{"collection":"earth","html_url":"https://unchartedknowledge.5gfusion.net/browse/earth/toe/toe30.htm","path":"earth/toe/toe30.htm","source_url":"https://sacred-texts.com/earth/toe/toe30.htm","text":"Theory of the Earth, by James Hutton, [1788 and 1795]\nA View of the Economy of Nature, and necessity\n of Wasting the Surface of the Earth,\n in serving the purposes of this World.\nThere is not perhaps one circumstance, in the constitution of this terraqueous globe, more necessary to the present theory, than to see clearly that the solid land must be destroyed, in undergoing the operations which are natural to the surface of the earth, and in serving the purposes which are necessary in the system of this living world. For, all the land of the present earth being a certain composition of materials, perfectly similar to such as would result from the gradual destruction of a continent in the operations of the inhabited world, this composition of our land could not be explained without having recourse to preternatural means, were there not in the constitution of this earth an active cause necessarily, in the course of time, destroying continents.\nIt is therefore of great importance to this Theory, to show, that the land is naturally wasted, though with the utmost economy; and that the continents of this earth must be in time destroyed. It is of importance to the happiness of man, to find consummate wisdom in the constitution of this earth, by which things are so contrived that nothing is wanting, in the bountiful provision of nature, for the pleasure and propagation of created beings; more particularly of those who live in order to know their happiness, and who know their happiness on purpose to see the bountiful source from whence it flows.\nWe are to conceive the continent of the earth, when first produced above the surface of the ocean, to be in general consolidated, with regard to its structure, by the same mineral operations which are necessarily employed in raising it from its primary situation at the bottom of the sea, to that in which we now inhabit it.\nWe are now to consider the purpose of this mineral body, exposed to the influences of the atmosphere, that so we may see the intention of its solid composition, as well as that of its resolution, or natural solubility when thus exposed; and we are to trace the ultimate effects of this order of action in the economy of the globe, that so we may perceive the wisdom of nature perpetuating the system of a living world in an endless succession, of changing perishable forms.\nThe purpose of the land of this earth, in being placed above the sea and immersed in the atmosphere, is to sustain a system of plants and animals. But; for the purpose of plants; there is required a soil; and, as there is in the vegetable system a vast variety of plants with different habits or natural constitutions, there is also required a diversity of soils, in which those vegetable bodies are to be made to live and prosper. From the bare rock exposed to the sun and wind, to the tender mud immersed in water, there is a series to be observed; and in every stage or step of this gradation, there are plants adapted to those various soils or situations. Therefore nothing short of that diversity of soils and situations, which we find upon the surface of the earth, could fulfill the purpose of nature, in producing a system of vegetables endued with such a diversity of forms and habits.\nThe soil or surface of this earth is no more properly contrived for the life and sustenance of plants, than are those plants for that diversity of animals, which will thus appear to be the peculiar care of nature in forming a world. Scarce a plant perhaps that has not its peculiar animal which feeds upon its various productions; scarce an animal that has not its peculiar tribe of plants on which the economy of its life, its pleasure, or its prosperity must depend.\nIf we shall suppose the continent of our earth to be a solid rock, on which the rain might fall, and the wind and waves might dash perpetually, without impairing its mass or changing its constitution, what an imperfect world would we have! how ill adapted to the preservation of animal and vegetable life! But the opposite extreme would equally frustrate the intention of nature, in producing bounteously for the various demands of that multiplicity of species which the author of this world has thought proper to produce.\nFor if, instead of a solid rock, we shall suppose a continent composed of either dry sand or watery mud, without solidity or stability, how imperfect still would be that world for the purpose of sustaining lofty trees and affording fruitful soils!\nWe have now mentioned the two extreme states of things; but the constitution of this earth is no other than an indefinite number of soils and situations, placed between those two extremes, and graduating from the one extreme, in which some species of animals and plants delight in finding their prosperity, to the other, in which another species, which would perish in the first, are made to grow luxuriantly. That is to say, the surface of this earth, which is so widely adapted to the purpose of an extensive system of vegetating bodies and breathing animals, must consist of a gradation from solid rock to tender earth, from watery soil to dry situations; all this is requisite, and nothing short of this can fulfil the purpose of that world which we actually see.\nWe have been representing this continent of our earth as coming out of the ocean a solid mass, which surely it is in general, or in a great degree; but we find the surface of this body at present in a very different state; and now it will be proper to take a view of this change from solid rock to fertile soil.\nUpon this occasion I shall give the description of nature from the writings of a philosopher who has particularly studied this subject. It is true that M. de Luc, who furnishes the description, draws, from this process of nature, an argument for the perpetual duration or stability of mountains; and this is the very opposite of that view which I have taken of the subject; but as, in this operation of nature producing plants on stones, he allows the surface of the solid stone to be changed into earth and vegetables, it is indifferent to the present theory how he shall employ this earth and vegetable substance, provided it be acknowledged that there is a change from the solid state of rock to the loose or tender nature of an earth, from the state of a body immovable by the floods and impenetrable to the roots of plants, to one in which some part of the body may be penetrated and removed.\n8\u00abLes pluies et les ros\u00e9es forment partout o\u00f9 elles s\u00e9journent, des d\u00e9p\u00f4ts qui sont la premi\u00e8re source de toute v\u00e9g\u00e9tation. Ces d\u00e9p\u00f4ts sont toujours m\u00eal\u00e9s des semences des mousses, que l'air charie continuellement, et auxquelles se joignent bient\u00f4t les semences presque aussi abondantes des gramens, qui sont l'herbe dominante de nos prairies. Ainsi partout o\u00f9 la pluie a form\u00e9 quelque petit d\u00e9p\u00f4t, il cro\u00eet de la mousse ou des gramens. Ceux-ci demandent un peu plus de terre v\u00e9g\u00e9tale pour cro\u00eetre, ils germent, et se conservent principalement dans les intervalles et les creux des pierres: mais la mousse cro\u00eet bient\u00f4t sur la surface la plus unie. Il n'est aucune pierre long-temps expos\u00e9e \u00e0 l'air, qui soit parfaitement polie; l'action de l'air, du soleil, des eaux, des gel\u00e9es, detruiroit ce poli quand il existeroit. Le moindre creux alors re\u00e7oit un d\u00e9p\u00f4t de la pluie, et nourrit un brin de mousse, ces brins poussent des racines; et de nouveaux jets autour d'eux, qui contribuent \u00e0 arr\u00eater l'eau de la pluie et de la ros\u00e9e, et par ce moyen \u00e0 arr\u00eater les d\u00e9p\u00f4ts Nourriciers.\u00bb\n\u00abQuand la mousse a multipli\u00e9 ses filets, les d\u00e9p\u00f4ts s'augmentent plus rapidement encore; les brins de la mousse, en s\u00e9chant et pourrissant, en forment eux-m\u00eames; car leur substance n'\u00e9toit que ces m\u00eames d\u00e9p\u00f4ts fa\u00e7onn\u00e9s: d'autres semences charri\u00e9es par l'air, qui au-paravant glissaient sur les pierres, parce que rien ne les retenoit, tombent dans le fond de la mousse, et y trouvent l'humidit\u00e9 n\u00e9cessaire pour produire leurs premi\u00e8res racines: celles-ci s'entrelassent dans la mousse, o\u00f9 elles se conservent \u00e0 l'abri du soleil, et sont alors autant de petites bouches qui pompent les sucs, que l'air, les pluies, et les ros\u00e9es y d\u00e9posent. Ces premi\u00e8res plantes sont foibles, quelque fois m\u00eame elles ne parviennent pas \u00e0 leur perfection: mais elles ont contribu\u00e9 \u00e0 fixer la terre v\u00e9g\u00e9table. En s\u00e9chant et se d\u00e9composant, elles se transforment en cette terre, qui tombe au fond de la mousse, et qui pr\u00e9pare ainsi de la nourriture pour de nouvelles plantes qui alors prosp\u00e8rent et fructifient.\n\u00abNous connoissons peu encore ce que c'est que cette terre v\u00e9g\u00e9table, ce d\u00e9p\u00f4t des pluies ou en g\u00e9n\u00e9ral de l'air. Cependant, en rassemblant les ph\u00e9nom\u00e8nes, on peut conjecturer, que la plupart des corps terrestres sont susceptibles d'\u00eatre chang\u00e9s en cette substance, et qu'il ne s'agit pour cette transformation que de les d\u00e9composer. J'entends par l\u00e0 une telle division de leurs parties, que devenant presque des \u00e9l\u00e9mens, elles puissent \u00eatre intimement m\u00eal\u00e9es \u00e0 l'eau, et pomp\u00e9es avec elle par les tuyaux capillaires des plantes. En un mot, il semble suffisant qu'une mati\u00e8re puisse entrer en circulation dans les v\u00e9g\u00e9taux, pour qu'elle serve \u00e0 en d\u00e9velopper le tissu, et qu'elle y prenne la figure et les qualit\u00e9s que chacun de ces laboratoires est propres \u00e0 produire.\n\u00abNous pouvons acc\u00e9l\u00e9rer de bien des mani\u00e8res la transformation des mati\u00e8res terrestres en terre v\u00e9g\u00e9table. La fermentation, la calcination, une plus grande exposition \u00e0 l'air, diff\u00e9rens m\u00e9langes, rendent propres \u00e0 la v\u00e9g\u00e9tation, des mati\u00e8res qui ne l'\u00e9toient par elles-m\u00eames: voila ce que peuvent nos soins. Mais l'air travaille sans cesse et en mille mani\u00e8res. Son simple frottement sur tous les corps, en enl\u00e8ve des particules si att\u00e9nu\u00e9es que nous ne les reconnoissons plus. La poussi\u00e8re de nos appartemens en est peut-\u00eatre un exemple. De quelque nature que soient les corps dont elle se d\u00e9tache, c'est une poudre gris\u00e2tre qui semble \u00eatre partout la m\u00eame. La formation de la terre v\u00e9g\u00e9table a probablement quelque rapport \u00e0 celle-l\u00e0. Toute la surface de la terre, les rocs les plus durs, les sables et les graviers les plus arides, les m\u00e9taux m\u00eame, \u00e9prouvent l'action rongeante de l'air et leurs particules att\u00e9nu\u00e9es, d\u00e9compos\u00e9es, recompos\u00e9es de mille mani\u00e8res, sont probablement la source principal de la v\u00e9g\u00e9tation. L'air lui-m\u00eame ainsi que l'eau, s'y combinent: beaucoup d'observations et d'exp\u00e9riences nous prouvent que ces deux fluides fournissent leur propre substance aux parties solides des v\u00e9g\u00e9taux, et par cons\u00e9quent \u00e0 la terre v\u00e9g\u00e9table qui les produit et qu'ils d\u00e9posent. Quantit\u00e9 de plantes se nourrissent de l'eau seule, et nous laissant cependant en se s\u00e9chant, un r\u00e9sidu de mati\u00e8re solide permanente. L'air aussi se fixe dans les corps terrestres, il fait partie de leur substance solide; les chimistes savent de plus en plus, et le fixer, et lui redonner son \u00e9lasticit\u00e9 primitive, par divers proc\u00e9d\u00e9s: et avant la multitude d'exp\u00e9riences qui se sont de nos jours sur cet objet int\u00e9ressant de la physique, le Dr. Hales avoit montr\u00e9, que les v\u00e9g\u00e9taux renferment une tr\u00e8s-grande quantit\u00e9 d'air, qui s'y trouve sans ressort et comme mati\u00e8re constituante.\n\u00abVoila donc probablement les sources o\u00f9 la nature puise peu \u00e0 peu la terre v\u00e9g\u00e9table dont elle recouvre la surface de nos continens. Ce sont les particules, peut-\u00eatre, de tous les corps tant solides que fluides, extraites ou fix\u00e9es par des proc\u00e9d\u00e9s qui les rapprochent de leurs premiers \u00e9l\u00e9mens, et leur font prendre \u00e0 nos yeux une m\u00eame apparence. Ces particules sont ainsi rendues propres \u00e0 circuler dans les semences des plantes, \u00e0 en \u00e9tendre le tissu \u00e0 y prendre toutes les propri\u00e9t\u00e9s qui caract\u00e9risent chaque esp\u00e9ce, et \u00e0 les conserver tant que la plante existe. Ces m\u00eames particules, apr\u00e8s la destruction des plantes, prennent le caract\u00e8re g\u00e9n\u00e9ral de terre v\u00e9g\u00e9table, c'est-\u00e0-dire de provision toute faite pour la v\u00e9g\u00e9tation.\n\u00abLes plus petits recoins des montagnes, qui peuvent arr\u00eater l'eau de la pluie, sont certainement fertilis\u00e9s; ce ne sont pas seulement les grandes surfaces plates, ni les pentes; ce sont m\u00eame les faces escarp\u00e9es des rochers les plus durs. S'il s'y fait quelque crevasse, un arbre s'y \u00e9tablit bient\u00f4t; et souvent il contribue, par l'accroissement de ses racines, \u00e0 acc\u00e9l\u00e9rer la chute du lambeau de rocher qui l'avoit re\u00e7u. S'il y a quelque petite terrasse, ou seulement quelque partie saillante grande comme la main, elle est bient\u00f4t gazonn\u00e9e. Les plus petites sinuosit\u00e9s se peuplent de plantes; et les surfaces les plus unies, celles m\u00eames qui sont tourn\u00e9es vers la bas, re\u00e7oivent au moins quelqu'une de ces mousses plates, nomm\u00e9s lichen par les botanistes, qui ne font en apparence que passer une couleur sur la pierre. Mais cette couche est \u00e9caill\u00e9e, et elle loge bient\u00f4t de petites plantes dans ses replis; de celles qui veulent l'ardeur du soleil, si le rocher est au midi, ou la fra\u00eecheur de l'ombre, s'il est au nord: c'est sur ces rochers en un mot, qui paroissent nues aux spectateurs ordinaires, que se trouve la plus grande vari\u00e9t\u00e9 de ces petites plantes, qui font les d\u00e9lices des botanistes, et l'une des sources les plus abondantes o\u00f9 la m\u00e9dicine puise les secours r\u00e9els qu'elle fournit \u00e0 l'humanit\u00e9.\n\u00abQuelle richesse dans les ressources de la nature! La pesanteur n'est pas plus pr\u00eate \u00e0 entra\u00eener les pierres qui se d\u00e9tachent des montagnes, que l'air \u00e0 fournir de semences celles qui se fixent: et d\u00e8s qu'une fois elles sont recouvertes de plantes, elles sont certainement fix\u00e9es pour toujours, du moins contre les injures de l'air. Le fait m\u00eame nous l'annonce. Si ces ravins ou ces terreins quelconques, tendoient encore \u00e0 rouler ou \u00e0 se d\u00e9grader, en un mot \u00e0 se detruire de quelque mani\u00e8re que ce fut, ils ne le recouvriroient, ni de mousses ni d'aucune autre plante. La premi\u00e8re v\u00e9g\u00e9tation est due \u00e0 quelque d\u00e9p\u00f4t de terre v\u00e9g\u00e9table; et les pluies ou l'air n'en forment que lentement; le moindre mouvement la d\u00e9truite. Le terrein est donc bien certainement fixe quand il se recouvre de plantes; et s'il s'y accumule de la terre v\u00e9g\u00e9table, c'est un signe bien evident que rien ne l'attaque plus: car elle seroit la premi\u00e8re emport\u00e9e si quelque cause ext\u00e9rieure tendoit a detruire le sol qui la porte.\u00bb\nThe doctrine here laid down by our author consists in this; first, That there is a genus of plants calculated to grow upon rocks or stones; those hard bodies then decay, in decomposing themselves, and affording sustenance to the plants which they sustain. Secondly, That by this dissolution of those rocks, and the accumulation of those vegetable bodies, there is soil prepared for the nurture and propagation of another genus of plants, by which the surface of the earth, naturally barren, is to be fertilised. It is also in this natural progress of things that the solid parts of the globe come to be wasted in the operations of the surface, and that lofty rocks are levelled, in always tending to bring the uneven surface of the earth to a slope of vegetating or fertile soil.\nHere we are to distinguish carefully between the facts described by this author, who has seen so much of nature, and the conclusion which he would draw from his principles. The surface of most stones are dissolved, or corroded by the air and moisture. This gives lodgement to the roots of plants, which grow, die, and decay; and these are carried away with the earthy parts of the solid stone, in order to form a vegetable soil for larger plants, growing upon some bottom or resting place to which that earth is carried. Here is so far the purpose of rocks, to sustain a genus of plants which are contrived to live upon that soil; and here is so far a purpose for certain plants, in decomposing rocks to form a soil for other plants which have been made upon a larger scale, and are adapted to the use of man, the ultimate in the view of nature.\nOur author concludes thus: (p. 37.) \u00abLe tems ne fera qu'augmenter l'\u00e9paisseur de la couche de terre v\u00e9g\u00e9table qui couvre les montagnes, et qui les garantit ainsi de plus en plus de cette destruction \u00e0 laquelle on les croit expos\u00e9s: les pluies en un mot, au lieu de les d\u00e9grader comme on se l'imagine y accumuleront leurs d\u00e9p\u00f4ts. Tel est l'agent simple qu'employe si admirablement le Createur pour la conservation de son ouvrage.\u00bb\nSuch, indeed, is the admirable contrivance of the system, that, in the works of nature, nothing shall be destroyed more than is necessary for the preservation of the whole. But, that the whole is preserved by the necessary destruction of every individual body, and the change of every part which comes within the examination of our senses, is sufficiently evident to require no farther illustration in this place, where we are contemplating the destruction of the strongest things, by means the most effectual, though really slow, and apparently most feeble.\nIn his 30th letter, this author describes the progress of nature, in bringing precipitous rocks to that slope and covering of soil which is to maintain plants of every kind, and to establish woods. (P. 40.) \u00abJ'ai l'honneur d'exposer \u00e0 V.M. les causes qui garantissent de destruction ext\u00e9rieure les terreins sur lesquels la pesanteur ne peut plus agir que pour les consolider. Mais ce n'est pas ainsi que sont actuellement la plupart de nos montagnes; il en est peu qui soyent d\u00e9j\u00e0 parvenus \u00e0 cet \u00e9tat permanent. Tout roc nud est attaqu\u00e9 par l'air et les m\u00e9t\u00e9ores, et il tend \u00e0 se d\u00e9truire quelle que soit sa duret\u00e9. Mais ce seroit peu que cette destruction ext\u00e9rieure; elle pourroit m\u00eame cesser enfin totalement par l'effet seul des mousses, s'il n'y avoit pas des causes plus puissantes qui pendant quelque tems agissent dans l'int\u00e9rieur.\n\u00abIl n'est presque point de rocher qui offre \u00e0 l'air une seule masse compacte; ils sont ou crevass\u00e9s, ou form\u00e9s par couches; et l'eau s'insinue toujours dans ces fentes. Quand cette eau vient \u00e0 se geler, elle agit comme un coin pour \u00e9carter les pi\u00e8ces entre lesquelles elle se trouve. V.M. seroit \u00e9tonn\u00e9e de la grandeur des masses que cette cause peut mouvoir: elle agit exactement comme la poudre \u00e0 canon dans les mines; d\u00e9tachant toutes les pi\u00e8ces ext\u00e9rieures qui commencent \u00e0 se s\u00e9parer, et en d\u00e9couvrant ainsi de nouvelles. Chaque hiver renouvelle donc la surface de certains rochers, ou facilite l'ouvrage pour les hivers suivans.\nPlusieurs autres causes agissent encore pour s\u00e9parer les rochers d\u00e9j\u00e0 crevass\u00e9s, qui se trouvent \u00e0 l'ext\u00e9rieur des faces escarp\u00e9es. Le petit moellon qui s'y accumule, les d\u00e9p\u00f4ts des pluies, les plantes qui y croissent, les alternatives de l'humidit\u00e9 et de la s\u00e9cheresse, les vicissitudes de la chaleur, les vents m\u00eame, sont autant de causes continuellement agissantes quand la pesanteur les seconde. Les rochers escarp\u00e9s se d\u00e9truisent donc par de continuels \u00e9boulemens.\n\u00abMais toutes ces mati\u00e8res qui tombent, ne sont pas perdues pour les montagnes; il s'en perd m\u00eame bien peu. Elles s'arr\u00eatent au pied des rochers dont elles sont successivement d\u00e9tach\u00e9es; et l\u00e0 elles s'entassent, s'\u00e9levant en forme de talus contre ces rochers eux-m\u00eames.\u00bb\nIf the solid body of the Alps, the most consolidated masses of our land, is thus reduced to the state of soil upon the surface of the earth contrived for the use of plants, a fortiori, softer bodies, less elevated and less consolidated masses, will be considered as easily arriving at the purpose for which the surface of the earth has been intended. We only wish now to see the ultimate effect that necessarily follows from this progress of things; and how, in this course of nature, the land must end, however long protracted shall be the duration of this body, and however much economy may be perceived in this gradual waste of land;\u2014a waste which by no means is so slow as not to be perceived by men reasoning in science; although scientific men, either reasoning for the purpose of a system which they had devised, or, deceived by the apparent state of things which truly change, may not acknowledge the necessary consequence of what they had perceived.\nLet us now suppose all the solid mass of land, contained in our continent, to be transformed into soil and vegetable earth, it must be evident that no covering of plants, or interlacing of vegetable fibres, could protect this mass of loose or incoherent materials from the ravages of floods, so long as rivers flowed, nor from being swallowed by the ocean, so long as there were winds and tides. From the border of the land upon the shore, to the middle of the ocean, there is either at present an equable declivity at the bottom of the sea, or every thing tends to form this declivity, in gradually moving bodies along this bottom. But, however gradual the declivity of the bottom, or however slow the progress of loose materials from the shore towards the deepest bottom of the sea, so long as there are moving powers for those materials, they must have a progress to that end; the law of gravitation, always active, must prevail, and sooner or later the moving sea must swallow up the land.\nBut, along the borders of our continent, and in the courses of our rivers, there are rocks; these must be surmounted or destroyed, before the parts which they protect can be delivered up to the influence of those moving powers which tend to form a level; and we may be assured that those bulwarks waste. The bare inspection of our rocky coasts and rivers will satisfy the enlightened observator of this truth; and to endeavour to prove this to a person who has not principles by which to reason upon the subject, or to one who has false principles, by which he would create perpetual stability to decaying things, would be but labour lost.\nIn proportion as the solid bulwark is destroyed, so is the soil which had been protected by it; and, in proportion as the solid parts of the mass of land are exposed to the influences of the atmosphere and water, by the ablution of the soil, more soil is prepared for the growth of plants, and more earth is detached from the solid rock, to form deep soils upon the surface of the earth, and to establish fertile countries at the mouths of rivers, even in making encroachment on the space allotted for the sea. But this production of land, in augmentation of our coasts, is only made by the destruction of the higher country. While, therefore, we allow that there is any augmentation made to the coast, or any earthy matter travelling in our rivers, the land above the coast cannot be stable, nor the constitution of our earth fixed in a state which has no tendency to be removed.\nM. de Luc, in his Histoire de la Terre, would make the mountains last for ever, after they have come to a certain slope. He sums up his reasoning upon this subject in these words: \u00abL'adoucissement des pentes arr\u00eate d'abord l'effet de ces deux grandes causes causes de destruction de montagnes, la pesanteur et les eaux: la v\u00e9g\u00e9tation ensuite arr\u00eat\u00e9 l'effet de toutes les petites cause.\u00bb\nIf all the great and little causes of demolition are arrested by the slope of mountains and the growth of plants, the surface of the earth might then remain without any farther change; and this would be a fact in opposition to the present theory, which represents the surface of the earth as constantly tending to decay, for the purpose of vegetation, and as being only preserved from a quick destruction by the solid rocks protecting, from the ravages of the floods and sea, the loose materials of the land. It will therefore be proper to show, that this author's argument does not go to prove his proposition in the terms which he has given it, which is, that those sloped mountains are to last for ever, but only that these causes, which he has so well described, make the destruction of the mountains become more slow 9.\nThe slope which our author gives to his mountains, in order to secure them from the ravages of time, is that which, according to his own reasoning, renders them fertile and proper for the culture of man; but fertile soil yields always something to the floods to carry away; and, while any thing is carried from the soil, the land must waste, although it may not then waste at the rate of those within the valleys of the Alps. According to the doctrine of this author, our mountains of Tweeddale and Tiviotdale, being all covered with vegetation, are arrived at that period in the course of things when they should be permanent. But is it really so? Do they never waste? Look at the rivers in a flood;\u2014if these run clear, this philosopher has reasoned right, and I have lost my argument. Our clearest streams run muddy in a flood. The great causes, therefore, for the degradation of mountains never stop as long as there is water to run; although, as the heights of mountains diminish, the progress of their diminution may be more and more retarded.\nLet us now see how far our author has reasoned justly with regard to vegetation, which, he says, stops the effects of all the little causes of destruction; this is the more necessary, as, in the present theory, it is the little causes, long continued, which are considered as bringing about the greatest changes of the earth.\nAlong the courses of our rivers there are plains between the mountains of greater or lesser extent; these are almost always fertile, and generally cultivated when large; when small, they are in pasture. The origin of these fertile soils, and their perpetual change, is to be described with a view to show, that vegetation, although most powerful in stopping the ravages of water, and for accumulating soil retained by this means, does it only for a time; after which the soil is again abandoned to the ravages of the running water, when no more protected by the vegetation.\nLet us suppose the river running upon the one side of the haugh (which is the name we gave those little fertile plains) and close by the side of the mountain. In this case the bed of the river is deepest at the side of the mountain, which it undermines, leaving a falling (un \u00e9boulement) on that side; on the other side, the river shelves gradually from the plain, and leaves soil in its bottom or stony bed upon the side of the haugh, in proportion as it makes advances in carrying away the bank at the bottom of the sloping mountain. The part which vegetation takes in this operation is now to be considered.\nWhen the river has enlarged its bed by preying upon one side, whether of the mountain or the haugh, the water only covers it in a flood; at other times, it leaves it dry. Here, among the rocks and stones, the feeds of plants, left by the water or blown by the wind, spring up and grow; and, in little floods, some sand and mud is left among those plants; this encourages the growth of other plants, which more and more retain the fertile spoils of the river in its floods. At last, this bed of the river is covered perfectly with plants, which having retained plenty of fertile soil, although still rooted among the stones, opposes to the river a resistance which its greatest velocity is not able to overcome. In this state, the haugh is always deepening or increasing its soil, and has its surface heightened. At last, when this soil becomes so high as only to be flooded now and then, it becomes most fertile, as the heavier parts are carried in the bed of the river, and the lighter soil deposited upon the plain. The operations of the river, upon the plain, thus increase at the same time the height and fertility of the haugh. But this operation, of accumulated soil upon the stony bottom, has a period, at which time the river must return again upon its steps, and sweep away the haugh which it had formed. This is the natural course of things; and it happens necessarily from the deepening of the soil. Let us then examine this operation.\nWhen no more soil is left upon the stony bottom than is sufficient for the covering of the ground, and rooting of plants which are also fixed in the solid ground or bottom of the soil, the water is not able to carry away the plants; and these plants protect the surface of loose soil. When again there is a depth of soil accumulated upon the haugh, the surface only is protected by the vegetable covering. But what avails it to the soil to be protected from above, when undermined by the enemy! The vegetable roots now no longer reaching to the bottom where solidity is found, the tender soil below is easily washed away by the continued efforts of the stream; and the unsupported meadow, with the impregnable texture of its leaves, its roots, and its fibres, falls ruinously into the river, and is born away in triumph by the flood. The water thus reclaims its long deserted bed,\u2014only in order to pass from it again, and circulate or meander from hill to hill in varying perpetually its course.\nNow this progress of the river, or this changing of its bed, is determined by the strong resistance of the new made haugh, humbly standing firm in the protection of its vegetation, while the elevated surface of the older haugh, deserted by the inferior soil which it had ceased to protect, falls a victim to its exalted state, and passes away to aggrandize another. This is the fate of haughs or plains erected by the operations of a river, and again destroyed in the natural course of things, or in the very continuation of that active cause by which they had been formed.\nThe water is constantly carrying the moveable soil from the higher to the lower place; vegetation often disputes the possession of these spoils of ruined mountains for a while; but, in the end, this vegetable protector, not only delivers up to the destroying cause the mineral soil which it had preserved, but, by its buoyancy in water, it facilitates the transportation of the stony parts to which this fibrous body is attached. Over and over a thousand times may be repeated this alternate possession of the transferable soil, by moving water on the one part and by fixed vegetation on the other, but at last all must land upon the shore, whether the river tends. Thus the mountain and the plain, the vegetable earth and the plants produced in that soil, must all return into the sea from whence either they themselves or their materials had come. In proportion as the mountains are diminished, the haugh or plain between them grows more wide, and also on a lower level; but, while there is a river running in a plain, and floods produced in the seasons of rain, there can be nothing stable in this constitution of things evidently founded upon change.\nThe description now given is from the rivers of this country, where it is not unfrequent to see relicts of three or four different haughs which had occupied the same spot of ground upon different levels, consequently which had been formed and destroyed at different periods of time. But the same operation is transacted every where; it is seen upon the plains of Indostan, as in the haughs of Scotland; the Ganges operates upon its banks, and is employed in changing its bed continually as well as the Tweed 10. The great city of Babylon was built upon the haugh of a river. What is become of that city? nothing remains,\u2014even the place, on which it stood, is not known.\nv2:8 Histoire de la Terre, Tom. 2. page 26.\nv2:9 This also would appear to be a part of that wise system of nature, in which nothing is done in vain, and in which every thing tends to accomplish the end with the greatest marks of economy and benevolence. Had it been otherwise, and the demolishing powers of the land increased, in a growing rate with the diminution of the height, the changes of this earth and renovation of our continent, in which occasionally animal life must suffer, would necessarily require to be often repeated; and, in that case, chaos and confusion would seem to be introduced into that system which at present appears to be established with such order and economy that man suspects not any change; it requires the views of scientific men to perceive that things are not at present such as they were created; it requires all the observation of a natural philosopher to know that in this earth there had been change, although it is not every natural philosopher that observes the benevolence accompanying this constitution of things which must subsist in change.\nv2:10 An Account of the Ganges and Burrampooter Rivers, by James Rennel, Esquire. Philosophical Transactions, 1781.","title":"Theory of the Earth: Theory of the Earth [1795], Vol. II ...","type":"page"}