A. As the distance between the front and back of their eye is not great enough, the reflection of near objects is thrown beyond the ret’ina; therefore, they hold objects a long way off, in order to bring their images forward (so as to cast it on the ret’ina).
Q. Why are hawks able to see such an immense way off?
A. Because they have a muscle in the eye which enables them to flatten their cor’nea, by drawing back the crystalline lens.
This muscle is called the “marsupium.”
Q. Why can hawks not only see such a long way off, but also objects within half-an-inch of their eye?
A. Because their eyes are furnished with a broad circular rim which confines the action of this muscle, and throws the cor’nea forward.
Q. Into how many parts may a ray of light be divided?
A. Into three parts: Blue, Yellow, and Red.
N.B. These 3 colours, by combination, make seven. 1.—Red. 2.—Red and yellow form orange. 3.—Yellow. 4.—Yellow and blue make green. 5.—Blue. 6 and 7.—Shades of blue called indigo and violet.