A reply to Mr. Robin's remarks on the Essay upon distinct and indistinct vision published at the end of Dr. Smith's Complete system of optiks / by James Jurin.
- James Jurin
- Date:
- 1739
Licence: Public Domain Mark
Credit: A reply to Mr. Robin's remarks on the Essay upon distinct and indistinct vision published at the end of Dr. Smith's Complete system of optiks / by James Jurin. Source: Wellcome Collection.
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![[ 22 ] dent rays of that fpecies, as the reflected and in¬ cident rays of any other fpecies bear to one ano¬ ther. But by the laft propofition, the reflected rays are to the incident rays of any one fpecies, as the extent of the fit of reflexion to the whole interval in that fpecies. Confequently, the pro¬ portion between the extent of the fit of reflexion and the whole interval is juft the fame in every fpecies of rays. 1 Proposition XI. When white or compound light falls perpen¬ dicularly upon the plane furface of a tranfparent fubftance, which indifferently reflects or tranfmits every fpecies of rays, the quantity of light re¬ flected is to the whole incident light, in the fame proportion, as the extent of the fit of reflexion in any one ray bears to the whole interval in the fame ray. This is evident from the two preceding Pro- pofitions. Corollary i. Hence *' it appears, that in common half the light incident upon any furface is not in a ft of tranfmiffon, and the other half in a fit of re¬ flexion. Other wife, half the light muft be reflect¬ ed at allfurfaces. 4 Corollary 2. 2 Hence alfo it appears, howgrof- ly erroneous it is to think, that whether more or lefs light be reflected from a body, the extent of the fits of reflexion in the incident rays is the fame. From](https://iiif.wellcomecollection.org/image/b30780287_0030.jp2/full/800%2C/0/default.jpg)
