"Truly the light is sweet, and a pleasant thing it is for the eyes to behold the sun."—Ecclesiastes xi.
966. Why are we enabled to see large objects upon so small a surface?
Because the lenses and humours of the eye collect the rays of light coming from every direction, and, bringing them into a focus, transmit them to the retina, where each ray impresses upon the nervous surface the qualities it received from the object which reflected it.
Fig. 61.—THE EYEBALL AND ITS MUSCLES.
A. Portion of bone through which the optic nerve passes in its communication between the brain and the eye.