e the angle is the same. The same law of reflection applies whether the surface of the reflector is a convex or a concave part of a sphere : the two angles must be the same. For those who do not understand anything about angles it must be explained that every circle is supposed to be divided into… … Division of Circle into degrees. From A to B would be divided into 90 divisions, and the angle at E would be an angle of 90°, called a right angle ; the inner circle would also be divided into 90 parts, so that the angle at E is precisely the same ; lengthening the lines does not alter the opening…
Light · Color · Optical illusions · Optics
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
![An illustration from Works. Popular edition.] 2 series (1886)](https://img.insideoutlibrary.com/img/200/bl-bl_003191336_9-384-1.webp)
![An illustration from Cosmographia in qvatvor libros distribvta summo ordine, miraqve facilitate, ac breuitate ad magnam Ptolemæi mathematicam constructionem, ad vniuersamque astrologiam institutens. Francisco Barocio ... avtore. Cum præfatione eiusdem autoris, in qua perfecta quidem astrologiæ diuisio, & enarratio autorum illustrium, & voluminum ab eis conscriptorum in singulis astrologiæ partibus habetur: Joannis de Sacrobosco verò 84 errores, et alij permulti suorum expositorum, & sectatorum ostenduntur. rationibusq[uam] redarguuntur. Præcesserunt etiam quædam communia mathematica, necnon arithmetica, & geometrica principia, nonnullæq[uam] propositiones, de quibus in toto opere sæpe fit mentio: ac demum locupletissimus index eorum, quæ ipsa Cosmographia continentur .. (1585)](https://img.insideoutlibrary.com/img/200/ia-cosmographiainqv00baro-446-117.webp)
