The third day the soldiers began to be weary of such a march. They seemed afraid to penetrate any further into such boundless and terrible solitudes. They had been obliged to bring water with them in goat-skins, which were carried by camels. The camel is the only beast of burden which can be employed upon the deserts. There is a peculiarity in the anatomical structure of this animal by which he can take in, at one time, a supply of water for many days. He is formed, in fact, for the desert. In his native state he lives in the oases and in the valleys. He eats the herbage which grows among the rocks and hills that alternate with the great sandy plains in all these countries. In passing from one of his scanty pasturages to another, he has long journeys to make across the sands, where, though he can find food here and there, there is no water. Providence has formed him with a structure adapted to this exigency, and by means of it he becomes extremely useful to man.