Man's only carriage at first was of course his own feet. When he wanted to go to any place he had to take "Walker's hack," if a playful expression may be pardoned. As a traveler on foot, man soon surpassed all other animals. He could walk down the deer and wear out the horse. When it came to carrying things from place to place, in the beginning he had to rely upon his own limbs and muscles. It was not long, however, before he learned that there were good ways and bad ways of carrying things, and he soon set about finding the best way. We may believe that he began by making a snug bundle and carrying it on his shoulder. Then he found that he could carry a heavier burden upon his back, and he invented a pack or frame on which he could carry things on his back (Fig. 1) after the manner of one of our modern pack peddlers. [Illustration: FIG. 1.--A HUMAN BURDEN BEARER. (From a Model in National Museum.)] In the course of time man tamed one or more of the wild beasts which roamed near him. Then the burden was shifted from the back of a man to the back of a beast. The first beast of burden in South America was the llama; in India it was the elephant; in Arabia it was the camel (Fig. 2). In Europe and in parts of Asia and in Egypt the horse first became man's burden bearer and the nations which had the services of this swift and strong animal outstripped the other nations of the world. "Which is the most useful of animals?" asked one Egyptian god of another. "The horse," was the reply, "because the horse enables a man to overtake and slay his enemy." [Illustration: FIG. 2.--A SHIP OF THE DESERT.] [Illustration: FIG. 3.--A CART WITHOUT WHEELS. (From a Model in the National Museum.)] It is often easier to drag a thing along than it is to carry it. This fact led to the invention of what we may call the first and simplest form of carriage. This was the drag or travail (tra-vay´), a cart without wheels (Fig. 3). Two long saplings were fastened at the large end to the strap across the horse's breast and the small end upon which the burden was placed dragged upon the ground. Mr. Arthur Mitchell in his delightful book, "The Past in the Present," tells us that he saw carts of this kind in actual use in the highlands of Scotland as late as 1864! An improvement upon the travail was the sledge made of the forked limb of a tree (Fig. 4). This primitive sledge was really a travail consisting of one piece. [Illustration: FIG. 4.--A PRIMITIVE SLEDGE. (From a Model in National Museum.)]