It has been suggested that although in a generality of cases nature has forestalled the ingenious mechanician, man for his wheel has had to evolve an apparatus which has no counterpart in his primitive environment—in other words, that there is nothing in nature which corresponds to the _wheel_. Yet even the most superficial inquiry into the nature of the earliest vehicles must do much to refute such a suggestion. Primitive wheels were simply thick logs cut from a tree-trunk, probably for firewood. At some time or another these logs must have rolled of their own accord from a higher to a lower piece of ground, and from man’s observation of this simple phenomenon must have come the first idea of a wheel. If a round object could roll of its own accord, it could also be made to roll. Yet it is to be noticed that the earliest methods of locomotion, other than those purely muscular, such as walking and riding, knew nothing of wheels. Such methods depended primarily upon the enormously significant discovery that a man could drag a heavier weight than he could carry, and what applied to a man also applied to a beast. Possibly such discovery followed on the mere observation of objects being carried down the stream of some river, and perhaps a rudely constructed raft should be considered to be the earliest form of vehicle. From the raft proper to a raft to be used upon land was but a step, and the first land vehicle, whenever or wherever it was made, assuredly took a form which to this day is in common use in some countries. This was the sledge. On a sledge heavy loads could be dragged over the ground, and experience sooner or later must have shown what was the best form of apparatus for such work. As so often happens, moreover, in mechanical contrivances, the earliest sledge of which there is record—a sculptured representation in an Egyptian temple—bears a remarkable resemblance to those in use at the present time.[1] Then, as now, men used two long runners with upturned ends in front and cross-pieces to unite them and bear the load. Such sledges were largely used to convey the huge stones with which the Egyptians raised their solemn masses of masonry and, incidentally, also as a hearse. In time, however, it was found that better results were obtained by the use of another and rather more complicated apparatus which had for its chief component—a wheel. This second discovery that to roll a burden proved an easier task than to drag it was fraught with such tremendous consequences as altered the entire history of the world.