproduce with magnets, we can imitate with coils of galvanic wire.\nThat galvanism exists in the earth, we need no proof. Electricity,\nwhich appears to be only galvanism in equilibrium, is there in\nabundance; and recently, Mr. Fox[13] has shown by experiment that\nmetalliferous veins, as they lie in the earth, exercise a galvanic\ninfluence on each other. Something of this kind might have been\nanticipated; for masses of metal in contact, if they differ in\ntemperature or other circumstances, are known to produce a galvanic\ncurrent. Hence we have undoubtedly streams of galvanic influence\nmoving along in the earth. Whether or not such causes as these\nproduce the directive power of the magnetic needle, we cannot here\npretend to decide; they can hardly fail to affect it. The Aurora\nBorealis too, probably an electrical phenomenon, is said, under\nparticular circumstances, to agitate the magnetic needle. It is\nnot surprising, therefore, that, if electricity have an important\noffice in the atmosphere, magnetism should exist in the earth. It\nseems likely, that the magnetic properties of the earth may be\ncollateral results of the existence of the same cause by which\nelectrical agency operates; an agency which, as we have already\nseen, has important offices in the processes of vegetable life. And\nthus magnetism belongs to the same system of beneficial contrivance\nto which electricity has been already traced.\n\nWe see, however, on this subject very dimly and a very small way.\nIt can hardly be doubted that magnetism has other functions than\nthose we have noticed.\n\n\n\n\nCHAPTER XIII.\n\n_The Properties of Light with regard to Vegetation._\n\n\nThe illuminating power of light will come under our consideration\nhereafter. Its agency, with regard to organic life, is too\nimportant not to be noticed, though this must be done briefly.\nLight appears to be as necessary to the health of plants as air\nof moisture. A plant may, indeed, grow without it, but it does\nnot appear that a species could be so continued. Under such a\nprivation, the parts which are usually green, assume a white\ncolour, as is the case with vegetables grown in a cellar, or\nprotected by a covering for the sake of producing this very effect;\nthus, celery, is in this manner blanched, or _etiolated_.\n\nThe part of the process of vegetable life for which light is\nespecially essential, appears to be the functions of the leaves;\nthese are affected by this agent in a very remarkable manner.\nThe moisture which plants imbibe is, by their vital energies,\ncarried to their leaves; and is then brought in contact with the\natmosphere, which, besides other ingredients, contains, in general,\na portion of carbonic acid. _So long as light is present_, the\nleaf decomposes the carbonic acid, appropriates the carbon to the\nformation of its own proper juices, and returns the disengaged\noxygen into the atmosphere; thus restoring the atmospheric air to\na condition in which it is more fitted than it was before for the\nsupport of animal life. The plant thus prepares the support of\nlife for other creatures at the same time that it absorbs its own.\nThe greenness of those members which affect that colour, and the\ndisengagement of oxygen, are the indications that its vital powers\nare in healthful action: as soon as we remove light from the plant,\nthese indications cease: it has no longer power to imbibe carbon\nand disengage oxygen, but on the contrary, it gives back some of\nthe carbon already obtained, and robs the atmosphere of oxygen for\nthe purpose of reconverting this into carbonic acid.\n\nIt cannot well be conceived that such effects of light on\nvegetables, as we have described, should occur, if that agent, of\nwhatever nature it is, and those organs, had not been adapted to\neach other. But the subject is here introduced that the reader may\nthe more readily receive the conviction of combining purpose which\nmust arise, on finding that an agent possessing these very peculiar\nchemical properties, is employed to produce also those effects of\nillumination, vision, &c., which form the most obvious portion of\nthe properties of light.\n\n\n\n\nCHAPTER XIV.\n\n_Sound._\n\n\nBesides the function which air discharges as the great agent in the\nchanges of meteorology and vegetation, it has another office, also\nof great and extensive importance, as the vehicle of sound.\n\n1. The communication of sound through the air takes place by means\nof a process altogether different from anything of which we have\nyet spoken: namely, by the propagation of minute _vibrations_ of\nthe particles from one part of the fluid mass to another, without\nany local motion of the fluid itself.\n\nPerhaps we may most distinctly conceive the kind of effect here\nspoken of, by comparing it to the motion produced by the wind in a\nfield of standing corn; grassy waves travel visibly over the field,\nin the direction in which the wind blows, but this appearance of\nan object moving is delusive. The only real motion is that of the\nears of grain, of which each goes and returns, as the stalk stoops\nand recovers itself. This motion affects _successively_ a line of\nears in the direction of the wind, and affects _simultaneously_ all\nthose ears of which the elevation or depression forms one visible\nwave. The elevations and depressions are propagated in a constant\ndirection, while the parts with which the space is filled only\nvibrate to and fro. Of exactly such a nature is the propagation\nof sound through the air. The particles of air go and return\nthrough very minute spaces, and this vibratory motion runs through\nthe atmosphere from the sounding body to the ear. Waves, not of\nelevation and depression, but of condensation and rarefaction, are\ntransmitted; and the sound thus becomes an object of sense to the\norgan.\n\nAnother familiar instance of the propagation of vibrations we have\nin the circles on the surface of smooth water, which diverge from\nthe point where it is touched by a small object, as a drop of\nrain. In the beginning of a shower, for instance, when the drops\ncome distinct, though frequent, we may see each drop giving rise\nto a ring, formed of two or three close concentric circles, which\ngrow and spread, leaving the interior of the circles smooth, and\ngradually reaching parts of the surface more and more distant from\ntheir origin. In this instance, it is clearly not a portion of the\nwater which flows onwards; but the disturbance, the rise and fall\nof the surface which makes the ring-formed waves, passes into wider\nand wider circles, and thus the undulation is transmitted from its\nstarting-place, to points in all directions on the surface of the\nfluid.\n\nThe diffusion of these ring-formed undulations from their centre\nresembles the diffusion of a sound from the place where it is\nproduced to the points where it is heard. The disturbance, or\nvibration, by which it is conveyed, travels at the same rate in\nall directions, and the waves which are propagated are hence of a\ncircular form. They differ, however, from those on the surface of\nwater; for sound is communicated upwards and downwards, and in all\nintermediate directions, as well as horizontally; hence the waves\nof sound are spherical, the point where the sound is produced being\nthe centre of the sphere.\n\nThis diffusion of vibrations in spherical shells of successive\ncondensation and rarefaction, will easily be seen to be different\nfrom any local motion of the air, as wind, and to be independent of\nthat. The circles on the surface of water will spread on a river\nwhich is flowing, provided it be smooth, as well as on a standing\ncanal.\n\nNot only are such undulations propagated almost undisturbed by\nany local motion of the fluid in which they take place, but also,\nmany may be propagated in the same fluid at the same time, without\ndisturbing each other. We may see this effect on water. When\nseveral drops fall near each other, the circles which they produce\ncross each other, without either of them being lost, and the\nseparate courses of the rings may still be traced.\n\nAll these consequences, both in water, in air, and in any other\nfluid, can be very exactly investigated upon mechanical principles,\nand the greater part of the phenomena can thus be shown to result\nfrom the properties of the fluids.\n\nThere are several remarkable circumstances in the way in which air\nanswers its purpose as the vehicle of sound, of which we will now\npoint out a few.\n\n2. The _loudness_ of sound is such as is convenient for common\npurposes. The organs of speech can, in the present constitution of\nthe air, produce, without fatigue, such a tone of voice as can be\nheard with distinctness and with comfort. That any great alteration\nin this element might be incommodious, we may judge from the\ndifficulties to which persons are subject who are dull of hearing,\nand from the disagreeable effects of a voice much louder than\nusual, or so low as to be indistinct. Sounds produced by the human\norgans, with other kinds of air, are very different from those in\nour common air. If a man inhale a quantity of hydrogen gas, and\nthen speak, his voice is scarcely audible.\n\nThe loudness of sounds become smaller in proportion as they come\nfrom a greater distance. This enables us to judge of the distance\nof objects, in some degree at least, by the sounds which proceed\nfrom them. Moreover, it is found that we can judge of the position\nof objects by the ear: and this judgment seems to be formed by\ncomparing the loudness of the impression of the same sound on the\ntwo ears and two sides of the head.[14]\n\nThe loudness of sounds appears to depend on the _extent_ of\nvibration of the particles of air, and this is determined by the\nvibrations of the sounding body.\n\n3. The _pitch_, or the _differences of acute and grave_, in sounds,\nform another important property, and one which fits them for a\ngreat part of their purposes. By the succession of different\n_notes_, we have all the results of melody and harmony in musical\nsound; and of intonation and modulation of the voice, of accent,\ncadence, emphasis, expression, passion, in speech. The song of\nbirds, which is one of their principal modes of communication,\ndepends chiefly for its distinctions and its significance upon the\ncombinations of acute and grave.\n\nThese differences are produced by the different _rapidity_ of\nvibration of the particles of air. The gravest sound has about\neighty vibrations in a second, the most acute about one thousand.\nBetween these limits each sound has a musical character, and from\nthe different relations of the number of vibrations in a second\narise all the differences of musical intervals, concords and\ndiscords.\n\n4. The _quality_ of sounds is another of their differences. This is\nthe name given to the difference of notes of the same pitch, that\nis the same note as to acute and grave, when produced by different\ninstruments. If a flute and a violin be in unison, the notes are\nstill quite different sounds. It is this kind of difference which\ndistinguishes the voice of one man from that of another: and it is\nmanifestly therefore one of great consequence; since it connects\nthe voice with the particular person, and is almost necessary in\norder that language may be a medium of intercourse between men.\n\n5. The _articulate_ character of sounds is for us one of the most\nimportant arrangements which exist in the world; for it is by this\nthat they become the interpreters of thought, will and feeling, the\nmeans by which a person can convey his wants, his instructions,\nhis promises, his kindness, to others; by which one man can\nregulate the actions and influence the convictions and judgments\nof another. It is in virtue of the possibility of shaping air into\nwords, that the imperceptible vibrations which a man produces in\nthe atmosphere, become some of his most important actions; the\nfoundations of the highest moral and social relations; and the\ncondition and instrument of all the advancement and improvement of\nwhich he is susceptible.\n\nIt appears that the differences of articulate sound arise from\nthe different form of the cavity through which the sound is made\nto proceed immediately _after_ being produced. In the human voice\nthe sound is produced in the larynx, and modified by the cavity of\nthe mouth, and the various organs which surround this cavity. The\nlaws by which articulate sounds are thus produced have not yet been\nfully developed, but appear to be in the progress of being so.\n\nThe properties of sounds which have been mentioned, differences\nof loudness, of pitch, of quality, and articulation, appear to be\nall requisite in order that sound shall answer its purposes in\nthe economy of animal and of human life. And how was the air made\ncapable of conveying these four differences, at the same time that\nthe organs were made capable of producing them? Surely by a most\nrefined and skilful adaptation, applied with a most comprehensive\ndesign.\n\n6. Again; is it by chance that the air and the _ear_ exist\ntogether? Did the air produce the organization of the ear? or the\near, independently organized, anticipate the constitution of the\natmosphere? Or is not the only intelligible account of the matter,\nthis, that one was made for the other: that there is a mutual\nadaptation produced by an Intelligence which was acquainted with\nthe properties of both; which adjusted them to each other as we\nfind them adjusted, in order that birds might communicate by song,\nthat men might speak and hear, and that language might play its\nextraordinary part in its operation upon men\u2019s thoughts, actions,\ninstitutions, and fortunes?\n\nThe vibrations of an elastic fluid like the air, and their\nproperties, follow from the laws of motion; and whether or not\nthese laws of the motion of fluids might in reality have been other\nthan they are, they appear to us inseparably connected with the\nexistence of matter, and as much a thing of necessity as we can\nconceive any thing in the universe to be. The propagation of such\nvibrations, therefore, and their properties, we may at present\nallow to be a necessary part of the constitution of the atmosphere.\nBut what is it that makes these vibrations become sound? How is it\nthat they produce such an effect on our senses, and, through those,\non our minds? The vibrations of the air seem to be of themselves\nno more fitted to produce sound, than to produce smell. We know\nthat such vibrations do not universally produce sound, but only\nbetween certain limits. When the vibrations are fewer than eighty\nin a second, they are perceived as separate throbs, and not as a\ncontinued sound; and there is a certain limit of rapidity, beyond\nwhich the vibrations become inaudible. This limit is different to\ndifferent ears, and we are thus assured by one person\u2019s ear that\nthere are vibrations, though to that of another they do not produce\nsound. How was the human ear adapted so that its perception of\nvibrations as sounds should fall within these limits?--the very\nlimits within which the vibrations fall, which it most concerns\nus to perceive: those of the human voice for instance? How nicely\nare the organs adjusted with regard to the most minute mechanical\nmotions of the elements?\n\n\n\n\nCHAPTER XV.\n\n_The Atmosphere._\n\n\nWe have considered in succession a number of the properties and\noperations of the atmosphere, and have found them separately very\ncurious. But an additional interest belongs to the subject when we\nconsider them as combined. The atmosphere under this point of view\nmust appear a contrivance of the most extraordinary kind. To answer\nany of its purposes, to carry on any of its processes, separately,\nrequires peculiar arrangements and adjustments; to answer, all at\nonce, purposes so varied, to combine without confusion so many\ndifferent trains, implies powers and attributes which can hardly\nfail to excite in a high degree our admiration and reverence.\n\nIf the atmosphere be considered as a vast machine, it is\ndifficult to form any just conception of the profound skill and\ncomprehensiveness of design which it displays. It diffuses and\ntempers the heat of different climates; for this purpose it\nperforms a circulation occupying the whole range from the pole to\nthe equator; and while it is doing this, it executes many smaller\ncircuits between the sea and the land. At the same time, it is\nthe means of forming clouds and rain, and for this purpose, a\nperpetual circulation of the watery part of the atmosphere goes on\nbetween its lower and upper regions. Besides this complication of\ncircuits, it exercises a more irregular agency, in the occasional\nwinds which blow from all quarters, tending perpetually to restore\nthe equilibrium of heat and moisture. But this incessant and\nmultiplied activity discharges only a part of the functions of the\nair. It is, moreover, the most important and universal material of\nthe growth and sustenance of plants and animals; and is for this\npurpose every where present and almost uniform in its quantity.\nWith all its local motion, it has also the office of a medium\nof communication between intelligent creatures, which office it\nperforms by another set of motions, entirely different both from\nthe circulation and the occasional movements already mentioned;\nthese different kinds of motions not interfering materially with\neach other: and this last purpose, so remote from the others\nin its nature, it answers in a manner so perfect and so easy,\nthat we cannot imagine that the object could have been more\ncompletely attained, if this had been the sole purpose for which\nthe atmosphere had been created. With all these qualities, this\nextraordinary part of our terrestrial system is scarcely ever in\nthe way: and when we have occasion to do so, we put forth our hand\nand push it aside, without being aware of its being near us.\n\nWe may add, that it is, in addition to all that we have hitherto\nnoticed, a constant source of utility and beauty in its effects\non light. Without air we should see nothing, except objects on\nwhich the sun\u2019s rays fell, directly or by reflection. It is the\natmosphere which converts sunbeams into daylight, and fills the\nspace in which we are with illumination.\n\nThe contemplation of the atmosphere, as a machine which answers all\nthese purposes, is well suited to impress upon us the strongest\nconviction of the most refined, far-seeing, and far-ruling\ncontrivance. It seems impossible to suppose that these various\nproperties were so bestowed and so combined, any otherwise than by\na beneficent and intelligent Being, able and willing to diffuse\norganization, life, health, and enjoyment through all parts of\nthe visible world; possessing a fertility of means which no\nmultiplicity of objects could exhaust, and a discrimination of\nconsequences which no complication of conditions could embarrass.\n\n\n\n\nCHAPTER XVI.\n\n_Light._\n\n\nBesides the hearing and sound there is another mode by which we\nbecome sensible of the impressions of external objects, namely,\nsight and light. This subject also offers some observations bearing\non our present purpose.\n\nIt has been declared by writers on Natural Theology, that the\nhuman eye exhibits such evidence of design and skill in its\nconstruction, that no one, who considers it attentively, can resist\nthis impression: nor does this appear to be saying too much. It\nmust, at the same time, be obvious that this construction of the\neye could not answer its purposes, except the constitution of light\ncorresponded to it. Light is an element of the most peculiar kind\nand properties, and such an element can hardly be conceived to have\nbeen placed in the universe without a regard to its operation and\nfunctions. As the eye is made for light, so light must have been\nmade, at least among other ends, for the eye.\n\n1. We must expect to comprehend imperfectly only the mechanism\nof the elements. Still, we have endeavoured to show that in some\ninstances the arrangements by which their purposes are effected\nare, to a certain extent, intelligible. In order to explain,\nhowever, in what manner light answers those ends which appear to us\nits principal ones, we must know something of the nature of light.\nThere have, hitherto, been, among men of science, two prevailing\nopinions upon this subject: some considering light as consisting\nin the emission of luminous particles; others accounting for\nits phenomena by the propagation of vibrations through a highly\nsubtle and elastic _ether_. The former opinion has, till lately,\nbeen most generally entertained in this country, having been the\nhypothesis on which Newton made his calculations; the latter is\nthe one to which most of those persons have been led, who, in\nrecent times, have endeavoured to deduce general conclusions from\nthe newly discovered phenomena of light. Among these persons, the\n_theory of undulations_ is conceived to be established in nearly\nthe same manner, and almost as certainly, as the doctrine of\nuniversal gravitation; namely, by a series of laws inferred from\nnumerous facts, which, proceeding from different sets of phenomena,\nare found to converge to one common view; and by calculations\nfounded upon the theory, which, indicating new and untried facts,\nare found to agree exactly with experiment.\n\nWe cannot here introduce a sketch of the progress by which the\nphenomena have thus led to the acceptance of the theory of\nundulations. But this theory appears to have such claims to our\nassent, that the views which we have to offer with regard to the\ndesign exercised in the adaptation, of light to its purposes, will\ndepend on the undulatory theory, so far as they depend on theory at\nall.[15]\n\n2. The impressions of sight, like those of hearing, differ in\nintensity and in kind. _Brightness_ and _Colour_ are the principal\ndifferences among visible things, as loudness and pitch are among\nsounds. But there is a singular distinction between these senses\nin one respect: every object and part of an object seen, is\nnecessarily and inevitably referred to some _position_ in the space\nbefore us; and hence visible things have place, magnitude, form,\nas well as light, shade, and colour. There is nothing analogous\nto this in the sense of hearing; for though we can, in some\napproximate degree, _guess_ the situation of the point from which\na sound proceeds, this is a secondary process, distinguishable from\nthe perception of the sound itself; whereas we cannot conceive\nvisible things without form and place.\n\nThe law according to which the sense of vision is thus affected,\nappears to be this. By the properties of light, the external scene\nproduces, through the transparent parts of the eye, an image or\npicture exactly resembling the reality, upon the back part of the\nretina: and each point which we see, is seen in the direction of a\nline passing from its image on the retina, through the centre of\nthe pupil of the eye.[16] In this manner we perceive by the eye the\nsituation of every point, at the same time that we perceive its\nexistence; and by combining the situations of many points, we have\nforms and outlines of every sort.\n\nThat we should receive from the eye this notice of the position\nof the object as well as of its other visible qualities, appears\nto be absolutely necessary for our intercourse with the external\nworld; and the faculty of doing so is so intimate a part of our\nconstitution that we cannot conceive ourselves divested of it.\nYet in order to imagine ourselves destitute of this faculty, we\nhave only to suppose that the eye should receive its impressions\nas the ear does, and should apprehend red and green, bright and\ndark, without placing them side by side; as the ear takes in the\ndifferent sounds which compose a concert, without attributing them\nto different parts of space.\n\nThe peculiar property thus belonging to vision, of perceiving\nposition, is so essential to us, that we may readily believe that\nsome particular provision has been made for its existence. The\nremarkable mechanism of the eye (precisely resembling that of a\n_camera obscura_,) by which it produces an image on the nervous\nweb forming its hinder part, seems to have this effect for its\nmain object. And this mechanism necessarily supposes certain\ncorresponding properties in light itself, by means of which such an\neffect becomes possible.\n\nThe main properties of light which are concerned in this\narrangement, are _reflexion_ and _refraction_: reflexion by which\nlight is reflected and scattered by all objects, and thus comes to\nthe eye from all: and refraction, by which its course is bent, when\nit passes obliquely out of one transparent medium into another;\nand by which, consequently, convex transparent substances, such as\nthe cornea and humours of the eye, possess the power of making the\nlight converge to a _focus_ or point; an assemblage of such points\nforming the images on the retina, which we have mentioned.\n\nReflexion and refraction are therefore the essential and\nindispensable properties of light; and so far as we can understand,\nit appears that it was necessary that light should possess such\nproperties, in order that it might form a medium of communication\nbetween man and the external world. We may consider its power of\npassing through transparent media (as air) to be given in order\nthat it may enlighten the earth; its affection of reflexion, for\nthe purpose of making colours visible; and its refraction to\nbe bestowed, that it may enable us to discriminate figure and\nposition, by means of the lenses of the eye.\n\nIn this manner light may be considered as constituted with a\npeculiar reference to the eyes of animals, and its leading\nproperties may be looked upon as contrivances or adaptations to\nfit it for its visual office. And in such a point of view the\nperfection of the contrivance or adaptation must be allowed to be\nvery remarkable.\n\n3. But besides the properties of reflexion and refraction, the most\nobvious laws of light, an extraordinary variety of phenomena have\nlately been discovered, regulated by other laws of the most curious\nkind, uniting great complexity with great symmetry. We refer to the\nphenomena of diffraction, polarisation, and periodical colours,\nproduced by crystals and by thin plates. We have, in these facts,\na vast mass of properties and laws, offering a subject of study\nwhich has been pursued with eminent skill and intelligence. But\nthese properties and laws, so far as has yet been discovered,\nexert no agency whatever, and have no purpose, in the general\neconomy of nature. Beams of light polarised in contrary directions\nexhibit the most remarkable differences when they pass through\ncertain crystals, but manifest no discoverable difference in their\nimmediate impression on the eye. We have, therefore, here, a number\nof laws of light, which we cannot perceive to be established with\nany design which has a reference to the other parts of the universe.\n\nUndoubtedly it is exceedingly possible that these differences of\nlight may operate in some quarter, and in some way, which we cannot\ndetect; and that these laws may have purposes and may answer ends\nof which we have no suspicion. All the analogy of nature teaches\nus a lesson of humility, with regard to the reliance we are to\nplace on our discernment and judgment as to such matters. But with\nour present knowledge, we may observe, that this curious system of\nphenomena appears to be a collateral result of the mechanism by\nwhich the effects of light are produced; and therefore a necessary\nconsequence of the existence of that element of which the offices\nare so numerous and so beneficent.\n\nThe new properties of light, and the speculations founded upon\nthem, have led many persons to the belief of the undulatory theory;\nwhich, as we have said, is considered by some philosophers as\ndemonstrated. If we adopt this theory, we consider the luminiferous\nether to have no local motion; and to produce refraction and\nreflexion by the operation of its elasticity alone. We must\nnecessarily suppose the tenuity of the ether to be extreme; and\nif we moreover suppose its tension to be very great, which the\nvast velocity of light requires us to suppose, the vibrations by\nwhich light is propagated will be _transverse_ vibrations, that\nis the motion to and fro will be athwart the line along which the\nundulation travels; and from this circumstance all the laws of\npolarisation necessarily follow. And the properties of transverse\nvibrations, combined with the properties of vibrations in general,\ngive rise to all the curious and numerous phenomena of colours of\nwhich we have spoken.\n\nIf the vibrations be transverse, they may be resolved into two\ndifferent planes; this is _polarisation_: if they fall on a\nmedium which has different elasticity in different directions,\nthey will be divided into two sets of vibrations; this is _double\nrefraction_; and so on. Some of the new properties, however, as the\nfringes of shadows and the colours of thin plates, follow from the\nundulatory theory, whether the vibrations be transverse or not.\n\nIt would appear, therefore, that the propagation of light by\nmeans of a subtle medium, leads necessarily to the extraordinary\ncollection of properties which have recently been discovered; and,\nat any rate, its propagation by the transverse vibrations of such a\nmedium does lead inevitably to these results.\n\nLeaving it therefore to future times to point out the other reasons\n(or _uses_ if they exist) of these newly discovered properties of\nlight, in their bearing on other parts of the world, we may venture\nto say, that if light was to be propagated through transparent\nmedia by the undulations of a subtle fluid, these properties must\nresult, as necessarily as the rainbow results from the unequal\nrefrangibility of different colours. This phenomenon and those,\nappear alike to be the collateral consequences of the law\u2019s\nimpressed on light with a view to its principal offices.\n\nThus the exquisitely beautiful and symmetrical phenomena and laws\nof polarisation, and of crystalline and other effects, may be\nlooked upon as indications of the delicacy and subtlety of the\nmechanism by which man, through his visual organs, is put in\ncommunication with the external world; is made acquainted with the\nforms and qualities of objects in the most remote regions of space;\nand is enabled, in some measure, to determine his position and\nrelation in a universe in which he is but an atom.\n\n4. If we suppose it clearly established that light is produced\nby the vibrations of an ether, we find considerations offer\nthemselves, similar to those which occurred in the case of sound.\nThe vibrations of this ether affect our organs with the sense of\nlight and colour. Why, or how do they do this? It is only within\ncertain limits that the effect is produced, and these limits are\ncomparatively narrower here than in the case of sound. The whole\nscale of colour, from violet to crimson, lies between vibrations\nwhich are four hundred and fifty-eight million millions, and seven\nhundred and twenty-seven million millions in a second; a proportion\nmuch smaller than the corresponding ratio for perceptible sounds.\nWhy should such vibrations produce perception in the eye, and\nno others? There must be here some peculiar adaptation of the\nsensitive powers to these wonderfully minute and condensed\nmechanical motions. What happens when the vibrations are slower\nthan the red, or quicker than the blue? They do not produce vision:\ndo they produce any effect? Have they any thing to do with heat or\nwith electricity? We cannot tell. The ether must be as susceptible\nof these vibrations, as of those which produce vision. But the\nmechanism of the eye is adjusted to this latter kind only; and this\nprecise kind, (whether alone or mixed with others,) proceeds from\nthe sun and from other luminaries, and thus communicates to us the\nstate of the visible universe. The mere material elements then are\nfull of properties which we can understand no otherwise, than as\nthe results of a refined contrivance.\n\n\n\n\nCHAPTER XVII.\n\n_The Ether._\n\n\nIn what has just been said, we have spoken of light, only with\nrespect to its power of illuminating objects, and conveying the\nimpression of them to the eye. It possesses, however, beyond all\ndoubt, many other qualities. Light is intimately connected with\nheat, as we see in the case of the sun and of flame; yet it is\nclear that light and heat are not identical. Light is evidently\nconnected too with electricity and galvanism; and perhaps, through\nthese, with magnetism: it is, as has already been mentioned,\nindispensably necessary to the healthy discharge of the functions\nof vegetable life; without it plants cannot duly exercise their\nvital powers: it manifests also chemical action in various ways.\n\nThe luminiferous _ether_ then, if we so call the medium in which\nlight is propagated, must possess many other properties besides\nthose mechanical ones on which the illuminating power depends. It\nmust not be merely like a fluid poured into the vacant spaces and\ninterstices of the material world, and exercising no action on\nobjects; it must affect the physical, chemical and vital powers of\nwhat it touches. It must be a great and active agent in the work\nof the universe, as well as an active reporter of what is done\nby other agents. It must possess a number of complex and refined\ncontrivances and adjustments which we cannot analyze, bearing upon\nplants and chemical compounds, and the imponderable agents; as well\nas those laws which we conceive that we have analyzed, by which it\nis the vehicle of illumination and vision.\n\nWe have had occasion to point out how complex is the machinery of\nthe atmosphere, and how varied its objects; since, besides being\nthe means of communication as the medium of sound, it has known\nlaws which connect it with heat and moisture; and other laws, in\nvirtue of which it is decomposed by vegetables. It appears, in\nlike manner, that the ether is not only the vehicle of light,\nbut has also laws, at present unknown, which connect it with\nheat, electricity, and other agencies; and other laws through\nwhich it is necessary to vegetables, enabling them to decompose\nair. All analogy leads us to suppose that if we knew as much of\nthe constitution of the luminiferous ether as we know of the\nconstitution of the atmosphere, we should find it a machine as\ncomplex and artificial, as skilfully and admirably constructed.\n\nWe know at present very little indeed of the construction of this\nmachine. Its _existence_ is, perhaps, satisfactorily made out;\nin order that we may not interrupt the progress of our argument,\nwe shall refer to other works for the reasonings which appear to\nlead to this conclusion. But whether heat, electricity, galvanism,\nmagnetism, be fluids; or effects or modifications of fluids; and\nwhether such fluids or _ethers_ be the same with the luminiferous\nether, or with each other; are questions of which all or most\nappear to be at present undecided, and it would be presumptuous and\npremature here to take one side or the other.\n\nThe mere fact, however, that there is such an ether, and that\nit has properties related to other agents, in the way we have\nsuggested, is well calculated to extend our views of the structure\nof the universe, and of the resources, if we may so speak, of the\nPower by which it is arranged. The solid and fluid matter of the\nearth is the most obvious to our senses; over this, and in its\ncavities, is poured an invisible fluid, the air, by which warmth\nand life are diffused and fostered, and by which men communicate\nwith men: over and through this again, and reaching, so far as we\nknow, to the utmost bounds of the universe, is spread another most\nsubtle and attenuated fluid, which, by the play of another set of\nagents, aids the energies of nature, and which, filling all parts\nof space, is a means of communication with other planets and other\nsystems.\n\nThere is nothing in all this like any material necessity,\ncompelling the world to be as it is and no otherwise. How should\nthe properties of these three great classes of agents, visible\nobjects, air, and light, so harmonize and assist each other, that\norder and life should be the result. Without all the three, and\nall the three constituted in their present manner, and subject to\ntheir present laws, living things could not exist. If the earth had\nno atmosphere, or if the world had no ether, all must be inert and\ndead. Who constructed these three extraordinary complex pieces of\nmachinery, the earth with its productions, the atmosphere, and the\nether? Who fitted them into each other in many parts, and thus made\nit possible for them to work together? We conceive there can be but\none answer; a most wise and good God.\n\n\n\n\nCHAPTER XVIII.\n\n_Recapitulation._\n\n\n1. It has been shown in the preceding chapters that a great number\nof quantities and laws appear to have been _selected_ in the\nconstruction of the universe; and that by the adjustment to each\nother of the magnitudes and laws thus selected, the constitution\nof the world is what we find it, and is fitted for the support\nof vegetables and animals, in a manner in which it could not have\nbeen, if the properties and quantities of the elements had been\ndifferent from what they are. We shall here recapitulate the\nprincipal of the laws and magnitudes to which this conclusion has\nbeen shown to apply.\n\n  1. The Length of the Year, which depends on the force of the\n  attraction of the sun, and its distance from the earth.\n\n  2. The Length of the Day.\n\n  3. The Mass of the Earth, which depends on its magnitude and\n  density.\n\n  4. The Magnitude of the Ocean.\n\n  5. The Magnitude of the Atmosphere.\n\n  6. The Law and Rate of the Conducting Power of the Earth.\n\n  7. The Law and Rate of the Radiating Power of the Earth.\n\n  8. The Law and Rate of the Expansion of Water by Heat.\n\n  9. The Law and Rate of the Expansion of Water by Cold, below 40\n  degrees.\n\n  10. The Law and Quantity of the Expansion of Water in Freezing.\n\n  11. The Quantity of Latent Heat absorbed in Thawing.\n\n  12. The Quantity of Latent Heat absorbed in Evaporation.\n\n  13. The Law and Rate of Evaporation with regard to Heat.\n\n  14. The Law and Rate of the Expansion of Air by Heat.\n\n  15. The Quantity of Heat absorbed in the Expansion of Air.\n\n  16. The Law and Rate of the Passage of Aqueous Vapour through Air.\n\n  17. The Laws of Electricity; its relations to Air and Moisture.\n\n  18. The Fluidity, Density, and Elasticity of the Air, by means of\n  which its vibrations produce Sound.\n\n  19. The Fluidity, Density, and Elasticity of the Ether, by means\n  of which its vibrations produce Light.\n\n2. These are the _data_, the _elements_, as astronomers call\nthe quantities which determine a planet\u2019s orbit, on which the\nmere _inorganic_ part of the universe is constructed. To these,\nthe constitution of the organic world is adapted in innumerable\npoints, by laws of which we can trace the results, though we cannot\nanalyze their machinery. Thus, the vital functions of vegetables\nhave periods which correspond to the length of the year, and of\nthe day; their vital powers have forces which correspond to the\nforce of gravity; the sentient faculties of man are such that\nthe vibrations of air (within certain limits,) are perceived as\nsound, those of ether, as light. And while we are enumerating these\ncorrespondencies, we perceive that there are thousands of others,\nand that we can only select a very small number of those where\nthe relation happens to be most clearly made out or most easily\nexplained.\n\nNow, in the list of the mathematical _elements_ of the universe\nwhich has just been given, why have we such laws and such\nquantities as there occur, and no other? For the most part, the\ndata there enumerated are independent of each other, and might be\naltered separately, so far as the mechanical conditions of the case\nare concerned. Some of these data probably depend on each other.\nThus the latent heat of aqueous vapour is perhaps connected with\nthe difference of the rate of expansion of water and of steam. But\nall natural philosophers will, probably, agree, that there must be,\nin this list, a great number of things entirely without any mutual\ndependence, as the year and the day, the expansion of air and the\nexpansion of steam. There are, therefore, it appears, a number\nof things which, in the structure of the world, might have been\notherwise, and which are what they are in consequence of choice or\nof chance. We have already seen, in many of the cases separately,\nhow unlike chance every thing looks:--that substances, which might\nhave existed any how, so far as they themselves are concerned,\nexist exactly in such a manner and measure as they should, to\nsecure the welfare of other things:--that the laws are tempered\nand fitted together in the only way in which the world could have\ngone on, according to all that we can conceive of it. This must,\ntherefore, be the work of choice; and if so, it cannot be doubted,\nof a most wise and benevolent Chooser.\n\n3. The appearance of choice is still further illustrated by the\nvariety as well as the number of the laws selected. The laws are\nunlike one another. Steam certainly expands at a very different\n_rate_ from air by the application of heat, probably according to a\ndifferent _law_: water expands in freezing, but mercury contracts:\nheat travels in a manner quite different through solids and fluids.\nEvery separate substance has its own density, gravity, cohesion,\nelasticity, its relations to heat, to electricity, to magnetism;\nbesides all its chemical affinities, which form an endless throng\nof laws, connecting every one substance in creation with every\nother, and different for each pair anyhow taken. Nothing can\nlook less like a world formed of atoms operating upon each other\naccording to some universal and inevitable laws, than this does: if\nsuch a system of things be conceivable, it cannot be our system.\nWe have, it may be, fifty simple substances in the world; each of\nwhich is invested with properties, both of chemical and mechanical\naction, altogether different from those of any other substance.\nEvery portion, however minute, of any of these, possesses all\nthe properties of the substance. Of each of these substances\nthere is a certain unalterable quantity in the universe; when\ncombined, their compounds exhibit new chemical affinities, new\nmechanical laws. Who gave these different laws to the different\nsubstances? who proportioned the quantity of each? But suppose\nthis done. Suppose these substances in existence; in contact, in\ndue proportion to each other. Is _this_ a world, or at least our\nworld? No more than the mine and the forest are the ship of war and\nthe factory. These elements, with their constitution perfect, and\ntheir proportion suitable, are still a mere chaos. They must be put\nin their places. They must not be where their own properties would\nplace them. They must be made to assume a particular arrangement,\nor we can have no regular and permanent course of nature. This\narrangement must again have additional peculiarities, or we can\nhave no organic portion of the world. The millions of millions\nof particles which the world contains, must be finished up in\nas complete a manner, and fitted into their places with as much\nnicety, as the most delicate wheel or spring in a piece of human\nmachinery. What are the habits of thought to which it can appear\npossible that this could take place without design, intention,\nintelligence, purpose, knowledge?\n\nIn what has just been said, we have spoken only of the constitution\nof the inorganic part of the universe. The mechanism, if we may\nso call it, of vegetable and animal life, is so far beyond our\ncomprehension, that though some of the same observations might be\napplied to it, we do not dwell upon the subject. We know that in\nthese processes also, the mechanical and chemical properties of\nmatter are necessary, but we know too that these alone will not\naccount for the phenomena of life. There is something more than\nthese. The lowest stage of vitality and irritability appears to\ncarry us beyond mechanism, beyond affinity. All that has been said\nwith regard to the exactness of the adjustments, the combination of\nvarious means, the tendency to continuance, to preservation, is\napplicable with additional force to the organic creation, so far\nas we can perceive the means employed. These, however, belong to a\ndifferent province of the subject, and must be left to other hands.\n\n\n\n\nBOOK II.\n\nCOSMICAL ARRANGEMENTS.\n\n\nWhen we turn our attention to the larger portions of the universe,\nthe sun, the planets, and the earth as one of them, the moon and\nother satellites, the fixed stars and other heavenly bodies;--the\nviews which we obtain concerning their mutual relations,\narrangement and movements, are called, as we have already\nstated, _cosmical_ views. These views will, we conceive, afford\nus indications of the wisdom and care of the Power by which the\nobjects which we thus consider, were created and are preserved: and\nwe shall now proceed to point out some circumstances in which these\nattributes may be traced.\n\nIt has been observed by writers on Natural Theology, that the\narguments for the being and perfections of the Creator, drawn\nfrom cosmical considerations, labour under some disadvantages\nwhen compared with the arguments founded on those provisions\nand adaptations which more immediately affect the well-being of\norganized creatures. The structure of the solar system has far less\nanalogy with such machinery as we can construct and comprehend,\nthan we find in the structure of the bodies of animals, or even in\nthe causes of the weather. Moreover, we do not see the immediate\nbearing of cosmical arrangements on that end which we most readily\nacknowledge to be useful and desirable, the support and comfort\nof sentient natures. So that, from both causes, the impression of\nbenevolent design in this case is less striking and pointed than\nthat which results from the examination of some other parts of\nnature.\n\nBut in considering the universe, according to the view we have\ntaken, as a collection of _laws_, astronomy, the science which\nteaches us the laws of the motions of the heavenly bodies,\npossesses some advantages, among the subjects from which we may\nseek to learn the character of the government of the world. For our\nknowledge of the laws of the motions of the planets and satellites\nis far more complete and exact, far more thorough and satisfactory,\nthan the knowledge which we possess in any other department of\nNatural Philosophy. Our acquaintance with the laws of the solar\nsystem is such, that we can calculate the precise place and motion\nof most of its parts at any period, past or future, however\nremote; and we can refer the changes which take place in these\ncircumstances to their proximate cause, the attraction of one mass\nof matter to another, acting between all the parts of the universe.\n\nIf, therefore, we trace indications of the Divine care, either in\nthe form of the laws which prevail among the heavenly bodies, or\nin the arbitrary quantities which such laws involve; (according\nto the distinction explained in the former part of this work;) we\nmay expect that our examples of such care, though they may be less\nnumerous and obvious, will be more precise than they can be in\nother subjects, where the laws of facts are imperfectly known, and\ntheir causes entirely hid. We trust that this will be found to be\nthe case with regard to some of the examples which we shall adduce.\n\n\n\n\nCHAPTER I.\n\n_The Structure of the Solar System._\n\n\nIn the cosmical considerations which we have to offer, we shall\nsuppose the general truths concerning the structure of the solar\nsystem and of the universe, which have been established by\nastronomers and mathematicians, to be known to the reader. It is\nnot necessary to go into much detail on this subject. The five\nplanets known to the ancients, Mercury, Venus, Mars, Jupiter,\nSaturn, revolve round the sun, at different distances, in orbits\nnearly circular, and nearly in one plane. Between Venus and Mars,\nour Earth, herself one of the planets, revolves in like manner.\nBeyond Saturn, Uranus has been discovered describing an orbit of\nthe same kind; and between Mars and Jupiter, four smaller bodies\nperform their revolutions in orbits somewhat less regular than\nthe rest. These planets are all nearly globular, and all revolve\nupon their axis. Some of them are accompanied by satellites, or\nattendant bodies which revolve about them; and these bodies also\nhave their orbits nearly circular, and nearly in the same plane as\nthe others. Saturn\u2019s ring is a solitary example, so far as we know,\nof such an appendage to a planet.\n\nThese circular motions of the planets round the sun, and of the\nsatellites round their primary planets, are all kept going by the\n_attraction_ of the respective central bodies, which restrains the\ncorresponding revolving bodies from flying off. It is perhaps not\nvery easy to make this operation clear to common apprehension. We\ncannot illustrate it by a comparison with any machine of human\ncontrivance and fabrication: in such machines every thing goes\non by contact and impulse: pressure, and force of all kinds, is\nexercised and transferred from one part to another, by means of a\nmaterial connexion; by rods, ropes, fluids, gases. In the machinery\nof the universe there is, so far as we know, no material connexion\nbetween the parts which act on each other. In the solar system no\npart touches or drives another: all the bodies affect each other\n_at a distance_, as the magnet affects the needle. The production\nand regulation of such effects, if attempted by our mechanicians,\nwould require great skill and nicety of adjustment; but our artists\nhave not executed any examples of this sort of machinery, by\nreference to which we can illustrate the arrangements of the solar\nsystem.\n\nPerhaps the following comparison may serve to explain the kind of\nadjustments of which we shall have to speak. If there be a wide\nshallow round basin of smooth marble, and if we take a smooth ball,\nas a billiard ball or a marble pellet, and throw it along the\nsurface of the inside of the basin, the ball will generally make\nmany revolutions round the inside of the bowl, gradually tending to\nthe bottom in its motion. The gradual diminution of the motion, and\nconsequent tendency of the ball to the bottom of the bowl, arises\nfrom the friction; and in order to make the motion correspond to\nthat which takes place through the action of a central force,\nwe must suppose this friction to be got rid of. In this case,\nthe ball, once set a going, would run round the basin for ever,\ndescribing either a circle, or various kinds of ovals, according to\nthe way in which it was originally thrown; whether quick or slow,\nand whether more or less obliquely along the surface.\n\nSuch a motion would be capable of the same kind of variety, and the\nsame sort of adjustments, as the motion of a body revolving about\na larger one by means of a central force. Perhaps the reader may\nunderstand what kind of adjustments these are, by supposing such a\nbowl and ball to be used for a game of skill. If the object of the\nplayers be to throw the pellet along the surface of the basin, so\nthat after describing its curved path it shall pass through a small\nhole in a barrier at some distance from the starting point, it will\neasily be understood that some nicety in the regulation of the\nforce and direction with which the ball is thrown will be necessary\nfor success. In order to obtain a better image of the solar system,\nwe must suppose the basin to be very large and the pellet very\nsmall. And it will easily be understood that as many pellets as\nthere are planets might run round the bowl at the same time with\ndifferent velocities. Such a contrivance might form a _planetarium_\nin which the mimic planets would be regulated by the laws of motion\nas the real planets are; instead of being carried by wires and\nwheels, as is done in such machines of the common construction:\nand in this planetarium the tendency of the planets to the sun is\nreplaced by the tendency of the representative pellets to run down\nthe slope of the bowl. We shall refer again to this basin, thus\nrepresenting the solar system with its loose planetary balls.\n\n\n\n\nCHAPTER II.\n\n_The Circular Orbits of the Planets round the Sun._\n\n\nThe orbit which the earth describes round the sun is very nearly\na circle: the sun is about one thirtieth nearer to us in winter\nthan in summer. This nearly circular form of the orbit, on a little\nconsideration, will appear to be a remarkable circumstance.\n\nSupposing the attraction of a planet towards the sun to exist, if\nthe planet were put in motion in any part of the solar system, it\nwould describe about the sun an orbit _of some kind_; it might\nbe a long oval, or a shorter oval, or an exact circle. But if\nwe suppose the result left to chance, the chances are infinitely\nagainst the last mentioned case. There is but one circle; there\nare an infinite number of ovals. Any original impulse would give\nsome oval, but only one particular impulse, determinate in velocity\nand direction, will give a circle. If we suppose the planet to be\noriginally _projected_, it must be projected perpendicularly to\nits distance from the sun, and with a certain precise velocity, in\norder that the motion may be circular.\n\nIn the basin to which we have compared the solar system, the\nadjustment requisite to produce circular motion would require us\nto project our pellet so that after running half round the surface\nit should touch a point exactly at an equal distance from the\ncentre, on the other side, passing neither too high nor too low.\nAnd the pellet, it may be observed, should be in size only one\nten thousandth part of the distance from the centre, to make the\ndimensions correspond with the cast of the earth\u2019s orbit. If the\nmark were set up and hit, we should hardly attribute the result to\nchance.\n\nThe earth\u2019s orbit, however, is not exactly a circle. The mark is\nnot precisely a single point, but is a space of the breadth of one\nthirtieth of the distance from the centre. Still this is much too\nnear an agreement with the circle to be considered as the work of\nchance. The chances were great against the ball passing so nearly\nat the same distance, for there were twenty-nine equal spaces\nthrough which it might have gone, between the mark and the centre,\nand an indefinite number outside the mark.\n\nBut it is not the earth\u2019s orbit alone which is nearly a circle:\nthe rest of the planets also approach very nearly to that form:\nVenus more nearly still than the earth: Jupiter, Saturn, and Uranus\nhave a difference of about one tenth, between their greatest and\nleast distances from the sun: Mars has his extreme distances in the\nproportion of five to six nearly; and Mercury in the proportion of\ntwo to three. The last mentioned case is a considerable deviation,\nand two of the small planets which lie between Mars and Jupiter,\nnamely Juno and Pallas, exhibit an inequality somewhat greater\nstill; but the smallness of these bodies, and other circumstances,\nmake it probable that there may be particular causes for the\nexception in their case. The orbits of the satellites of the Earth,\nof Jupiter and of Saturn, are also nearly circular.\n\nTaking the solar system altogether, the regularity of its structure\nis very remarkable. The diagram which represents the orbits of the\nplanets might have consisted of a number of ovals, narrow and wide\nin all degrees, intersecting and interfering with each other in\nall directions. The diagram does consist, as all who have opened a\nbook of astronomy know, of a set of figures which appear at first\nsight concentric circles, and which are very nearly so; no where\napproaching to any crossing or interfering, except in the case of\nthe small planets, already noticed as irregular. No one, looking at\nthis common diagram, can believe that the orbits were made to be\nso nearly circles by chance; any more than he can believe that a\ntarget, such as archers are accustomed to shoot at, was painted in\nconcentric circles by the accidental dashes of a brush in the hands\nof a blind man.\n\nThe regularity, then, of the solar system excludes the notion of\naccident in the arrangement of the orbits of the planets. There\nmust have been an express adjustment to produce this circular\ncharacter of the orbits. The velocity and direction of the motion\nof each planet must have been subject to some original regulation;\nor, as it is often expressed, the projectile force must have been\naccommodated to the centripetal force. This once done, the motion\nof each planet, taken by itself, would go on for ever, still\nretaining its circular character, by the laws of motion.\n\nIf some original cause adjusted the orbits of the planets to\ntheir circular form and regular arrangement, we can hardly avoid\nincluding in our conception of this cause, the intention and will\nof a Creating Power. We shall consider this argument more fully\nin a succeeding chapter; only observing here, that the presiding\nIntelligence, which has selected and combined the properties of the\norganic creation, so that they correspond so remarkably with the\narbitrary quantities of the system of the universe, may readily\nbe conceived also to have selected the arbitrary velocity and\ndirection of each planet\u2019s motion, so that the adjustment should\nproduce a close approximation to a circular motion.\n\nWe have argued here only from the _regularity_ of the solar\nsystem; from the selection of the single symmetrical case and the\nrejection of all the unsymmetrical cases. But this subject may be\nconsidered in another point of view. The system thus selected is\nnot only regular and symmetrical, but also it is, so far as we can\njudge, the only one which would answer the purpose of the earth,\nperhaps of the other planets, as the seat of animal and vegetable\nlife. If the earth\u2019s orbit were more eccentric, as it is called,\nif for instance the greatest and least distances were as three\nto one, the inequality of heat at two seasons of the year would\nbe destructive to the existing species of living creatures. A\ncircular, or nearly circular, orbit, is the only case in which we\ncan have a course of seasons such as we have at present, the only\ncase in which the climates of the northern and southern hemispheres\nare nearly the same; and what is more clearly important, the only\ncase in which the character of the seasons would not vary from\ncentury to century. For if the eccentricity of the earth\u2019s orbit\nwere considerable, the difference of heat at different seasons,\narising from the different distances of the sun, would be combined\nwith the difference, now the only considerable one, which depends\non the position of the earth\u2019s axis. And as by the motion of\nthe _perihelion_, or place of the nearest distance of the earth\nto the sun, this nearest distance would fall in different ages\nat different parts of the year, the whole distribution of heat\nthrough the year would thus be gradually subverted. The summer and\nwinter of the _tropical_ year, as we have it now, being combined\nwith the heat and cold of the _anomalistic_ year, a period of\ndifferent length, the difference of the two seasons might sometimes\nbe neutralized altogether, and at other times exaggerated by the\naccumulation of the inequalities, so as to be intolerable.\n\nThe circular form of the orbit therefore, which, from its unique\ncharacter, appears to be chosen with _some_ design, from its\neffects on the seasons appears to be chosen with this design,\nso apparent in other parts of creation, of securing the welfare\nof organic life, by a steadfast and regular order of the solar\ninfluence upon the planet.\n\n\n\n\nCHAPTER III.\n\n_The Stability of the Solar System._\n\n\nThere is a consequence resulting from the actual structure of the\nsolar system, which has been brought to light by the investigations\nof mathematicians concerning the cause and laws of its motions, and\nwhich has an important bearing on our argument. It appears that the\narrangement which at present obtains is precisely that which is\nnecessary to secure the _stability_ of the system. This point we\nmust endeavour to explain.\n\nIf each planet were to revolve round the sun without being affected\nby the other planets, there would be a certain degree of regularity\nin its motion; and this regularity would continue for ever. But it\nappears, by the discovery of the law of universal gravitation,\nthat the planets do not execute their movements in this insulated\nand independent manner. Each of them is acted on by the attraction\nof all the rest. The Earth is constantly drawn by Venus, by Mars,\nby Jupiter, bodies of various magnitudes, perpetually changing\ntheir distances and positions with regard to the earth; the Earth\nin return is perpetually drawing these bodies. What, in the course\nof time, will be the result of this mutual attraction?\n\nAll the planets are very small compared with the sun, and therefore\nthe derangement which they produce in the motion of one of their\nnumber will be very small in the course of one revolution. But this\ngives us no security that the derangement may not become very large\nin the course of many revolutions. The cause acts perpetually,\nand it has the whole extent of time to work in. Is it not easily\nconceivable then that in the lapse of ages the derangements of\nthe motions of the planets may accumulate, the orbits may change\ntheir form, their mutual distances may be much increased or much\ndiminished? Is it not possible that these changes may go on without\nlimit, and end in the complete subversion and ruin of the system?\n\nIf, for instance, the result of this mutual gravitation should be\nto increase considerably the eccentricity of the earth\u2019s orbit,\nthat is to make it a longer and longer oval; or to make the moon\napproach perpetually nearer and nearer the earth every revolution;\nit is easy to see that in the one case our year would change its\ncharacter, as we have noticed in the last section; in the other,\nour satellite might finally fall to the earth, which must of\ncourse bring about a dreadful catastrophe. If the positions of\nthe planetary orbits, with respect to that of the earth, were to\nchange much, the planets might sometimes come very near us, and\nthus exaggerate the effects of their attraction beyond calculable\nlimits. Under such circumstances, we might have \u201cyears of unequal\nlength, and seasons of capricious temperature, planets and moons of\nportentous size and aspect, glaring and disappearing at uncertain\nintervals;\u201d tides like deluges, sweeping over whole continents;\nand, perhaps, the collision of two of the planets, and the\nconsequent destruction of all organization on both of them.\n\nNor is it, on a common examination of the history of the solar\nsystem, at all clear that there is no tendency to indefinite\nderangement. The fact really is, that changes are taking place\nin the motions of the heavenly bodies, which have gone on\nprogressively from the first dawn of science. The eccentricity\nof the earth\u2019s orbit has been diminishing from the earliest\nobservations to our times. The moon has been moving quicker and\nquicker from the time of the first recorded eclipses, and is now\nin advance, by about four times her own breadth, of what her place\nwould have been if it had not been affected by this acceleration.\nThe obliquity of the ecliptic also is in a state of diminution, and\nis now about two-fifths of a degree less than it was in the time\nof Aristotle. Will these changes go on without limit or reaction?\nIf so, we tend by natural causes to a termination of the present\nsystem of things: If not, by what adjustment or combination are we\nsecured from such a tendency? Is the system _stable_, and if so,\nwhat is the condition on which its stability depends?\n\nTo answer these questions is far from easy. The mechanical problem\nwhich they involve is no less than this;--Having given the\ndirections and velocities with which about thirty bodies are moving\nat one time, to find their places and motions after any number of\nages; each of the bodies, all the while, attracting all the others,\nand being attracted by them all.\n\nIt may readily be imagined that this is a problem of extreme\ncomplexity, when it is considered that every new _configuration_\nor arrangement of the bodies will give rise to a new amount of\naction on each; and every new action to a new configuration.\nAccordingly, the mathematical investigation of such questions as\nthe above was too difficult to be attempted in the earlier periods\nof the progress of Physical Astronomy. Newton did not undertake to\ndemonstrate either the stability or the instability of the system.\nThe decision of this point required a great number of preparatory\nsteps and simplifications, and such progress in the invention\nand improvement of mathematical methods, as occupied the best\nmathematicians of Europe for the greater part of last century.\nBut, towards the end of that time, it was shown by Lagrange and\nLaplace that the arrangements of the solar system are stable: that\nin the long run, the orbits and motions remain unchanged; and that\nthe changes in the orbits, which take place in shorter periods,\nnever transgress certain very moderate limits. Each orbit undergoes\ndeviations on this side and on that of its average state; but these\ndeviations are never very great, and it finally recovers from them,\nso that the average is preserved. The planets produce perpetual\nperturbations in each other\u2019s motions, but these perturbations\nare not indefinitely progressive, they are periodical: they reach\na _maximum_ value and then diminish. The periods which this\nrestoration requires are, for the most part, enormous; not less\nthan thousands, and, in some instances, millions of years; and\nhence it is, that some of these apparent derangements have been\ngoing on in the same direction since the beginning of the history\nof the world. But the restoration is in the sequel as complete as\nthe derangement; and in the meantime the disturbance never attains\na sufficient amount seriously to alter the adaptations of the\nsystem.[17]\n\nThe same examination of the subject by which this is proved, points\nout also the conditions on which this stability depends. \u201cI have\nsucceeded in demonstrating,\u201d says Laplace, \u201cthat whatever be the\nmasses of the planets, in consequence of the fact that they all\nmove in the same direction, in orbits of small eccentricity, and\nslightly inclined to each other--their secular inequalities are\nperiodical and included within narrow limits; so that the planetary\nsystem will only oscillate about a mean state, and will never\ndeviate from it except by a very small quantity. The ellipses of\nthe planets have been, and always will be, nearly circular. The\necliptic will never coincide with the equator, and the entire\nextent of the variation in its inclination cannot exceed three\ndegrees.\u201d\n\nThere exists, therefore, it appears, in the solar system, a\nprovision for the permanent regularity of its motions; and this\nprovision is found in the fact that the orbits of the planets are\nnearly circular, and nearly in the same plane, and the motions all\nin the same direction, namely, from west to east.[18]\n\nNow is it probable that the occurrence of these conditions of\nstability in the disposition of the solar system is the work of\nchance? Such a supposition appears to be quite inadmissible. Any\none of the orbits might have had any eccentricity.[19] In that\nof Mercury, where it is much the greatest, it is only one-fifth.\nHow came it to pass that the orbits were not more elongated? A\nlittle more or a little less velocity in their original motions\nwould have made them so. They might have had any inclination to\nthe ecliptic from _no_ degrees to 90 degrees. Mercury, which again\ndeviates most widely, is inclined 7\u00be degrees, Venus 3\u00be, Saturn\n2\u00be, Jupiter 1\u00bd, Mars 2. How came it that their motions are thus\ncontained within such a narrow strip of the sky? One, or any number\nof them, might have moved from east to west: none of them does so.\nAnd these circumstances, which appear to be, each in particular,\nrequisite for the stability of the system and the smallness of its\ndisturbances, are all found in combination. Does not this imply\nboth clear purpose and profound skill?\n\nIt is difficult to convey an adequate notion of the extreme\ncomplexity of the task thus executed. A number of bodies, all\nattracting each other, are to be projected in such a manner that\ntheir revolutions shall be permanent and stable, their mutual\nperturbations always small. If we return to the basin with its\nrolling balls, by which we before represented the solar system, we\nmust complicate with new conditions the trial of skill which we\nsupposed. The problem must now be to project at once seven such\nballs, all connected by strings which influence their movements, so\nthat each may hit its respective mark. And we must further suppose,\nthat the marks are to be hit after many thousand revolutions of the\nballs. No one will imagine that this could be done by accident.\n\nIn fact it is allowed by all those who have considered this\nsubject, that such a coincidence of the existing state with the\nmechanical requisites of permanency cannot be accidental. Laplace\nhas attempted to calculate the probability that it is not the\nresult of accident. He takes into account, in addition to the\nmotions which we have mentioned, the revolutions of the satellites\nabout their primaries, and of the sun and planets about their\naxes: and he finds that there is a probability, far higher than\nthat which we have for the greater part of undoubted historical\nevents, that these appearances are not the effect of chance. \u201cWe\nought, therefore,\u201d he says, \u201cto believe, with at least the same\nconfidence, that a primitive cause has directed the planetary\nmotions.\u201d\n\nThe solar system is thus, by the confession of all sides,\ncompletely different from any thing which we might anticipate from\nthe casual operation of its known laws. The laws of motion are no\nless obeyed to the letter in the most irregular than in the most\nregular motions; no less in the varied circuit of the ball which\nflies round a tennis court, than in the going of a clock; no less\nin the fantastical jets and leaps which breakers make when they\nburst in a corner of a rocky shore, than in the steady swell of the\nopen sea. The laws of motion alone will not produce the regularity\nwhich we admire in the motions of the heavenly bodies. There must\nbe an original adjustment of the system on which these laws are\nto act; a selection of the arbitrary quantities which they are to\ninvolve; a primitive cause which shall dispose the elements in\ndue relation to each other, in order that regular recurrence may\naccompany constant change; that perpetual motion may be combined\nwith perpetual stability; that derangements which go on increasing\nfor thousands or for millions of years may finally cure themselves;\nand that the same laws which lead the planets slightly aside from\ntheir paths, may narrowly limit their deviations, and bring them\nback from their almost imperceptible wanderings.\n\nIf a man does not deny that any possible peculiarity in the\ndisposition of the planets with regard to the sun could afford\nevidence of a controlling and ordering purpose, it seems difficult\nto imagine how he could look for evidence stronger than that\nwhich there actually is. Of all the innumerable possible cases of\nsystems, governed by the existing laws of force and motion, that\none is selected which alone produces such a steadfast periodicity,\nsuch a constant average of circumstances, as are, so far as we can\nconceive, necessary conditions for the existence of organic and\nsentient life. And this selection is so far from being an obvious\nor easily discovered means to this end, that the most profound and\nattentive consideration of the properties of space and number, with\nall the appliances and aids we can obtain, are barely sufficient to\nenable _us_ to see that the end is thus secured, and that it can be\nsecured in no other way. Surely the obvious impression which arises\nfrom this view of the subject is, that the solar system, with\nits adjustments, is the work of an intelligence, who perceives,\nas self-evident, those truths, to which we attain painfully and\nslowly, and after all imperfectly; who has employed in every part\nof creation refined contrivances, which we can only with effort\nunderstand; and who, in innumerable instances, exhibits to us what\nwe should look upon as remarkable difficulties remarkably overcome,\nif it were not that, through the perfection of the provision, the\ntrace of the difficulty is almost obliterated.\n\n\n\n\nCHAPTER IV.\n\n_The Sun in the Centre._\n\n\nThe next circumstance which we shall notice as indicative of design\nin the arrangement of the material portions of the solar system,\nis the position of the sun, the source of light and heat, in the\ncentre of the system. This could hardly have occurred by any\nthing which we can call chance. Let it be granted, that the law of\ngravitation is established, and that we have a large mass, with\nothers much smaller in its comparative vicinity. The small bodies\nmay then move round the larger, but this will do nothing towards\nmaking it a _sun_ to them. Their motions might take place, the\nwhole system remaining still utterly dark and cold, without day or\nsummer. In order that we may have something more than this blank\nand dead assemblage of moving clods, the machine must be lighted\nup and warmed. Some of the advantages of placing the lighting\nand warming apparatus in the centre are obvious to us. It is in\nthis way only that we could have those regular periodical returns\nof solar influence, which, as we have seen, are adapted to the\nconstitution of the living creation. And we can easily conceive,\nthat there may be other incongruities in a system with a travelling\nsun, of which we can only conjecture the nature. No one probably\nwill doubt that the existing system, with the sun in the centre, is\nbetter than any one of a different kind would be.\n\nNow this lighting and warming by a central sun are something\nsuperadded to the mere mechanical arrangements of the universe.\nThere is no apparent reason why the largest mass of gravitating\nmatter should diffuse inexhaustible supplies of light and heat in\nall directions, while the other masses are merely passive, with\nrespect to such influences. There is no obvious connexion between\nmass and luminousness, or temperature. No one, probably, will\ncontend that the materials of our system are necessarily luminous\nor hot. According to the conjectures of astronomers, the heat and\nlight of the sun do not reside in its mass, but in a coating which\nlies on its surface. If such a coating were fixed there by the\nforce of universal gravitation, how could we avoid having a similar\ncoating on the surface of the earth, and of all the other globes of\nthe system. If light consist in the vibrations of an ether, which\nwe have mentioned as a probable opinion, why has the sun alone the\npower of exciting such vibrations? If light be the emission of\nmaterial particles, why does the sun alone emit such particles?\nSimilar questions may be asked, with regard to heat, whatever be\nthe theory we adopt on that subject. Here then we appear to find\nmarks of contrivance. The sun might become, we will suppose, the\ncentre of the motions of the planets by mere mechanical causes:\nbut what caused the centre of their motions to be also the source\nof those vivifying influences? Allowing that no interposition was\nrequisite to regulate the revolutions of the system, yet observe\nwhat a peculiar arrangement in other respects was necessary, in\norder that these revolutions might produce days and seasons! The\nmachine will move of itself, we may grant: but who constructed the\nmachine, so that its movements might answer the purposes of life?\nHow was the candle placed upon the candlestick? How was the fire\ndeposited on the hearth, so that the comfort and well-being of the\nfamily might be secured? Did these too fall into their places by\nthe casual operation of gravity? And, if not, is there not here\na clear evidence of intelligent design, of arrangement with a\nbenevolent end?\n\nThis argument is urged with great force by Newton himself. In his\nfirst letter to Bentley, he allows that matter might form itself\ninto masses by the force of attraction. \u201cAnd thus,\u201d says he, \u201cmight\nthe sun and fixed stars be formed, supposing the matter were of\na lucid nature. But how the matter should divide itself into two\nsorts; and that part of it which is fit to compose a shining body\nshould fall down into one mass, and make a sun; and the rest, which\nis fit to compose an opaque body, should coalesce, not into one\ngreat body, like the shining matter, but into many little ones; or\nif the sun at first were an opake body like the planets, or the\nplanets lucid bodies like the sun, how he alone should be changed\ninto a shining body, whilst all they continue opake; or all they\nbe changed into opake ones, while he continued unchanged: I do not\nthink explicable by mere natural causes, but am forced to ascribe\nit to the counsel and contrivance of a voluntary Agent.\u201d\n\n\n\n\nCHAPTER V.\n\n_The Satellites._\n\n\n1. A person of ordinary feelings, who, on a fine moonlight night,\nsees our satellite pouring her mild radiance on field and town,\npath and moor, will probably not only be disposed to \u201cbless the\nuseful light,\u201d but also to believe that it was \u201cordained\u201d for that\npurpose;--that the lesser light was made to rule the night as\ncertainly as the greater light was made to rule the day.\n\nLaplace, however, does not assent to this belief. He observes,\nthat \u201csome partisans of final causes have imagined that the moon\nwas given to the earth to afford light during the night:\u201d but he\nremarks that this cannot be so, for that we are often deprived at\nthe same time of the light of the sun and the moon; and he points\nout how the moon might have been placed so as to be always \u201cfull.\u201d\n\nThat the light of the moon affords, _to a certain extent_, a\nsupplement to the light of the sun, will hardly be denied. If\nwe take man in a condition in which he uses artificial light\nscantily only, or not at all, there can be no doubt that the\nmoonlight nights are for him a very important addition to the time\nof daylight. And as a small proportion only of the whole number\nof nights are without some portion of moonlight, the fact that\nsometimes both luminaries are invisible very little diminishes the\nvalue of this advantage. Why we have not more moonlight, either in\nduration or in quantity, is an inquiry which a philosopher could\nhardly be tempted to enter upon, by any success which has attended\nprevious speculations of a similar nature. Why should not the moon\nbe ten times as large as she is? Why should not the pupil of man\u2019s\neye be ten times as large as it is, so as to receive more of the\nlight which does arrive? We do not conceive that our inability\nto answer the latter question prevents our knowing that the eye\nwas made for seeing: nor does our inability to answer the former,\ndisturb our persuasion that the moon was made to give light upon\nthe earth.\n\nLaplace suggests that if the moon had been placed at a certain\ndistance beyond the earth, it would have revolved about the sun in\nthe same time as the earth does, and would have always presented\nto us a full moon. For this purpose it must have been about four\ntimes as far from us as it really is; and would therefore, other\nthings remaining unchanged, have only been _one sixteenth_ as\nlarge to the eye as our present full moon. We shall not dwell on\nthe discussion of this suggestion, for the reason just intimated.\nBut we may observe that in such a system as Laplace proposes,\nit is not yet proved, we believe, that the arrangement would be\nstable under the influence of the disturbing forces. And we may add\nthat such an arrangement, in which the motion of one body has a\n_co-ordinate_ reference to two others, as the motion of the moon on\nthis hypothesis would have to the sun and the earth, neither motion\nbeing subordinate to the other, is contrary to the whole known\nanalogy of cosmical phenomena, and therefore has no claim to our\nnotice as a subject of discussion.\n\n2. In turning our consideration to the satellites of the other\nplanets of our system, there is one fact which immediately arrests\nour attention;--the number of such attendant bodies appears to\nincrease as we proceed to planets farther and farther from the\nsun. Such at least is the general rule. Mercury and Venus, the\nplanets nearest the sun, have no such attendants: the Earth has\none. Mars, indeed, who is still farther removed, has none; nor\nhave the minor planets, Juno, Vesta, Ceres, Pallas; so that the\nrule is only approximately verified. But Jupiter, who is at five\ntimes the earth\u2019s distance, has four satellites; and Saturn, who\nis again at a distance nearly twice as great, has seven, besides\nthat most extraordinary phenomenon his ring, which, for purposes of\nillumination, is equivalent to many thousand satellites. Of Uranus\nit is difficult to speak, for his great distance renders it almost\nimpossible to observe the smaller circumstances of his condition.\nIt does not appear at all probable that he has a ring, like Saturn;\nbut he has at least five satellites which are visible to us, at the\nenormous distance of nine hundred millions of miles; and we believe\nthat the astronomer will hardly deny that he may possibly have\nthousands of smaller ones circulating about him.\n\nBut leaving conjecture, and taking only the ascertained cases\nof Venus, the Earth, Jupiter, and Saturn, we conceive that a\nperson of common understanding will be strongly impressed with\nthe persuasion that the satellites are placed in the system\nwith a view to compensate for the diminished light of the sun\nat greater distances. The smaller planets, Juno, Vesta, Ceres,\nand Pallas, differ from the rest in so many ways, and suggest so\nmany conjectures of reasons for such differences, that we should\nalmost expect to find them exceptions to such a rule. Mars is a\nmore obvious exception. Some persons might conjecture from his\ncase, that the arrangement itself, like other useful arrangements,\nhas been brought about by some wider law which we have not yet\ndetected. But whether or not we entertain such a guess, (it can be\nnothing more,) we see in other parts of creation, so many examples\nof apparent exceptions to rules, which are afterwards found to be\nexplained, or provided for by particular contrivances, that no one,\nfamiliar with such contemplations, will, by one anomaly, be driven\nfrom the persuasion that the end which the arrangements of the\nsatellites seem suited to answer is really one of the ends of their\ncreation.\n\n\n\n\nCHAPTER VI.\n\n_The Stability of the Ocean._\n\n\nWhat is meant by the stability of the ocean may perhaps be\nexplained by means of the following illustration. If we suppose\nthe whole globe of the Earth to be composed of water, a sphere\nof cork, immersed in any part of it, would come to the surface\nof the water, except it were placed exactly at the centre of the\nearth; and even if it were the slightest displacement of the cork\nsphere would end in its rising and floating. This would be the case\nwhatever were the size of the cork sphere, and even if it were so\nlarge as to leave comparatively little room for the water; and the\nresult would be nearly the same, if the cork sphere, when in its\ncentral position, had on its surface prominences which projected\nabove the surface of the water. Now this brings us to the case in\nwhich we have a globe resembling our present earth, composed like\nit of water and of a solid centre, with islands and continents,\nbut having these solid parts all made of cork. And it appears by\nthe preceding reasoning, that in this case, if there were any\ndisturbance either of the solid or fluid parts, the solid parts\nwould rise from the centre of the watery sphere as far as they\ncould: that is, all the water would run to one side and leave the\nland on the other. Such an ocean would be in _unstable_ equilibrium.\n\nNow a question naturally occurs, is the equilibrium of our present\nocean of this unstable kind, or is it stable? The sea, after its\nmost violent agitations, appears to return to its former state of\nrepose; but may not some extraordinary cause produce in it some\nderangement which may go on increasing till the waters all rush one\nway, and thus drown the highest mountains? And if we are safe from\nthis danger, what are the conditions by which we are so secured?\n\nThe illustration which we have employed obviously suggests the\nanswer to this question; namely, that the equilibrium is unstable,\nso long as the solid parts are of such a kind as to float in the\nfluid parts; and of course we should expect that the equilibrium\nwill be stable whenever the contrary is the case, that is, when\nthe solid parts of the earth are of greater specific gravity than\nthe sea. A more systematic mathematical calculation has conducted\nLaplace to a demonstration of this result.\n\nThe mean specific gravity of the earth appears to be about _five_\ntimes that of water, so that the condition of the stability of the\nocean is abundantly fulfilled. And the provision by which this\nstability is secured was put in force through the action of those\ncauses, whatever they were, which made the density of the solid\nmaterials and central parts of the earth greater than the density\nof the incumbent fluid.\n\nWhen we consider, however, the manner in which the wisdom of the\nCreator, even in those cases in which his care is most apparent,\nas in the structure of animals, works by means of intermediate\ncauses and general laws, we shall not be ready to reject all belief\nof an end in such a case as this, merely because the means are\nmechanical agencies. Laplace says, \u201cin virtue of gravity, the most\ndense of the strata of the earth are those nearest to the centre;\nand thus the mean density exceeds that of the waters which cover\nit; which suffices to secure the stability of the equilibrium of\nthe seas, and to put a bridle upon the fury of the waves.\u201d This\nstatement, if exact, would not prove that He who subjected the\nmaterials of the earth to the action of gravity did not _intend_\nto restrain the rage of the waters: but the statement is not true\nin fact. The lower strata, so far as man has yet examined, are\nvery far from being constantly, or even generally, heavier than\nthe superincumbent ones. And certainly solidification by no means\nimplies a greater density than fluidity: the density of Jupiter\nis one fourth, that of Saturn less than one seventh, of that of\nthe earth. If an ocean of water were poured into the cavities upon\nthe surface of Saturn, its equilibrium would _not_ be stable. It\nwould leave its bed on one side of the globe; and the planet would\nfinally be composed of one hemisphere of water and one of land.\nIf the Earth had an ocean of a fluid six times as heavy as water,\n(quicksilver is thirteen times as heavy,) we should have, in like\nmanner, a dry and a fluid hemisphere. Our inland rivers would\nprobably never be able to reach the shores, but would be dried up\non their way, like those which run in torrid desarts; perhaps the\nevaporation from the ocean would never reach the inland mountains,\nand we should have no rivers at all. Without attempting to imagine\nthe details of such a condition, it is easy to see, that to secure\nthe existence of a different one is an end which is in harmony with\nall that we see of the preserving care displayed in the rest of\ncreation.[20]\n\n\n\n\nCHAPTER VII.\n\n_The Nebular Hypothesis._\n\n\nWe have referred to Laplace, as a profound mathematician, who has\nstrongly expressed the opinion, that the arrangement by which\nthe stability of the solar system is secured is not the result\nof chance; that \u201c_a primitive cause_ has directed the planetary\nmotions.\u201d This author, however, having arrived, as we have done,\nat this conviction, does not draw from it the conclusion which has\nappeared to us so irresistible, that \u201cthe admirable arrangement\nof the solar system cannot but be the work of an intelligent and\nmost powerful being.\u201d He quotes these expressions, which are\nthose of Newton, and points at them as instances where that great\nphilosopher had deviated from the method of true philosophy.\nHe himself proposes an hypothesis concerning the nature of the\n_primitive cause_ of which he conceives the existence to be thus\nprobable: and this hypothesis, on account of the facts which it\nattempts to combine, the view of the universe which it presents,\nand the eminence of the person by whom it is propounded, deserves\nour notice.\n\n1. Laplace conjectures that in the original condition of the solar\nsystem, the sun revolved upon his axis, surrounded by an atmosphere\nwhich, in virtue of an excessive heat, extended far beyond the\norbits of all the planets, the planets as yet having no existence.\nThe heat gradually diminished, and as the solar atmosphere\ncontracted by cooling, the rapidity of its rotation increased by\nthe laws of rotatory motion, and an exterior zone of vapour was\ndetached from the rest, the central attraction being no longer able\nto overcome the increased centrifugal force. This zone of vapour\nmight in some cases retain its form, as we see it in Saturn\u2019s\nring; but more usually the ring of vapour would break into several\nmasses, and these would generally coalesce into one mass, which\nwould revolve about the sun. Such portions of the solar atmosphere,\nabandoned successively at different distances, would form \u201cplanets\nin the state of vapour.\u201d These planets, it appears from mechanical\nconsiderations, would have each its rotatory motion, and as the\ncooling of the vapour still went on, would each produce a planet,\nwhich might have satellites and rings, formed from the planet in\nthe same manner as the planets were formed from the atmosphere of\nthe sun.\n\nIt may easily be conceived that all the primary motions of a system\nso produced would be nearly circular, nearly in the plane of the\noriginal equator of the solar rotation, and in the direction of\nthat rotation. Reasons are offered also to show that the motions\nof the satellites thus produced and the motions of rotation of the\nplanets must be in the same direction. And thus it is held that the\nhypothesis accounts for the most remarkable circumstances in the\nstructure of the solar system: namely, the motions of the planets\nin the same direction, and almost in the same plane; the motions\nof the satellites in the same direction as those of the planets;\nthe motions of rotation of these different bodies still in the same\ndirection as the other motions, and in planes not much different;\nthe small eccentricity of the orbits of the planets, upon which\ncondition, along with some of the preceding ones, the stability of\nthe system depends; and the position of the source of light and\nheat in the centre of the system.\n\nIt is not necessary for the purpose, nor suitable to the plan\nof the present treatise, to examine, on physical grounds, the\nprobability of the above hypothesis. It is proposed by its author,\nwith great diffidence, as a conjecture only. We might, therefore,\nvery reasonably put off all discussion of the bearings of this\nopinion upon our views of the government of the world, till the\nopinion itself should have assumed a less indistinct and precarious\nform. It can be no charge against our doctrines, that there is\na difficulty in reconciling with them arbitrary guesses and\nhalf-formed theories. We shall, however, make a few observations\nupon this _nebular hypothesis_, as it may be termed.\n\n2. If we grant, for a moment, the hypothesis, it by no means proves\nthat the solar system was formed without the intervention of\nintelligence and design. It only transfers our view of the skill\nexercised, and the means employed, to another part of the work.\nFor, how came the sun and its atmosphere to have such materials,\nsuch motions, such a constitution, that these consequences\nfollowed from their primordial condition? How came the parent\nvapour thus to be capable of coherence, separation, contraction,\nsolidification? How came the laws of its motion, attraction,\nrepulsion, condensation, to be so fixed, as to lead to a beautiful\nand harmonious system in the end? How came it to be neither too\nfluid nor too tenacious, to contract neither too quickly nor too\nslowly, for the successive formation of the several planetary\nbodies? How came that substance, which at one time was a luminous\nvapour, to be at a subsequent period, solids and fluids of many\nvarious kinds? What but design and intelligence prepared and\ntempered this previously existing element, so that it should by its\nnatural changes produce such an orderly system?\n\nAnd if in this way we suppose a planet to be produced, what sort\nof a body would it be?--something, it may be presumed, resembling\na large meteoric stone. How comes this mass to be covered with\nmotion and organization, with life and happiness? What primitive\ncause stocked it with plants and animals, and produced all the\nwonderful and subtle contrivances which we find in their structure,\nall the wide and profound mutual dependencies which we trace in\ntheir economy? Was man, with his thought and feeling, his powers\nand hopes, his will and conscience, also produced as an ultimate\nresult of the condensation of the solar atmosphere? Except we allow\na prior purpose and intelligence presiding over this material\n\u201cprimitive cause,\u201d how irreconcilable is it with the evidence which\ncrowds in upon us from every side!\n\n3. In the next place, we may observe concerning this hypothesis,\nthat it carries us back to the beginning of the present system\nof things; but that it is impossible for our reason to stop at\nthe point thus presented to it. The sun, the earth, the planets,\nthe moons were brought into their present order out of a previous\nstate, and, as is supposed in the theory, by the natural operation\nof laws. But how came that previous state to exist? We are\ncompelled to suppose that it, in like manner, was educed from a\nstill prior state of things; and this, again, must have been the\nresult of a condition prior still. Nor is it possible for us to\nfind, in the tenets of the nebular hypothesis, any resting place or\nsatisfaction for the mind. The same reasoning faculty, which seeks\nfor the origin of the present system of things, and is capable\nof assenting to, or dissenting from the hypothesis propounded\nby Laplace as an answer to this inquiry, is necessarily led to\nseek, in the same manner, for the origin of any previous system\nof things, out of which the present may appear to have grown: and\nmust pursue this train of inquiries unremittingly, so long as the\nanswer which it receives describes a mere assemblage of matter and\nmotion; since it would be to contradict the laws of matter and the\nnature of motion, to suppose such an assemblage to be the _first_\ncondition.\n\nThe reflection just stated, may be illustrated by the further\nconsideration of the Nebular Hypothesis. This opinion refers us,\nfor the origin of the solar system, to a sun surrounded with an\natmosphere of enormously elevated temperature, revolving and\ncooling. But as we ascend to a still earlier period, what state\nof things are we to suppose?--a still higher temperature, a still\nmore diffused atmosphere. Laplace conceives that, in its primitive\nstate, the sun consisted in a diffused luminosity so as to resemble\nthose nebul\u00e6 among the fixed stars, which are seen by the aid of\nthe telescope, and which exhibit a nucleus, more or less brilliant,\nsurrounded by a cloudy brightness. \u201cThis anterior state was itself\npreceded by other states, in which the nebulous matter was more and\nmore diffuse, the nucleus being less and less luminous. We arrive,\u201d\nLaplace says, \u201cin this manner, at a nebulosity so diffuse, that its\nexistence could scarcely be suspected.\u201d\n\n\u201cSuch is,\u201d he adds, \u201cin fact, the first state of the nebul\u00e6 which\nHerschel carefully observed by means of his powerful telescopes.\nHe traced the progress of condensation, not indeed on one nebula,\nfor this progress can only become perceptible to us in the course\nof centuries; but in the assemblage of nebul\u00e6; much in the same\nmanner as in a large forest we may trace the growth of trees among\nthe examples of different ages which stand side by side. He saw in\nthe first place the nebulous matter dispersed in patches, in the\ndifferent parts of the sky. He saw in some of these patches this\nmatter feebly condensed round one or more faint nuclei. In other\nnebul\u00e6, these nuclei were brighter in proportion to the surrounding\nnebulosity; when by a further condensation the atmosphere of each\nnucleus becomes separate from the others, the result is multiple\nnebulous stars, formed by brilliant nuclei very near each other,\nand each surrounded by an atmosphere: sometimes the nebulous matter\ncondensing in a uniform manner has produced nebulous systems\nwhich are called _planetary_. Finally, a still greater degree of\ncondensation transforms all these nebulous systems into stars. The\nnebul\u00e6, classed according to this philosophical view, indicate with\nextreme probability their future transformation into stars, and\nthe anterior nebulous condition of the stars which now exist.\u201d\n\nIt appears then that the highest point to which this series of\nconjectures can conduct us, is, \u201can extremely diffused nebulosity,\u201d\nattended, we may suppose, by a far higher degree of heat, than that\nwhich, at a later period of the hypothetical process, keeps all the\nmaterials of our earth and planets in a state of vapour. Now is it\nnot impossible to avoid asking, whence was this light, this heat,\nthis diffusion? How came the laws which such a state implies, to be\nalready in existence? Whether light and heat produce their effects\nby means of fluid vehicles or otherwise, they have complex and\nvaried laws which indicate the existence of some subtle machinery\nfor their action. When and how was this machinery constructed?\nWhence too that enormous expansive power which the nebulous matter\nis supposed to possess? And if, as would seem to be supposed in\nthis doctrine, all the material ingredients of the earth existed\nin this diffuse nebulosity, either in the state of vapour, or in\nsome state of still greater expansion, whence were they and their\nproperties? how came there to be of each simple substance which\nnow enters into the composition of the universe, just so much and\nno more? Do we not, far more than ever, require an origin of this\norigin? an explanation of this explanation? Whatever may be the\nmerits of the opinion as a physical hypothesis, with which we do\nnot here meddle, can it for a moment prevent our looking beyond\nthe hypothesis, to a First Cause, an Intelligent Author, an origin\nproceeding from free volition, not from material necessity?\n\nBut again: let us ascend to the highest point of the hypothetical\nprogression: let us suppose the nebulosity diffused throughout\nall space, so that its course of running into patches is not yet\nbegun. How are we to suppose it distributed? Is it equably diffused\nin every part? clearly not; for if it were, what should cause it\nto gather into masses, so various in size, form and arrangement?\nThe separation of the nebulous matter into distinct nebul\u00e6 implies\nnecessarily some original inequality of distribution; some\ndetermining circumstances in its primitive condition. Whence were\nthese circumstances? this inequality? we are still compelled to\nseek some ulterior agency and power.\n\nWhy must the primeval condition be one of change at all? Why should\nnot the nebulous matter be equably diffused throughout space, and\ncontinue for ever in its state of equable diffusion, as it must\ndo, from the absence of all cause to determine the time and manner\nof its separation? why should this nebulous matter grow cooler and\ncooler? why should it not retain for ever the same degree of heat,\nwhatever heat be? If heat be a fluid, if to cool be to part with\nthis fluid, as many philosophers suppose, what becomes of the fluid\nheat of the nebulous matter, as the matter cools down? Into what\nunoccupied region does it find its way?\n\nInnumerable questions of the same kind might be asked, and the\nconclusion to be drawn is, that every new physical theory which\nwe include in our view of the universe, involves us in new\ndifficulties and perplexities, if we try to erect it into an\nultimate and final account of the existence and arrangement of\nthe world in which we live. With the evidence of such theories,\nconsidered as scientific generalizations of ascertained facts,\nwith their claims to a place in our natural philosophy, we have\nhere nothing to do. But if they are put forwards as a disclosure\nof the ultimate cause of that which occurs, and as superseding\nthe necessity of looking further or higher; if they claim a place\nin our Natural Theology, as well as our Natural Philosophy;\nwe conceive that their pretensions will not bear a moment\u2019s\nexamination.\n\nLeaving then to other persons and to future ages to decide upon the\nscientific merits of the nebular hypothesis, we conceive that the\nfinal fate of this opinion cannot, in sound reason, affect at all\nthe view which we have been endeavouring to illustrate;--the view\nof the universe as the work of a wise and good Creator. Let it be\nsupposed that the point to which this hypothesis leads us, is the\nultimate point of physical science: that the farthest glimpse we\ncan obtain of the material universe by our natural faculties, shows\nit to us occupied by a boundless abyss of luminous matter: still we\nask, how space came to be thus occupied, how matter came to be thus\nluminous? If we establish by physical proofs, that the first fact\nwhich can be traced in the history of the world, is that \u201cthere\nwas light;\u201d we shall still be led, even by our natural reason,\nto suppose that before this could occur, \u201cGod said, let there be\nlight.\u201d\n\n\n\n\nCHAPTER VIII.\n\n_The Existence of a Resisting Medium in the Solar System._\n\n\nThe question of a _plenum_ and a _vacuum_ was formerly much\ndebated among those who speculated concerning the constitution of\nthe universe; that is, they disputed whether the celestial and\nterrestrial spaces are absolutely full, each portion being occupied\nby some matter or other; or whether there are, between and among\nthe material parts of the world, empty spaces free from all matter,\nhowever rare. This question was often treated by means of abstract\nconceptions and _\u00e0 priori_ reasonings; and was sometimes considered\nas one in which the result of the struggle between rival systems of\nphilosophy, the Cartesian and Newtonian for instance, was involved.\nIt was conceived by some that the Newtonian doctrine of the motions\nof the heavenly bodies, according to mechanical laws, required\nthat the space in which they moved should be, absolutely and\nmetaphysically speaking, a vacuum.\n\nThis, however, is not necessary to the truth of the Newtonian\ndoctrines, and does not appear to have been intended to be asserted\nby Newton himself. Undoubtedly, according to his theory, the\nmotions of the heavenly bodies were calculated _on the supposition_\nthat they do move in a space void of any resisting fluid; and the\ncomparison of the places so calculated with the places actually\nobserved, (continued for a long course of years, and tried in\ninnumerable cases,) did not show any difference which implied the\nexistence of a resisting fluid. The Newtonian, therefore, was\njustified in asserting that _either_ there was no such fluid, _or_\nthat it was so thin and rarefied, that no phenomenon yet examined\nby astronomers was capable of betraying its effects.\n\nThis was all that the Newtonian needed or ought to maintain; for\nhis philosophy, founded altogether upon observation, had nothing to\ndo with abstract possibilities and metaphysical necessities. And in\nthe same manner in which observation and calculation thus showed\nthat there could be none but a very rare medium pervading the solar\nsystem, it was left open to observation and calculation to prove\nthat there was such a medium, if any facts could be discovered\nwhich offered suitable evidence.\n\nWithin the last few years, facts have been observed which show,\nin the opinion of some of the best mathematicians of Europe, that\nsuch a very rare medium does really occupy the spaces in which the\nplanets move; and it may be proper and interesting to consider the\nbearing of this opinion upon the views and arguments which we have\nhad here to present.\n\n1. Reasons might be offered, founded on the universal diffusion of\nlight and on other grounds, for believing that the planetary spaces\ncannot be entirely free from matter of some kind; and wherever\nmatter is, we should expect resistance. But the facts which have\nthus led astronomers to the conviction that such a resisting\nmedium really exists, are certain circumstances occurring in the\nmotion of a body revolving round the sun, which is now usually\ncalled _Encke\u2019s comet_. This body revolves in a very eccentric\nor oblong orbit, its greatest or aphelion distance from the sun,\nand its nearest, or perihelion distance, being in the proportion\nof more than ten to one. In this respect it agrees with other\ncomets; but its time of revolution about the sun is much less\nthan that of the comets which have excited most notice; for while\nthey appear only at long intervals of years, the body of which we\nare now speaking returns to its perihelion every twelve hundred\nand eight days, or in about three years and one-third. Another\nobservable circumstance in this singular body, is its extreme\napparent tenuity: it appears as a loose indefinitely formed speck\nof vapour, through which the stars are visible with no perceptible\ndiminution of their brightness. This body was first seen by\nMechain and Messier, in 1786,[21] but they obtained only two\nobservations, whereas three, at least, are requisite to determine\nthe path of a heavenly body. Miss Herschel discovered it again in\n1795, and it was observed by several European astronomers. In 1805\nit was again seen, and again in 1819. Hitherto it was supposed\nthat the four comets thus observed were all different; Encke,\nhowever, showed that the observations could only be explained by\nconsidering them as returns of the same revolving body; and by\ndoing this, well merited that his name should be associated with\nthe subject of his discovery. The return of this body in 1822,\nwas calculated beforehand, and observed in New South Wales, the\ncomet being then in the southern part of the heavens; but on\ncomparing the calculated and the observed places, Encke concluded\nthat the observations could not be exactly explained, without\nsupposing a resisting medium. This comet was again generally\nobserved in Europe in 1825 and 1828, and the circumstances of the\nlast appearance were particularly favourable for determining the\nabsolute amount of the retardation arising from the medium, which\nthe other observations had left undetermined.\n\nThe effect of this retarding influence is, as might be supposed\nfrom what has already been said, extremely slight; and would\nprobably not have been perceptible at all, but for the loose\ntexture and small quantity of matter of the revolving body. It will\neasily be conceived that a body which has perhaps no more solidity\nor coherence than a cloud of dust, or a wreath of smoke, will have\nless force to make its way through a fluid medium, however thin,\nthan a more dense and compact body would have. In atmospheric air\nmuch rarefied, a bullet might proceed for miles without losing any\nof its velocity, while such a loose mass as the comet is supposed\nto be would lose its projectile motion in the space of a few\nyards. This consideration will account for the circumstance, that\nthe existence of such a medium has been detected by observing the\nmotions of Encke\u2019s comet, though the motions of the heavenly bodies\npreviously observed showed no trace of such an impediment.\n\nIt will appear perhaps remarkable that a body so light and loose as\nwe have described this comet to be, should revolve about the sun by\nlaws as fixed and certain as those which regulate the motions of\nthose great and solid masses, the Earth and Jupiter. It is however\ncertain from observation, that this comet is acted upon by exactly\nthe same force of solar attraction, as the other bodies of the\nsystem; and not only so, but that it also experiences the same kind\nof disturbing force from the action of the other planets, which\nthey exercise upon each other. The effect of all these causes has\nbeen calculated with great care and labour; and the result has been\nan agreement with observation sufficiently close to show that these\ncauses really act, but at the same time a _residual phenomenon_\n(as Sir J. Herschel expresses it) has come to light: and from this\nhas been collected the inference of a resisting medium.\n\nThis medium produces a very small effect upon the motion of the\ncomet, as will easily be supposed from what has been said. By\nEncke\u2019s calculation, it appears that the effect of the resistance,\nsupposing the comet to move in the earth\u2019s orbit, would be about\nan eight hundred and fiftieth of the sun\u2019s force on the body. The\neffect of such resistance may appear, at first sight, paradoxical;\nit would be to make the comet _move_ more slowly, but _perform\nits revolutions_ more quickly. This, however, will perhaps be\nunderstood if it be considered that by _moving_ more slowly the\ncomet will be more rapidly _drawn_ towards the centre, and that in\nthis way a revolution will be described by a shorter path than it\nwas before. It appears that in getting round the sun, the comet\ngains more in this way than it loses by the diminution of its\nvelocity. The case is much like that of a stone thrown in the air;\nthe stone moves more slowly than it would do if there were no air;\nbut yet it comes to the earth _sooner_ than it would do on that\nsupposition.\n\nIt appears that the effect of the resistance of the ethereal\nmedium, from the first discovery of the comet up to the present\ntime, has been to diminish the time of revolution by about two\ndays: and the comet is ten days in advance of the place which it\nwould have reached, if there had been no resistance.\n\n2. The same medium which is thus shown to produce an effect upon\nEncke\u2019s comet, must also act upon the planets which move through\nthe same spaces. The effect upon the planets, however, must be very\nmuch smaller than the effect upon the comet, in consequence of\ntheir greater quantity of matter.\n\nIt is not easy to assign any probable value, or even any certain\nlimit, to the effect of the resisting medium upon the planets.\nWe are entirely ignorant of the comparative mass of the comet,\nand of any of the planets; and hence, cannot make any calculation\nfounded on such a comparison. Newton has endeavoured to show how\nsmall the resistance of the medium must be, if it exist.[22] The\nresult of his calculation is, that if we take the density of the\nmedium to be that which our air will have at two hundred miles from\nthe earth\u2019s surface, supposing the law of diminution of density\nto go on unaltered, and if we suppose Jupiter to move in such a\nmedium, he would in a million years lose less than a millionth\npart of his velocity. If a planet, revolving about the sun, were\nto lose any portion of its velocity by the effect of resistance,\nit would be drawn proportionally nearer the sun, the tendency\ntowards the centre being no longer sufficiently counteracted by\nthat centrifugal force which arises from the body\u2019s velocity. And\nif the resistance were to continue to act, the body would be drawn\nperpetually nearer and nearer to the centre, and would describe its\nrevolutions quicker and quicker, till at last it would reach the\ncentral body, and the system would cease to be a system.\n\nThis result is true, however small be the velocity lost by\nresistance; the only difference being, that when the resistance\nis small, the time requisite to extinguish the whole motion will\nbe proportionally longer. In all cases the times which come under\nour consideration in problems of this kind, are enormous to common\napprehension. Thus Encke\u2019s comet, according to the results of\nthe observations already made, will lose, in ten revolutions, or\nthirty-three years, less than one thousandth of its velocity:\nand if this law were to continue, the velocity would not be\nreduced to one-half its present value in less than seven thousand\nrevolutions or twenty-three thousand years. If Jupiter were to\nlose one-millionth of his velocity in a million years, (which,\nas has been seen, is far more than can be considered in any way\nprobable,) he would require seventy millions of years to lose\none-thousandth of the velocity; and a period seven hundred times as\nlong to reduce the velocity to one-half. These are periods of time\nwhich quite overwhelm the imagination; and it is not pretended that\nthe calculations are made with any pretensions to accuracy. But\nat the same time it is beyond doubt that though the intervals of\ntime thus assigned to these changes are highly vague and uncertain,\nthe changes themselves must, sooner or later, take place, in\nconsequence of the existence of the resisting medium. Since there\nis such a retarding force perpetually acting, however slight it\nbe, it must in the end destroy all the celestial motions. It may\nbe millions of millions of years before the earth\u2019s retardation\nmay perceptibly affect the apparent motion of the sun; but still\nthe day will come (if the same Providence which formed the system,\nshould permit it to continue so long) when this cause will entirely\nchange the length of our year and the course of our seasons, and\nfinally stop the earth\u2019s motion round the sun altogether. The\nsmallness of the resistance, however small we choose to suppose it,\ndoes not allow us to escape this certainty. There is a resisting\nmedium; and, therefore, the movements of the solar system cannot go\non for ever. The moment such a fluid is ascertained to exist, the\neternity of the movements of the planets becomes as impossible as a\nperpetual motion on the earth.\n\n3. The vast periods which are brought under our consideration\nin tracing the effects of the resisting medium, harmonize with\nall that we learn of the constitution of the universe from\nother sources. Millions, and millions of millions of years are\nexpressions that at first sight appear fitted only to overwhelm and\nconfound all our powers of thought; and such numbers are no doubt\nbeyond the limits of any thing which we distinctly conceive. But\nour powers of conception are suited rather to the wants and uses\nof common life, than to a complete survey of the universe. It is in\nno way unlikely that the whole duration of the solar system should\nbe a period immeasurably great in our eyes, though demonstrably\nfinite. Such enormous numbers have been brought under our notice\nby all the advances we have made in our knowledge of nature. The\nsmallness of the objects detected by the microscope and of their\nparts;--the multitude of the stars which the best telescopes of\nmodern times have discovered in the sky;--the duration assigned\nto the globe of the earth by geological investigation;--all these\nresults require for their probable expression, numbers, which so\nfar as we see, are on the same gigantic scale as the number of\nyears in which the solar system will become entirely deranged.\nSuch calculations depend in some degree on our relation to the\nvast aggregate of the works of our Creator; and no person who is\naccustomed to meditate on these subjects will be surprised that\nthe numbers which such an occasion requires should oppress our\ncomprehension. No one who has dwelt on the thought of a universal\nCreator and Preserver, will be surprised to find the conviction\nforced upon the mind by every new train of speculation, that viewed\nin reference to Him, our space is a point, our time a moment, our\nmillions a handful, our permanence a quick decay.\n\nOur knowledge of the vast periods, both geological and\nastronomical, of which we have spoken, is most slight. It is in\nfact little more than that such periods exist; that the surface of\nthe earth has, at wide intervals of time, undergone great changes\nin the disposition of land and water, and in the forms of animal\nlife; and that the motions of the heavenly bodies round the sun\nare affected, though with inconceivable slowness, by a force which\nmust end by deranging them altogether. It would therefore be rash\nto endeavour to establish any analogy between the periods thus\ndisclosed; but we may observe that they _agree_ in this, that\nthey reduce all things to the general rule of _finite duration_.\nAs all the geological states of which we find evidence in the\npresent state of the earth, have had their termination, so also the\nastronomical conditions under which the revolutions of the earth\nitself proceed, involve the necessity of a future cessation of\nthese revolutions.\n\nThe contemplative person may well be struck by this universal law\nof the creation. We are in the habit sometimes of contrasting the\ntransient destiny of man with the permanence of the forests, the\nmountains, the ocean,--with the unwearied circuit of the sun. But\nthis contrast is a delusion of our own imagination; the difference\nis after all but one of degree. The forest tree endures for its\ncenturies and then decays; the mountains crumble and change, and\nperhaps subside in some convulsion of nature; the sea retires,\nand the shore ceases to resound with the \u201ceverlasting\u201d voice of\nthe ocean: such reflections have already crowded upon the mind of\nthe geologist; and it now appears that the courses of the heavens\nthemselves are not exempt from the universal law of decay; that not\nonly the rocks and the mountains, but the sun and the moon have\nthe sentence \u201cto end\u201d stamped upon their foreheads. They enjoy\nno privilege beyond man except a longer respite. The ephemeron\nperishes in an hour; man endures for his three score years and ten;\nan empire, a nation, numbers its centuries, it may be its thousands\nof years; the continents and islands which its dominion includes\nhave perhaps their date, as those which preceded them have had; and\nthe very revolutions of the sky by which centuries are numbered\nwill at last languish and stand still.\n\nTo dwell on the moral and religious reflections suggested by\nthis train of thought is not to our present purpose; but we may\nobserve that it introduces a _homogeneity_, so to speak, into\nthe government of the universe. Perpetual change, perpetual\nprogression, increase and diminution, appear to be the rules of\nthe material world, and to prevail without exception. The smaller\nportions of matter which we have near us, and the larger, which\nappear as luminaries at a vast distance, different as they are\nin our mode of conceiving them, obey the same laws of motion;\nand these laws produce the same results; in both cases motion is\nperpetually destroyed, except it be repaired by some living power;\nin both cases the relative rest of the parts of a material system\nis the conclusion to which its motion tends.\n\n4. It may perhaps appear to some, that this acknowledgment of\nthe tendency of the system to derangement through the action of\na resisting medium is inconsistent with the argument which we\nhave drawn in a previous chapter, from the provisions for its\nstability. In reality, however, the two views are in perfect\nagreement, so far as our purpose is concerned. The main point\nwhich we had to urge, in the consideration of the stability of\nthe system, was, not that it is constructed to last for ever,\nbut that while it lasts, the deviations from its mean condition\nare very small. It is this property which fits the world for\nits uses. To maintain either the past or the future eternity of\nthe world, does not appear consistent with physical principles,\nas it certainly does not fall in with the convictions of the\nreligious man, in whatever way obtained. We conceive that this\nstate of things has had a beginning; we conceive that it will have\nan end. But in the mean time we find it fitted, by a number of\nremarkable arrangements, to be the habitation of living creatures.\nThe conditions which secure the stability, and the smallness of\nthe perturbations of the system, are among these provisions. If\nthe eccentricity of the orbit of Venus, or of Jupiter, were much\ngreater than it is, not only might some of the planets, at the\nclose of ages, fall into the sun or fly off into infinite space,\nbut also, in the intermediate time, the earth\u2019s orbit might become\nmuch more eccentric; the course of the seasons and the average of\ntemperature might vary from what they now are, so as to injure\nor destroy the whole organic creation. By certain original\narrangements these destructive oscillations are prevented. So long\nas the bodies continue to revolve, their orbits will not be much\ndifferent from what they now are. And this result is not affected\nby the action of the resisting medium. Such a medium cannot\nincrease the small eccentricities of the orbits. The range of the\nperiodical oscillations of heat and cold will not be extended by\nthe mechanical effect of the medium, nor would be, even if its\ndensity were incomparably greater than it is. The resisting medium\ntherefore does not at all counteract that which is most important\nin the provision for the permanency of the solar system. If the\nstability of the system had not been secured by the adjustments\nwhich we described in a former chapter, the course of the seasons\nmight have been disturbed to an injurious or even destructive\nextent in the course of a few centuries, or even within the limits\nof one generation; by the effect of the resisting medium, the order\nof nature remains unchanged for a period, compared with which the\nknown duration of the human race is insignificant.\n\nBut, it may be objected, the effect of the medium must be\nultimately to affect, the duration of the earth\u2019s revolution round\nthe sun, and thus to derange those adaptations which depend on the\nlength of the year. And, without question, if we permit ourselves\nto look forward to that inconceivably distant period at which the\neffect of the medium will become sensible, this must be allowed\nto be true, as has been already stated. Millions, and probably\nmillions of millions, of years express inadequately the distance of\ntime at which this cause would produce a serious effect. That the\nmachine of the universe is so constructed that it may answer its\npurposes for such a period, is surely sufficient proof of the skill\nof its workmanship, and of the reality of its purpose: and those\npersons, probably, who are best convinced that it is the work of\na wise and good Creator, will be least disposed to consider the\nsystem as imperfect, because in its present condition it is not\nfitted for eternity.\n\n5. The doctrine of a Resisting Medium leads us towards a point\nwhich the Nebular Hypothesis assumes;--a _beginning_ of the present\norder of things. There must have been a commencement of the motions\nnow going on in the solar system. Since these motions, when once\nbegun, would be deranged and destroyed in a period which, however\nlarge, is yet finite, it is obvious we cannot carry their origin\nindefinitely backwards in a range of past duration. There is a\nperiod in which these revolutions, whenever they had begun, would\nhave brought the revolving bodies into contact with the central\nmass; and this period has in our system not yet elapsed. The watch\nis still going, and therefore it must have been wound up within a\nlimited time.\n\nThe solar system, at this its beginning, must have been arranged\nand put in motion by some cause. If we suppose this cause to\noperate by means of the configurations and the properties of\npreviously existing matter, these configurations must have resulted\nfrom some still previous cause, these properties must have produced\nsome previous effects. We are thus led to a condition still earlier\nthan the assumed beginning;--to an origin of the original state of\nthe universe; and in this manner we are carried perpetually further\nand further back, through a labyrinth of mechanical causation,\nwithout any possibility of finding any thing in which the mind\ncan acquiesce or rest, till we admit \u201ca First Cause which is not\nmechanical.\u201d\n\nThus the argument which was before urged against those in\nparticular, who put forwards the Nebular Hypothesis in opposition\nto the admission of an Intelligent Creator, offers itself again, as\ncogent in itself, when we adopt the opinion of a resisting medium,\nfor which the physical proofs have been found to be so strong.\nThe argument is indeed forced upon our minds, whatever view we\ntake of the past history of the universe. Some have endeavoured\nto evade its force by maintaining that the world as it now exists\nhas existed from eternity. They assert that the present order of\nthings, or an order of things in some way resembling the present,\nproduced by the same causes, governed by the same laws, has\nprevailed through an infinite succession of past ages. We shall\nnot dwell upon any objections to this tenet which might be drawn\nfrom our own conceptions, or from what may be called metaphysical\nsources. Nor shall we refer to the various considerations which\nhistory, geology, and astronomical records supply, and which tend\nto show, not only that the past duration of the present course of\nthings is finite, but that it is short, compared with such periods\nas we have had to speak of. But we may observe, that the doctrine\nof a resisting medium once established, makes this imagination\nuntenable; compels us to go back to the origin, not only of the\npresent course of the world, not only of the earth, but of the\nsolar system itself; and thus sets us forth upon that path of\nresearch into the series of past causation, where we obtain no\nanswer of which the meaning corresponds to our questions, till\nwe rest in the conclusion of a most provident and most powerful\nCreating Intelligence.\n\nIt is related of Epicurus that when a boy, reading with his\npreceptor these verses of Hesiod,\n\n      \u0397\u03c4\u03bf\u03b9 \u03bc\u03b5\u03bd \u03c0\u03c1\u03c9\u03c4\u03b9\u03b6\u03b1 \u03a7\u03b1\u03bf\u03c2 \u03b3\u03b5\u03bd\u03b5\u03c4\u2019, \u03b1\u03c5\u03c4\u03b1\u03c1 \u03b5\u03c0\u03b5\u03b9\u03c4\u03b1\n      \u0393\u03b1\u03b9\u2019 \u03b5\u03c5\u03c1\u03c5\u03b6\u03b5\u03c1\u03bd\u03bf\u03c2 \u03c0\u03b1\u03bd\u03c4\u03c9\u03bd \u03b5\u03b4\u03bf\u03c2 \u03b1\u03c3\u03c6\u03b1\u03bb\u03b5\u03c2 \u03b1\u03b9\u03b5\u03b9\n      \u0391\u03b8\u03b1\u03bd\u03b1\u03c4\u03c9\u03bd,\n\n  Eldest of beings, Chaos first arose,\n  Thence Earth wide stretched, the steadfast seat of all\n  The Immortals,\n\nthe young scholar first betrayed his inquisitive genius by asking\n\u201cAnd chaos whence?\u201d When in his riper years he had persuaded\nhimself that this question was sufficiently answered by saying that\nchaos arose from the concourse of atoms, it is strange that the\nsame inquisitive spirit did not again suggest the question \u201cand\natoms whence?\u201d And it is clear that however often the question\n\u201cwhence?\u201d had been answered, it would still start up as at first.\nNor could it suffice as an answer to say, that earth, chaos, atoms,\nwere portions of a series of changes which went back to eternity.\nThe preceptor of Epicurus informed him, that to be satisfied on the\nsubject of his inquiry, he must have recourse to the philosophers.\nIf the young speculator had been told that chaos (if chaos indeed\npreceded the present order) was produced by an Eternal Being, in\nwhom resided purpose and will, he would have received a suggestion\nwhich, duly matured by subsequent contemplation, might have led\nhim to a philosophy far more satisfactory than the material scheme\ncan ever be, to one who looks, either abroad into the universe, or\nwithin into his own bosom.\n\n\n\n\nCHAPTER IX.\n\n_Mechanical Laws._\n\n\nIn the preceding observations we have supposed the laws, by which\ndifferent kinds of matter act and are acted upon, to be already in\nexistence; and have endeavoured to point out evidences of design\nand adaptation, displayed in the selection and arrangement of these\nmaterials of the universe. These materials are, it has appeared,\nsupplied in such measures and disposed in such forms, that by means\nof their properties and laws the business of the world goes on\nharmoniously and beneficially. But a further question occurs: how\ncame matter to have such properties and laws? Are these also to\nbe considered as things of selection and institution? And if so,\ncan we trace the reasons why the laws were established in their\npresent form; why the properties which matter actually possesses\nwere established and bestowed and bestowed upon it? We have already\nattempted, in a previous part of this work, to point out some of\nthe advantages which are secured by the existing laws of heat,\nlight and moisture. Can we, in the same manner, point out the\nbenefits which arise from the present constitution of those laws\nof matter which are mainly concerned in the production of cosmical\nphenomena?\n\nIt will readily be perceived that the discussion of this point\nmust necessarily require some effort of abstract thought. The laws\nand properties of which we have here to speak, the laws of motion\nand the universal properties of matter, are so closely interwoven\nwith our conceptions of the external world, that we have great\ndifficulty in conceiving them not to exist, or to exist other than\nthey are. When we press or lift a stone, we can hardly imagine that\nit could, by possibility, do otherwise than resist our effort by\nits hardness and by its heaviness, qualities so familiar to us:\nwhen we throw it, it seems inevitable that its motion should depend\non the impulse we give, just as we find that it invariably does.\n\nNor is it easy to say how far it is really possible to suppose\nthe fundamental attributes of matter to be different from what\nthey are. If we, in our thoughts, attempt to divest matter of its\npowers of resisting and moving, it ceases to be matter, according\nto our conceptions, and we can no longer reason upon it with any\ndistinctness. And yet it is certain that we can conceive the laws\nof hardness and weight and motion to be quite different from what\nthey are, and can point out some of the consequences which would\nresult from such difference. The properties of matter, even the\nmost fundamental and universal ones, do not obtain by any absolute\nnecessity, resembling that which belongs to the properties of\ngeometry. A line touching a circle is _necessarily_ perpendicular\nto a line drawn to the centre through the point touched; for\nit may be shown that the contrary involves a contradiction. But\nthere is no contradiction in supposing that a body\u2019s motion should\nnaturally diminish, or that its weight should increase in removing\nfurther from the earth\u2019s centre.\n\nThus the properties of matter and the laws of motion are what we\nfind them, not by virtue of any internal necessity which we can\nunderstand. The study of such laws and properties may therefore\ndisclose to us the character of that external agency by which\nwe conceive them to have been determined to be what they are;\nand this must be the same agency by which all other parts of the\nconstitution of the universe were appointed and ordered.\n\nBut we can hardly expect, with regard to such subjects, that\nwe shall be able to obtain any complete or adequate view of\nthe reasons why these general laws are so selected, and so\nestablished. These laws are the universal basis of all operations\nwhich go on, at any moment, in every part of space, with regard\nto every particle of matter, organic and inorganic. All other\nlaws and properties must have a reference to these, and must be\ninfluenced by them; both such as men have already discovered, and\nthe far greater number which remain still unknown. The general\neconomy and mutual relations of all parts of the universe, must\nbe subordinate to the laws of motion and matter of which we\nhere speak. We can easily suppose that the various processes of\nnature, and the dependencies of various creatures, are affected\nin the most comprehensive manner by these laws;--are simplified\nby _their_ simplicity, made consistent by _their_ universality;\nrendered regular by _their_ symmetry. We can easily suppose that\nin this way there may be the most profound and admirable reasons\nfor the existence of the present universal properties of matter,\nwhich we cannot apprehend in consequence of the limited nature\nof our knowledge, and of our faculties. For, compared with the\nwhole extent of the universe, the whole aggregate of things and\nrelations and connexions which exist in it, our knowledge is\nmost narrow and partial, most shallow and superficial. We cannot\nsuppose, therefore, that the reasons which we discover for the\npresent form of the laws of nature go nearly to the full extent, or\nto the bottom of the reasons, which a more complete and profound\ninsight would enable us to perceive. To do justice to such reasons,\nwould require nothing less than a perfect acquaintance with the\nwhole constitution of every part of creation; a knowledge which man\nhas not, and, so far as we can conceive, never can have.\n\nWe are certain, therefore, that our views, with regard to this\npart of our subject, must be imperfect and limited. Yet still man\nhas _some_ knowledge with regard to various portions of nature;\nand with regard to those most general and comparatively simple\nfacts to which we now refer, his knowledge is more comprehensive,\nand goes deeper than it does in any other province. We conceive,\ntherefore, that we shall not be engaged in any rash or presumptuous\nattempt, if we endeavour to point out some of the advantages which\nare secured by the present constitution of some of the general\nmechanical laws of nature; and to suggest the persuasion of that\npurpose and wise design, which the selection of such laws will thus\nappear to imply.\n\n\n\n\nCHAPTER X.\n\n_The Law of Gravitation._\n\n\nWe shall proceed to make a few observations on the Law of Gravity,\nin virtue of which the motions of planets about the sun, and of\nsatellites about their planets take place; and by which also are\nproduced the fall downwards of all bodies within our reach, and\nthe pressure which they exert upon their supports when at rest.\nThe identification of the latter forces with the former, and the\ndiscovery of the single law by which these forces are every where\nregulated, was the great discovery of Newton: and we wish to make\nit appear that this law is established by an intelligent and\ncomprehensive selection.\n\nThe law of the sun\u2019s attraction upon the planets is, that this\nattraction varies _inversely_ as the square of the distance; that\nis, it decreases as that square increases. If we take three points\nor planets of the solar system, the distances of which from the\nsun are in proper proportion one, two, three; the attractive force\nwhich the sun at these distances exercises, is as one, one-fourth,\nand one-ninth respectively. In the smaller variations of distance\nwhich occur in the elliptical motion of one planet, the variations\nof the force follow the same law. Moreover, not only does the\nsun attract the planets, but they attract each other according\nto the same law; the tendency to the earth which makes bodies\nheavy, is one of the effects of this law: and all these effects of\nthe attractions of large masses may be traced to the attractions\nof the particles of which they are composed; so that the final\ngeneralization, including all the derivative laws, is, that every\nparticle of matter in the universe attracts every other, according\nto the law of the inverse square of the distance.\n\nSuch is the law of universal gravitation. Now, the question\nis, why do either the attractions of masses, or those of their\ncomponent particles, follow this law of the inverse square of the\ndistance rather than any other? When the distance becomes one,\ntwo, and three, why should not the force also become one, two, and\nthree?--or if it must be weaker at points more remote from the\nattracting body, why should it not be one, a half, a third? or one,\nan eighth, a twenty-seventh? Such law\u2019s could easily be expressed\nmathematically, and their consequences calculated. Can any reason\nbe assigned why the law which we find in operation _must_ obtain?\nCan any be assigned why it _should_ obtain?\n\nThe answer to this is, that no reason, at all satisfactory, can be\ngiven why such a law must, of necessity, be what it is; but that\nvery strong reasons can be pointed out why, for the beauty and\nadvantage of the system, the present one is better than others. We\nwill point out some of these reasons.\n\n1. In the first place, the system could not have subsisted, if\nthe force had followed a _direct_ instead of an inverse law, with\nrespect to the distance; that is, if it had increased when the\ndistance increased. It has been sometimes said, that \u201call direct\nlaws of force are excluded on account of the danger from perturbing\nforces;\u201d[23] that if the planets had pulled at this earth, the\nharder the further off they were, they would have dragged it\nentirely out of its course. This is not an exact statement of\nwhat would happen: if the force were to be simply in the direct\nratio of the distance, any number of planets might revolve in the\nmost regular and orderly manner. Their mutual effects, which we\nmay call perturbations if we please, would be considerable; but\nthese perturbations would be so combined with the unperturbed\nmotion, as to produce a new motion not less regular than the\nother. This curious result would follow, that every body in the\nsystem would describe, or seem to describe, about every other,\nan exact elliptical orbit; and that the times of the revolution\nof every body in its orbit would be all equal. This is proved by\nNewton, in the sixty-fourth proposition of the Principia. There\nwould be nothing to prevent all the planets, on this supposition,\nfrom moving round the sun in orbits exactly circular, or nearly\ncircular, according to the mode in which they were set in motion.\n\nBut though the perturbations of the system would not make this\nlaw inadmissible, there are other circumstances which would do so.\nUnder this law, the gravity of bodies at the earth\u2019s surface would\ncease to exist. Nothing would fall or weigh downwards. The greater\naction of the distant sun and planets would exactly neutralize the\ngravity of the earth: a ball thrown from the hand, however gently,\nwould immediately become a satellite of the earth, and would for\nthe future accompany it in its course, revolving about it in the\nspace of one year. All terrestrial things would float about with no\nprinciple of coherence or stability: they would obey the general\nlaw of the system, but would acknowledge no particular relation\nto the earth. We can hardly pretend to judge of the abstract\npossibility of such a system of things; but it is clear that it\ncould not exist without an utter subversion of all that we can\nconceive of the economy and structure of the world which we inhabit.\n\nWith any other direct law of force, we should in like manner\nlose gravity, without gaining the theoretical regularity of\nthe planetary motions which we have described in the case just\nconsidered.\n\n2. Among _inverse_ laws of the distance, (that is, those according\nto which the force diminishes as the distance from the origin of\nforce increases,) all which diminish the central force faster than\nthe _cube_ of the distance increases are inadmissible, because they\nare incompatible with the permanent revolution of a planet. Under\nsuch laws it would follow, that a planet would describe a spiral\nline about the sun, and would either approach nearer and nearer to\nhim perpetually, or perpetually go further and further off: nearly\nas a stone at the end of a string, when the string is whirled\nround, and is allowed to wrap round the hand, or to unwrap from it,\napproaches to or recedes from the hand.\n\nIf we endeavour to compare the law of the inverse square of\nthe distance, which really regulates the central force, with\nother laws, not obviously inadmissible, as for instance, the\ninverse simple ratio of the distance, a considerable quantity\nof calculation is found to be necessary in order to trace the\nresults, and especially the perturbations in the two cases. The\nperturbations in the supposed case have not been calculated;\nsuch a calculation being a process so long and laborious that it\nis never gone through, except for the purpose of comparing the\nresults of theory with those of observation, as we can do with\nregard to the law of inverse square. We can only say, therefore,\nthat the stability of the system, and the moderate limits of the\nperturbations, which we know to be secured by the existing law,\nwould not, so far as we know, be obtained by any different law.\n\nWithout going into further examination of the subject, we may\nobserve that there are some circumstances in which the present\nsystem has a manifest superiority in its simplicity over the\ncondition which would have belonged to it if the force had followed\nany other law. Thus, with the present law of gravitation the\nplanets revolve, returning perpetually on the same track, very\nnearly. The earth describes an oval, in consequence of which motion\nshe is nearer to the sun in our winter than in our summer by about\none-thirtieth part of the whole distance. And, as the matter now\nis, the nearest approach to the sun, and the farthest recess\nfrom him, occur always at the same points of the orbit. There is\nindeed a slight alteration in these points arising from disturbing\nforces, but this is hardly sensible in the course of several ages.\nNow if the force had followed any other law, we should have had\nthe earth running perpetually on a new track. The greatest and\nleast distances would have occurred at different parts in every\nsuccessive revolution. The orbit would have perpetually intersected\nand been interlaced with the path described in former revolutions;\nand the simplicity and regularity which characterizes the present\nmotion would have been quite wanting.\n\n3. Another peculiar point of simplicity in the present law of\nmutual attraction is this: that it makes the law of attraction for\nspherical masses the same as for single particles. If particles\nattract with forces which are inversely as the square of the\ndistance, spheres composed of such particles, will exert a force\nwhich follows the same law. In this character the present law\nis singular, among all possible laws, excepting that of the\ndirect distance which we have already discussed. If the law of\nthe gravitation of particles had been that of the inverse simple\ndistance, the attraction of a sphere would have been expressed by\na complex series of mathematical expressions, each representing\na simple law. It is truly remarkable that the law of the inverse\nsquare of the distance, which appears to be selected as that of\nthe _masses_ of the system, and of which the mechanism is, that it\narises from the action of the _particles_ of the system, should\nlead us to the same law for the action of these particles: there is\na striking _prerogative_ of simplicity in the law thus adopted.\n\nThe law of gravitation actually prevailing in the solar system has\nthus great and clear advantages over any law widely different from\nit; and has moreover, in many of its consequences, a simplicity\nwhich belongs to this precise law alone. It is in many such\nrespects a _unique_ law; and when we consider that it possesses\nseveral _properties_ which are _peculiar_ to it, and several\n_advantages_ which may be peculiar to it, and which are certainly\nnearly so; we have some ground, it would appear, to look upon its\npeculiarities and its advantages as connected. For the reasons\nmentioned in the last chapter, we can hardly expect to see fully\nthe way in which the system is benefited by the simplicity of this\nlaw, and by the mathematical elegance of its consequences: but when\nwe see that it has some such beauties, and some manifest benefits,\nwe may easily suppose that our ignorance and limited capacity alone\nprevent our seeing that there are, for the selection of this law of\nforce, reasons of a far more refined and comprehensive kind than\nwe can distinctly apprehend.\n\n4. But before quitting this subject we may offer a few further\nobservations on the question, whether gravitation and the law of\ngravitation be _necessary_ attributes of matter. We have spoken of\nthe selection of this law, but is it selected? Could it have been\notherwise? Is not the force of attraction a necessary consequence\nof the fundamental properties of matter?\n\nThis is a question which has been much agitated among the followers\nof Newton. Some have maintained, as Cotes, that gravity is an\ninherent property of all matter; others, with Newton himself, have\nconsidered it as an appendage to the essential qualities of matter,\nand have proposed hypotheses to account for the mode in which its\neffects are produced.\n\nThe result of all that can be said on the subject appears to be\nthis: that no one can demonstrate the possibility of deducing\ngravity from the acknowledged fundamental properties of matter: and\nthat no philosopher asserts, that matter has been found to exist,\nwhich was destitute of gravity. It is a property which we have no\nright to call _necessary_ to matter, but every reason to suppose\n_universal_.\n\nIf we could show gravity to be a necessary consequence of those\nproperties which we adopt as essential to our notion of matter,\n(extension, solidity, mobility, inertia) we might then call it also\none of the essential properties. But no one probably will assert\nthat this is the case. Its universality is a fact of observation\nmerely. How then can a property,--in its existence so needful for\nthe support of the universe, in its laws so well adapted to the\npurposes of creation,--how came it to be thus universal? Its being\nfound every where is necessary for its uses; but this is so far\nfrom being a sufficient explanation of its existence, that it is\nan additional fact to be explained. We have here, then, an agency\nmost simple in its rule, most comprehensive in its influence, most\neffectual and admirable in its operation. What evidence could be\nafforded of design, by laws of mechanical action, which this law\nthus existing and thus operating does not afford us?\n\n5. It is not necessary for our purpose to consider the theories\nwhich have been proposed to account for the action of gravity. They\nhave proceeded on the plan of reducing this action to the result of\npressure or impulse. Even if such theories could be established,\nthey could not much, or at all, affect our argument; for the\narrangements by which pressure or impact could produce the effects\nwhich gravity produces, must be at least as clearly results of\ncontrivance, as gravity itself can be.\n\nIn fact, however, none of these attempts can be considered as at\nall successful. That of Newton is very remarkable: it is found\namong the Queries in the second edition of his Optics. \u201cTo show,\u201d\nhe says, \u201cthat I do not take gravity for an essential property of\nbodies, I have added one question concerning its cause, choosing to\npropose it by way of question, because I am not yet satisfied about\nit for want of experiments.\u201d The hypothesis which he thus suggests\nis, that there is an elastic medium pervading all space, and\nincreasing in elasticity as we proceed from dense bodies outwards:\nthat this \u201ccauses the gravity of such dense bodies to each other:\nevery body endeavouring to go from the denser parts of the medium\ntowards the rarer.\u201d Of this hypothesis we may venture to say, that\nit is in the first place quite gratuitous; we cannot trace in any\nother phenomena a medium possessing these properties: and in the\nnext place, that the hypothesis contains several suppositions which\nare more complex than the fact to be explained, and none which\nare less so. Can we, on Newton\u2019s principles, conceive an elastic\nmedium otherwise than as a collection of particles, repelling each\nother? and is the repulsion of such particles a simpler fact than\nthe attraction of those which gravitate? And when we suppose that\nthe medium becomes more elastic as we proceed from each attracting\nbody, what cause can we conceive capable of keeping it in such a\ncondition, except a repulsive force emanating from the body itself:\na supposition at least as much requiring to be accounted for, as\nthe attraction of the body. It does not appear, then, that this\nhypothesis will bear examination; although, for our purpose, the\nargument would be rather strengthened than weakened, if it could be\nestablished.\n\n6. Another theory of the cause of gravity, which at one time\nexcited considerable notice, was that originally proposed by M.\nLe Sage, in a memoir entitled \u201cLucrece Newtonien,\u201d and further\nillustrated by M. Prevost; according to which all space is occupied\nby currents of matter, moving perpetually in straight lines, in\nall directions, with a vast velocity, and penetrating all bodies.\nWhen two bodies are near each other, they intercept the current\nwhich would flow in the intermediate space if they were not there,\nand thus receive a tendency towards each other from the pressure\nof the currents on their farther sides. Without examining further\nthis curious and ingenious hypothesis, we may make upon it the same\nkind of observations as before;--that it is perfectly gratuitous,\nexcept as a means of explaining the phenomena; and that, if it were\nproved, it would still remain to be shown what necessity has caused\nthe existence of these _two kinds_ of matter; the first kind being\nthat which is commonly called matter, and which alone affects our\nsenses, while it is inert as to any tendency to motion; the second\nkind being something imperceptible to our senses, except by the\neffects it produces on matter of the former kind; yet exerting an\nimpulse on every material body, permeating every portion of common\nmatter, flowing with inconceivable velocity, in inexhaustible\nabundance, from every part of the abyss of infinity on one side,\nto the opposite part of the same abyss; and so constituted that\nthrough all eternity it can never bend its path, or return, or\ntarry in its course.\n\nIf we were to accept this theory, it would little or nothing\ndiminish our wonder at the structure of the universe. We might well\ncontinue to admire the evidence of contrivance, if such a machinery\nshould be found to produce all the effects which flow from the law\nof gravitation.\n\n7. The arguments for and against the necessity of the law of\nthe inverse square of the distance in the force of gravity,\nwere discussed with great animation about the middle of the\nlast century. Clairault, an eminent mathematician, who did\nmore than almost any other person for the establishment and\ndevelopment of the Newtonian doctrines, maintained, at one period\nof his researches, not only that the inverse square was not the\n_necessary_ law, but also that it was not the _true_ law. The\noccasion of this controversy was somewhat curious.\n\nNewton and other astronomers had found that the line of the moon\u2019s\n_apsides_ (that is of her greatest and least distances from the\nearth) moves round to different parts of the heavens with a\nvelocity twice as great as that which the calculation from the law\nof gravitation seems at first to give. According to the theory,\nit appeared that this line ought to move round once in eighteen\nyears; according to observation, it moves round once in nine\nyears. This difference, the only obvious failure of the theory of\ngravitation, embarrassed mathematicians exceedingly. It is true,\nit was afterwards discovered that the apparent discrepancy arose\nfrom a mistake; the calculation, which is long and laborious, was\nsupposed to have been carried far enough to get close to the truth;\nbut it appeared afterwards that the residue which had been left out\nas insignificant, produced, by an unexpected turn in the reckoning,\nan effect as large as that which had been taken for the whole. But\nthis discovery was not made till afterwards; and in the mean time\nthe law of the inverse square appeared to be at fault. Clairault\ntried to remedy the defect by supposing that the force of the\nearth\u2019s gravity consisted of a large force varying as the square of\nthe distance, and a very small force varying as the fourth power\n(the square of the square.) By such a supposition, observation and\ntheory could be reconciled; but on the suggestion of it, Buffon\ncame forward with the assertion that the force _could_ not vary\naccording to any other law than the inverse square. His arguments\nare rather metaphysical than physical or mathematical. Gravity,\nhe urges, is a quality, an emanation; and all emanations are\ninversely as the square of the distance, as light, odours. To this\nClairault replies by asking, how we know that light and odours\nhave their intensity inversely as the square of the distance from\ntheir origin: not, he observes, by measuring the intensity, but\nby _supposing_ these effects to be material emanations. But who,\nhe asks, supposes gravity to be a material emanation _from_ the\nattracting body.\n\nBuffon again pleads that so many facts prove the law of the inverse\nsquare, that a single one, which occurs to interfere with this\nagreement, must be in some manner capable of being explained away.\nClairault replies, that the facts do _not_ prove this law to obtain\nexactly; that small effects, of the same order as the one under\ndiscussion, have been neglected; and that therefore the law is only\nknown to be true, _as far_ as such an approximation goes, and no\nfarther.\n\nBuffon then argues, that there can be no such additional fraction\nof the force, following a different law, as Clairault supposes: for\nwhat, he asks, is there to determine the magnitude of the fraction\nto one amount rather than another? why should nature select for it\nany particular magnitude? To this it is replied, that, whether we\ncan explain the fact or not, nature does select certain magnitudes\nin preference to others: that where we ascertain she does this,\nwe are not to deny the fact because we cannot assign the grounds\nof her preference. What is there, it is asked, to determine the\nmagnitude of the whole force at any fixed distance? We cannot tell;\nyet the force is of a certain definite intensity and no other.\n\nFinally, Clairault observes, that we have, in cohesion, capillary\nattraction, and various other cases, examples of forces varying\naccording to other laws than the inverse square; and that therefore\nthis cannot be the only possible law.\n\nThe discrepancy between observation and theory which gave rise to\nthis controversy was removed, as has been already stated, by a more\nexact calculation: and thus, as Laplace observes, in this case\nthe metaphysician turned out to be right and the mathematician to\nbe wrong. But most persons, probably, who are familiar with such\ntrains of speculation, will allow, that Clairault had the best of\nthe argument, and that the attempts to show the law of gravitation\nto be necessarily what it is, are fallacious and unsound.\n\n8. We may observe, however, that the law of gravitation according\nto the inverse square of the distance, which thus regulates the\nmotions of the solar system, is not confined to that province of\nthe universe, as has been shown by recent researches. It appears\nby the observations and calculations of Sir John Herschel, that\nseveral of the stars, called _double stars_, consist of a pair of\nluminous bodies which revolve above each other in ellipses, in such\na manner as to show that the force, by which they are attracted\nto each other, varies according to the law of the inverse square.\nWe thus learn a remarkable fact concerning bodies which seemed so\nfar removed that no effort of our science could reach them; and we\nfind that the same law of mutual attraction which we have before\ntraced to the farthest bounds of the solar system, prevails also\nin spaces at a distance compared with which the orbit of Saturn\nshrinks into a point. The establishment of such a truth certainly\nsuggests, as highly probable, the prevalence of this law among\nall the bodies of the universe. And we may therefore suppose, that\nthe same ordinance which gave to the parts of our system that rule\nby which they fulfil the purposes of their creation, impressed\nthe same rule on the other portions of matter which are scattered\nin the most remote parts of the universe; and thus gave to their\nmovements the same grounds of simplicity and harmony which we find\nreason to admire, as far as we can acquire any knowledge of our own\nmore immediate neighbourhood.\n\n\n\n\nCHAPTER XI.\n\n_The Laws of Motion._\n\n\nWe shall now make a few remarks on the general Laws of Motion by\nwhich all mechanical effects take place. Are we to consider these\nas instituted laws? and if so, can we point out any of the reasons\nwhich we may suppose to have led to the selection of those laws\nwhich really exist?\n\nThe observations formerly made concerning the inevitable narrowness\nand imperfection of our conclusions on such subjects, apply here,\neven more strongly than in the case of the law of gravitation. We\ncan hardly conceive matter divested of these laws; and we cannot\nperceive or trace a millionth part of the effects which they\nproduce. We cannot, therefore, expect to go far in pointing out the\nadvantages of these laws such as they now obtain.\n\nIt would be easy to show that the fundamental laws of motion, in\nwhatever form we state them, possess a very preeminent simplicity,\ncompared with almost all others, which we might imagine as\nexisting. This simplicity has indeed produced an effect on men\u2019s\nminds which, though delusive, appears to be very natural; several\nwriters have treated these laws as self-evident, and necessarily\nflowing from the nature of our conceptions. We conceive that this\nis an erroneous view, and that these laws are known to us to be\nwhat they are, by experience only; that they might, so far as we\ncan discern, have been any others. They appear therefore to be\nselected for their fitness to answer their purposes; and we may,\nperhaps, be able to point out some instances in which this fitness\nis apparent to us.\n\nNewton, and many English philosophers, teach the existence of\n_three_ separate fundamental laws of motion, while most of the\neminent mathematicians of France reduce these to _two_, the law\nof inertia and the law that force is proportioned to velocity. As\nan example of the views which we wish to illustrate, we may take\nthe law of inertia, which is identical with Newton\u2019s first Law of\nMotion. This law asserts, that a body at rest continues at rest,\nand that a body in motion goes on moving with its velocity and\ndirection unchanged, except so far as it is acted on by extraneous\nforces.[24]\n\nWe conceive that this law, simple and universal as it is, cannot\nbe shown to be necessarily true. It might be difficult to discuss\nthis point in general terms with any clearness; but let us take\nthe only example which we know of a motion absolutely uniform, in\nconsequence of the absence of any force to accelerate or retard\nit;--this motion is the rotation of the earth on its axis.\n\n1. It is scarcely possible that discussions on such subjects\nshould not have a repulsive and scholastic aspect, and appear like\ndisputes about words rather than things. For mechanical writers\nhave exercised all their ingenuity so to circumscribe their notions\nand so to define their terms that these fundamental truths should\nbe expressed in the simplest manner: the consequence of which has\nbeen, that they have been made to assume the appearance rather\nof identical assertions than of general facts of experience. But\nin order to avoid this inconvenience, as far as may be, let us\ntake the _first law of motion_ as exemplified in a particular\ncase, the rotation of the earth. Of all the motions with which\nwe are acquainted this is alone invariable. Each day, measured\nby the passages of the stars, is so precisely of the same length\nthat, according to Laplace\u2019s calculations, it is impossible\nthat a difference of hundredth of a second of time should have\nobtained between the length of the day in the earliest ages and\nat the present time. Now why is this? How is this very remarkable\nuniformity preserved in this particular phenomenon, while all the\nother motions of the system are subject to inequalities? How is it\nthat in the celestial machine no retardation takes place by the\nlapse of time, as would be the case in any machine which it would\nbe possible for human powers to construct? The answer is, that in\nthe earth\u2019s revolution on her axis no cause operates to retard\nthe speed, like the imperfection of materials, the friction of\nsupports, the resistance of the ambient medium; impediments which\ncannot, in any human mechanism, however perfect, be completely\nannihilated. But here we are led to ask again, why should the\nspeed continue the same when not affected by an extraneous cause?\nWhy should it not languish and decay of itself by the mere lapse\nof time? That it might do so, involves no contradiction, for\nit was the common, though erroneous, belief of all mechanical\nspeculators, to the time of Galileo. We can conceive velocity to\ndiminish in proceeding from a certain point of time, as easily as\nwe can conceive force to diminish in proceeding from a certain\npoint of space, which in attractive forces really occurs. But,\nit is sometimes said, the _motion_ (that is the velocity) _must_\ncontinue the same from one instant to another, for there is nothing\nto change it. This appears to be taking refuge in words. We may\ncall the velocity, that is the speed of a body, its motion; but\nwe cannot, by giving it this name, make it a _thing_ which has\nany _\u00e0 priori_ claim to permanence, much less any self-evident\nconstancy. Why must the speed of a body, left to itself, continue\nthe same, any more than its temperature? Hot bodies grow cooler of\nthemselves, why should not quick bodies go slower of themselves?\nWhy must a body describe one thousand feet in the next second\nbecause it has described one thousand feet in the last? Nothing\nbut experience, under proper circumstances, can inform us whether\nbodies, abstracting from external agency, do move according to\nsuch a rule. We find that they do so, we learn that all diminution\nof their speed which ever takes place, can be traced to external\ncauses. Contrary to all that men had guessed, motion appears to\nbe of itself endless and unwearied. In order to account for the\nunalterable permanence of the length of our day, all that is\nrequisite is to show that there is no let or hindrance in the way\nof the earth\u2019s rotation;--no resisting medium or alteration of\nsize,--she \u201cspinning _sleeps_\u201d on her axle, as the poet expresses\nit, and may go on sleeping with the same regularity for ever, so\nfar as the experimental properties of motion are concerned.\n\nSuch is the necessary consequence of the first law of motion;\nbut the law itself has no necessary existence, so far as we can\nsee. It was discovered only after various perplexities and false\nconjectures of speculators on mechanics. We have learnt that it is\nso, but we have not learnt, nor can any one undertake to teach us,\nthat it must have been so. For aught we can tell, it is one among\na thousand equally possible laws, which might have regulated the\nmotions of bodies.\n\n2. But though we have thus no reason to consider this as the only\npossible law, we have good reason to consider it as the best, or at\nleast as possessing all that we can conceive of advantage. It is\nthe _simplest_ conceivable of such laws. If the velocity had been\ncompelled to change with the time, there must have been a law of\nthe change, and the kind and amount of this change must have been\ndetermined by its dependence on the time and other conditions.\nThis, though quite supposable, would undoubtedly have been more\ncomplex than the present state of things. And though complexity\ndoes not appear to embarrass the operations of the laws of nature,\nand is admitted, without scruple, when there is reason for it,\nsimplicity is the usual character of such laws, and appears to have\nbeen a ground of selection in the formation of the universe, as it\nis a mark of beauty to us in our contemplation of it.\n\nBut there is a still stronger apparent reason for the selection\nof this law of the preservation of motion. If the case had been\notherwise, the universe must necessarily in the course of ages\nhave been reduced to a state of rest, or at least to a state not\nsensibly differing from it. If the earth\u2019s motion, round its\naxis, had slackened by a very small quantity, for instance, by\na hundredth of a second in a revolution, and in this proportion\ncontinued, the day would have been already lengthened by six hours\nin the six thousand years which have elapsed since the history\nof the world began; and if we suppose a longer period to precede\nor to follow, the day might be increased to a month or to any\nlength. All the adaptations which depend on the length of the day\nwould consequently be deranged. But this would not be all; for\nthe same law of motion is equally requisite for the preservation\nof the annual motion of the earth. If her motion were retarded by\nthe establishment of any other law instead of the existing one,\nshe would wheel nearer and nearer to the sun at every revolution,\nand at last reach the centre, like a falling hoop. The same would\nhappen to the other planets; and the whole solar system would,\nin the course of a certain period, be gathered into a heap of\nmatter without life or motion. In the present state of things on\nthe other hand, the system, as we have already explained, is, by\na combination of remarkable provisions, calculated for an almost\nindefinite existence, of undiminished fitness for its purposes.\n\nThere are, therefore, manifest reasons, why, of all laws which\ncould occupy the place of the first law of motion, the one which\nnow obtains is the only one consistent with the durability and\nuniformity of the system;--the one, therefore, which we may\nnaturally conceive to be selected by a wise contriver. And as,\nalong with this, it has appeared that we have no sort of right to\nattribute the establishment of this law to any thing but selection,\nwe have here a striking evidence, to lead us to a perception of\nthat Divine mind, by which means so simple are made to answer\npurposes so extensive and so beneficial.\n\n\n\n\nCHAPTER XII.\n\n_Friction._[25]\n\n\nWe shall not pursue this argument of the last chapter, by\nconsidering the other laws of motion in the same manner as we have\nthere considered the first, which might be done. But the facts\nwhich form exceptions and apparent contradictions to the first law\nof which we have been treating, and which are very numerous, offer,\nwe conceive, an additional exemplification of the same argument;\nand this we shall endeavour to illustrate.\n\nThe rule that a body naturally moves for ever with an undiminished\nspeed, is so far from being obviously true, that it appears on a\nfirst examination to be manifestly false. The hoop of the school\nboy, left to itself, runs on a short distance, and then stops; his\ntop spins a little while, but finally flags and falls; all motion\non the earth appears to decay by its own nature; all matter which\nwe move appears to have a perpetual tendency to divest itself of\nthe velocity which we communicate to it. How is this reconcileable\nwith the first law of motion on which we have been insisting?\n\nIt is reconciled principally by considering the effect of\n_Friction_. Among terrestrial objects friction exerts an agency\nalmost as universal and constant as the laws of motion themselves;\nan agency which completely changes and disguises the results of\nthose laws. We shall consider some of these effects.\n\nIt is probably not necessary to explain at any length the nature\nand operation of friction. When a body cannot move without causing\ntwo surfaces to rub together, this rubbing has a tendency to\ndiminish the body\u2019s motion or to prevent it entirely. If the\nbody of a carriage be placed on the earth without the wheels, a\nconsiderable force will be requisite in order to move it at all:\nit is here the friction against the ground which obstructs the\nmotion. If the carriage be placed on its wheels, a much less force\nwill move it, but if moved it will soon stop: it is the friction at\nthe ground and at the axles which stops it: placed on a level rail\nroad, with well made and well oiled wheels, and once put in motion,\nit might run a considerable distance alone, for the friction is\nhere much less; but there is friction, and therefore the motion\nwould after a time cease.\n\n1. The friction which we shall principally consider is the friction\nwhich _prevents_ motion. So employed, friction is one of the most\nuniversal and important agents in the mechanism of our daily\ncomforts and occupations. It is a force which is called into play\nto an extent incomparably greater than all the other forces with\nwhich we are concerned in the course of our daily life. We are\ndependent upon it at every instant and in every action; and it is\nnot possible to enumerate the ways in which it serves us; scarcely\neven to suggest a sufficient number of them to give us a true\nnotion of its functions.\n\nWhat can appear a more simple operation than standing and walking?\nyet it is easy to see that without the aid of friction these simple\nactions would scarcely be possible. Every one knows how difficult\nand dangerous they are when performed on smooth ice. In such a\nsituation we cannot always succeed in standing: if the ice be very\nsmooth, it is by no means easy to walk, even when the surface is\nperfectly level; and if it were ever so little inclined, no one\nwould make the attempt. Yet walking on the ice and on the ground\ndiffer only in our experiencing more friction in the latter case.\nWe say _more_, for there is a considerable friction even in the\ncase of ice, as we see by the small distance which a stone slides\nwhen thrown along the surface. It is this friction of the earth\nwhich, at every step we take, prevents the foot from sliding back;\nand thus allows us to push the body and the other foot forwards.\nAnd when we come to violent bodily motions, to running, leaping,\npulling or pushing objects, it is easily seen how entirely we\ndepend upon the friction of the ground for our strength and force.\nEvery one knows how completely powerless we become in any of these\nactions by the _foot slipping_.\n\nIn the same manner it is the friction of objects to which the\nhand is applied, which enables us to hold them with any degree\nof firmness. In some contests it was formerly the custom for the\ncombatants to rub their bodies with oil, that the adversary might\nnot be able to keep his grasp. If the pole of the boatman, the rope\nof the sailor, were thus smooth and lubricated, how weak would be\nthe thrust and the pull! Yet this would only be the removal of\nfriction.\n\nOur buildings are no less dependent on this force for their\nstability. Some edifices are erected without the aid of cement; and\nif the stones be large and well squared, such structures may be\nhighly substantial and durable; even when rude and slight, houses\nso built answer the purposes of life. These are entirely upheld\nby friction, and without that agent they would be thrown down by\nthe Zephyr, far more easily than if all the stones were lumps of\nice with a thawing surface. But even in cases where cement _binds_\nthe masonry, it does not take the duty of _holding_ it together.\nIn consequence of the existence of friction, there is no constant\ntendency of the stones to separate; they are in a state of repose.\nIf this were not so, if every shock and every breeze required to be\ncounteracted by the cement, no composition exists which would long\nsustain such a wear and tear. The cement excludes the corroding\nelements, and helps to resist extraordinary violence; but it is\nfriction which gives the habitual state of rest.\n\nWe are not to consider friction as a _small_ force, slightly\nmodifying the effects of other agencies. On the contrary its\namount is in most cases very great. When a body lies loose on the\nground, the friction is equal to one-third or one-half, or in some\ncases the whole of its weight. But in cases of bodies supported by\noblique pressure, the amount is far more enormous. In the arch of a\nbridge, the friction which is called into play between two of the\nvaulting stones, may be equal to the whole weight of the bridge.\nIn such cases this conservative force is so great, that the common\ntheory, which neglects it, does not help us even to guess what\nwill take place. According to the theory, certain forms of arches\nonly will stand, but in practice almost any form will stand, and it\nis not easy to construct a model of a bridge which will fall.\n\nWe may see the great force of friction in the _brake_, by which\na large weight running down a long inclined plane has its motion\nmoderated and stopt; in the windlass, where a few coils of the\nrope round a cylinder sustain the stress and weight of a large\niron anchor; in the nail or screw which holds together large\nbeams; in the mode of raising large blocks of granite by an iron\nrod driven into a hole in the stone. Probably no greater forces\nare exercised in any processes in the arts than the force of\nfriction; and it is always employed to produce rest, stability,\nmoderate motion. Being always ready and never wearied, always at\nhand and augmenting with the exigency, it regulates, controls,\nsubdues all motions;--counteracts all other agents;--and finally\ngains the mastery over all other terrestrial agencies, however\nviolent, frequent, or long continued. The perpetual action of all\nother terrestrial forces appears, on a large scale, only as so many\ninterruptions of the constant and stationary rule of friction.\n\nThe objects which every where surround us, the books or dishes\nwhich stand on our tables, our tables and chairs themselves, the\nloose clods and stones in the field, the heaviest masses produced\nby nature or art, would be in a perpetual motion, quick or slow\naccording to the forces which acted on them, and to their size, if\nit were not for the tranquillizing and steadying effects of the\nagent we are considering. Without this, our apartments, if they\nkept their shape, would exhibit to us articles of furniture, and of\nall other kinds, sliding and creeping from side to side with every\npush and every wind, like loose objects in a ship\u2019s cabin, when she\nis changing her course in a gale.\n\nHere, then, we have a force, most extensive and incessant in its\noperation, which is absolutely essential to the business of this\nterrestrial world, according to any notion which we can form. The\nmore any one considers its effects, and the more he will find how\nuniversally dependent he is upon it, in every action of his life;\nresting or moving, dealing with objects of art or of nature, with\ninstruments of enjoyment or of action.\n\n2. Now we have to observe concerning this agent, Friction, that\nwe have no ground for asserting it to be a necessary result of\nother properties of matter, for instance, of their solidity and\ncoherency. Philosophers have not been able to deduce the laws of\nfriction from the other known properties of matter, nor even to\nexplain what we know experimentally of such laws, (which is not\nmuch,) without introducing new hypotheses concerning the surfaces\nof bodies, &c.--hypotheses which are not supplied us by any other\nset of phenomena. So far as our knowledge goes, friction is a\nseparate property, and may be conceived to have been bestowed upon\nmatter for particular purposes. How well it answers the purpose\nof fitting matter for the uses of the daily life of man, we have\nalready seen.\n\nWe may make suppositions as to the mode in which friction is\nconnected with the texture of bodies; but little can be gained for\nphilosophy, or for speculation of any kind, by such conjectures\nrespecting unknown connexions. If, on the other hand, we consider\nthis property of friction, and find that it prevails there, and\nthere only, where the general functions, analogies, and relations\nof the universe require it, we shall probably receive a strong\nimpression that it was introduced into the system of the world _for\na purpose_.\n\n3. It is very remarkable that this force, which is thus so\nefficacious and discharges such important offices in all earthly\nmechanism, disappears altogether when we turn to the mechanism\nof the heavens. All motions on the earth soon stop;--a machine\nwhich imitates the movements of the stars cannot go long without\nwinding up: but the stars themselves have gone on in their courses\nfor ages, with no diminution of their motions, and offer no\nobvious prospect of any change. This is so palpable a fact, that\nthe first attempts of men to systematize their mechanical notions\nwere founded upon it. The ancients held that motions were to be\ndistinguished into _natural_ motions and _violent_,--the former\ngo on without diminution--the latter are soon extinguished;--the\nmotions of the stars are of the former kind;--those of a stone\nthrown, and in short all terrestrial motions, of the latter. Modern\nphilosophers maintain that the laws of motion are the same for\ncelestial and terrestrial bodies;--that all motions are _natural_\naccording to the above description;--but that in terrestrial\nmotions, friction comes in and alters their character,--destroys\nthem so speedily that they appear to have existed only during an\neffort. And that this is the case will not now be contested. Is\nit not then somewhat remarkable that the same laws which produce\na state of permanent motion in the heavens, should, on the earth,\ngive rise to a condition in which rest is the rule and motion the\nexception? The air, the waters, and the lighter portions of matter\nare, no doubt, in a state of perpetual motion; over these friction\nhas no empire: yet even their motions are interrupted, alternate,\nvariable, and on the whole slight deviations from the condition of\nequilibrium. But in the solid parts of the globe, rest predominates\nincomparably over motion: and this, not only with regard to the\nportions which cohere as parts of the same solid; for the whole\nsurface of the earth is covered with loose masses, which, if the\npower of friction were abolished, would rush from their places and\nbegin one universal and interminable dance, which would make the\nearth absolutely uninhabitable.\n\nIf, on the other hand, the dominion of friction were extended in\nany considerable degree into the planetary spaces, there would\nsoon be an end of the system. If the planet had moved in a fluid,\nas the Cartesians supposed, and if this fluid had been subject to\nthe rules of friction which prevail in terrestrial fluids, their\nmotions could not have been of long duration. The solar system must\nsoon have ceased to be a system of revolving bodies.\n\nBut friction is neither abolished on the earth, nor active in the\nheavens. It operates where it is wanted, it is absent where it\nwould be prejudicial. And both these circumstances occasion, in\na remarkable manner, the steadiness of the course of nature. The\nstable condition of the objects in man\u2019s immediate neighbourhood,\nand the unvarying motions of the luminaries of heaven, are alike\nconducive to his well-being. This requires that he should be able\nto depend upon a fixed order of place, a fixed course of time. It\nrequires, therefore, that terrestrial objects should be affected by\nfriction, and that celestial should not; as is the case, in fact.\nWhat further evidence of benevolent design could this part of the\nconstitution of the universe supply?\n\n4. There is another view which may be taken of the forces which\noperate on the earth to produce permanency or change. Some parts\nof the terrestrial system are under the dominion of powers which\nact energetically to prevent all motion, as the crystalline forces\nby which the parts of rocks are bound together; other parts are\ninfluenced by powers which produce a perpetual movement and change\nin the matter of which they consist; thus plants and animals\nare in a constant state of internal movement, by the agency of\nthe vital forces. In the former case rigid immutability, in the\nlatter perpetual developement, are the tendencies of the agencies\nemployed. Now in the case of objects affected by friction, we\nhave a kind of intermediate condition, between the constantly\nfixed and the constantly moveable. Such objects can and do move;\nbut they move but for a short time if left to the laws of nature.\nWhen at rest, they can easily be put in motion, but still not\nwith unlimited ease; a certain finite effort, different in\ndifferent cases, is requisite for their purpose. Now this immediate\ncondition, this capacity of receiving readily and alternately the\nstates of rest and motion, is absolutely requisite for the nature\nof man, for the exertion of will, of contrivance, of foresight, as\nwell as for the comfort of life and the conditions of our material\nexistence. If all objects were fixed and immoveable, as if frozen\ninto one mass; or if they were susceptible of such motions only\nas are found in the parts of vegetables, we attempt in vain to\nconceive what would come of the business of the world. But besides\nthe state of a particle which cannot be moved, and of a particle\nwhich cannot be stopped, we have the state of a particle moveable\nbut not moved; or moved, but moved only while we choose: and this\nstate is that about which the powers, the thoughts, and the wants\nof man are mainly conversant.\n\nThus the forces by which solidity and by which organic action\nare produced, the laws of permanence and of developement, do not\nbring about all that happens. Besides these, there is a mechanical\ncondition, that of a body exposed to friction, which is neither\none of absolute permanency nor one naturally progressive; but is\nyet one absolutely necessary to make material objects capable of\nbeing instruments and aids to man; and this is the condition of by\nfar the greater part of terrestrial things. The habitual course of\nevents with regard to motion and rest is not the same for familiar\nmoveable articles, as it is for the parts of the mineral, or of\nthe vegetable world, when left to themselves; such articles are in\na condition far better adapted than any of those other conditions\nwould be, to their place and purpose. Surely this shows us an\n_adaptation_, an adjustment, of the constitution of the material\nworld to the nature of man. And as the organization of plants\ncannot be conceived otherwise than as having their life and growth\nfor its object, so we cannot conceive that friction should be\none of the leading agencies in the world in which man is placed,\nwithout supposing that it was intended to be of use when man should\nwalk and run, and build houses and ships, and bridges, and execute\ninnumerable other processes, all of which would be impossible,\nadmirably constituted as man is in other respects, if friction did\nnot exist. And believing, as we conceive we cannot but believe,\nthat the laws of motion and rest were thus given with reference\nto their ends, we perceive in this instance, as in others, how\nwide and profound this reference is, how simple in its means, how\nfertile in its consequences, how effective in its details.\n\n\n\n\nBOOK III.\n\nRELIGIOUS VIEWS.\n\n\nThe contemplation of the material universe exhibits God to us as\nthe author of the laws of material nature; bringing before us a\nwonderful spectacle, in the simplicity, the comprehensiveness,\nthe mutual adaptation of these laws, and in the vast variety of\nharmonious and beneficial effects produced by their mutual bearing\nand combined operation. But it is the consideration of the moral\nworld, of the results of our powers of thought and action, which\nleads us to regard the Deity in that light in which our relation\nto him becomes a matter of the highest interest and importance. We\nperceive that man is capable of referring his actions to principles\nof right and wrong; that both his faculties and his virtues may\nbe unfolded and advanced by the discipline which arises from the\ncircumstances of human society; that good men can be discriminated\nfrom the bad, only by a course of trial, by struggles with\ndifficulty and temptation; that the best men feel deeply the need\nof relying, in such conflicts, on the thought of a superintending\nSpiritual power; that our views of justice, our capacity for\nintellectual and moral advancement, and a crowd of hopes and\nanticipations which rise in our bosoms unsought, and cling there\nwith inexhaustible tenacity, will not allow us to acquiesce in the\nbelief that this life is the end of our existence. We are thus led\nto see that our relation the Superintender of our moral being, to\nthe Depositary of the supreme law of just and right, is a relation\nof incalculable consequence. We find that we cannot be permitted\nto be merely contemplators and speculators with regard to the\nGovernor of the moral world; we must obey His will; we must turn\nour affections to Him; we must advance in His favour; or we offend\nagainst the nature of our position in the scheme of which He is the\nauthor and sustainer.\n\nIt is far from our purpose to represent natural religion, as of\nitself sufficient for our support and guidance; or to underrate the\nmanner in which our views of the Lord of the universe have been,\nmuch more, perhaps, than we are sometimes aware, illustrated and\nconfirmed by lights derived from revelation. We do not here speak\nof the manner in which men have come to believe in God, as the\nGovernor of the moral world; but of the fact, that by the aid of\none or both of these two guides, Reason or Revelation, reflecting\npersons in every age have been led to such a belief. And we\nconceive it may be useful to point out some connexion between such\na belief of a just and holy Governor, and the conviction, which we\nhave already endeavoured to impress upon the reader, of a wise and\nbenevolent Creator of the physical world. This we shall endeavour\nto do in the present book.\n\nAt the same time that men have thus learnt to look upon God as\ntheir Governor and Judge, the source of their support and reward,\nthey have also been led, not only to ascribe to him power and\nskill, knowledge and goodness, but also attribute to him these\nqualities in a mode and degree excluding all limit:--to consider\nhim as almighty, all-wise, of infinite knowledge and inexhaustible\ngoodness; every where present and active, but incomprehensible by\nour minds, both in the manner of his agency, and the degree of his\nperfections. And this impression concerning the Deity appears to be\nthat which the mind receives from all objects of contemplation and\nall modes of advance towards truth. To this conception it leaps\nwith alacrity and joy, and in this it acquiesces with tranquil\nsatisfaction and growing confidence; while any other view of the\nnature of the Divine Power which formed and sustained the world,\nis incoherent and untenable, exposed to insurmountable objections\nand intolerable incongruities. We shall endeavour to show that the\nmodes of employment of the thoughts to which the well conducted\nstudy of nature gives rise, do tend, in all their forms, to\nproduce or strengthen this impression on the mind; and that such\nan impression, and no other, is consistent with the widest views\nand most comprehensive aspects of nature and of philosophy, which\nour Natural Philosophy opens to us. This will be the purpose of\nthe latter part of the present book. In the first place we shall\nproceed with the object first mentioned, the connexion which may\nbe perceived between the evidences of creative power, and of moral\ngovernment, in the world.\n\n\n\n\nCHAPTER I.\n\n_The Creator of the Physical World is the Governor of the Moral\nWorld._\n\n\nWith our views of the moral government of the world and the\nreligious interests of man, the study of material nature is not and\ncannot be directly and closely connected. But it may be of some\nservice to trace in these two lines of reasoning, seemingly so\nremote, a manifest convergence to the same point, a demonstrable\nunity of result. It may be useful to show that we are thus led, not\nto two rulers of the universe, but to one God;--to make it appear\nthat the Creator and Preserver of the world is also the Governor\nand Judge of men;--that the Author of the Laws of Nature is also\nthe Author of the Law of Duty;--that He who regulates corporeal\nthings by properties of attraction and affinity and assimilating\npower, is the same Being who regulates the actions and conditions\nof men, by the influence of the feeling of responsibility, the\nperception of right and wrong, the hope of happiness, the love of\ngood.\n\nThe conviction that the Divine attributes which we are taught by\nthe study of the material world, and those which we learn from\nthe contemplation of man as a responsible agent, belong to the\nsame Divine Being, will be forced upon us, if we consider the\nmanner in which all the parts of the universe, the corporeal and\nintellectual, the animal and moral, are connected with each other.\nIn each of these provinces of creation we trace refined adaptations\nand arrangements which lead us to the Creator and Director of so\nskilful a system; but these provinces are so intermixed, these\ndifferent trains of contrivance so interwoven, that we cannot,\nin our thoughts, separate the author of one part from the author\nof another. The Creator of the Heavens and of the Earth, of the\ninorganic and of the organic world, of animals and of man, of the\naffections and the conscience, appears inevitably to be one and the\nsame God.\n\nWe will pursue this reflection a little more into detail.\n\n1. The _Atmosphere_ is a mere mass of fluid floating on the\nsurface of the ball of the earth; it is one of the inert and\ninorganic portions of the universe, and must be conceived to have\nbeen formed by the same Power which formed the solid mass of the\nearth and all other parts of the solar system. But how far is the\natmosphere from being inert in its effects on organic beings, and\nunconnected with the world of life! By what wonderful adaptations\nof its mechanical and chemical properties, and of the vital powers\nof plants, to each other, are the developement and well-being\nof plants and animals secured! The creator of the atmosphere\nmust have been also the creator of plants and animals: we cannot\nfor an instant believe the contrary. But the atmosphere is not\nonly subservient to the life of animals, and of man among the\nrest; it is also the vehicle of voice; it answers the purpose of\nintercourse; and, in the case of man, of rational intercourse.\nWe have seen how remarkably the air is fitted for this office;\nthe construction of the organs of articulation, by which they are\nenabled to perform their part of the work, is, as is well known,\na most exquisite system of contrivances. But though living in an\natmosphere capable of transmitting articulate sound, and though\nprovided with organs fitted to articulate, man would never attain\nto the use of language, if he were not also endowed with another\nset of faculties. The powers of abstraction and generalization,\nmemory and reason, the tendencies which occasion the inflexions\nand combinations of words, are all necessary to the formation and\nuse of language. Are not these parts of the same scheme of which\nthe bodily faculties by which we are able to speak are another\npart? Has man his mental powers independently of the creator of\nhis bodily frame? To what purpose then, or by what cause was\nthe curious and complex machinery of the tongue, the glottis,\nthe larynx produced? These are useful for speech, and full of\ncontrivances which suggest such a use as the end for which those\norgans were constructed. But speech appears to have been no less\ncontemplated in the intellectual structure of man. The processes\nof which we have spoken, generalization, abstraction, reasoning,\nhave a close dependence on the use of speech. These faculties are\npresupposed in the formation of language, but they are developed\nand perfected by the use of language. The mind of man then, with\nall its intellectual endowments, is the work of the same artist by\nwhose hands his bodily frame was fashioned; as his bodily faculties\nagain are evidently constructed by the maker of those elements on\nwhich their action depends. The creator of the atmosphere and of\nthe material universe is the creator of the human mind, and the\nauthor of those wonderful powers of thinking, judging, inferring,\ndiscovering, by we are able to reason concerning the world in which\nwe are placed; and which aid us in lifting our thoughts to the\nsource of our being himself.\n\n2. _Light_, or the means by which light is propagated, is another\nof the inorganic elements which forms a portion of the mere\nmaterial world. The luminiferous ether, if we adopt that theory,\nor the fluid light of the theory of emission, must indubitably\npervade the remotest regions of the universe, and must be supposed\nto exist, as soon as we suppose the material parts of the universe\nto be in existence. The origin of light then must be at least as\nfar removed from us as the origin of the solar system. Yet how\nclosely connected are the properties of light with the structure\nof our own bodies! The mechanism of the organs of vision and the\nmechanism of light are, as we have seen, most curiously adapted to\neach other. We must suppose, then, that the same power and skill\nproduced one and the other of these two sets of contrivances, which\nso remarkably _fit into_ each other. The creator of light is the\nauthor of our visual powers. But how small a portion does mere\nvisual perception constitute of the advantages which we derive from\nvision! We possess ulterior faculties and capacities by which sight\nbecomes a source of happiness and good to man. The sense of beauty,\nthe love of art, the pleasure arising from the contemplation of\nnature, are all dependent on the eye; and we can hardly doubt that\nthese faculties were bestowed on man to further the best interests\nof his being. The sense of beauty both animates and refines his\ndomestic tendencies; the love of art is a powerful instrument for\nraising him above the mere cravings and satisfactions of his animal\nnature; the expansion of mind which rises in us at the sight of the\nstarry sky, the cloud-capt mountain, the boundless ocean, seems\nintended to direct our thoughts by an impressive though indefinite\nfeeling, to the Infinite Author of All. But if these faculties be\nthus part of the scheme of man\u2019s inner being, given him by a good\nand wise creator, can we suppose that this creator was any other\nthan the creator also of those visual organs, without which the\nfaculties could have no operation and no existence? As clearly as\nlight and the eye are the work of the same author, so clearly also\ndo our capacities for the most exalted visual pleasures, and the\nfeelings flowing from them, proceed from the same Divine Hand.\n\n3. The creator of the earth must be conceived to be the author also\nof all those qualities in the soil, chemical and whatever else, by\nwhich it supports vegetable life, under all the modifications of\nnatural and artificial condition. Among the attributes which the\nearth thus possesses, there are some which seem to have an especial\nreference to man in a state of society. Such are--the power of the\nearth to increase its produce under the influence of cultivation,\nand the necessary existence of property in land, in order that this\ncultivation may be advantageously applied; the rise, under such\ncircumstances, of a _surplus_ produce, of a quantity of subsistence\nexceeding the wants of the cultivators alone; and the consequent\npossibility of inequalities of rank, and of all the arrangements\nof civil society. These are all parts of the constitution of the\nearth. But these would all remain mere idle possibilities, if the\nnature of man had not a corresponding direction. If man had not a\nsocial and economical tendency, a disposition to congregate and\nco-operate, to distribute possessions and offices among the members\nof the community, to make and obey and enforce laws, the earth\nwould in vain be ready to respond to the care of the husbandman.\nMust we not then suppose that this attribute of the earth was\nbestowed upon it by Him who gave to man those corresponding\nattributes, through which the apparent niggardliness of the soil\nis the source of general comfort and security, of polity and law?\nMust we not suppose that He who created the soil also inspired man\nwith those social desires and feelings which produce cities and\nstates, laws and institutions, arts and civilization; and that thus\nthe apparently inert mass of earth is a part of the same scheme as\nthose faculties and powers with which man\u2019s moral and intellectual\nprogress is most connected?\n\n4. Again:--It will hardly be questioned that the author of the\nmaterial elements is also the author of the structure of animals,\nwhich is adapted to and provided for by the constitution of the\nelements in such innumerable ways. But the author of the bodily\nstructure of animals must also be the author of their instincts,\nfor without these the structure would not answer its purpose. And\nthese instincts frequently assume the character of affections\nin a most remarkable manner. The love of offspring, of home, of\ncompanions, are often displayed by animals, in a way that strikes\nthe most indifferent observer; and yet these affections will hardly\nbe denied to be a part of the same scheme as the instincts by which\nthe same animals seek food and the gratifications of sense. Who can\ndoubt that the anxious and devoted affection of the mother-bird\nfor her young after they are hatched, is a part of the same system\nof Providence as the instinct by which she is impelled to sit\nupon her eggs? and this, of the same by which her eggs are so\norganized that incubation leads to the birth of the young animal?\nNor, again, can we imagine that while the structure and affections\nof animals belong to one system of things, the affections of man,\nin many respects so similar to those of animals, and connected\nwith the bodily frame in a manner so closely analogous, can belong\nto a different scheme. Who, that reads the touching instances of\nmaternal affection, related so often of the women of all nations,\nand of the females of all animals, can doubt that the principle\nof action is the same in the two cases, though enlightened in one\nof them by the rational faculty: And who can place in separate\nprovinces the supporting and protecting love of the father and\nthe mother? or consider as entirely distinct from these, and\nbelonging to another part of our nature, the other kinds of family\naffection? or disjoin man\u2019s love of his home, his clan, his tribe,\nhis country, from the affection which he bears to his family? The\nlove of offspring, home, friends, in man, is then part of the same\nsystem of contrivances of which bodily organization is another\npart. And thus the author of our corporeal frame is also the author\nof our capacity of kindness and resentment, of our love and of our\nwish to be loved, of all the emotions which bind us to individuals,\nto our families, and to our kind.\n\nIt is not necessary here to follow out and classify these emotions\nand affections; or to examine how they are combined and connected\nwith our other motives of action, mutually giving and receiving\nstrength and direction. The desire of esteem, of power, of\nknowledge, of society, the love of kindred, of friends, of our\ncountry, are manifestly among the main forces by which man is urged\nto act and to abstain. And as these parts of the constitution of\nman are clearly intended, as we conceive, to impel him in his\nappointed path; so we conceive that they are no less clearly the\nwork of the same great Artificer who created the heart, the eye,\nthe hand, the tongue, and that elemental world in which, by means\nof these instruments, man pursues the objects of his appetites,\ndesires, and affections.\n\n5. But if the Creator of the world be also the author of our\nintellectual powers, of our feeling for the beautiful and the\nsublime, of our social tendencies, and of our natural desires and\naffections, we shall find it impossible not to ascribe also to Him\nthe higher directive attributes of our nature, the conscience and\nthe religious feeling, the reference of our actions to the rule of\nduty and to the will of God.\n\nIt would not suit the plan of the present treatise to enter into\nany detailed analysis of the connexion of these various portions\nof our moral constitution. But we may observe that the existence\nand universality of the conception of duty and right cannot be\ndoubted, however men may differ as to its original or derivative\nnature. All men are perpetually led to form judgments concerning\nactions, and emotions which lead to action, as right or wrong;\nas what they _ought_ or _ought not_ to do or feel. There is a\nfaculty which approves and disapproves, acquits or condemns the\nworkings of our other faculties. Now, what shall we say of such\na judiciary principle, thus introduced among our motives to\naction? Shall we conceive that while the other springs of action\nare balanced against each other by our Creator, this, the most\npervading and universal regulator, was no part of the original\nscheme? That--while the love of animal pleasures, of power, of\nfame, the regard for friends, the pleasure of bestowing pleasure,\nwere infused into man as influences by which his course of life\nwas to be carried on, and his capacities and powers developed and\nexercised;--this reverence for a moral law, this acknowledgment\nof the obligation of duty,--a feeling which is every where found,\nand which may become a powerful, a predominating motive of\naction,--was given for no purpose, and belongs not to the design?\nSuch an opinion would be much as if we should acknowledge the\nskill and contrivance manifested in the other parts of a ship, but\nshould refuse to recognize the rudder as exhibiting any evidence\nof a purpose. Without the reverence which the opinion of right\ninspires, and the scourge of general disapprobation inflicted on\nthat which is accounted wicked, society could scarcely go on; and\ncertainly the feelings and thoughts and characters of men could\nnot be what they are. Those impulses of nature which involve no\nacknowledgment of responsibility, and the play and struggle of\ninterfering wishes, might preserve the species in some shape of\nexistence, as we see in the case of brutes. But a person must be\nstrangely constituted, who, living amid the respect for law, the\nadmiration for what is good, the order and virtues and graces of\ncivilized nations, (all which have their origin in some degree in\nthe feeling of responsibility) can maintain that all these are\ncasual and extraneous circumstances, no way contemplated in the\nformation of man; and that a condition in which there should be\nobligation in law, no merit in self-restraint, no beauty in virtue,\nis equally suited to the powers and the nature of man, and was\nequally contemplated when those powers were given him.\n\nIf this supposition be too extravagant to be admitted, as\nit appears to be, it remains then that man, intended, as we\nhave already seen from his structure and properties, to be\na discoursing, social being, acting under the influence of\naffections, desires, and purposes, was also intended to act under\nthe influence of a sense of duty; and that the acknowledgment of\nthe obligation of a moral law is as much part of his nature, as\nhunger or thirst, maternal love or the desire of power; that,\ntherefore, in conceiving man as the work of a Creator, we must\nimagine his powers and character given him with an intention on\nthe Creator\u2019s part that this sense of duty should occupy its place\nin his constitution as an active and thinking being: and that this\ndirective and judiciary principle is a part of the work of the same\nAuthor who made the elements to minister to the material functions,\nand the arrangements of the world to occupy the individual and\nsocial affections of his living creatures.\n\nThis principle of conscience, it may further be observed, does not\nstand upon the same level as the other impulses of our constitution\nby which we are prompted or restrained. By its very nature and\nessence, it possesses a supremacy over all others. \u201cYour obligation\nto obey this law is its being the law of your nature. That your\nconscience approves of and attests such a course of action is\nitself alone an obligation. Conscience does not only offer itself\nto show us the way we should walk in, but it likewise carries its\nown authority with it, that it is our natural guide: the guide\nassigned us by the author of our nature.\u201d[26] That we ought to do\nan action, is of itself a sufficient and ultimate answer to the\nquestions, _why_ we should do it?--how we are _obliged_ to do it?\nThe conviction of duty implies the soundest reason, the strongest\nobligation, of which our nature is susceptible.\n\nWe appear then to be using only language which is well capable of\nbeing justified, when we speak of this irresistible esteem for what\nis right, this conviction of a rule of action extending beyond the\ngratification of our irreflective impulses, as an impress stamped\nupon the human mind by the Deity himself; a trace of His nature; an\nindication of His will; an announcement of His purpose; a promise\nof His favour: and though this faculty may need to be confirmed and\nunfolded, instructed and assisted by other aids, it still seems to\ncontain in itself a sufficient intimation that the highest objects\nof man\u2019s existence are to be attained, by means of a direct and\nintimate reference of his thoughts and actions to the Divine Author\nof his being.\n\nSuch then is the Deity to which the researches of Natural Theology\npoint; and so far is the train of reflections in which we have\nengaged, from being merely speculative and barren. With the\nmaterial world we cannot stop. If a superior Intelligence _have_\nordered and adjusted the succession of seasons and the structure\nof the plants of the field, we must allow far more than this at\nfirst sight would seem to imply. We must admit still greater\npowers, still higher wisdom for the creation of the beasts of the\nforest with their faculties; and higher wisdom still and more\ntranscendent attributes, for the creation of man. And when we reach\nthis point, we find that it is not knowledge only, not power only,\nnot foresight and beneficence alone, which we must attribute\nto the Maker of the World; but that we must consider him as the\nAuthor, in us, of a reverence for moral purity and rectitude; and,\nif the author of such emotions in us, how can we conceive of Him\notherwise, than that these qualities are parts of his nature; and\nthat he is not only wise and great, and good, incomparably beyond\nour highest conceptions, but also conformed in his purposes to the\nrule which he thus impresses upon us, that is, Holy in the highest\ndegree which we can imagine to ourselves as possible.\n\n\n\n\nCHAPTER II.\n\n_On the Vastness of the Universe._\n\n\n1. The aspect of the world, even without any of the peculiar lights\nwhich science throws upon it, is fitted to give us an idea of the\ngreatness of the power by which it is directed and governed, far\nexceeding any notions of power and greatness which are suggested by\nany other contemplation. The number of human beings who surround\nus--the various conditions requisite for their life, nutrition,\nwell-being, all fulfilled;--the way in which these conditions are\nmodified, as we pass in thought to other countries, by climate,\ntemperament, habit;--the vast amount of the human population of the\nglobe thus made up;--yet man himself but one among almost endless\ntribes of animals;--the forest, the field, the desert, the air,\nthe ocean, all teeming with creatures whose bodily wants are as\ncarefully provided for as his;--the sun, the clouds, the winds,\nall attending, as it were, on these organized beings;--a host of\nbeneficent energies, unwearied by time and succession, pervading\nevery corner of the earth;--this spectacle cannot but give the\ncontemplator a lofty and magnificent conception of the Author of\nso vast a work, of the Ruler of so wide and rich an empire, of the\nProvider for so many and varied wants, the Director and Adjuster of\nsuch complex and jarring interests.\n\nBut when we take a more exact view of this spectacle, and aid our\nvision by the discoveries which have been made of the structure and\nextent of the universe, the impression is incalculably increased.\n\nThe number and variety of animals, the exquisite skill displayed\nin their structure, the comprehensive and profound relations by\nwhich they are connected, far exceed any thing which we could in\nany degree have imagined. But the view of the universe expands also\non another side. The earth, the globular body thus covered with\nlife, is not the only globe in the universe. There are, circling\nabout our own sun, six others, so far as we can judge, perfectly\nanalogous in their nature: besides our moon and other bodies\nanalogous to it. No one can resist the temptation to conjecture,\nthat these globes, some of them much larger than our own, are\nnot dead and barren;--that they are, like ours, occupied with\norganization, life, intelligence. To conjecture is all that we can\ndo, yet even by the perception of such a possibility, our view of\nthe kingdom of nature is enlarged and elevated. The outermost of\nthe planetary globes of which we have spoken is so far from the\nsun, that the central luminary must appear to the inhabitants of\nthat planet, if any there are, no larger than Venus does to us; and\nthe length of their year will be eighty-two of ours.\n\nBut astronomy carries us still onwards. It teaches us that, with\nthe exception of the planets already mentioned, the stars which\nwe see have no immediate relation to our system. The obvious\nsupposition is that they are of the nature and order of our\nsun: the minuteness of their apparent magnitude agrees, on this\nsupposition, with the enormous and almost inconceivable distance\nwhich, from all the measurements of astronomers, we are led to\nattribute to them. If then these are suns, they may, like our sun,\nhave planets revolving round them; and these may, like our planet,\nbe the seats of vegetable and animal and rational life:--we may\nthus have in the universe worlds, no one knows how many, no one can\nguess how varied:--but however many, however varied, they are still\nbut so many provinces in the same empire, subject to common rules,\ngoverned by a common power.\n\nBut the stars which we see with the naked eye are but a very small\nportion of those which the telescope unveils to us. The most\nimperfect telescope will discover some that are invisible without\nit; the very best instrument perhaps does not show us the most\nremote. The number which crowds some parts of the heavens is truly\nmarvellous. Dr. Herschel calculated that a portion of the milky\nway, about ten degrees long and two and a half broad, contained two\nhundred and fifty-eight thousand. In a sky so occupied, the moon\nwould eclipse two thousand of such stars at once.\n\nWe learn too from the telescope that even in this province the\nvariety of nature is not exhausted. Not only do the stars differ in\ncolour and appearance, but some of them grow periodically fainter\nand brighter, as if they were dark on one side, and revolved on\ntheir axes. In other cases two stars appear close to each other,\nand in some of these cases it has been clearly established,\nthat the two have a motion of revolution about each other; thus\nexhibiting an arrangement before unguessed, and giving rise,\npossibly, to new conditions of worlds. In other instances again,\nthe telescope shows, not luminous points, but extended masses of\ndilute light, like bright clouds, hence called _nebul\u00e6_. Some\nhave supposed (as we have noticed in the last book) that such\nnebul\u00e6 by further condensation might become suns; but for such\nopinions we have nothing but conjecture. Some stars again have\nundergone permanent changes, or have absolutely disappeared, as the\ncelebrated star of 1572, in the constellation Cassiopea.\n\nIf we take the whole range of created objects in our own system,\nfrom the sun down to the smallest animalcule, and suppose such a\nsystem, or something in some way analogous to it, to be repeated\nfor each of the millions of stars thus revealed to us, we have a\nrepresentation of the material part of the universe, according to a\nview which many minds receive as a probable one; and referring this\naggregate of systems to the Author of the universe, as in our own\nsystem we have found ourselves led to do, we have thus an estimate\nof the extent to which his creative energy would thus appear to\nhave been exercised in the material world.\n\nIf we consider further the endless and admirable contrivances and\nadaptations which philosophers and observers have discovered in\nevery portion of our own system, every new step of our knowledge\nshowing us something new in this respect; and if we combine this\nconsideration with the thought how small a portion of the universe\nour knowledge includes, we shall, without being able at all to\ndiscern the extent of the skill and wisdom thus displayed, see\nsomething of the character of the design, and of the copiousness\nand ampleness of the means which the scheme of the world exhibits.\nAnd when we see that the tendency of all the arrangements which\nwe can comprehend is to support the existence, to develope the\nfaculties, to promote the well-being of these countless species of\ncreatures; we shall have some impression of the beneficence and\nlove of the Creator, as manifested in the physical government of\nhis creation.\n\n2. It is extremely difficult to devise any means of bringing\nbefore a common apprehension the scale on which the universe is\nconstructed, the enormous proportion which the larger dimensions\nbear to the smaller, and the amazing number of steps from large to\nsmaller, or from small to larger, which the consideration of it\noffers. The following comparative representations may serve to\ngive the reader to whom the subject is new some idea of these steps.\n\nIf we suppose the earth to be represented by a globe a foot in\ndiameter, the distance of the sun from the earth will be about two\nmiles; the diameter of the sun, on the same supposition, will be\nsomething above one hundred feet, and consequently his bulk such\nas might be made up of two hemispheres, each about the size of the\ndome of St. Paul\u2019s. The moon will be thirty feet from us, and her\ndiameter three inches, about that of a cricket ball. Thus the sun\nwould much more than occupy all the space within the moon\u2019s orbit.\nOn the same scale, Jupiter would be above ten miles from the sun,\nand Uranus forty. We see then how thinly scattered through space\nare the heavenly bodies. The fixed stars would be at an unknown\ndistance, but, probably, if all distances were thus diminished, no\nstar would be nearer to such a one-foot earth, than the moon now is\nto us.\n\nOn such a terrestrial globe the highest mountains would be\nabout an eightieth of an inch high, and consequently only just\ndistinguishable. We may imagine therefore how imperceptible would\nbe the largest animals. The whole organized covering of such a\nglobe would be quite undiscoverable by the eye, except perhaps by\ncolour, like the bloom on a plum.\n\nIn order to restore this earth and its inhabitants to their true\ndimensions, we must magnify them forty millions of times; and to\npreserve the proportions, we must increase equally the distances\nof the sun and of the stars from us. They seem thus to pass off\ninto infinity; yet each of them thus removed, has its system of\nmechanical and perhaps of organic processes going on upon its\nsurface.\n\nBut the arrangements of organic life which we can see with the\nnaked eye are few, compared with those which the microscope\ndetects. We know that we may magnify objects thousands of times,\nand still discover fresh complexities of structure; if we suppose,\ntherefore, that we increase every particle of matter in our\nuniverse in such a proportion, in length, breadth, and thickness,\nwe may conceive that we tend thus to bring before our apprehension\na true estimate of the quantity of organized adaptations which are\nready to testify the extent of the Creator\u2019s power.\n\n3. The other numerical quantities which we have to consider in\nthe phenomena of the universe are on as gigantic a scale as the\ndistances and sizes. By the rotation of the earth on its axis, the\nparts of the equator move at the rate of a thousand miles an hour,\nand the portions of the earth\u2019s surface which are in our latitude,\nat about six hundred. The former velocity is nearly that with\nwhich a cannon ball is discharged from the mouth of a gun; but,\nlarge as it is, it is inconsiderable compared with the velocity\nof the earth in its orbit about the sun. This latter velocity is\nsixty-five times the former. By the rotatory motion of the earth,\na point of its surface is carried sometimes forwards and sometimes\nbackwards with regard to the annual progression; but in consequence\nof the great predominance of the latter velocity in amount, the\nformer scarcely affects it either way. And even the latter velocity\nis inconsiderable compared with that of light; which comparison,\nhowever, we shall not make; since, according to the theory we have\nconsidered as most probable, the motion of light is not a transfer\nof matter but of motion from one part of space to another.\n\nThe extent of the scale of density of different substances has\nalready been mentioned; gold is twenty times as heavy as water; air\nis eight hundred and thirty times lighter, steam eight thousand\ntimes lighter than water; the luminiferous ether is incomparably\nrarer than steam: and this is true of the matter of light, whether\nwe adopt the undulatory theory or any other.\n\n4. The above statements are vast in amount, and almost oppressive\nto our faculties. They belong to the measurement of the powers\nwhich are exerted in the universe, and of the spaces through which\ntheir efficacy reaches (for the most distant bodies are probably\nconnected both by gravity and light.) But these estimates cannot be\nsaid so much to give us any notion of the powers of the Deity, as\nto correct the errors we should fall into by supposing his powers\nat all to resemble ours:--by supposing that numbers, and spaces,\nand forces, and combinations, which would overwhelm us, are any\nobstacle to the arrangements which his plan requires. We can easily\nunderstand that to an intelligence surpassing ours in degree only,\nthat may be easy which is impossible to us. The child who cannot\ncount beyond four, the savage who has no name for any number above\nfive, cannot comprehend the possibility of dealing with thousands\nand millions: yet a little additional developement of the intellect\nmakes such numbers manageable and conceivable. The difficulty\nwhich appears to reside in numbers and magnitudes and stages of\nsubordination, is one produced by judging from ourselves--by\nmeasuring with our own sounding line; when that reaches no bottom,\nthe ocean appears unfathomable. Yet in fact, how is a hundred\nmillions of miles a _great_ distance? how is a hundred millions\nof times a _great_ ratio? Not in itself: this _greatness_ is no\nquality of the numbers which can be proved like their mathematical\nproperties; on the contrary, all that absolutely belongs to number,\nspace, and ratio, must, we know demonstrably, be equally true of\nthe largest and the smallest. It is clear that the _greatness_ of\nthese expressions of measure has reference to _our_ faculties only.\nOur astonishment and embarrassment take for granted the limits\nof our own nature. We have a tendency to treat a difference of\ndegree and of addition, as if it were a difference of kind and of\ntransformation. The existence of the attributes, design, power,\ngoodness, is a matter depending on obvious grounds: about these\nqualities there can be no mistake: if we can know any thing, we\ncan know these attributes when we see them. But the extent, the\nlimits of such attributes must be determined by their effects; our\nknowledge of their limits by what we see of the effects. Nor is any\nextent, any amount of power and goodness improbable beforehand: we\nknow that these must be great, we cannot tell how great. We should\nnot expect beforehand to find them bounded; and therefore when the\nboundless prospect opens before us, we may be bewildered, but we\nhave no reason to be shaken in our conviction of the reality of\nthe cause from which their effects proceed: we may feel ourselves\nincapable of following the train of thought, and may stop, but we\nhave no rational motive for quitting the point which we have thus\nattained in tracing the Divine Perfections.\n\nOn the contrary, those magnitudes and proportions which leave our\npowers of conception far behind;--that ever-expanding view which\nis brought before us, of the scale and mechanism, the riches and\nmagnificence, the population and activity of the universe;--may\nreasonably serve, not to disturb, but to enlarge and elevate our\nconceptions of the Maker and Master of all; to feed an ever-growing\nadmiration of His wonderful nature; and to excite a desire to be\nable to contemplate more steadily and conceive less inadequately\nthe scheme of his government and the operation of his power.\n\n\n\n\nCHAPTER III.\n\n_On Man\u2019s Place in the Universe._\n\n\nThe mere aspect of the starry heavens, without taking into account\nthe view of them to which science introduces us, tends strongly\nto force upon man the impression of his own insignificance. The\nvault of the sky arched at a vast and unknown distance over our\nheads; the stars, apparently infinite in number, each keeping its\nappointed place and course, and seeming to belong to a wide system\nof things which has no relation to the earth; while man is but one\namong many millions of the earth\u2019s inhabitants;--all this makes\nthe contemplative spectator feel how exceedingly small a portion\nof the universe he is; how little he must be, in the eyes of an\nintelligence which can embrace the whole. Every person, in every\nage and country, will recognize as irresistibly natural the train\nof thought expressed by the Hebrew psalmist: \u201cwhen I consider the\nheavens the work of thy hands--the moon and the stars which thou\nhast ordained--Lord what is man that thou art mindful of him, or\nthe son of man that thou regardest him?\u201d\n\nIf this be the feeling of the untaught person, when he contemplates\nthe aspect of the skies, such as they offer themselves to a\ncasual and unassisted glance, the impression must needs be\nincalculably augmented, when we look at the universe with the aid\nof astronomical discovery and theory. We then find, that a few of\nthe shining points which we see scattered on the face of the sky\nin such profusion, appear to be of the same nature as the earth,\nand may perhaps, as analogy would suggest, be like the earth, the\nhabitations of organized beings;--that the rest of \u201cthe host of\nheaven\u201d may, by a like analogy, be conjectured to be the centres of\nsimilar systems of revolving worlds;--that the vision of man has\ngone travelling onwards, to an extent never anticipated, through\nthis multitude of systems, and that while myriads of new centres\nstart up at every advance, he appears as yet not to have received\nany intimation of a limit. Every person probably feels, at first,\nlost, confounded, overwhelmed, with the vastness of this spectacle;\nand seems to himself, as it were, annihilated by the magnitude\nand multitude of the objects which thus compose the universe.\nThe distance between him and the Creator of the world appears to\nbe increased beyond measure by this disclosure. It seems as if a\nsingle individual could have no chance and no claim for the regard\nof the Ruler of the whole.\n\nThe mode in which the belief of God\u2019s government of the physical\nworld is important and interesting to man, is, as has already\nbeen said, through the connexion which this belief has with the\nconviction of God\u2019s government of the moral world; this latter\ngovernment being, from its nature, one which has a personal\nrelation to each individual, his actions and thoughts. It will,\ntherefore, illustrate our subject to show that this impression\nof the difficulty of a personal superintendence and government,\nexercised by the Maker of the world over each of his rational and\nfree creatures, is founded upon illusory views; and that on an\nattentive and philosophical examination of the subject, such a\ngovernment is in accordance with all that we can discover of the\nscheme and the scale of the universe.\n\n1. We may, in the first place, repeat the observation made in\nthe last chapter, on the confusion which sometimes arises in our\nminds, and makes us consider the number of the objects of the\nDivine care as a difficulty in the way of its exercise. If we\ncan conceive this care employed on a million of persons, on the\npopulation of a kingdom, of a city, of a street, there is no real\ndifficulty in supposing it extended to every planet in the solar\nsystem, admitting each to be peopled as ours is; nor to every\npart of the universe, supposing each star the centre of such a\nsystem. _Numbers_ are nothing in themselves; and when we reject the\nknown, but unessential limits of our own faculties, it is quite as\nallowable to suppose a million millions of earths, as one, to be\nunder the moral government of God.\n\n2. In the next place we may remark, not only that no reason can be\nassigned why the Divine care should not extend to a much greater\nnumber of individuals than we at first imagine, but that in fact\nwe know that it _does_ so extend. It has been well observed, that\nabout the same time when the invention of the telescope showed us\nthat there might be myriads of other worlds claiming the Creator\u2019s\ncare; the invention of the microscope proved to us that there were\nin our own world myriads of creatures, before unknown, which this\ncare was preserving. While one discovery seemed to remove the\nDivine Providence further from us, the other gave us most striking\nexamples that it was far more active in our neighbourhood than we\nhad supposed: while the first extended the boundaries of God\u2019s\nknown kingdom, the second made its known administration more minute\nand careful. It appeared that in the leaf and in the bud, in solids\nand in fluids, animals existed hitherto unsuspected; the apparently\ndead masses and blank spaces of the world were found to swarm with\nlife. And yet, of the animals thus revealed, all, though unknown to\nus before, had never been forgotten by Providence. Their structure,\ntheir vessels and limbs, their adaptation to their situation, their\nfood and habitations, were regulated in as beautiful and complete\na manner as those of the largest and apparently most favoured\nanimals. The smallest insects are as exactly finished, often as\ngaily ornamented, as the most graceful beasts or the birds of\nbrightest plumage. And when we seem to go out of the domain of the\ncomplex animal structure with which we are familiar, and come to\nanimals of apparently more scanty faculties, and less developed\npowers of enjoyment and action, we still find that their faculties\nand their senses are in exact harmony with their situation and\ncircumstances; that the wants which they have are provided for, and\nthe powers which they possess called into activity. So that M\u00fcller,\nthe patient and accurate observer of the smallest and most obscure\nmicroscopical animalcula, declares that all classes alike, those\nwhich have manifest organs, and those which have not, offer a vast\nquantity of new and striking views of the animal economy; every\nstep of our discoveries leading us to admire the design and care\nof the Creator.[27] We find, therefore, that the Divine Providence\nis, in fact, capable of extending itself adequately to an immense\nsuccession of tribes of beings, surpassing what we can imagine or\ncould previously have anticipated; and thus we may feel secure, so\nfar as analogy can secure us, that the mere multitude of created\nobjects cannot remove us from the government and superintendence of\nthe Creator.\n\n3. We may observe further, that, vast as are the parts and\nproportions of the universe, we still appear to be able to perceive\nthat it is _finite_; the subordination of magnitudes and numbers\nand classes appears to have its limits. Thus, for any thing which\nwe can discover, the sun is the largest body in the universe;\nand at any rate, bodies of the order of the sun are the largest\nof which we have any evidence: we know of no substance denser\nthan gold, and it is improbable that one denser, or at least much\ndenser, should ever be detected: the largest animals which exist\nin the sea and on the earth are almost certainly known to us. We\nmay venture also to say, that the smallest animals which possess\nin their structure a clear analogy with larger ones, have been\nalready seen. Many of the animals which the microscope detects, are\nas complete and complex in their organization as those of larger\nsize: but beyond a certain point, they appear, as they become\nmore minute, to be reduced to a homogeneity and simplicity of\ncomposition which almost excludes them from the domain of animal\nlife. The smallest microscopical objects which can be supposed\nto be organic, are points,[28] or gelatinous globules,[29] or\nthreads,[30] in which no distinct organs, interior or exterior,\ncan be discovered. These, it is clear, cannot be considered as\nindicating an indefinite progression of animal life in a descending\nscale of minuteness. We can, mathematically speaking, conceive one\nof these animals as perfect and complicated in its structure as\nan elephant or an eagle, but we do not find it so in nature. It\nappears, on the contrary, in these objects, as if we were, at a\ncertain point of magnitude, reaching the boundaries of the animal\nworld. We need not here consider the hypotheses and opinions to\nwhich these ambiguous objects have given rise; but, without any\ntheory, they tend to show that the subordination of organic life is\nfinite on the side of the little as well as of the great.\n\nSome persons might, perhaps, imagine that a ground for believing\nthe smallness of organized beings to be limited, might be found in\nwhat we know of the constitution of matter. If solids and fluids\nconsist of particles of a definite, though exceeding smallness,\nwhich cannot further be divided or diminished, it is manifest\nthat we have, in the smallness of these particles, a limit to the\npossible size of the vessels and organs of animals. The fluids\nwhich are secreted, and which circulate in the body of a mite, must\nneeds consist of a vast number of particles, or they would not be\nfluids: and an animal might be so much smaller than a mite, that\nits tubes could not contain a sufficient collection of the atoms\nof matter, to carry on its functions. We should, therefore, of\nnecessity reach a limit of minuteness in organic life, if we could\ndemonstrate that matter is composed of such indivisible atoms. We\nshall not, however, build any thing on this argument; because,\nthough the _atomic theory_ is sometimes said to be proved, what is\nproved is, that chemical and other effects take place as if they\nwere the aggregate of the effects of certain particles of elements,\nthe _proportions_ of which particles are fixed and definite; but\nthat any limit can be assigned to the smallness of these particles,\nhas never yet been made out. We prefer, therefore, to rest the\nproof of the finite extent of animal life, as to size, on the\nmicroscopical observations previously referred to.\n\nProbably we cannot yet be said to have reached the limit of the\nuniverse with the power of our telescopes; that is, it does\nnot appear that telescopes have yet been used, so powerful in\nexhibiting small stars, that we can assume that more powerful\ninstruments would not discover new stars. Whether or no, however,\nthis degree of perfection has been reached, we have no proof that\nit does not exist; if it were once obtained we should have, with\nsome approximation, the limit of the universe as to the number of\nworlds, as we have already endeavoured to show we have obtained\nthe limits with regard to the largeness and smallness of the\ninhabitants of our own world.\n\nIn like manner, although the discovery of new species in some of\nthe kingdoms of nature has gone on recently with enormous rapidity,\nand to an immense extent;--for instance in botany, where the\nspecies known in the time of Linn\u00e6us were about ten thousand, and\nare now probably fifty thousand;--there can be no doubt that the\nnumber of species and genera is really limited; and though a great\nextension of our knowledge is required to reach these limits, it\nis our ignorance merely, and not their nonexistence, which removes\nthem from us.\n\nIn the same way it would appear that the universe, so far as it\nis an object of our knowledge, is finite in other respects also.\nNow when we have once attained this conviction, all the oppressive\napprehension of being overlooked in the government of the universe\nhas no longer any rational source. For in the superintendence\nof a finite system of things, what is there which can appear\ndifficult or overwhelming to a Being such as we must, from what\nwe know, conceive the Creator to be? Difficulties arising from\nspace, number, gradation, are such as we can conceive _ourselves_\ncapable of overcoming, merely by an extension of our present\nfaculties. Is it not then easy to imagine that such difficulties\nmust vanish before Him who made us and our faculties? Let it be\nconsidered how enormous a proportion the largest work of man bears\nto the smallest;--the great pyramid to the point of a needle. This\ncomparison does not overwhelm us, because we know that man has\nmade both. Yet the difference between this proportion and that of\nthe sun to the claw of a mite, does not at all correspond to the\ndifference which we must suppose to obtain between the Creator and\nthe creature. It appears then that, if the first flash of that view\nof the universe which science reveals to us, does sometimes dazzle\nand bewilder men, a more attentive examination of the prospect, by\nthe light we thus obtain, shows us how unfounded is the despair\nof our being the objects of Divine Providence, how absurd the\npersuasion that we have discovered the universe to be too large for\nits ruler.\n\n4. Another ground of satisfactory reflection, having the same\ntendency, is to be found in the admirable order and consistency,\nthe subordination and proportion of parts, which we find to prevail\nin the universe, as far as our discoveries reach. We have, it\nmay be, a multitude almost innumerable of worlds, but no symptom\nof crowding, of confusion, of interference. All such defects are\navoided by the manner in which these worlds are distributed into\nsystems;--these systems, each occupying a vast space, but yet\ndisposed at distances before which their own dimensions shrink\ninto insignificance;--all governed by one law, yet this law so\nconcentrating its operation on each system, that each proceeds as\nif there were no other, and so regulating its own effects that\nperpetual change produces permanent uniformity. This is the kind of\nharmonious relation which we perceive in that part of the universe,\nthe mechanical part namely, the laws of which are best known to\nus. In other provinces, where our knowledge is more imperfect, we\ncan see glimpses of a similar vastness of combination, producing,\nby its very nature, completeness of detail. Any analogy by which\nwe can extend such views to the moral world, must be of a very\nwide and indefinite kind; yet the contemplation of this admirable\nrelation of the arrangements of the physical creation, and the\nperfect working of their laws, is well calculated to give us\nconfidence in a similar beauty and perfection in the arrangements\nby which our moral relations are directed, our higher powers and\nhopes unfolded. We may readily believe that there is, in this part\nof the creation also, an order, a subordination of some relations\nto others, which may remove all difficulty arising from the vast\nmultitude of moral agents and actions, and make it possible that\nthe superintendence of the moral world shall be directed with as\nexact a tendency to moral good, as that by which the government of\nthe physical world is directed to physical good.\n\nWe may perhaps see glimpses of such an order, in the arrangements\nby which our highest and most important duties depend upon our\nrelation to a small circle of persons immediately around us: and\nagain, in the manner in which our acting well or ill results from\nthe operation of a few principles within us; as our conscience, our\ndesire of moral excellence, and of the favour of God. We can hardly\nconsider such principles otherwise than as intended to occupy\ntheir proper place in the system by which man\u2019s destination is to\nbe determined; and thus, as among the means of the government and\nsuperintendence of God in the moral world.\n\nThat there must be an order and a system to which such regulative\nprinciples belong, the whole analogy of creation compels us to\nbelieve. It would be strange indeed, if, while the mechanical\nworld, the system of inert matter, is so arranged that we\ncannot contemplate its order without an elevated intellectual\npleasure;--while organized life has no faculties without their\nproper scope, no tendencies without their appointed object;--the\nrational faculties and moral tendencies of man should belong to no\nsystematic order, should operate with no corresponding purpose:\nthat, while the perception of sweet and bitter has its acknowledged\nand unmistakeable uses, the universal perception of right and\nwrong, the unconquerable belief of the merit of certain feelings\nand actions, the craving alike after moral advancement and after\nthe means of attaining it, should exist only to delude, perplex,\nand disappoint man. No one, with his contemplations calmed and\nfilled and harmonized by the view of the known constitution of\nthe universe, its machinery \u201cwheeling unshaken\u201d in the farthest\nskies and in the darkest cavern, its vital spirit breathing alike\neffectively in the veins of the philosopher and the worm;--no one,\nunder the influence of such a train of contemplations, can possibly\nadmit into his mind a persuasion which makes the moral part of\nour nature a collection of inconsistent and futile impressions,\nof idle dreams and warring opinions, each having the same claims\nto our acceptance. Wide as is the distance between the material\nand the moral world; shadowy as all reasonings necessarily are\nwhich attempt to carry the inferences of one into the other;\nelevated above the region of matter as all the principles and\ngrounds of truth must be, which belong to our responsibilities\nand hopes; still the astronomical and natural philosopher can\nhardly fail to draw from their studies an imperturbable conviction\nthat our moral nature cannot correspond to those representations\naccording to which it has no law, coherency, or object. The mere\nnatural reasoner may, or must stop far short of all that it is\nhis highest interest to know, his first duty to pursue; but even\nhe, if he take any elevated and comprehensive views of his own\nsubject, must escape from the opinions, as unphilosophical as they\nare comfortless, which would expel from our view of the world\nall reference to duty and moral good, all reliance on the most\nuniversal grounds of trust and hope.\n\nMen\u2019s belief of their duty, and of the reasons for practising it,\nconnected as it is with the conviction of a personal relation to\ntheir Maker, and of His power of superintendence and reward, is as\nmanifest a fact in the moral, as any that can be pointed out is\nin the natural world. By mere analogy which has been intimated,\ntherefore, we cannot but conceive that this fact belongs in some\nmanner or other to the order of the moral world, and of its\ngovernment.\n\nWhen any one acknowledges a moral governor of the world; perceives\nthat domestic and social relations are perpetually operating and\nseem intended to operate, to retain and direct men in the path of\nduty; and feels that the voice of conscience, the peace of heart\nwhich results from a course of virtue, and the consolations of\ndevotion, are ever ready to assume their office as our guides\nand aids in the conduct of all our actions;--he will probably be\nwilling to acknowledge also that the means of moral government\nare not wanting, and will no longer be oppressed or disturbed by\nthe apprehension that the superintendence of the world may be\ntoo difficult for its Ruler, and that any of His subjects and\nservants may be overlooked. He will no more fear that the moral\nthan that the physical laws of God\u2019s creation should be forgotten\nin any particular case: and as he knows that every sparrow which\nfalls to the ground contains in its structure innumerable marks\nof the Divine care and kindness, he will be persuaded that every\nindividual, however apparently humble and insignificant, will have\nhis moral being dealt with according to the laws of God\u2019s wisdom\nand love; will be enlightened, supported, and raised, if he use the\nappointed means which God\u2019s administration of the world of moral\nlight and good offers to his use.\n\n\n\n\nCHAPTER IV.\n\n  _On the Impression produced by the Contemplation of Laws of\n  Nature; or, on the Conviction that Law implies Mind._\n\n\nThe various trains of thought and reasoning which lead men from\na consideration of the natural world to the conviction of the\nexistence, the power, the providence of God, do not require, for\nthe most part, any long or laboured deduction, to give them their\neffect on the mind. On the contrary, they have, in every age and\ncountry, produced their impression on multitudes who have not\ninstituted any formal reasonings upon the subject, and probably\nupon many who have not put their conclusions in the shape of any\nexpress propositions. The persuasion of a superior intelligence and\nwill, which manifests itself in every part of the material world,\nis, as is well known, so widely diffused and deeply infixed, as to\nhave made it a question among speculative men whether the notion\nof such a power is not universal and innate. It is our business to\nshow only how plainly and how universally such a belief results\nfrom the study of the appearances about us. That in many nations,\nin many periods, this persuasion has been mixed up with much that\nwas erroneous and perverse in the opinions of the intellect or\nthe fictions of fancy, does not weaken the force of such consent.\nThe belief of a supernatural and presiding power runs through all\nthese errors: and while the perversions are manifestly the work\nof caprice and illusion, and vanish at the first ray of sober\ninquiry, the belief itself is substantial and consistent, and grows\nin strength upon every new examination. It was the firmness and\nsolidity of the conviction of _something_ Divine which gave a\nhold and permanence to the figments of so many false divinities.\nAnd those who have traced the progress of human thought on other\nsubjects, will not think it strange, that while the fundamental\npersuasion of a Deity was thus irremovably seated in the human\nmind, the developement of this conception into a consistent, pure,\nand steadfast belief in one Almighty and Holy Father and God,\nshould be long missed, or never attained, by the struggle of the\nhuman faculties; should require long reflection to mature it, and\nthe aid of revelation to establish it in the world.\n\nThe view of the universe which we have principally had occasion to\npresent to the reader, is that in which we consider its appearances\nas reducible to certain fixed and general laws. Availing ourselves\nof some of the lights which modern science supplies, we have\nendeavoured to show that the adaptation of such laws to each other,\nand their fitness to promote the harmonious and beneficial course\nof the world, may be traced, wherever we can discover the laws\nthemselves; and that the conceptions of the Divine Power, Goodness\nand Superintendence which we thus form, agree in a remarkable\nmanner with the views of the Supreme Being, to which reason,\nenlightened by the divine revelation, has led.\n\nBut we conceive that the general impressions of mankind would\ngo further than a mere assent to the argument as we have thus\nstated it. To most persons it appears that the mere existence of\na law connecting and governing any class of phenomena, implies a\npresiding intelligence which has preconceived and established the\nlaw. When events are regulated by precise rules of time and space,\nof number and measure, men conceive these rules to be the evidence\nof thought and mind, even without discovering in the rules any\npeculiar adaptations, or without supposing their purpose to be\nknown.\n\nThe origin and the validity of such an impression on the human\nmind may appear to some matters of abstruse and doubtful\nspeculation: yet the tendency to such a belief prevails strongly\nand widely, both among the common class of minds whose thoughts\nare casually and unsystematically turned to such subjects, and\namong philosophers to whom laws of nature are habitual subjects\nof contemplation. We conceive therefore that such a tendency may\ndeserve to be briefly illustrated; and we trust also that some\nattention to this point may be of service in throwing light upon\nthe true relation of the study of nature to the belief in God.\n\n1. A very slight attention shows us how readily order and\nregularity suggest to a common apprehension the operation of a calm\nand untroubled intelligence presiding over the course of events.\nThus the materialist poet, in accounting for the belief in the\nGods, though he does not share it, cannot deny the habitual effect\nof this manifestation.\n\n      Pr\u00e6terea c\u0153li rationes _ordine certo_\n      Et _varia_ annorum cernebant _tempora_ vorti;\n      Nec poterant quibus id fieret cognoscere caussis.\n      Ergo perfugium sibi habebant Omnia Divis\n      Tradere et illorum nutu facere omnia flecti.\n                                       LUCRET. v. 1182.\n\n      They saw the skies in constant order run,\n      The varied seasons and the circling sun,\n      Apparent rule, with unapparent cause,\n      And thus they sought in Gods the source of laws.\n\nThe same feeling may be traced in the early mythology of a large\nportion of the globe. We might easily, taking advantage of the\nlabours of learned men, exemplify this in the case of the oriental\nnations, of Greece, and of many other countries. Nor does there\nappear much difficulty in pointing out the error of those who\nhave maintained that all religion had its _origin_ in the worship\nof the stars and the elements; and who have insinuated that all\nsuch impressions are unfounded, inasmuch as these are certainly\nnot right objects of human worship. The religious feeling, the\nconviction of a supernatural power, of an intelligence connecting\nand directing the phenomena of the world, had not its _origin_\nin the worship of sun, or stars, or elements; but was itself the\nnecessary though unexpressed foundation of all worship, and all\nforms of false, as well as true, religion. The contemplation of\nthe earth and heavens called into action this religious tendency\nin man; and to say that the worship of the material world formed\nor suggested this religious feeling, is to invert the order of\npossible things in the most unphilosophical manner. Idolatry is\nnot the source of the belief in God, but is a compound of the\npersuasion of a supernatural government, with certain extravagant\nand baseless conceptions as to the manner in which this government\nis exercised.\n\nWe will quote a passage from an author who has illustrated at\nconsiderable length the hypothesis that all religious belief is\nderived from the worship of the elements.\n\n\u201cLight, and darkness its perpetual contrast; the succession of\ndays and nights, the periodical order of the seasons; the career\nof the brilliant luminary which regulates their course; that of\nthe moon his sister and rival; night, and the innumerable fires\nwhich she lights in the blue vault of heaven; the revolutions of\nthe stars, which exhibit them for a longer or a shorter period\nabove our horizon; the constancy of this period in the fixed stars,\nits variety in the wandering stars, the planets; their direct and\nretrograde course, their momentary rest; the phases of the moon\nwaxing, full, waning, divested of all light; the progressive motion\nof the sun upwards, downwards; the successive order of the rising\nand setting of the fixed stars, which mark the different points of\nthe course of the sun, while the various aspects which the earth\nitself assumes mark, here below also, the same periods of the sun\u2019s\nannual motion; * * * all these different pictures, displayed before\nthe eyes of man, formed the great and magnificent spectacle by\nwhich I suppose him surrounded at the moment when _he is about to\ncreate his gods_.\u201d[31]\n\nWhat is this (divested of its wanton levity of expression) but to\nsay, that when man has so far traced the course of nature as to be\nirresistibly impressed with the existence of order, law, variety in\nconstancy, and fixity in change; of relations of form and space,\nduration and succession, cause and consequence, among the objects\nwhich surround him; there springs up in his breast, unbidden\nand irresistibly, the thought of superintending intelligence,\nof a mind which comprehended from the first and completely that\nwhich he late and partially comes to know? The worship of earth\nand sky, of the host of heaven and the influences of nature, is\nnot the ultimate and fundamental fact in the early history of\nthe religious impressions of mankind. These are but derivative\nstreams, impure and scanty, from the fountain of religious feeling\nwhich appears to be disclosed to us by the contemplation of the\nuniverse, as the seat of law and the manifestation of intellect.\nTime suggests to man the thought of eternity; space of infinity;\nlaw of intelligence; order of purpose; and however difficult and\nlong a task it may be to develope these suggestions into clear\nconvictions, these thoughts are the real parents of our natural\nreligious belief. The only relation between true religion and\nthe worship of the elemental world is, that the latter is the\npartial and gross perversion, the former the consistent and pure\ndevelopement of the same original idea.\n\n2. The connexion of the laws of the material world with an\nintelligence which preconceived and instituted the law, which\nis thus, as we perceive, so generally impressed on the common\napprehension of mankind, has also struck no less those who have\nstudied nature with a more systematic attention, and with the\npeculiar views which belong to science. The laws which such\npersons learn and study, seem, indeed, most naturally to lead to\nthe conviction of an intelligence which originally gave to the law\nits form.\n\nWhat we call a general law is, in truth, a form of expression\nincluding a number of facts of like kind. The facts are separate;\nthe unity of view by which we associate them, the character of\ngenerality and of law, resides in those relations which are the\nobject of the intellect. The law once apprehended by us, takes\nin our minds the place of the facts themselves, and is said to\n_govern_ or determine them, because it determines our anticipations\nof what they will be. But we cannot, it would seem, conceive a law,\nfounded on such intelligible relations, to govern and determine\nthe facts themselves, any otherwise than by supposing also an\nintelligence by which these relations are contemplated, and these\nconsequences realized. We cannot then represent to ourselves the\nuniverse governed by general laws otherwise than by conceiving an\nintelligent and conscious Deity, by whom these laws were originally\ncontemplated, established, and applied.\n\nThis perhaps will appear more clear, when it is considered that\nthe laws of which we speak are often of an abstruse and complex\nkind, depending upon relations of space, time, number, and other\nproperties, which we perceive by great attention and thought.\nThese relations are often combined so variously and curiously,\nthat the most subtle reasonings and calculations which we can form\nare requisite in order to trace their results. Can such laws be\nconceived to be instituted without any exercise of knowledge and\nintelligence? Can material objects apply geometry and calculation\nto themselves? Can the lenses of the eye, for instance, be formed\nand adjusted with an exact suitableness to their refractive\npowers, while there is in the agency which has framed them, no\nconsciousness of the laws of light, of the course of rays, of\nthe visible properties of things? This appears to be altogether\ninconceivable.\n\nEvery particle of matter possesses an almost endless train of\nproperties, each acting according to its peculiar and fixed\nlaws. For every atom of the same kind of matter these laws are\ninvariably and perpetually the same, while for the different kinds\nof matter the difference of these properties is equally constant.\nThis constant and precise resemblance, this variation equally\nconstant and equally regular, suggest irresistibly the conception\nof some cause, independent of the atoms themselves, by which their\nsimilarity and dissimilarity, the agreement and difference of their\ndeportment under the same circumstances, have been determined. Such\na view of the constitution of matter, as is observed by an eminent\nwriter of our own time, effectually destroys the idea of its\neternal and self-existent nature, \u201cby giving to each of its atoms\nthe essential characters, at once, of a _manufactured article_ and\na _subordinate agent_.\u201d[32]\n\nThat such an impression, and the consequent belief in a divine\nAuthor of the universe, by whom its laws were ordained and\nestablished, does result from the philosophical contemplation of\nnature, will, we trust, become still more evident by tracing the\neffect produced upon men\u2019s minds by the discovery of such laws and\nproperties as those of which we have been speaking; and we shall\ntherefore make a few observations on this subject.\n\n\n\n\nCHAPTER V.\n\n_On Inductive Habits; or, on the Impression produced on Men\u2019s Minds\nby discovering Laws of Nature._\n\n\nThe object of physical science is to discover such laws and\nproperties as those of which we have spoken in the last chapter.\nIn this task, undoubtedly a progress has been made on which we may\nwell look with pleasure and admiration; yet we cannot hesitate to\nconfess that the extent of our knowledge on such subjects bears no\nproportion to that of our ignorance. Of the great and comprehensive\nlaws which rule over the widest provinces of natural phenomena, few\nhave yet been disclosed to us. And the names of the philosophers,\nwhose high office it has been to detect such laws, are even yet far\nfrom numerous. In looking back at the path by which science has\nadvanced to its present position, we see the names of the great\ndiscoverers shine out like luminaries, few and scattered along the\nline: by far the largest portion of the space is occupied by those\nwhose comparatively humble office it was to verify, to develope, to\napply the general truths which the discoverers brought to light.\n\nIt will readily be conceived that it is no easy matter, if it be\npossible, to analyse the process of thought by which laws of nature\nhave thus been discovered; a process which, as we have said, has\nbeen in so few instances successfully performed. We shall not here\nmake any attempt at such an analysis. But without this, we conceive\nit may be shown that the constitution and employment of the mind\non which such discoveries depend, are friendly to that belief in\na wise and good Creator and Governor of the world, which it has\nbeen our object to illustrate and confirm. And if it should appear\nthat those who see further than their fellows into the bearings\nand dependencies of the material things and elements by which they\nare surrounded, have also been, in almost every case, earnest and\nforward in acknowledging the relation of all things to a supreme\nintelligence and will; we shall be fortified in our persuasion\nthat the true scientific perception of the general constitution\nof the universe, and of the mode in which events are produced and\nconnected, is fitted to lead us to the conception and belief of God.\n\nLet us consider for a moment what takes place in the mind of a\nstudent of nature when he attains to the perception of a law\npreviously unknown, connecting the appearances which he has\nstudied. A mass of facts which before seemed incoherent and\nunmeaning, assume, on a sudden, the aspect of connexion and\nintelligible order. Thus, when Kepler discovered the law which\nconnects the periodic times with the diameters of the planetary\norbits; or, when Newton showed how this and all other known\nmathematical properties of the solar system were included in the\nlaw of universal gravitation according to the inverse square of\nthe distance; particular circumstances which, before, were merely\nmatter of independent record, became, from that time, indissolubly\nconjoined by the laws so discovered. The separate occurrences and\nfacts, which might hitherto have seemed casual and without reason,\nwere now seen to be all exemplifications of the same truth. The\nchange is like that which takes place when we attempt to read a\nsentence written in difficult or imperfect characters. For a time\nthe separate parts appear to be disjointed and arbitrary marks; the\nsuggestions of possible meanings, which succeed each other in the\nmind, fail, as fast as they are tried, in combining or accounting\nfor these symbols: but at last the true supposition occurs; some\nwords are found to coincide with the meaning thus assumed; the\nwhole line of letters appear to take definite shapes and to leap\ninto their proper places; and the truth of the happy conjecture\nseems to flash upon us from every part of the inscription.\n\nThe discovery of laws of nature, truly and satisfactorily\nconnecting and explaining phenomena, of which, before, the\nconnexion and causes had been unknown, displays much of a similar\nprocess, of obscurity succeeded by evidence, of effort and\nperplexity followed by conviction and repose. The innumerable\nconjectures and failures, the glimpses of light perpetually\nopening and as often clouded over, the unwearied perseverance and\ninexhaustible ingenuity exercised by Kepler in seeking for the\nlaws which he finally discovered, are, thanks to his communicative\ndisposition, curiously exhibited in his works, and have been\nnarrated by his biographers; and such efforts and alternations,\nmodified by character and circumstances, must generally precede\nthe detection of any of the wider laws and dependencies by which\nthe events of the universe are regulated. We may readily conceive\nthe satisfaction and delight with which, after this perplexity and\nstruggle, the discoverer finds himself in light and tranquillity;\nable to look at the province of nature which has been the subject\nof his study, and to read there an intelligible connexion, a\nsufficing reason, which no one before him had understood or\napprehended.\n\nThis step so much resembles the mode in which one intelligent being\nunderstands and apprehends the conceptions of another, that we\ncannot be surprised if those persons in whose minds such a process\nhas taken place, have been most ready to acknowledge the existence\nand operation of a superintending intelligence, whose ordinances it\nwas their employment to study. When they had just read a sentence\nof the table of the laws of the universe, they could not doubt\nwhether it had had a legislator. When they had deciphered there a\ncomprehensive and substantial truth, they could not believe that\nthe letters had been thrown together by chance. They could not but\nreadily acknowledge that what their faculties had enabled them to\nread, must have been written by some higher and profounder mind.\nAnd accordingly, we conceive it will be found, on examining the\nworks of those to whom we owe our knowledge of the laws of nature,\nand especially of the wider and more comprehensive laws, that\nsuch persons have been strongly and habitually impressed with the\npersuasion of a Divine Purpose and Power which had regulated the\nevents which they had attended to, and ordained the laws which they\nhad detected.\n\nTo those who have pursued science without reaching the rank of\ndiscoverers;--who have possessed a derivative knowledge of the laws\nof nature which others had disclosed, and have employed themselves\nin tracing the consequences of such laws, and systematizing the\nbody of truth thus produced, the above description does not apply;\nand we have not therefore in these cases the same ground for\nanticipating the same frame of mind. If among men of science of\nthis class, the persuasion of a supreme Intelligence has at some\nperiods been less vivid and less universal, than in that higher\nclass of which we have before spoken, the fact, so far as it has\nexisted, may perhaps be in some degree accounted for. But whether\nthe view which we have to give of the mental peculiarities of men\nwhose science is of this derivative kind be well founded, and\nwhether the account we have above offered of that which takes\nplace in the minds of original discoverers of laws in scientific\nresearches be true, or not, it will probably be considered a matter\nof some interest to point out historically that in fact, such\ndiscoverers have been peculiarly in the habit of considering the\nworld as the work of God. This we shall now proceed to do.\n\nAs we have already said, the names of _great_ discoverers are\nnot very numerous. The sciences which we may look upon as having\nreached or at least approached their complete and finished form,\nare Mechanics, Hydrostatics, and Physical Astronomy. Galileo is\nthe father of modern Mechanics; Copernicus, Kepler, and Newton are\nthe great names which mark the progress of Astronomy. Hydrostatics\nshared in a great measure the fortunes of the related science of\nMechanics; Boyle and Pascal were the persons mainly active in\ndeveloping its more peculiar principles. The other branches of\nknowledge which belong to natural philosophy, as Chemistry and\nMeteorology, are as yet imperfect, and perhaps infant sciences;\nand it would be rash to presume to select, in them, names of equal\npreeminence with those above mentioned: but it may not be difficult\nto show, with sufficient evidence, that the effect of science upon\nthe authors of science is, in these subjects as in the former ones,\nfar other than to alienate their minds from religious trains of\nthought, and a habit of considering the world as the work of God.\n\nWe shall not dwell much on the first of the above mentioned great\nnames, Galileo; for his scientific merit consisted rather in\nadopting the sound philosophy of others, as in the case of the\nCopernican system, and in combating prevalent errors, as in the\ncase of the Aristotelian doctrines concerning motion, than in\nany marked and prominent discovery of new principles. Moreover\nthe mechanical laws which he had a share in bringing to light,\ndepending as they did, rather on detached experiments and transient\nfacts, than on observation of the general course of the universe,\ncould not so clearly suggest any reflection on the government of\nthe world at that period, as they did afterwards when Newton showed\ntheir bearing on the cosmical system. Yet Galileo, as a man of\nphilosophical and inventive mind, who produced a great effect on\nthe progress of physical knowledge, is a person whose opinions must\nnaturally interest us, engaged in our present course of reasoning.\nThere is in his writings little which bears upon religious views,\nas there is in the nature of his works little to lead him to such\nsubjects. Yet strong expressions of piety are not wanting, both\nin his letters, and in his published treatises. The persecution\nwhich he underwent, on account of his writings in favour of the\nCopernican system, was grounded, not on his opposition to the\ngeneral truths of natural religion, which is our main concern at\npresent, nor even on any supposed rejection of any articles of\nChristian faith, but on the alleged discrepancy between his adopted\nastronomical views and the declarations of scripture. Some of his\nremarks may interest the reader.\n\nIn his third dialogue on the Copernican system he has occasion\nto speak of the opinion which holds all parts of the world to be\nframed for man\u2019s use alone: and to this he says, \u201cI would that we\nshould not so shorten the arm of God in the government of human\naffairs; but that we should rest in this, that we are certain\nthat God and nature are so occupied in the government of human\naffairs, that they could not more attend to us if they were charged\nwith the care of the human race alone.\u201d In the same spirit, when\nsome objected to the asserted smallness of the Medicean stars, or\nsatellites of Jupiter, and urged this as a reason why they were\nunworthy the regard of philosophers, he replied that they are the\nworks of God\u2019s power, the objects of His care, and therefore may\nwell be considered as sublime subjects for man\u2019s study.\n\nIn the Dialogues on Mechanics, there occur those observations\nconcerning the use of the air-bladder in fishes, and concerning the\nadaptation of the size of animals to the strength of the materials\nof which they are framed, which have often since been adopted by\nwriters on the wisdom of Providence. The last of the dialogues on\nthe system of the world is closed by a religious reflection, put\nin the mouth of the interlocutor who usually expresses Galileo\u2019s\nown opinions. \u201cWhile it is permitted us to speculate concerning the\nconstitution of the world, we are also taught (perhaps in order\nthat the activity of the human mind may not pause or languish) that\nour powers do not enable us to comprehend the works of His hands.\nMay success therefore attend this intellectual exercise, thus\npermitted and appointed for us; by which we recognize and admire\nthe greatness of God the more, in proportion as we find ourselves\nthe less able to penetrate the profound abysses of his wisdom.\u201d\nAnd that this train of thought was habitual to the philosopher we\nhave abundant evidence in many other parts of his writings. He had\nalready said in the same dialogue, \u201cNature (or God, as he elsewhere\nspeaks) employs means in an admirable and inconceivable manner;\nadmirable, that is, and inconceivable to us, but not to her, who\nbrings about with consummate facility and simplicity things which\naffect our intellect with infinite astonishment. That which is to\nus most difficult to understand is to her most easy to execute.\u201d\n\nThe establishment of the Copernican and Newtonian views of the\nmotions of the solar system and their causes, were probably the\noccasions on which religious but unphilosophical men entertained\nthe strongest apprehensions that the belief in the government of\nGod may be weakened when we thus \u201cthrust some mechanic cause into\nhis place.\u201d It is therefore fortunate that we can show, not only\nthat this ought not to occur, from the reason of the thing, but\nalso that in fact the persons who are the leading characters in the\nprogress of these opinions were men of clear and fervent piety.\n\nIn the case of Copernicus himself it does not appear that,\noriginally, any apprehensions were entertained of any dangerous\ndiscrepancy between his doctrines and the truths of religion,\neither natural or revealed. The work which contains these memorable\ndiscoveries was addressed to Pope Paul III., the head, at that\ntime, (1543) of the religious world; and was published, as the\nauthor states in the preface, at the urgent entreaty of friends,\none of whom was a cardinal, and another a bishop.[33] \u201cI know,\u201d\nhe says, \u201cthat the thoughts of a philosopher are far removed from\nthe judgment of the vulgar; since it is his study to search out\ntruth in all things, as far as that is permitted by God to human\nreason.\u201d And though the doctrines are for the most part stated as\nportions of a mathematical calculation, the explanation of the\narrangement by which the sun is placed in the centre of the system\nis accompanied by a natural reflection of a religious cast; \u201cWho in\nthis fair temple would place this lamp in any other or better place\nthan there whence it may illuminate the whole? We find then under\nthis ordination an admirable symmetry of the world, and a certain\nharmonious connexion of the motion and magnitude of the orbs,\nsuch as in any other way cannot be found. Thus the progressions\nand regressions of the planets all arise from the same cause, the\nmotion of the earth. And that no such movements are seen in the\nfixed stars, argues their immense distance from us, which causes\nthe apparent magnitude of the earth\u2019s annual course to become\nevanescent. So great, in short, is this divine fabric of the great\nand good God;\u201d[34] \u201cthis best and most regular artificer of the\nuniverse,\u201d as he elsewhere speaks.\n\nKepler was the person, who by further studying \u201cthe connexion of\nthe motions and magnitude of the orbs,\u201d to which Copernicus had\nthus drawn the attention of the astronomers, detected the laws of\nthis connexion, and prepared the way for the discovery, by Newton,\nof the mechanical laws and causes of such motions. Kepler was\na man of strong and lively piety; and the exhortation which he\naddresses to his reader before entering on the exposition of some\nof his discoveries, may be quoted not only for its earnestness but\nits reasonableness also. \u201cI beseech my reader, that not unmindful\nof the divine goodness bestowed on man, he do with me praise and\ncelebrate the wisdom and greatness of the Creator, which I open\nto him from a more inward explication of the form of the world,\nfrom a searching of causes, from a detection of the errors of\nvision: and that thus, not only in the firmness and stability\nof the earth he perceive with gratitude the preservation of all\nliving things in nature as the gift of God, but also that in its\nmotion, so recondite, so admirable, he acknowledge the wisdom of\nthe Creator. But him who is too dull to receive this science, or\ntoo weak to believe the Copernican system without harm to his\npiety, him, I say, I advise that, leaving the school of astronomy,\nand condemning, if he please, any doctrines of the philosophers,\nhe follow his own path, and desist from this wandering through the\nuniverse, and lifting up his natural eyes, with which alone he\ncan see, pour himself out from his own heart in praise of God the\nCreator; being certain that he gives no less worship to God than\nthe astronomer, to whom God has given to see more clearly with his\ninward eye, and who, for what he has himself discovered, both can\nand will glorify God.\u201d\n\nThe next great step in our knowledge of the universe, the discovery\nof the mechanical causes by which its motions are produced, and\nof their laws, has in modern times sometimes been supposed, both\nby the friends of religion and by others, to be unfavourable\nto the impression of an intelligent first cause. That such a\nsupposition is founded in error we have offered what appear to us\ninsurmountable reasons for believing. That in the mind of the great\ndiscoverer of this mechanical cause, Newton, the impression of a\ncreating and presiding Deity was confirmed, not shaken, by all\nhis discoveries, is so well known that it is almost superfluous\nto insist upon the fact. His views of the tendency of science\ninvested it with no dangers of this kind. \u201cThe business of\nnatural philosophy is,\u201d he says, (Optics, Qu. 28,) \u201cto argue from\nphenomena without feigning hypotheses, and to deduce cause from\neffects, till we come to the very first cause, which is certainly\nnot mechanical.\u201d \u201cThough every true step made in this philosophy\nbrings us not immediately to the knowledge of the first cause, yet\nit brings us nearer to it, and is on that account highly to be\nvalued.\u201d The Scholium, or note, which concludes his great work,\nthe Principia, is a well known and most striking evidence on this\npoint, \u201cThis beautiful system of sun, planets, and comets, could\nhave its origin in no other way than by the purpose and command of\nan intelligent and powerful Being. He governs all things, not as\nthe soul of the world, but as the lord of the universe. He is not\nonly God, but Lord or Governor. We know him only by his properties\nand attributes, by the wise and admirable structure of things\naround us, and by their final causes; we admire him on account of\nhis perfections, we venerate and worship him on account of his\ngovernment.\u201d\n\nWithout making any further quotations, it must be evident to\nthe reader that the succession of great philosophers through\nwhom mankind have been led to the knowledge of the greatest of\nscientific truths, the law of universal gravitation, did, for\ntheir parts, see the truths which they disclosed to men in such a\nlight that their religious feelings, their reference of the world\nto an intelligent Creator and Preserver, their admiration of his\nattributes, were exalted rather than impaired by the insight which\nthey obtained into the structure of the universe.\n\nHaving shown this with regard to the most perfect portion of human\nknowledge, our knowledge of the motions of the solar system, we\nshall adduce a few other passages, illustrating the prevalence\nof the same fact in other departments of experimental science;\nalthough, for reasons which have already been intimated, we\nconceive that sciences of experiment do not conduct so obviously as\nsciences of observation to the impression of a Divine Legislator of\nthe material world.\n\nThe science of Hydrostatics was constructed in a great measure by\nthe founders of the sister science of Mechanics. Of those who were\nemployed in experimentally establishing the principles peculiarly\nbelonging to the doctrine of fluids, Pascal and Boyle are two of\nthe most eminent names. That these two great philosophers were\nnot only religious, but both of them remarkable for their fervent\nand pervading devotion, is too well known to be dwelt on. With\nregard to Pascal, however, we ought not perhaps to pass over an\nopinion of his, that the existence of God cannot be proved from the\nexternal world. \u201cI do not undertake to prove this,\u201d says he, \u201cnot\nonly because I do not feel myself sufficiently strong to find in\nnature that which shall convince obstinate atheists, but because\nsuch knowledge without Jesus Christ is useless and steril.\u201d It is\nobvious that such a state of mind would prevent this writer from\nencouraging or dwelling upon the grounds of natural religion; while\nyet he himself is an example of that which we wish to illustrate,\nthat those who have obtained the furthest insight into nature,\nhave been in all ages firm believers in God. \u201cNature,\u201d he says, in\nanother place, \u201chas perfections in order to show that she is the\nimage of God, and defects in order to show that she is only his\nimage.\u201d[35]\n\nBoyle was not only a most pious man as well as a great philosopher,\nbut he exerted himself very often and earnestly in his writings\nto show the bearing of his natural philosophy upon his views of\nthe Divine attributes, and of the government of the world. Many\nof these dissertations convey trains of thought and reasoning\nwhich have never been surpassed for their combination of judicious\nsobriety in not pressing his arguments too far, with fervent\ndevotion in his conceptions of the Divine nature. As examples of\nthese merits, we might adduce almost any portion of his tracts on\nthese subjects; for instance, his \u201cInquiry into the Final Causes\nof Natural Things;\u201d his \u201cFree Inquiry into the Vulgar Notion of\nNature;\u201d his \u201cChristian Virtuoso;\u201d and his essay entitled \u201cThe High\nVeneration Man\u2019s Intellect owes to God.\u201d It would be superfluous to\nquote at any length from these works. We may observe, however, that\nhe notices that general fact which we are at present employed in\nexemplifying, that \u201cin almost all ages and countries the generality\nof philosophers and contemplative men were persuaded of the\nexistence of a Deity from the consideration of the phenomena of the\nuniverse; whose fabric and conduct they rationally concluded could\nnot justly be ascribed either to chance or to any other cause than\na Divine Being.\u201d And in speaking of the religious uses of science,\nhe says: \u201cThough I am willing to grant that some impressions of\nGod\u2019s wisdom are so conspicuous that even a superficial philosopher\nmay thence infer that the author of such works must be a wise\nagent; yet how wise an agent he has in these works expressed\nhimself to be, none but an experimental philosopher can well\ndiscern. And \u2019tis not by a slight survey, but by a diligent and\nskilful scrutiny, of the works of God, that a man must be, by a\nrational and affective conviction, engaged to acknowledge that\nthe author of nature \u2018is wonderful in counsel, and excellent in\nworking.\u2019\u201d\n\nAfter the mechanical properties of fluids, the laws of the\noperation of the chemical and physical properties of the elements\nabout us, offer themselves to our notice. The relations of heat\nand of moisture in particular, which play so important a part, as\nwe have seen, in the economy of our world, have been the subject\nof various researches; and they have led to views of the operation\nof such agents, some of which we have endeavoured to present to\nthe reader, and to point out the remarkable arrangements by which\ntheir beneficial operation is carried on. That the discoverers\nof the laws by which such operations are regulated, were not\ninsensible to the persuasion of a Divine care and contrivance\nwhich those arrangements suggest, is what we should expect, in\nagreement with what we have already said, and it is what we find.\nAmong the names of the philosophers to whom we owe our knowledge\non these subjects, there are none greater than those of Black,\nthe discoverer of the laws of latent heat, and Dalton, who first\ngave us a true view of the mode in which watery vapour exists and\noperates in the atmosphere. With regard to the former of these\nphilosophers, we shall quote Dr. Thomson\u2019s account of the views\nwhich the laws of latent heat suggested to the discoverer.[36] \u201cDr.\nBlack quickly perceived the vast importance of this discovery,\nand took a pleasure in laying before his students a view of\nthe beneficial effects of this habitude of heat in the economy\nof nature. During the summer season a vast magazine of heat is\naccumulated in the water, which by gradually emerging during\ncongelation serves to temper the cold of winter. Were it not for\nthis accumulation of heat in water and other bodies, the sun would\nno sooner go a few degrees to the south of the equator than we\nshould feel all the horrors of winter.\u201d\n\nIn the same spirit are Mr. Dalton\u2019s reflections, after pointing\nout the laws which regulate the balance of evaporation and\nrain,[37] which he himself first clearly explained. \u201cIt is scarcely\npossible,\u201d says he, \u201cto contemplate without admiration the\nbeautiful system of nature by which the surface of the earth is\ncontinually supplied with water, and that unceasing circulation of\na fluid so essentially necessary to the very being of the animal\nand vegetable kingdom takes place.\u201d\n\nSuch impressions appear thus to rise irresistibly in the breasts\nof men, when they obtain a sight, for the first time, of the\nvaried play and comprehensive connexions of the laws by which the\nbusiness of the material world is carried on and its occurrences\nbrought to pass. To dwell upon or develope such reflections is not\nhere our business. Their general prevalence in the minds of those\nto whom these first views of new truths are granted, has been, we\ntrust, sufficiently illustrated. Nor are the names adduced above,\ndistinguished as they are, brought forwards as _authorities_\nmerely. We do not claim for the greatest discoverers in the realms\nof science any immunity from error. In their general opinions they\nmay, as others may, judge or reason ill. The articles of their\nreligious belief may be as easily and as widely as of other men\u2019s,\nimperfect, perverted, unprofitable. But on this one point, the\ntendency of our advances in scientific knowledge of the universe\nto lead us up to a belief in a most wise maker and master of the\nuniverse, we conceive that they who make these advances, and who\nfeel, as an original impression, that which others feel only\nby receiving their teaching, must be looked to with a peculiar\nattention and respect. And what their impressions have commonly\nbeen, we have thus endeavoured to show.\n\n\n\n\nCHAPTER VI.\n\n  _On Deductive Habits; or, on the Impression produced on Men\u2019s\n  Minds by tracing the consequences of ascertained Laws._\n\n\nThe opinion illustrated in the last chapter, that the advances\nwhich men make in science tend to impress upon them the reality of\nthe Divine government of the world, has often been controverted.\nComplaints have been made, and especially of late years, that the\ngrowth of piety has not always been commensurate with the growth\nof knowledge, in the minds of those who make nature their study.\nViews of an irreligious character have been entertained, it is\nsometimes said, by persons eminently well instructed in all the\ndiscoveries of modern times, no less than by the superficial and\nignorant. Those who have been supposed to deny or to doubt the\nexistence, the providence, the attributes of God, have in many\ncases been men of considerable eminence and celebrity for their\nattainments in science. The opinion that this is the case, appears\nto be extensively diffused, and this persuasion has probably\noften produced inquietude and grief in the breasts of pious and\nbenevolent men.\n\nThis opinion, concerning the want of religious convictions among\nthose who have made natural philosophy their leading pursuit,\nhas probably gone far beyond the limits of the real fact. But if\nwe allow that there are any strong cases to countenance such an\nopinion, it may be worth our while to consider how far they admit\nof any satisfactory explanation. The fact appears at first sight\nto be at variance with the view we have given of the impression\nproduced by scientific discovery; and it is moreover always a\nmatter of uneasiness and regret, to have men of eminent talents\nand knowledge opposed to doctrines which we consider as important\ntruths.\n\nWe conceive that an explanation of such cases, if they should\noccur, may be found in a very curious and important circumstance\nbelonging to the process by which our physical sciences are formed.\nThe first discovery of new general truths, and the developement\nof these truths when once obtained, are two operations extremely\ndifferent; imply different mental habits, and may easily be\nassociated with different views and convictions on points out of\nthe reach of scientific demonstration. There would therefore be\nnothing surprising, or inconsistent with what we have maintained\nabove, if it should appear that while original discoverers of laws\nof nature are peculiarly led, as we have seen, to believe the\nexistence of a supreme intelligence and purpose; the far greater\nnumber of cultivators of science, whose employment it is to learn\nfrom others these general laws, and to trace, combine, and apply\ntheir consequences, should have no clearness of conviction or\nsecurity from error on this subject, beyond what belongs to persons\nof any other class.\n\nThis will, perhaps, become somewhat more evident by considering\na little more closely the distinction of the two operations of\ndiscovery and developement, of which we have spoken above, and the\ntendency which the habitual prosecution of them may be expected to\nproduce in the thoughts and views of the student.\n\nWe have already endeavoured in some measure to describe that which\ntakes place when a new law of nature is discovered. A number of\nfacts in which, before, order and connexion did not appear at all,\nor appeared by partial and contradictory glimpses, are brought\ninto a point of view in which order and connexion become their\nessential character. It is seen that each fact is but a different\nmanifestation of the same principle; that each particular is that\nwhich it is, in virtue of the same general truth. The inscription\nis deciphered; the enigma is guessed; the principle is understood;\nthe truth is enunciated.\n\nWhen this step is once made, it becomes possible to deduce from the\ntruth thus established, a train of consequences often in no small\ndegree long and complex. The process of making these inferences\nmay properly be described by the word Deduction, while the very\ndifferent process by which a new principle is collected from an\nassemblage of facts, has been termed Induction; the truths so\nobtained and their consequences constitute the results of the\nInductive Philosophy; which is frequently and rightly described\nas a science which ascends from particular facts to general\nprinciples, and then descends again from these general principles\nto particular applications and exemplifications.\n\nWhile the great and important labours by which science is really\nadvanced consist in the successive steps of the _inductive_ ascent\nin the discovery of new laws perpetually more and more general; by\nfar the greater part of our books of physical science unavoidably\nconsists in _deductive_ reasoning, exhibiting the consequences\nand applications of the laws which have been discovered; and the\ngreater part of writers upon science have their minds employed in\nthis process of deduction and application.\n\nThis is true of many of those who are considered, and justly,\nas distinguished and profound philosophers. In the mechanical\nphilosophy, that science which applies the properties of matter\nand the laws of motion to the explanation of the phenomena of\nthe world, this is peculiarly the case. The laws, when once\ndiscovered, occupy little room in their statement, and when no\nlonger contested, are not felt to need a lengthened proof. But\ntheir consequences require far more room and far more intellectual\nlabour. If we take, for example, the laws of motion and the law\nof universal gravitation, we can express in a few lines, that\nwhich, when developed, represents and explains an innumerable\nmass of natural phenomena. But here the course of developement is\nnecessarily so long, the reasoning contains so many steps, the\nconsiderations on which it rests are so minute and refined, the\ncomplication of cases and of consequences is so vast, and even\nthe involution arising from the properties of space and number\nso serious, that the most consummate subtlety, the most active\ninvention, the most tenacious power of inference, the widest spirit\nof combination, must be tasked and tasked severely, in order to\nsolve the problems which belong to this portion of science. And\nthe persons who have been employed on these problems, and who\nhave brought to them the high and admirable qualities which such\nan office requires, have justly excited in a very eminent degree\nthe admiration which mankind feel for great intellectual powers.\nTheir names occupy a distinguished place in literary history; and\nprobably there are no scientific reputations of the last century\nhigher, and none more merited, than those earned by the great\nmathematicians who have laboured with such wonderful success in\nunfolding the mechanism of the heavens; such for instance as\nD\u2019Alembert, Clairault, Euler, Lagrange, Laplace.\n\nBut it is still important to recollect, that the mental employments\nof men, while they are occupied in this portion of the task of the\nformation of science, are altogether different from that which\ntakes place in the mind of a discoverer, who, for the first time,\nseizes the principle which connects phenomena before unexplained,\nand thus adds another original truth to our knowledge of the\nuniverse. In explaining, as the great mathematicians just mentioned\nhave done, the phenomena of the solar system by means of the law\nof universal gravitation, the conclusions at which they arrived\nwere really included in the truth of the law itself, whatever skill\nand sagacity it might require to develope and extricate them from\nthe general principle. But when Newton conceived and established\nthe law itself, he added to our knowledge something which was not\ncontained in any truth previously known, nor deducible from it by\nany course of mere reasoning. And the same distinction, in all\nother cases, obtains, between these processes which establish the\nprinciples, generally few and simple, on which our sciences rest,\nand those reasonings and calculations, founded on the principles\nthus obtained, which constitute by far the larger portion of\nthe common treatises on the most complete of the sciences now\ncultivated.\n\nSince the difference is so great between the process of inductive\ngeneralization of physical facts, and that of mathematical\ndeduction of consequences, it is not surprising that the two\nprocesses should imply different mental powers and habits. However\nrare the mathematical talent, in its highest excellence, may be,\nit is far more common, if we are to judge from the history of\nscience, than the genius which divines the general laws of nature.\nWe have several good mathematicians in every age; we have few great\ndiscoverers in the whole history of our species.\n\nThe distinction being thus clearly established between original\ndiscovery and derivative speculation, between the ascent to\nprinciples and the descent from them, we have further to observe,\nthat the habitual and exclusive prosecution of the latter process\nmay sometimes exercise an unfavourable effect on the mind of the\nstudent, and may make him less fitted and ready to apprehend and\naccept truths different from those with which his reasonings\nare concerned. We conceive, for example, that a person labours\nunder gross error, who believes the phenomena of the world to be\naltogether produced by mechanical causes, and who excludes from\nhis view all reference to an intelligent First Cause and Governor.\nBut we conceive that reasons may be shown which make it more\nprobable that error of such a kind should find a place in the mind\nof a person of deductive, than of inductive habits;--of a mere\nmathematician or logician, than of one who studies the facts of the\nnatural world and detects their laws.\n\nThe person whose mind is employed in reducing to law and order and\nintelligible cause the complex facts of the material world, is\ncompelled to look beyond the present state of his knowledge, and\nto turn his thoughts to the existence of principles higher than\nthose which he yet possesses. He has seen occasions when facts\nthat at first seemed incoherent and anomalous, were reduced to\nrule and connexion; and when limited rules were discovered to be\nincluded in some rule of superior generality. He knows that all\nfacts and appearances, all partial laws, however confused and\ncasual they at present seem, must still, in reality, have this\nsame kind of bearing and dependence;--must be bound together by\nsome undiscovered principle of order;--must proceed from some\ncause working by most steady rules;--must be included in some\nwide and fruitful general truth. He cannot therefore consider any\nprinciples which he has already obtained, as the ultimate and\nsufficient reason of that which he sees. There must be some higher\nprinciple, some ulterior reason. The effort and struggle by which\nhe endeavours to extend his view, makes him feel that there is a\nregion of truth not included in his present physical knowledge; the\nvery imperfection of the light in which he works his way, suggests\nto him that there must be a source of clearer illumination at a\ndistance from him.\n\nWe must allow that it is scarcely possible to describe in a manner\nfree from some vagueness and obscurity, the effect thus produced\nupon the mind by the efforts which it makes to reduce natural\nphenomena to general laws. But we trust it will still be allowed\nthat there is no difficulty in seeing clearly that a different\ninfluence may result from this process, and from the process\nof deductive reasoning which forms the main employment of the\nmathematical cultivators and systematic expositors of physical\nscience in modern times. Such persons are not led by their pursuits\nto any thing beyond the general principles, which form the basis\nof their explanations and applications. They acquiesce in these;\nthey make these their ultimate grounds of truth; and they are\nentirely employed in unfolding the particular truths which are\ninvolved in the general truth. Their thoughts dwell little upon the\npossibility of the laws of nature being other than we find them\nto be, or on the reasons why they are not so; and still less on\nthose facts and phenomena which philosophers have not yet reduced\nto any rule; which are lawless to us, though we know that, in\nreality, they are governed by some principle of order and harmony.\nOn the contrary, by assuming perpetually the existing laws as\nthe basis of their reasoning, without question or doubt, and by\nemploying such language that these laws can be expressed in the\nsimplest and briefest form, they are led to think and believe as\nif these laws were necessarily and inevitably what they are. Some\nmathematicians indeed have maintained that the highest laws of\nnature with which we are acquainted, the laws of motion and the\nlaw of universal gravitation, are not only necessarily true, but\nare even self-evident and certain _\u00e0 priori_, like the truths of\ngeometry. And though the mathematical cultivator of the science of\nmechanics may not adopt this as his speculative opinion, he may\nstill be so far influenced by the tendency from which it springs,\nas to rest in the mechanical laws of the universe as ultimate and\nall-sufficient principles, without seeing in them any evidence of\ntheir having been selected and ordained, and thus without ascending\nfrom the world to the thought of an Intelligent Ruler. He may thus\nsubstitute for the Deity certain axioms and first principles, as\nthe cause of all. And the follower of Newton may run into the error\nwith which he is sometimes charged, of thrusting some mechanic\ncause into the place of God, if he do not raise his views, as his\nmaster did, to some higher cause, to some source of all forces,\nlaws, and principles.\n\nWhen, therefore, we consider the mathematicians who are employed\nin successfully applying the mechanical philosophy, as men well\ndeserving of honour from those who take an interest in the progress\nof science, we do rightly; but it is still to be recollected, that\nin doing this they are not carrying us to any higher point of view\nin the knowledge of nature than we had attained before: they are\nonly unfolding the consequences, which were already virtually in\nour possession, because they were implied in principles already\ndiscovered:--they are adding to our knowledge of effects, but\nnot to our knowledge of causes:--they are not making any advance\nin that progress of which Newton spoke, and in which he made so\nvast a stride, in which \u201cevery step made brings us nearer to the\nknowledge of the first cause, and is on that account highly to be\nvalued.\u201d And as in this advance they have no peculiar privileges or\nadvantages, their errors of opinion concerning it, if they err, are\nno more to be wondered at, than those of common men; and need as\nlittle disturb or distress us, as if those who committed them had\nconfined themselves to the study of arithmetic or of geometry. If\nwe can console and tranquillize ourselves concerning the defective\nor perverted views of religious truth entertained by any of our\nfellow men, we need find no additional difficulty in doing so when\nthose who are mistaken are great mathematicians, who have added to\nthe riches and elegance of the mechanical philosophy. And if we\nare seeking for extraneous grounds of trust and comfort on this\nsubject, we may find them in the reflection;--that, whatever may\nbe the opinions of those who assume the causes and laws of that\nphilosophy and reason from them, the views of those admirable and\never-honoured men who first caught sight of these laws and causes,\nimpressed _them_ with the belief that this is \u201cthe fabric of a\ngreat and good God;\u201d that \u201cit is man\u2019s duty to pour out his soul in\npraise of the Creator;\u201d and that all this beautiful system must be\nreferred to \u201ca first cause, which is certainly not mechanical.\u201d\n\n2. We may thus, with the greatest propriety, deny to the mechanical\nphilosophers and mathematicians of recent times any authority\nwith regard to their views of the administration of the universe;\nwe have no reason whatever to expect from their speculations any\nhelp, when we attempt to ascend to the first cause and supreme\nruler of the universe. But we might perhaps go further, and assert\nthat they are in some respects less likely than men employed in\nother pursuits, to make any clear advance towards such a subject\nof speculation. Persons whose thoughts are thus entirely occupied\nin deduction are apt to forget that this is, after all, only one\nemployment of the reason among more; only one mode of arriving\nat truth, needing to have its deficiencies completed by another.\nDeductive reasoners, those who cultivate science, of whatever\nkind, by means of mathematical and logical processes alone, may\nacquire an exaggerated feeling of the amount and value of their\nlabours. Such employments, from the clearness of the notions\ninvolved in them, the irresistible concatenation of truths which\nthey unfold, the subtlety which they require, and their entire\nsuccess in that which they attempt, possess a peculiar fascination\nfor the intellect. Those who pursue such studies have generally\na contempt and impatience of the pretensions of all those other\nportions of our knowledge, where from the nature of the case, or\nthe small progress hitherto made in their cultivation, a more\nvague and loose kind of reasoning seems to be adopted. Now if this\nfeeling be carried so far as to make the reasoner suppose that\nthese mathematical and logical processes can lead him to all the\nknowledge and all the certainty which we need, it is clearly a\ndelusive feeling. For it is confessed on all hands, that all which\nmathematics or which logic can do, is to develope and extract\nthose truths, as conclusions, which were in reality involved in\nthe principles on which our reasonings proceeded.[38] And this\nbeing allowed, we cannot but ask how we obtain these principles?\nfrom what other source of knowledge we derive the original truths\nwhich we thus pursue into detail? since it is manifest that such\nprinciples cannot be derived from the proper stores of mathematics\nor logic. These methods can generate no new truth; and all the\ngrounds and elements of the knowledge which, through them, we\ncan acquire, must necessarily come from some extraneous source.\nIt is certain, therefore, that the mathematician and the logician\nmust derive from some process different from their own, the\nsubstance and material of all our knowledge, whether physical or\nmetaphysical, physiological or moral. This process, by which we\nacquire our first principles, (without pretending here to analyse\nit,) is obviously the general course of human experience, and the\nnatural exercise of the understanding; our intercourse with matter\nand with men, and the consequent growth in our minds of convictions\nand conceptions such as our reason can deal with, either by her\nsystematic or unsystematic methods of procedure. Supplies from this\nvast and inexhaustible source of original truths are requisite, to\ngive any value whatever to the results of our deductive processes,\nwhether mathematical or logical; while on the other hand, there are\nmany branches of our knowledge, in which we possess a large share\nof original and derivative convictions and truths, but where it is\nnevertheless at present quite impossible to erect our knowledge\ninto a complete system;--to state our primary and independent\ntruths, and to show how on these all the rest depend by the rules\nof art. If the mathematician is repelled from speculations on\nmorals or politics, on the beautiful or the right, because the\nreasonings which they involve have not mathematical precision\nand conclusiveness, he will remain destitute of much of the most\nvaluable knowledge which man can acquire. And if he attempts to\nmend the matter by giving to treatises on morals, or politics, or\ncriticism, a form and a phraseology borrowed from the very few\ntolerably complete physical sciences which exist, it will be found\nthat he is compelled to distort and damage the most important\ntruths, so as to deprive them of their true shape and import, in\norder to force them into their places in his artificial system.\n\nIf therefore, as we have said, the mathematical philosopher dwells\nin his own bright and pleasant land of deductive reasoning, till\nhe turns with disgust from all the speculations, necessarily less\nclear and conclusive, in which his imagination, his practical\nfaculties, his moral sense, his capacity of religious hope and\nbelief, are to be called into action, he becomes, more than common\nmen, liable to miss the road to truths of extreme consequence.\n\nThis is so obvious, that charges are frequently brought against\nthe study of mathematics, as unfitting men for those occupations\nwhich depend upon our common instinctive convictions and feelings,\nupon the unsystematic exercise of the understanding with regard\nto common relations and common occurrences. Bonaparte observed of\nLaplace, when he was placed in a public office of considerable\nimportance, that he did not discharge it in so judicious and\nclear sighted a manner as his high intellectual fame might lead\nmost persons to expect.[39] \u201cHe sought,\u201d that great judge of\ncharacter said, \u201csubtleties in every subject, and carried into\nhis official employments the spirit of the method of infinitely\nsmall quantities,\u201d by which the mathematician solves his more\nabstruse problems. And the complaint that mathematical studies\nmake men insensible to moral evidence and to poetical beauties, is\nso often repeated as to show that some opposition of tendency is\ncommonly perceived between that exercise of the intellect which\nmathematics requires and those processes which go on in our minds\nwhen moral character or imaginative beauty is the subject of our\ncontemplation.\n\nThus, while we acknowledge all the beauty and all the value of\nthe mathematical reasonings by which the consequences of our\ngeneral laws are deduced, we may yet consider it possible that\na philosopher, whose mind has been mainly employed, and his\nintellectual habits determined, by this process of deduction, may\npossess, in a feeble and imperfect degree only, some of those\nfaculties by which truth is attained, and especially those truths\nwhich regard our relation to that mind, the origin of all law, the\nsource of first principles, which must be immeasurably elevated\nabove all derivative truths. It would, therefore, be far from\nsurprising, if there should be found, among the great authors\nof the developements of the mechanical philosophy, some who had\nrefused to refer the phenomena of the universe to a supreme mind,\npurpose, and will. And though this world be, to a believer in the\nBeing and government of God, a matter of sorrow and pain, it need\nnot excite more surprise than if the same were true of a person\nof the most ordinary endowments, when it is recollected in what a\ndisproportionate manner the various faculties of such a philosopher\nmay have been cultivated. And our apprehensions of injury to\nmankind from the influence of such examples will diminish, when\nwe consider, that those mathematicians whose minds have been less\npartially exercised, the great discoverers of the truths which\nothers apply, the philosophers who have looked upwards as well as\ndownwards, to the unknown as well as to the known, to ulterior as\nwell as proximate principles, have never rested in this narrow\nand barren doctrine; but have perpetually looked forwards, beyond\nmere material laws and causes, to a First Cause of the moral and\nmaterial world, to which each advance in philosophy might bring\nthem nearer, though it must ever remain indefinitely beyond their\nreach.\n\nIt scarcely needs, perhaps, to be noticed, that what we here\nrepresent as the possible source of error is, not the perfection\nof the mathematical habits of the mind, but the deficiency of the\nhabit of apprehending truth of other kinds;--not a clear insight\ninto the mathematical consequences of principles, but a want of\na clear view of the nature and foundation of principles;--not\nthe talent for generalizing geometrical or mechanical relations,\nbut the tendency to erect such relations into ultimate truths\nand efficient causes. The most consummate mathematical skill may\naccompany and be auxiliary to the most earnest piety, as it often\nhas been. And an entire command of the conceptions and processes\nof mathematics is not only consistent with, but is the necessary\ncondition and principal instrument of every important step in the\ndiscovery of physical principles. Newton was eminent above the\nphilosophers of his time, in no one talent so much as in the power\nof mathematical deduction. When he had caught sight of the law of\nuniversal gravitation, he traced it to its consequences with a\nrapidity, a dexterity, a beauty of mathematical reasoning which no\nother person could approach; so that on this account, if there had\nbeen no other, the establishment of the general law was possible to\nhim alone. He still stands at the head of mathematicians as well\nas of philosophical discoverers. But it never appeared to him,\nas it may have appeared to some mathematicians who have employed\nthemselves on his discoveries, that the general law was an ultimate\nand sufficient principle: that the point to which he had hung his\nchain of deduction was the highest point in the universe. Lagrange,\na modern mathematician of transcendent genius, was in the habit\nof saying, in his aspirations after future fame, that Newton was\nfortunate in having had the system of the world for his problem,\nsince its theory could be discovered once only. But Newton himself\nappears to have had no such persuasion that the problem he had\nsolved was unique and final: he laboured to reduce gravity to some\nhigher law, and the forces of other physical operations to an\nanalogy with those of gravity, and declared that all these were\nbut steps in our advance towards a first cause. Between us and\nthis first cause, the source of the universe and of its laws, we\ncannot doubt that there intervene many successive steps of possible\ndiscovery and generalization, not less wide and striking than the\ndiscovery of universal gravitation: but it is still more certain\nthat no extent or success of physical investigation can carry us to\nany point which is not at an immeasurable distance from an adequate\nknowledge of Him.\n\n\n\n\nCHAPTER VII.\n\n_On Final Causes._\n\n\nWe have pointed out a great number of instances where the mode in\nwhich the arrangements of nature produce their effect, suggests,\nas we conceive, the belief that this effect is to be considered as\nthe _end_ and _purpose_ of these arrangements. The impression which\nthus arises, of design and intention exercised in the formation of\nthe world, or of the reality of _Final Causes_, operates on men\u2019s\nminds so generally, and increases so constantly on every additional\nexamination of the phenomena of the universe, that we cannot but\nsuppose such a belief to have a deep and stable foundation. And we\nconceive that in several of the comparatively few cases in which\nsuch a belief has been rejected, the averseness to it has arisen\nfrom the influence of some of the causes mentioned in the last\nchapter; the exclusive pursuit, namely, of particular trains and\nmodes of reasoning, till the mind becomes less capable of forming\nthe conceptions and making the exertions which are requisite for\nthe apprehension of truths not included among its usual subjects of\nthought.\n\n1. This seems to be the case with those who maintain that purpose\nand design cannot be _inferred_ or _deduced_ from the arrangements\nwhich we see around us by any process of reasoning. We can reason\nfrom effects to causes, say such writers, only in cases where we\nknow something of the nature of the cause. We can infer from the\nworks of men, the existence of design and purpose, because we\nknow, from past observation, what kind of works human design and\npurpose can produce. But the universe, considered as the work of\nGod, cannot be compared with any corresponding work, or judged\nof by any analogy with known examples. How then can we, in this\ncase, they ask, infer design and purpose in the artist of the\nuniverse? On what principles, on what axioms, can we proceed, which\nshall include this necessarily singular instance, and thus give\nlegitimacy and validity to our reasonings?\n\nWhat has already been said on the subject of the two different\nprocesses by which we obtain principles, and by which we reason\nfrom them, will suggest the reply to these questions. When we\ncollect design and purpose from the arrangements of the universe,\nwe do not arrive at our conclusion by a train of deductive\nreasoning, but by the conviction which such combinations as we\nperceive immediately and directly impress upon the mind. \u201cDesign\nmust have had a designer.\u201d But such a principle can be of no avail\nto one whom the contemplation or the description of the world does\nnot impress with the perception of design. It is not, therefore, at\nthe end, but at the beginning of our syllogisms, not among remote\nconclusions, but among original principles, that we must place the\ntruth, that such arrangements, manifestations, and proceedings\nas we behold about us imply a Being endowed with consciousness,\ndesign, and will, from whom they proceed.\n\nThis is inevitably the mode in which such a conviction is acquired;\nand that it is so, we may the more readily believe, when we\nconsider that it is the case with the design and will which we\nascribe to man, no less than in that which we believe to exist in\nGod. At first sight we might perhaps be tempted to say, that we\ninfer design and purpose from the works of man in one case, because\nwe have known these attributes in other cases produce effects in\nsome measure similar. But to this we must reply, by asking how we\ncome to know the existence of human design and purpose _at first_,\nand _at all_? What we see around us are certain appearances,\nthings, successions of events; how come we ever to ascribe to other\nmen the thought and will of which we are conscious ourselves? How\ndo we come to believe that there are other men? How are we led\nto elevate, in our conceptions, some of the _objects_ which we\nperceive into _persons_? No doubt their actions, their words induce\nus to do this. We see that the manifestations which we observe must\nbe so understood, and not otherwise. We feel that such actions,\nsuch events must be connected by consciousness and personality;\nthat the actions are not the actions of things, but of persons;\nnot necessary and without significance, like the falling of a\nstone, but voluntary and with purpose like what we do ourselves.\nBut this is not a result of reasoning: we do not infer this from\nany similar case which we have known; since we are now speaking of\nthe _first_ conception of a will and purpose different from our\nown. In arriving at such knowledge, we are aided only by our own\nconsciousness of what thought, purpose, will, are: and possessing\nthis regulative principle, we so decipher and interpret the complex\nappearances which surround us, that we receive irresistibly the\npersuasion of the existence of other men, with thought and will\nand purpose like our own. And just in the same manner, when we\nexamine attentively the adjustment of the parts of the human frame\nto each other and to the elements, the relation of the properties\nof the earth to those of its inhabitants, or of the physical to\nthe moral nature of man, the thought must arise and cling to our\nperceptions, however little it be encouraged, that this system,\nevery where so full of wonderful combinations, suited to the\npreservation, and well-being of living creatures, is also the\nexpression of the intention, wisdom, and goodness of a personal\ncreator and governor.\n\nWe conceive then that it is so far from being an unsatisfactory\nor unphilosophical process by which we collect the existence of\na Deity from the works of creation, that the process corresponds\nmost closely with that on which rests the most steadfast of our\nconvictions, next to that of our own existence, the belief of\nthe existence of other human beings. If any one ever went so far\nin scepticism as to doubt the existence of any other person than\nhimself, he might, so far as the argument from final causes is\nconcerned, reject the being of God as well as that of man; but,\nwithout dwelling on the possibility of such fantasies, when we\nconsider how impossible it is for men in general not to attribute\npersonality, purpose, thought, will to each other, in virtue of\ncertain combinations of appearances and actions, we must deem them\nmost consistent and reasonable in attributing also personality and\npurpose to God, in virtue of the whole assemblage of appearances\nand actions which constitute the universe, full as it is of\ncombinations from which such a suggestion springs. The vividness,\nthe constancy of the belief of a wise and good Being, thus\ngoverning the world, may be different in different men, according\nto their habit of directing their thoughts to the subject; but such\na belief is undoubtedly capable of becoming lively and steadfast\nin the highest degree. It has been entertained and cherished by\nenlightened and well-regulated minds in all ages; and has been,\nat least since the rise of Christianity, not only the belief, but\na pervading and ruling principle of action of many men, and of\nwhole communities. The idea may be rendered more faint by turning\nthe mind away from it, and perhaps by indulging too exclusively in\nabstract and general speculations. It grows stronger by an actual\nstudy of the details of the creation; and, as regards the practical\nconsequences of such a belief, by a habit of referring our actions\nand hopes to such a Governor. In this way it is capable of becoming\nas real and fixed an impression as that of a human friend and\nmaster; and all that we can learn, by observing the course of men\u2019s\nfeelings and actions, tends to convince us, that this belief of\nthe being and presence and government of God, leads to the most\nelevated and beneficial frame of mind of which man is capable.\n\n2. How natural and almost inevitable is this persuasion of the\nreality of Final Causes and consequent belief in the personality\nof the Deity, we may gather by observing how constantly it recurs\nto the thoughts, even of those who, in consequence of such\npeculiarities of mental discipline as have been described, have\nrepelled and resisted the impression.\n\nThus, Laplace, of whom we have already spoken, as one of the\ngreatest mathematicians of modern times, expresses his conviction\nthat the supposed evidence of final causes will disappear as our\nknowledge advances, and that they only seem to exist in those cases\nwhere our ignorance leaves room for such a mistake. \u201cLet us run\nover,\u201d he says, \u201cthe history of the progress of the human mind and\nits errors: we shall perpetually see final causes pushed away to\nthe bounds of its knowledge. These causes, which Newton removed\nto the limits of the solar system, were not long ago conceived to\nobtain in the atmosphere, and employed in explaining meteors: they\nare, therefore, in the eyes of the philosopher nothing more than\nthe expression of the ignorance in which we are of the real causes.\u201d\n\nWe may observe that we have endeavoured to give a very different,\nand, as we believe, a far truer view of the effect which philosophy\nhas produced on our knowledge of final causes. We have shown, we\ntrust, that the notion of design and end is transferred by the\nresearches of science, not from the domain of our knowledge to that\nof our ignorance, but merely from the region of facts to that of\nlaws. We hold that, in this form, final causes in the atmosphere\nare still to be conceived to obtain, no less than in an earlier\nstate of meteorological knowledge; and that Newton was right, when\nhe believed that he had established their reality in the solar\nsystem, not expelled them from it.\n\nBut our more peculiar business at present is to observe that\nLaplace himself, in describing the arrangements by which the\nstability of the solar system is secured, uses language which\nshows how irresistibly these arrangements suggest an adaptation\nto its preservation as an _end_. If in his expressions we were to\nsubstitute the Deity for the abstraction \u201cnature\u201d which he employs,\nhis reflection would coincide with that which the most religious\nphilosopher would entertain. \u201cIt seems that \u2018God\u2019 has ordered\nevery thing in the heavens to ensure the duration of the planetary\nsystem, by _views_ similar to those which He appears to us so\nadmirably to follow upon the earth, for the preservation of animals\nand the perpetuity of species.[40] This consideration alone would\nexplain the disposition of the system, if it were not the business\nof the geometer to go further.\u201d It may be possible for the geometer\nto go further; but he must be strangely blinded by his peculiar\npursuits, if, when he has discovered the mode in which these views\nare answered, he supposes himself to have obtained a proof that\nthere are no views at all. It would be as if the savage, who had\nmarvelled at the steady working of the steam engine, should cease\nto consider it a work of art, as soon as the self-regulating part\nof the mechanism had been explained to him.\n\nThe unsuccessful struggle in which those persons engage, who\nattempt to throw off the impression of design in the creation,\nappears in an amusing manner through the simplicity of the ancient\nRoman poet of this school. Lucretius maintains that the eye was not\nmade for seeing, nor the ear for hearing. But the terms in which he\nrecommends this doctrine show how hard he knew it to be for men to\nentertain such an opinion. His advice is,--\n\n      Illud in his rebus vitium _vehementer_ et istum\n      Effugere errorem, vitareque _pr\u00e6meditator_,\n      Lumina ne facias oculorum clara creata,\n      Prospicere ut possimus. iv. 823.\n\n      \u2019Gainst their preposterous error guard thy mind\n      Who say each organ was for use design\u2019d;\n      Think not the visual orbs, so clear, so bright,\n      Were furnish\u2019d for the purposes of sight.\n\nUndoubtedly the poet is so far right, that a most \u201cvehement\u201d\ncaution and vigilant \u201cpremeditation\u201d are necessary to avoid the\n\u201cvice and error\u201d of such a persuasion. The study of the adaptations\nof the human frame is so convincing, that it carries the mind with\nit, in spite of the resistance suggested by speculative systems.\nCabanis, a modern French physiological writer of great eminence,\nmay be selected as a proof of this. Both by the general character\nof his own speculations, and by the tone of thinking prevalent\naround him, the consideration of design in the works of nature was\nabhorrent from his plan. Accordingly, he joins in repeating Bacon\u2019s\nunfavourable mention of final causes. Yet when he comes to speak\nof the laws of reproduction of the human race, he appears to feel\nhimself compelled to admit the irresistible manner in which such\nviews force themselves on the mind. \u201cI regard,\u201d he says, \u201cwith the\ngreat Bacon, the philosophy of final causes as barren; but I have\nelsewhere acknowledged that it was very difficult for the most\ncautious man (l\u2019homme le plus reserv\u00e9) never to have recourse to\nthem in his explanations.\u201d[41]\n\n3. It may be worth our while to consider for a moment the opinion\nhere referred to by Cabanis, of the propriety of excluding the\nconsideration of final causes from our natural philosophy. The\ngreat authority of Bacon is usually adduced on this subject.\n\u201cThe handling of final causes,\u201d says he, \u201cmixed with the rest\nin physical inquiries, hath intercepted the severe and diligent\ninquiry of all real and physical causes, and given men the occasion\nto stay upon these satisfactory and specious causes, to the great\narrest and prejudice of farther discovery.\u201d[42]\n\nA moment\u2019s attention will show how well this representation agrees\nwith that which we have urged, and how far it is from dissuading\nthe reference to final causes in reasonings like those on which\nwe are employed. Final causes are to be excluded _from physical\ninquiry_; that is, we are not to assume that we know the objects\nof the Creator\u2019s design, and put this assumed purpose in the\nplace of a physical cause. We are not to think it a sufficient\naccount of the clouds that they are for watering the earth, (to\ntake Bacon\u2019s examples,) or \u201cthat the solidness of the earth is\nfor the station and mansion of living creatures.\u201d The physical\nphilosopher has it for his business to trace clouds to the laws of\nevaporation and condensation; to determine the magnitude and mode\nof action of the forces of cohesion and crystallization by which\nthe materials of the earth are made solid and firm. This he does,\nmaking no use of the notion of final causes: and it is precisely\nbecause he has thus established his theories independently of any\nassumption of an end, that the end, when after all, it returns upon\nhim and cannot be evaded, becomes an irresistible evidence of an\nintelligent legislator. He finds that the effects, of which the\nuse is obvious, are produced by most simple and comprehensive laws;\nand when he has obtained this view, he is struck by the beauty of\nthe means, by the refined and skilful manner in which the useful\neffects are brought about;--points different from those to which\nhis researches were directed. We have already seen, in the very\ncase of which we have been speaking, namely, the laws by which the\nclouds are formed and distribute their showers over the earth, how\nstrongly those who have most closely and extensively examined the\narrangements there employed (as Howard, Dalton, and Black) have\nbeen impressed with the harmony and beauty which these contrivances\nmanifest.\n\nWe may find a further assertion of this view of the proper use of\nfinal causes in philosophy, by referring to the works of one of\nthe greatest of our philosophers, and one of the most pious of\nour writers, Boyle, who has an Essay on this subject. \u201cI am by\nall means,\u201d says he, \u201cfor encouraging the contemplation of the\ncelestial part of the world, and the shining globes that adorn it,\nand especially the sun and moon, in order to raise our admiration\nof the stupendous power and wisdom of him who was able to frame\nsuch immense bodies; and notwithstanding their vast bulk and\nscarce conceivable rapidity, keep them for so many ages constant\nboth to the lines and degrees of their motion, without interfering\nwith one another. And doubtless we ought to return thanks and\npraises to the divine goodness for having so placed the sun and\nmoon, and determined the former, or else the earth, to move in\nparticular lines for the good of men and other animals; and how\ndisadvantageous it would have been to the inhabitants of the earth\nif the luminaries had moved after a different manner. I dare not,\nhowever, affirm that the sun, moon, and other celestial bodies\nwere made solely for the use of man: _much less presume to prove\none system of the world to be true and another false; because the\nformer is better fitted to the convenience of mankind, or the\nother less suited, or perhaps altogether useless to that end_.\u201d\n\nThis passage exhibits, we conceive, that combination of feelings\nwhich ought to mark the character of the religious natural\nphilosopher; an earnest piety ready to draw nutriment from the\ncontemplation of established physical truths; joined with a\nphilosophical caution, which is not seduced by the anticipation\nof such contemplations, to pervert the strict course of physical\ninquiry.\n\nIt is precisely through this philosophical care and scrupulousness\nthat our views of final causes acquire their force and value as\naids to religion. The object of such views is not to lead us to\nphysical truth, but to connect such truth, obtained by its proper\nprocesses and methods, with our views of God, the master of the\nuniverse, through those laws and relations which are thus placed\nbeyond dispute.\n\nBacon\u2019s comparison of final causes to the vestal virgins is one of\nthose poignant sayings, so frequent in his writings, which it is\nnot easy to forget. \u201cLike them,\u201d he says, \u201cthey are dedicated to\nGod, and are barren.\u201d But to any one who reads his work it will\nappear in what spirit this was meant. \u201cNot because those final\ncauses are not true and worthy to be inquired, being kept within\ntheir own province.\u201d (Of the Advancement of Learning, b. ii. p.\n142.) If he had had occasion to develope his simile, full of latent\nmeaning as his similes so often are, he would probably have said,\nthat to these final causes barrenness was no reproach, seeing they\nought to be, not the mothers but the daughters of our natural\nsciences; and that they were barren, not by imperfection of their\nnature but in order that they might be kept pure and undefiled, and\nso fit ministers in the temple of God.\n\n\n\n\nCHAPTER VIII.\n\n_On the Physical Agency of the Deity._\n\n\n1. We are not to expect that physical investigation can enable us\nto conceive the manner in which God acts upon the members of the\nuniverse. The question, \u201cCanst thou by searching find out God?\u201d\nmust silence the boastings of science as well as the repinings\nof adversity. Indeed, science shows us, far more clearly than\nthe conceptions of every day reason, at what an immeasurable\ndistance we are from any faculty of conceiving _how_ the universe,\nmaterial and moral, is the work of the Deity. But with regard\nto the material world, we can at least go so far as this;--we\ncan perceive that events are brought about, not by insulated\ninterpositions of divine power exerted in each particular case,\nbut by the establishment of general laws. This, which is the view\nof the universe proper to science, whose office it is to search\nout these laws, is also the view which, throughout this work, we\nhave endeavoured to keep present to the mind of the reader. We\nhave attempted to show that it combines itself most readily and\nharmoniously with the doctrines of Natural Theology; that the\narguments for those doctrines are strengthened, the difficulties\nwhich affect them removed, by keeping it steadily before us. We\nconceive, therefore, that the religious philosopher will do well to\nbear this conception in his mind. God is the author and governor of\nthe universe through the laws which he has given to its parts, the\nproperties which he has impressed upon its constituent elements;\nthese laws and properties are, as we have already said, the\ninstruments with which he works; the institution of such laws, the\nselection of the quantities which they involve, their combination\nand application, are the modes in which he exerts and manifests his\npower, his wisdom, his goodness: through these attributes, thus\nexercised, the Creator of all, shapes, moves, sustains, and guides\nthe visible creation.\n\nThis has been the view of the relation of the Deity to the universe\nentertained by the most sagacious and comprehensive minds ever\nsince the true object of natural philosophy has been clearly and\nsteadily apprehended. The great writer who was the first to give\nphilosophers a distinct and commanding view of this object, thus\nexpresses himself in his \u201cConfession of Faith:\u201d \u201cI believe--that\nnotwithstanding God hath rested and ceased from creating since the\nfirst Sabbath, yet, nevertheless, he doth accomplish and fulfil his\ndivine will in all things, great and small, singular and general,\nas fully and exactly by providence, as he could by miracle and\nnew creation, though his working be not immediate and direct, but\nby compass; not violating nature, which is his own law upon the\ncreature.\u201d\n\nAnd one of our own time, whom we can no longer hesitate to place\namong the worthiest disciples of the school of Bacon, conveys the\nsame thought in the following passage: \u201cThe Divine Author of the\nuniverse cannot be supposed to have laid down particular laws,\nenumerating all individual contingencies, which his materials\nhave understood and obey--this would be to attribute to him the\nimperfections of human legislation;--but rather, by creating them\nendued with certain fixed qualities and powers, he has impressed\nthem in their origin with the _spirit_, not the letter of his law,\nand made all their subsequent combinations and relations inevitable\nconsequences of this first impression.\u201d[43]\n\n2. This, which thus appears to be the mode of the Deity\u2019s operation\nin the material world, requires some attention on our part in\norder to understand it with proper clearness. One reason of this\nis, that it is a mode of operation altogether different from that\nin which we are able to make matter fulfil our designs. Man can\nconstruct exquisite machines, can call in vast powers, can form\nextensive combinations, in order to bring about results which he\nhas in view. But in all this he is only taking advantage of laws\nof nature which already exist; he is applying to his use qualities\nwhich matter already possesses. Nor can he by any effort do more.\nHe can establish no new law of nature which is not a result of the\nexisting ones. He can invest matter with no new properties which\nare not modifications of its present attributes. His greatest\nadvances in skill and power are made when he calls to his aid\nforces which before existed unemployed, or when he discovers so\nmuch of the habits of some of the elements as to be able to bend\nthem to his purpose. He navigates the ocean by the assistance of\nthe winds which he cannot raise or still: and even if we suppose\nhim able to control the course of these, his yet unsubjugated\nministers, this could only be done by studying their characters, by\nlearning more thoroughly the laws of air and heat and moisture. He\ncannot give the minutest portion of the atmosphere new relations,\na new course of expansion, new laws of motion. But the Divine\noperations, on the other hand, include something much higher. They\ntake in the establishment of the laws of the elements, as well\nas the combination of these laws and the determination of the\ndistribution and quantity of the materials on which they shall\nproduce their effect. We must conceive that the Supreme Power has\nordained that air shall be rarefied, and water turned into vapour,\nby heat; no less than that he has combined air and water so as to\nsprinkle the earth with showers, and determined the quantity of\nheat and air and water, so that the showers shall be as beneficial\nas they are.\n\nWe may and must, therefore, in our conceptions of the Divine\npurpose and agency, go beyond the analogy of human contrivances. We\nmust conceive the Deity, not only as constructing the most refined\nand vast machinery, with which, as we have already seen, the\nuniverse is filled; but we must also imagine him as establishing\nthose properties by which such machinery is possible: as giving to\nthe materials of his structure the qualities by which the material\nis fitted to its use. There is much to be found, in natural\nobjects, of the same kind of contrivance which is common to these\nand to human inventions; there are mechanical devices, operations\nof the atmospheric elements, chemical processes;--many such have\nbeen pointed out, many more exist. But besides these cases of the\ncombination of means, which, we seem able to understand without\nmuch difficulty, we are led to consider the Divine Being as the\n_author of the laws_ of chemical, of physical, and of mechanical\naction, and of such other laws as make matter what it is;--and\nthis is a view which no analogy of human inventions, no knowledge\nof human powers, at all assists us to embody or understand.\nScience, therefore, as we have said, while it discloses to us the\nmode of instrumentality employed by the Deity, convinces us, more\neffectually than ever, of the impossibility of conceiving God\u2019s\nactions by assimilating them to our own.\n\n3. The laws of material nature, such as we have described them,\noperate at all times, and in all places; affect every province of\nthe universe, and involve every relation of its parts. Wherever\nthese laws appear, we have a manifestation of the intelligence by\nwhich they were established. But a law supposes an agent, and a\npower; for it is the mode according to which the agent proceeds,\nthe order according to which the power acts. Without the presence\nof such an agent, of such a power, conscious of the relations\non which the law depends, producing the effects which the law\nprescribes, the law can have no efficacy, no existence. Hence we\ninfer that the intelligence by which the law is ordained, the\npower by which it is put in action, must be present at all times\nand in all places where the effects of the law occur; that thus the\nknowledge and the agency of the Divine Being pervade every portion\nof the universe, producing all action and passion, all permanence\nand change. The laws of nature are the laws which he, in his\nwisdom, prescribes to his own acts; his universal presence is the\nnecessary condition of any course of events, his universal agency\nthe only origin of any efficient force.\n\nThis view of the relation of the universe to God has been\nentertained by many of the most eminent of those who have combined\nthe consideration of the material world with the contemplation of\nGod himself. It may therefore be of use to illustrate it by a few\nquotations, and the more so, as we find this idea remarkably dwelt\nupon in the works of that writer whose religious views must always\nhave a peculiar interest for the cultivators of physical science,\nthe great Newton.\n\nThus, in the observations on the nature of the Deity with which\nhe closes the \u201cOpticks,\u201d he declares the various portions of the\nworld, organic and inorganic, \u201ccan be the effect of nothing else\nthan the wisdom and skill of a powerful ever living Agent, who\nbeing in all places, is more able by his will to move the bodies\nwithin his boundless uniform _sensorium_, and thereby to form and\nreform the parts of the universe, than we are by our will to move\nthe parts of our own bodies.\u201d And in the Scholium at the end of\nthe \u201cPrincipia,\u201d he says, \u201cGod is one and the same God always and\nevery where. He is omnipresent, not by means of his _virtue_ alone,\nbut also by his _substance_, for virtue cannot subsist without\nsubstance. In him all things are contained, and move, but without\nmutual passion: God is not acted upon by the motions of bodies;\nand they suffer no resistance from the omnipresence of God.\u201d And\nhe refers to several passages confirmatory of this view, not only\nin the Scriptures, but also in writers who hand down to us the\nopinions of some of the most philosophical thinkers of the pagan\nworld. He does not disdain to quote the poets, and among the rest,\nthe verses of Virgil;\n\n      Principio c\u0153lum ac terras camposque liquentes\n      Lucentemque globum lun\u00e6, Titaniaque astra,\n      Spiritus intus alit, totamque infusa per artus\n      Mens agitat molem et magno se corpore miscet:\n\nwarning his reader, however, against the doctrine which such\nexpressions as these are sometimes understood to express. \u201cAll\nthese things he rules, not as _the soul of the world_, but as the\nLord of all.\u201d\n\nClarke, the friend and disciple of Newton, is one of those who has\nmost strenuously put forwards the opinion of which we are speaking,\n\u201cAll things which we commonly say are the effects of the natural\npowers of matter and laws of motion, are indeed (if we will speak\nstrictly and properly,) the effects of God\u2019s acting upon matter\ncontinually and at every moment, either immediately by himself, or\nmediately by some created intelligent being. Consequently there is\nno such thing as the course of nature, or the power of nature,\u201d\nindependent of the effects produced by the will of God.\n\nDugald Stewart has adopted and illustrated the same opinion, and\nquotes with admiration the well-known passage of Pope, concerning\nthe Divine Agency, which\n\n      \u201cLives through all life, extends through all extent,\n      Spreads undivided, operates unspent.\u201d\n\nMr. Stewart, with no less reasonableness than charity, asserts the\npropriety of interpreting such passages according to the scope\nand spirit of the reasonings with which they are connected;[44]\nsince, though by a captious reader they might be associated with\nerroneous views of the Deity, a more favourable construction will\noften see in them only the results of the necessary imperfection\nof our language, when we dwell upon the omnipresence and universal\nactivity of God.\n\nFinally, we may add that the same opinions still obtain the assent\nof the best philosophers and divines of our time. Sir John Herschel\nsays, (Discourse on the Study of Natural Philosophy, p. 37.) \u201cWe\nwould no way be understood to deny the constant exercise of His\ndirect power in maintaining the system of nature; or the ultimate\nemanation, of every energy which material agents exert, from his\nimmediate will, acting in conformity with his own laws.\u201d And the\nBishop of London, in a note to his \u201cSermon on the duty of combining\nreligious instruction with intellectual culture,\u201d observes, \u201cthe\nstudent in natural philosophy will find rest from all those\nperplexities which are occasioned by the obscurity of causation, in\nthe supposition, which although it was discredited by the patronage\nof Malebranche and the Cartesians, has been adopted by Clarke and\nDugald Stewart, and which is by far the most simple and sublime\naccount of the matter; that all the events, which are continually\ntaking place in the different parts of the material universe, are\nthe _immediate_ effects of the divine agency.\u201d\n\n\n\n\nCHAPTER IX.\n\n  _On the Impression produced by considering the Nature and\n  Prospects of Science; or, on the Impossibility of the Progress of\n  our Knowledge ever enabling us to comprehend the Nature of the\n  Deity._\n\n\nIf we were to stop at the view presented in the last chapter,\nit might be supposed that--by considering God as eternal and\nomnipresent, conscious of all the relations, and of all the objects\nof the universe, instituting laws founded on the contemplation\nof these relations, and carrying these laws into effect by his\nimmediate energy,--we had attained to a conception, in some degree\ndefinite, of the Deity, such as natural philosophy leads us to\nconceive him. But by resting in this mode of conception, we should\noverlook, or at least should disconnect from our philosophical\ndoctrines, all that most interests and affects us in the character\nof the Creator and Preserver of the world;--namely, that he is the\nlawgiver and judge of our actions; the proper object of our prayer\nand adoration; the source from which we may hope for moral strength\nhere, and for the reward of our obedience and the elevation of our\nnature in another state of existence.\n\nWe are very far from believing that our philosophy alone can give\nus such assurance of these important truths as is requisite for\nour guidance and support; but we think that even our physical\nphilosophy will point out to us the necessity of proceeding far\nbeyond that conception of God, which represents him merely as the\nmind in which reside all the contrivance, law, and energy of the\nmaterial world. We believe that the view of the universe which\nmodern science has already opened to us, compared with the prospect\nof what she has still to do in pursuing the path on which she has\njust entered, will show us how immeasurably inadequate such a mode\nof conception would be: and that if we take into our account, as\nwe must in reason do, all that of which we have knowledge and\nconsciousness, and of which we have as yet no systematic science,\nwe shall be led to a conviction that the Creator and Preserver\nof the material world must also contain in him such properties\nand attributes as imply his moral character, and as fall in most\nconsistently with all that we learn in any other way of his\nprovidence and holiness, his justice and mercy.\n\n1. The sciences which have at present acquired any considerable\ndegree of completeness, are those in which an extensive and\nvaried collection of phenomena, and their proximate causes, have\nbeen reduced to a few simple general laws. Such are Astronomy\nand Mechanics, and perhaps, so far as its physical conditions\nare concerned, Optics. Other portions of human knowledge can\nbe considered as perfect sciences, in any strict sense of the\nterm, only when they have assumed this form; when the various\nappearances which they involve are reduced to a few principles,\nsuch as the laws of motion and the mechanical properties of the\nluminiferous ether. If we could trace the endless varieties of\nthe forms of crystals, and the complicated results of chemical\ncomposition, to some one comprehensive law necessarily pointing out\nthe crystalline form of any given chemical compound, Mineralogy\nwould become an exact science. As yet, however, we can scarcely\nboast of the existence of any other such sciences than those which\nwe at first mentioned: and so far therefore as we attempt to give\ndefiniteness to our conception of the Deity, by considering him\nas the intelligent depositary and executor of laws of nature, we\ncan subordinate to such a mode of conception no portion of the\ncreation, save the mechanical movements of the universe, and the\npropagation and properties of light.\n\n2. And if we attempt to argue concerning the nature of the laws\nand relations which govern those provinces of creation whither our\nscience has not yet reached, by applying some analogy borrowed from\ncases where it has been successful, we have no chance of attaining\nany except the most erroneous and worthless guesses. The history of\nhuman speculations, as well as the nature of the objects of them,\nshows how certainly this must happen. The great generalizations\nwhich have been established in one department of our knowledge,\nhave been applied in vain to the purpose of throwing light on\nthe other portions which still continue in obscurity. When the\nNewtonian philosophy had explained so many mechanical facts, by\nthe two great steps,--of resolving the action of a whole mass\ninto the actions of its minutest particles, and considering these\nparticles as centres of force,--attempts were naturally soon made\nto apply the same mode of explanation to facts of other different\nkinds. It was conceived that the whole of natural philosophy must\nconsist in investigating the laws of force by which particles of\ndifferent substances attracted and repelled, and thus produced\nmotions, or vibrations _to_ and _from_ the particles. Yet what were\nthe next great discoveries in physics? The action of a galvanic\nwire upon a magnet; which is not to attract or repel it, but to\nturn it to the _right_ and _left_; to produce motion, not to or\nfrom, but _transverse_ to the line drawn to the acting particles;\nand again, the undulatory theory of light, in which it appeared\nthat the undulations must not be longitudinal, as all philosophers,\nfollowing the analogy of all cases previously conceived, had,\nat first, supposed them to be, but _transverse_ to the path of\nthe ray. Here, though the step from the known to the unknown was\ncomparatively small, when made conjecturally it was made in a\ndirection very wide of the truth. How impossible then must it be to\nattain in this manner to any conception of a law which shall help\nus to understand the whole government of the universe!\n\n3. Still, however, in the laws of the luminiferous ether, and of\nthe other fluid, (if it be another fluid) by which galvanism and\nmagnetism are connected, we have something approaching nearly to\nmechanical action, and, possibly, hereafter to be identified with\nit. But we cannot turn to any other part of our physical knowledge,\nwithout perceiving that the gulf which separates it from the exact\nsciences is yet wider and more obscure. Who shall enunciate for\nus, and in terms of what notions, the general law of _chemical_\ncomposition and decomposition? sometimes indeed we give the name\nof _attraction_ to the affinity by which we suppose the particles\nof the various ingredients of bodies to be aggregated; but no one\ncan point out any common feature between this and the attractions\nof which alone we know the exact effects. He who shall discover the\ntrue general law of the forces by which elements form compounds,\nwill probably advance as far beyond the discoveries of Newton, as\nNewton went beyond Aristotle. But who shall say in what direction\nthis vast flight shall be, and what new views it shall open to us\nof the manner in which matter obeys the laws of the Creator?\n\n4. But suppose this flight performed;--we are yet but at the outset\nof the progress which must carry us towards Him. We have yet to\nbegin to learn all that we are to know concerning the ultimate laws\nof organized bodies. What is the principle of _life_? What is the\nrule of that action of which assimilation, secretion, developement,\nare manifestations? and which appears to be farther removed from\nmere chemistry than chemistry is from mechanics. And what again is\nthe new principle, as it seems to be, which is exhibited in the\n_irritability_ of an animal nerve? the existence of a sense? How\ndifferent is this from all the preceding notions! No efforts can\navoid or conceal the vast but inscrutable chasm. Those theorists,\nwho have maintained most strenuously the possibility of tracing\nthe phenomena of animal life to the influence of physical agents,\nhave constantly been obliged to suppose a mode of agency altogether\ndifferent from any yet known in physics. Thus Lamarck, one of\nthe most noted of such speculators, in describing the course of\nhis researches, says, \u201cI was soon persuaded that the _internal\nsentiment_ constituted a power which it was necessary to take into\naccount.\u201d And Bichat, another writer on the same subject, while\nhe declares his dissent from Stahl, and the earlier speculators,\nwho had referred every thing in the economy of life to a single\nprinciple, which they called the _anima_, the _vital principle_,\nand so forth, himself introduces several principles, or laws,\nall utterly foreign to the region of physics; namely, _organic\nsensibility_, _organic contractility_, _animal sensibility_,\n_animal contractility_, and the like. Supposing such principles\nreally to exist, how far enlarged and changed must our views be\nbefore we can conceive these properties, including the faculty of\nperception, which they imply, to be produced by the will and power\nof one supreme Being, acting by fixed laws. Yet without conceiving\nthis, we cannot conceive the agency of that Deity, who is\nincessantly thus acting, in countless millions of forms and modes.\n\nHow strongly then does science represent God to us as\nincomprehensible! his attributes as unfathomable! His power, his\nwisdom, his goodness, appear in each of the provinces of nature\nwhich are thus brought before us; and in each, the more we study\nthem, the more impressive, the more admirable do they appear.\nWhen then we find these qualities manifested in each of so many\nsuccessive ways, and each manifestation rising above the preceding\nby unknown degrees, and through a progression of unknown extent,\nwhat other language can we use concerning such attributes than that\nthey are _infinite_? What mode of expression can the most cautious\nphilosophy suggest, other than that He, to whom we thus endeavour\nto approach, is infinitely wise, powerful, and good?\n\n5. But with sense and consciousness the history of living things\nonly begins. They have instincts, affections, passions, will. How\nentirely lost and bewildered do we find ourselves when we endeavour\nto conceive these faculties communicated by means of general laws!\nYet they are so communicated from God, and of such laws he is the\nlawgiver. At what an immeasurable interval is he thus placed above\nevery thing which the creation of the inanimate world alone would\nimply; and how far must he transcend all ideas founded on such\nlaws as we find there!\n\n6. But we have still to go further and far higher. The world\nof reason and of morality is a part of the same creation, as\nthe world of matter and of sense. The will of man is swayed by\nrational motives; its workings are inevitably compared with a\nrule of action; he has a conscience which speaks of right and\nwrong. These are laws of man\u2019s nature no less than the laws of his\nmaterial existence, or his animal impulses. Yet what entirely new\nconceptions do they involve? How incapable of being resolved into,\nor assimilated to, the results of mere matter, or mere sense! Moral\ngood and evil, merit and demerit, virtue and depravity, if ever\nthey are the subjects of strict science, must belong to a science\nwhich views these things, not with reference to time or space,\nor mechanical causation, not with reference to fluid or ether,\nnervous irritability or corporeal feeling, but to their own proper\nmodes of conception; with reference to the relations with which\nit is possible that these notions may be connected, and not to\nrelations suggested by other subjects of a completely extraneous\nand heterogeneous nature. And according to such relations must the\nlaws of the moral world be apprehended, by any intelligence which\ncontemplates them at all.\n\nThere can be no wider interval in philosophy than the separation\nwhich must exist between the laws of mechanical force and motion,\nand the laws of free moral action. Yet the tendency of men to\nassume, in the portions of human knowledge which are out of\ntheir reach, a similarity of type to those with which they are\nfamiliar, can leap over even this interval. Laplace has asserted\nthat \u201can intelligence which, at a given instant, should know all\nthe forces by which nature is urged, and the respective situation\nof the beings of which nature is composed, if, moreover, it were\nsufficiently comprehensive to subject these data to calculation,\nwould include in the same _formula_, the movements of the largest\nbodies of the universe and those of the slightest atom. Nothing\nwould be uncertain to such an intelligence, and the future, no\nless than the past, would be present to its eyes.\u201d If we speak\nmerely of mechanical actions, this may, perhaps, be assumed to be\nan admissible representation of the nature of their connexion in\nthe sight of the supreme intelligence. But to the rest of what\npasses in the world, such language is altogether inapplicable. A\n_formula_ is a brief mode of denoting a rule of calculating in\nwhich numbers are to be used: and numerical measures are applicable\nonly to things of which the relation depend on time and space. By\nsuch elements, in such a mode, how are we to estimate happiness\nand virtue, thought and will? To speak of a formula with regard to\nsuch things, would be to assume that their laws must needs take the\nshape of those laws of the material world which our intellect most\nfully comprehends. A more absurd and unphilosophical assumption we\ncan hardly imagine.\n\nWe conceive, therefore, that the laws by which God governs his\nmoral creatures, reside in his mind, invested with that kind of\ngenerality, whatever it be, of which such laws are capable; but of\nthe character of such general laws, we know nothing more certainly\nthan this, that it must be altogether different from the character\nof those laws which regulate the material world. The inevitable\nnecessity of such a total difference is suggested by the analogy of\nall the knowledge which we possess and all the conceptions which we\ncan form. And, accordingly, no persons, except those whose minds\nhave been biassed by some peculiar habit or course of thought,\nare likely to run into the confusion and perplexity which are\nproduced by assimilating too closely the government and direction\nof voluntary agents to the production of trains of mechanical\nand physical phenomena. In whatever manner voluntary and moral\nagency depend upon the Supreme Being, it must be in some such way\nthat they still continue to bear the character of will, action,\nand morality. And, though too exclusive an attention to material\nphenomena may sometimes have made physical philosophers blind to\nthis manifest difference, it has been clearly seen and plainly\nasserted by those who have taken the most comprehensive views of\nthe nature and tendency of science. \u201cI believe,\u201d says Bacon, in\nhis Confession of Faith, \u201cthat, at the first the soul of man was\nnot produced by heaven or earth, but was breathed immediately from\nGod; so that _the ways and proceedings of God with spirits are not\nincluded in nature; that is in the laws of heaven and earth_; but\nare reserved to the law of his secret will and grace; wherein God\nworketh still, and resteth not from the work of redemption, as\nhe resteth from the work of creation; but continueth working to\nthe end of the world.\u201d We may be permitted to observe here, that,\nwhen Bacon has thus to speak of God\u2019s dealings with his moral\ncreatures, he does not take his phraseology from those sciences\nwhich can offer none but false and delusive analogies; but helps\nout the inevitable scantiness of our human knowledge, by words\nborrowed from a source more fitted to supply our imperfections.\nOur natural speculations cannot carry us to the ideas of \u201cgrace\u201d\nand \u201credemption;\u201d but in the wide blank which they leave, of all\nthat concerns our hopes of the Divine support and favour, the\ninestimable knowledge which revelation, as we conceive, gives us,\nfinds ample room and appropriate place.\n\n7. Yet even in the view of our moral constitution which natural\nreason gives, we may trace laws that imply a personal relation to\nour Creator. How can we avoid considering _that_ as a true view\nof man\u2019s being and place, without which, his best faculties are\nnever fully developed, his noblest energies never called out, his\nhighest point of perfection never reached? Without the thought of a\nGod over all, superintending our actions, approving our virtues,\ntranscending our highest conceptions of good, man would never rise\nto those higher regions of moral excellence which we know him to\nbe capable of attaining. \u201cTo deny a God,\u201d again says the great\nphilosopher, \u201cdestroys magnanimity and the raising of human nature;\nfor take an example of a dog, and mark what a generosity and\ncourage he will put on, when he finds himself maintained by a man;\nwho, to him, is instead of a God, or _melior natura_: which courage\nis manifestly such, as that creature, without that confidence of\na better nature than his own, could never attain. So man, when he\nresteth and assureth himself upon divine protection and favour,\ngathereth a force and faith, which human nature could not obtain.\nTherefore, as atheism is in all respects hateful, so in this, that\nit depriveth human nature of the means to exalt itself above human\nfrailty.\u201d[45]\n\nSuch a law, then, of reference to a Supremely Good Being, is\nimpressed upon our nature, as the condition and means of its\nhighest moral advancement. And strange indeed it would be if we\nshould suppose, that in a system where all besides indicates\npurpose and design, this law should proceed from no such origin;\nand no less inconceivable, that such a law, purposely impressed\nupon man to purify and elevate his nature, should delude and\ndeceive him.\n\n8. Nothing remains, therefore, but that the Creator, who, for\npurposes that even we can see to be wise and good, has impressed\nupon man this tendency to look to him for support, for advancement,\nfor such happiness as is reconcileable with holiness;--to believe\nhim to be the union of all perfection, the highest point of all\nintellectual and moral excellence;--IS, in reality, such a guardian\nand judge, such a good, and wise, and perfect Being, as we thus\nirresistibly conceive him. It would indeed be extravagant to assert\nthat the imagination of the creature, itself the work of God, can\ninvent a higher point of goodness, of justice, of holiness, than\nthe Creator himself possesses: that the Eternal Mind, from whom our\nnotions of good and right are derived, is not himself directed by\nthe rules which these notions imply.\n\nIt is difficult to dwell steadily on such thoughts. But they will\nat least serve to confirm the view which it was our object to\nillustrate; namely, how incomparably the nature of God must be\nelevated above any conceptions which our natural reason enables\nus to form; and we have been led to these reflections, it will be\nrecollected, by following the clue of which science gave us the\nbeginning. The Divine Mind must be conceived by us as the seat of\nthose laws of nature which we have discovered. It must be no less\nthe seat of those laws which we have not yet discovered, though\nthese may and must be of a character far different from any thing\nwe can guess. The Supreme Intelligence must therefore contain the\nlaws, each according to their true dependence, of organic life, of\nsense, of animal impulse, and must contain also the purpose and\nintent for which these powers were put in play. But the Governing\nMind must comprehend also the laws of the responsible creatures\nwhich the world contains, and must entertain the purposes for\nwhich their responsible agency was given them. It must include\nthese laws and purposes, connected by means of the notions, which\nresponsibility implies, of desert and reward, of moral excellence\nin various degrees, and of well-being as associated with right\ndoing. All the laws which govern the moral world are expressions\nof the thought and intentions of our Supreme Ruler. All the\ncontrivances for moral no less than for physical good, for the\npeace of mind, and other rewards of virtue, for the elevation and\npurification of individual character, for the civilization and\nrefinement of states, their advancement in intellect and virtue,\nfor the diffusion of good, and the repression of evil; all the\nblessings that wait on perseverance and energy in a good cause;\non unquenchable love of mankind, and unconquerable devotedness to\ntruth; on purity and self-denial; on faith, hope, and charity;--all\nthese things are indications of the character, will, and future\nintentions of that God, of whom we have endeavoured to track the\nfootsteps upon earth, and to show his handiwork in the heavens.\n\u201cThis God is our God, for ever and ever.\u201d And if, in endeavouring\nto trace the tendencies of the vast labyrinth of laws by which the\nuniverse is governed, we are sometimes lost and bewildered, and\ncan scarce, or not at all, discern the line by which pain, and\nsorrow, and vice fall in with a scheme directed to the strictest\nright and greatest good, we yet find no room to faint or falter;\nknowing that these are the darkest and most tangled recesses of our\nknowledge; that into them science has as yet cast no ray of light;\nthat in them reason has as yet caught sight of no general law by\nwhich we may securely hold: while, in those regions where we can\nsee clearly, where science has thrown her strongest illumination\nupon the scheme of creation; where we have had displayed to us\nthe general laws which give rise to all multifarious variety of\nparticular facts;--we find all full wisdom, and harmony, and\nbeauty: and all this wise selection of means, this harmonious\ncombination of laws, this beautiful symmetry of relations,\ndirected, with no exception which human investigation has yet\ndiscovered, to the preservation, the diffusion, the well-being\nof those living things, which, though of their nature we know\nso little, we cannot doubt to be the worthiest objects of the\nCreator\u2019s care.\n\n\nFINIS.\n\n\nFOOTNOTES:\n\n[1] Loudon, Encyclop\u00e6dia of Gardening, 848.\n\n[2] Dec. Phys. vol. ii. 478.\n\n[3] Fleming, Zool. i. 400.\n\n[4] Rapports du Physique et du Moral de l\u2019Homme, II. 371.\n\n[5] It will be observed that it is not here asserted that the\ndifference of native products depends on the difference of climate\n_alone_.\n\n[6] The resemblance consists in this; that we have a strip of\ngreater temperature accompanied by a strip of smaller temperature,\nthese strips arising from the diurnal and nocturnal impressions\nrespectively, and being in motion; as in the waves on a canal, we\nhave a moving strip of greater elevation accompanied by a strip\nof smaller elevation. We do not here refer to any hypothetical\nundulations in the fluid matter of heat.\n\n[7] Loudon, 1219.\n\n[8] Loudon, 1214.\n\n[9] Manchester Memoirs, v. 357.\n\n[10] Howard on the climate of London, vol. ii. pp. 216, 217.\n\n[11] Daniell, Meteor. Ess. p. 56.\n\n[12] Daniell. p. 129.\n\n[13] Phil. Trans. 1821.\n\n[14] Mr. Gough in Manch. Mem. vol. v.\n\n[15] The reader who is acquainted with the two theories of light,\nwill perceive that though we have adopted the doctrine of the\nether, the greater part of the arguments adduced would be equally\nforcible, if expressed in the language of the theory of emission.\n\n[16] Or rather through the _focal centre_ of the eye, which is\nalways near the centre of the pupil.\n\n[17] Laplace, Expos. du Syst. du Monde, p. 441.\n\n[18] In this statement of Laplace, however, one remarkable\nprovision for the stability of the system is not noticed.\nThe planets Mercury and Mars, which have much the largest\neccentricities among the old planets, are those of which the\nmasses are much the smallest. The mass of Jupiter is more than two\nthousand times that of either of these planets. If the orbit of\nJupiter were as eccentric as that of Mercury is, all the security\nfor the stability of the system, which analysis has yet pointed\nout, would disappear. The earth and the smaller planets might in\nthat case change their approximately circular orbits into very long\nellipses, and thus might fall into the sun, and fly off into remote\nspace.\n\nIt is further remarkable that in the newly discovered planets, of\nwhich the orbits are still more eccentric than that of Mercury, the\nmasses are still smaller, so that the same provision is established\nin this case also. It does not appear that any mathematician has\neven attempted to point out a necessary connexion between the mass\nof a planet and the eccentricity of its orbit on any hypothesis.\nMay we not then consider this combination of small masses with\nlarge eccentricities, so important to the purposes of the world, as\na mark of provident care in the Creator?\n\n[19] The _eccentricity_ of a planet\u2019s orbit is measured by taking\nthe proportion of the _difference_ of the greatest and least\ndistances from the sun, to the _sum_ of the same distances.\nMercury\u2019s greatest and least distances are as two and three; his\neccentricity, therefore, is one-fifth.\n\n[20] The stability of the axis of rotation about which the earth\nrevolves, has sometimes been adduced as an instance of preservative\ncare. The stability, however, would follow necessarily, if the\nearth, or its superficial parts, were originally fluid; and\nthat they were so is an opinion widely received, both among\nastronomers and geologists. The original fluidity of the earth\nis probably a circumstance depending upon the general scheme of\ncreation; and cannot with propriety be considered with reference\nto one particular result. We shall therefore omit any further\nconsideration of this argument.\n\n[21] Airy on Encke\u2019s Comet, p. 1, note.\n\n[22] Principia, b. iii. prop. x.\n\n[23] Paley.\n\n[24] If the Laws of Motion are stated as _three_, which we conceive\nto be the true view of the subject, the other two, as applied in\nmechanical reasonings, are the following:\n\n_Second Law._ When a force acts on a body in motion, it produces\nthe same effect as if the same force acted on a body at rest.\n\n_Third Law._ When a force of the nature of pressure produces\nmotion, the velocity produced is proportional to the force, other\nthings beings equal.\n\n[25] Though Friction is not concerned in any cosmical phenomena, we\nhave thought this the proper place to introduce the consideration\nof it; since the contrast between the cases in which it does act,\nand those in which it does not, is best illustrated by a comparison\nof cosmical with terrestrial motions.\n\n[26] Butler, Serm. 3.\n\n[27] M\u00fcller, Infusoria, Preface.\n\n[28] _Monas._ M\u00fcller. Cuvier.\n\n[29] _Volvox._\n\n[30] _Vibrio._ M\u00fcller. Cuvier.\n\n[31] Dupuis. Origine des Cultes.\n\n[32] Herschel on the Study of Nat. Phil. Art. 28.\n\n[33] Amici me cunctantem atque etiam reluctantem, retraxerunt,\ninter quos primus fuit Nicolaus Schonbergius, Cardinalis\nCapuanus, in omni genere literatum celebris; proximus ille\nvir mei amantissimus Tidemannus Gisius, episcopus Culmensis,\nsacrarum ut est et omnium bonarum literarum studiosissimus.--_De\nRevolutionibus. Pr\u00e6f. ad Paulum III._\n\n[34] Lib. i. cx.\n\n[35] Pens\u00e9es, Art. viii. 1.\n\n[36] Thomson\u2019s Hist. of Chemistry, vol. i. 321.\n\n[37] Manch. Mem. vol. v. p. 346.\n\n[38] \u201cSince all reasoning may be resolved into syllogisms,\nand since in a syllogism the premises do virtually assert the\nconclusion, it follows at once, that no truth can be elicited by\nany process of reasoning.\u201d--_Whately\u2019s Logic_, p. 223.\n\nMathematics is the _logic of quantity_, and to this science the\nobservation here quoted is strictly applicable.\n\n[39] A l\u2019int\u00e9rieur le ministre Quinette fut remplac\u00e9 par\nLaplace, g\u00e9om\u00eatre du premier rang, mais qui ne tarda pas \u00e0\nse montrer administrateur plus que m\u00e9diocre: des son premier\ntravail les consuls s\u2019aper\u00e7urent qu\u2019ils s\u2019\u00e9taient tromp\u00e9s:\nLaplace ne saisissait aucune question sous son vrai point de\nvue: il cherchait des subtilit\u00e9s partout, n\u2019avait que des id\u00e9es\nprobl\u00e9matiques, et portait enfin l\u2019esprit des infiniment petits\ndans l\u2019administration.--_M\u00e9moires \u00e9crits \u00e0 Ste H\u00e9l\u00e8ne_, i. 3.\n\n[40] Il semble que la nature ait tout dispos\u00e9 dans le ciel, pour\nassurer la dur\u00e9e du syst\u00eame plan\u00e9taire, par des vues semblables\n\u00e0 celles qu\u2019elle nous parait suivre si admirablement sur la\nterre, pour la conservation des individus et la perp\u00e9tuit\u00e9 des\nesp\u00e8ces.--_Syst. du Monde_, p. 442.\n\n[41] Rapports du Physique et du Moral de l\u2019Homme, i. 299.\n\n[42] De Augment. Sc. ii. 105.\n\n[43] Herschel on the Study of Nat. Phil. Art. 28.\n\n[44] Elem. of Phil. ii. p. 273.\n\n[45] Bacon. Essay on Atheism.\n\n\n\n\n  TRANSCRIBER\u2019S NOTE\n\n  Obvious typographical errors and punctuation errors have been\n  corrected after careful comparison with other occurrences within\n  the text and consultation of external sources.\n\n  Except for those changes noted below, all misspellings in the text,\n  and inconsistent or archaic usage, have been retained.\n\n  Pg 47: \u2018a slendar stalk\u2019 replaced by \u2018a slender stalk\u2019.\n  Pg 48: \u2018animal motious\u2019 replaced by \u2018animal motions\u2019.\n  Pg 54: \u2018the raingage\u2019 replaced by \u2018the rain gauge\u2019.\n  Pg 67: \u2018by Fourrier, and\u2019 replaced by \u2018by Fourier, and\u2019.\n  Pg 69: \u2018would dimininish\u2019 replaced by \u2018would diminish\u2019.\n  Pg 72: \u2018is obvitated by\u2019 replaced by \u2018is obviated by\u2019.\n  Pg 81: \u2018than 1-100dth to\u2019 replaced by \u2018than 1-100th to\u2019.\n  Pg 131: \u2018are nealy circular\u2019 replaced by \u2018are nearly circular\u2019.\n  Pg 139: \u2018by one anomally\u2019 replaced by \u2018by one anomaly\u2019.\n  Pg 153: \u2018would loose its\u2019 replaced by \u2018would lose its\u2019.\n  Pg 174: \u2018a memoir entited\u2019 replaced by \u2018a memoir entitled\u2019.\n  Pg 174: \u2018volocity, in\u2019 replaced by \u2018velocity, in\u2019.\n  Pg 178: \u2018effects take take place\u2019 replaced by \u2018effects take place\u2019.\n  Pg 196: \u2018and and Director of\u2019 replaced by \u2018and Director of\u2019.\n  Pg 200: \u2018for for her young\u2019 replaced by \u2018for her young\u2019.\n  Pg 205: \u2018in his puposes\u2019 replaced by \u2018in his purposes\u2019.\n  Pg 224: \u2018thus irremoveably\u2019 replaced by \u2018thus irremovably\u2019.\n  Pg 228: \u2018of knowlege and\u2019 replaced by \u2018of knowledge and\u2019.\n  Pg 259: \u2018and no othewise\u2019 replaced by \u2018and not otherwise\u2019.","title":"Astronomy and General Physics Considered with Reference to Natural Theology","tradition":"scripture-revelation","translated_text":null,"word_count":92001}