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.
28/64 page 20
![[ 20 ] Corollary. Therefore c the fpace, through which the fit of reflexion continues, or the extent of the fit of reflexion, does not depend altogether upon the medium, through which the light paffes, but partly upon that, whereon the light falls. Proposi tion VIL f \ _ • . ' When a ray of light falls obliquely upon a given refracting furface, the reflective power of that furface will be ftronger in regard to that ray, as the obliquity is greater. For inftance, a refracting furface, which would be barely ftrong enough to reflect a ray falling perpendicularly upon it in the point a or may by receiving it with a proper degree of obliquity, be able to reflect it back, when in the point b or /?. And if the obliquity be ftill greater, it may reflect the ray, when in the point c, or d, or e, where it is lefs difpofed to reflexion, '• • <: - : 1 • .1 Proposition VIII. From the two laft Propofitions it appears, that the interval between the fits being given, the extent of the fit of reflexion in one and the fame ray is not always the fame, but depends upon the ftrength of the reflexive power and the obliquity of the furface the ray is to fall upon, jointly, and'increafes as thefe two or either of them increafe. • • > ' • > 1 ! { * : A * ... if 1 ' ; \ ' * ! Prop o-](https://iiif.wellcomecollection.org/image/b30780287_0028.jp2/full/800%2C/0/default.jpg)
