All colors are rays of light differently reflected. The cause of their diversity was first rationally accounted for by Sir Isaac Newton. He has shown that color is not a specific property of bodies, but is caused by the different rays of light being reflected from the surface of the body; the rest of the rays passing into or through the body. He discovered that in the rays of light are all the colors in nature; and the primary colors he considered to be seven in number, namely, red, orange, yellow, green, blue, indigo and violet; and that bodies appear of different colors, as they have the property of reflecting some rays more powerfully than others. These colors are poetically enumerated by Thomson.
“First the flaming red
Sprung vivid forth; the tawny orange next;
And next delicious yellow; by whose side
Fell the kind beams of all-refreshing green:
Then the pure blue, that swells autumnal skies,
Ethereal play’d; and then, of sadder hue,
Emerg’d the deepen’d indigo, as when
The heavy-skirted evening droops with frost;
While the last gleamings of refracted light