Johnson's natural philosophy and key to philosophical charts : illustrated with 500 cuts; being reduced photographic copies of all the diagrams contained in the author's philosophical series of indestructible school charts ; for the use of schools and families (1878)
for a vast distance. Hence theeye may be considered an optical instrument embracing e\ery per-fection. 44^- Figure 6.—Method of adjusting the pupil or aper-ture of the eye.—The circular portion of the figure represents theiris, or that part of theeye which determines itscolor, as black, hazel,blue,… … 254 OPTICS. radiating lines, will contract and the circular ones expand, when theintensity of the light is insufficient, and so enlarge the pupil, that morerays may enter. The circular muscles, represented by the circles, onthe contrary, contract, and the radiating ones expand, when the inten-sity…
Physics · Astronomy
Internet Archive · University of Connecticut Library · Public Domain Mark 1.0. Free to use for anything.
