Q. Why do some things reflect one colour, and some another?
A. Because the surface of things is so differently constructed, both physically and chemically; and, therefore, some things reflect one ray; some two rays; some all the rays; and some none.
Q. What mainly determines the colour of any object?
A. The fluid or gas either in the body, or on its surface.
N. B. Nitrogen gives green,—Oxygen gives red,—Hydrogen gives blue colours.
Q. Why does dying a silk, &c. change its colour?
A. Because the materials used in dyeing alter the chemical construction of the substance dyed.
Q. Why is a rose red?
A. Because the surface of a rose absorbs the blue and yellow rays of light, and reflects only the red ones.