Page:Popular Science Monthly Volume 5.djvu/490

474 make a paste of them with the addition of glue, which is pompously named "Eastern essence." This is put inside glass beads, and gives them the native whiteness of pearls.

Many observations have been made lately by our naturalists as to the defense which color supplies to animals: hares, rabbits, stags, and goats, possess the most favorable shade for concealing them in the depths of the forest or in the fields. It is well known that when the Volunteer corps were enrolled, and the most suitable color for the riflemen was discussed, it was supposed to be green. Soldiers dressed in different shades were placed in woods and plains, to try which offered the best concealment. Contrary to expectation, that which escaped the eyes of the enemy was not green, but the fawn color of the doe. Among hunting quadrupeds, such as the tiger, the leopard, the jaguar, the panther, there is a shade of skin which man has always been anxious to appropriate for his own use. The old Egyptian tombs have paintings of the negroes of Soudan, their loins girt with the fine yellow skins for which there is still a great sale. All the birds which prey upon the smaller tribes, and fishes like the shark, are clothed in dead colors, so as to be the least seen by their victims.

There is an animal which, for two thousand years, has excited the curiosity and superstition of man by its change of color—that is, the chameleon. No reasonable observation was ever made upon it, until Perrault instituted some experiments in the seventeenth century. He observed that the animal became pale at night, and took a deeper color when in the sun, or when it was teased; while the idea that it took its color from surrounding objects was simply fabulous. He wrapped it in different kinds of cloth, and once only did it become paler when in white. Its colors were very limited, varying from gray to green and greenish brown.

Little more than this is known in the present day; under our skies it soon loses its intensity of color. Beneath the African sun, its livery is incessantly changing; sometimes a row of large patches appears on the sides, or the skin is spotted like a trout, the spots turning to the size of a pin's head. At other times, the figures are light on a brown ground, which a moment before were brown on a light ground, and these last during the day. A naturalist speaks of two chameleons which were tied together on a boat in the Nile, with sufficient length of string to run about, and so always submissive to the same influences of light, etc. They offered a contrast of color, though to a certain degree alike; but, when they slept under the straw chair which they chose for their domicile, they were exactly of the same shade during the hours of rest—a fine sea-green that never changed. The skin rested, as did the brain, so that it seemed probable that central activity, thought, will, or whatever name is given, has some effect in the change of color. The probability is that, as they become pale, the pigment does not leave the skin, but that it is collected in spheres