COLOR

—Bodies owe their color to the light which they reflect. White light is made up of the many c’s, and if it falls on a green body all the colored rays except green are absorbed by the body, while the green light is reflected. A plate of red gla allows red light only to pa through. Colored rays differ only in the frequency of ether vibrations which they set up, and the structure of the retina enables the eye to distinguish between these. Blue and yellow paints when mixed are green, because green rays are the only rays reflected by both and not absorbed by either. Complementary c’s are any two which combine to make white, e.g. blue and yellow, red and green. Primary c's are the chief c’s of the spectrum; they are red, orange, yellow, green, blue, indigo, violet (Newton’s theory); red, blue, and green (Young-Helmholtz theory).