Human physiology : designed for colleges and the higher classes in schools and for general reading . in Fig. 158, the diverging rays which enter it will be made todiverge still more. The ray, a, c, being perpendicular to the sur-face is unchanged in its course ; but the ray, a, d, is bent towardsthe perpendicular, e, into the line/, and the ray, a,j, is bent to-wards the perpendicular h into the line i. In the case of both FIG. the concave and the convex lens, the greater the curvature, thegreater is the change of direction in the rays. The greater thecurvature, therefore, the sooner are


Human physiology : designed for colleges and the higher classes in schools and for general reading . in Fig. 158, the diverging rays which enter it will be made todiverge still more. The ray, a, c, being perpendicular to the sur-face is unchanged in its course ; but the ray, a, d, is bent towardsthe perpendicular, e, into the line/, and the ray, a,j, is bent to-wards the perpendicular h into the line i. In the case of both FIG. the concave and the convex lens, the greater the curvature, thegreater is the change of direction in the rays. The greater thecurvature, therefore, the sooner are the rays brought to a focusin the case of the convex lens. There are other optical principles illustrated in the apparatusof vision, that will be brought out in the description of theeye, which I will now proceed to give. 436. The arrangement of the different parts of the eye youcan understand by Fig. 159, which is a mere map of a sectionof the eye, through its middle part from front to rear. It isintended merely to represent the arrangement of the parts dis-tinctly, without strict regard to proportion. The eye has three 290 HUMAN PHYSIOLOGY. Description of the parts of the eye. FIG. 159.


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Keywords: ., bookauthorhookerwo, bookcentury1800, bookdecade1850, bookyear1854