{"collection":"aor","html_url":"https://unchartedknowledge.5gfusion.net/browse/aor/dv/0199.htm","path":"aor/dv/0199.htm","source_url":"https://sacred-texts.com/aor/dv/0199.htm","text":"The Da Vinci Notebooks\nA disputed proposition.Certain mathematicians have maintained that a triangle, of which the base is turned to the light, casts no shadow on a plane; and this they prove by saying [5] that no spherical body smaller than the light can reach the middle with the shadow. The lines of radiant light are straight lines [6]; therefore, suppose the light to be g h and the triangle l m n, and let the plane be i k; they say the light g falls on the side of the triangle l n, and the portion of the plane i q. Thus again h like g falls on the side l m, and then on m n and the plane p k; and if the whole plane thus faces the lights g h, it is evident that the triangle has no shadow; and that which has no shadow can cast none. This, in this case appears credible. But if the triangle n p g were not illuminated by the two lights g and h, but by i p and g and k neither side is lighted by more than one single light: that is i p is invisible to h g and k will never be lighted by g; hence p q will be twice as light as the two visible portions that are in shadow.\n111:98 : 5--6. This passage is so obscure that it would be rash to offer an explanation. Several words seem to have been omitted.","title":"Vol. I: III. Six Books on Light and Shade: 199.","type":"page"}