Of Light and Colours;

and again when it is farthest distantfrom that Planet, we shall find, that in*he former Case those Eclipses happen toos°°n> and in the latter too late , by the Space8 Minutes and 13 Seconds ; which shews,in that Time the Light passes overSemidiameter of the Earth’s Orbit*^hich is about 82,000,000 Miles 5 whichls at the rate of 1 Jo,000 MileS in a Second^ Time, and which is therefore nearly80,000 times greater than the' Velocityof Sound (CXII).

Again :

^le, but. because the Eyfe can find no Point of Space in■ J the visible Hemisphere respecting that Point, bus^here it is visible, therefore a Ray of Light is reflectedb? 1T1 that Point to every Part of Space, from whence a^‘gbt Line to that Point can be drawn;

That the Rays of Light proceed in Right-linedp. lre ctions, is evident from hence, that whatever thej/Sure of the Body be, if it be held perpendicular toj. e Rays of Light, it will always cast a Shadow of theFigure against a parallel Plane. Thus a Circleh ^ produce a circular Shadow, a Triangle a triangularand so on. Which plainly (hews, that the Raysjp Right pass by the Extremities of those Bodies in^fiht-lincd Directions, excepting those only which passli'fguous to the Edges of the Body, for they will be aj inflected, which will cause the Extremity of thetyy °w to be not so distinct and well defined as it other-Jjg e would be ; of which we shall take farther NoticeRafter.

j. As all the other Affections of Light, soL, °fV elocity, was utterly unknown to all the ancient,•p- Ntost of the modern Philosophers, who, before theof Mr. Reaumur , were of opinion that the Mo-

II; T . tion