We are hardly justified in ascribing this uneconomic arrangement to the “stupidity” of Nature. Any other arrangement, such as the use of levers of the “second order,” would have involved a much bulkier and clumsier build of the muscular system. Nor can we conceive of the adoption by man of the Six Machines as a deliberate imitation of Nature, or an improvement upon observed natural processes. The Six Machines are obviously the crude results of long-continued experience, and it was not until the middle of the nineteenth century that their real significance in the system of mechanics was recognized. The real importance of these contrivances lies in the fact that they increase the power of the human body without any further evolution of the human organism. The adoption of mechanism was a turning point in evolution, and an event the significance of which can only be classed with such far-reaching innovations as the birth of life itself or that adoption of locomotion as an aid to nutrition which gave rise to the animal kingdom. The most widely useful of the Six Machines was undoubtedly the Wedge. Its use was usually accompanied by that of the projected stone. The latter, after being swung by muscular force, was a reservoir of energy, which is the power of performing work. If brought to rest within a shorter distance than the curve of the swing, it required a correspondingly greater force to stop it. And that force could be still further increased by applying it to the end of a wedge whose sides bore upon the object to be split. The combination of mass and wedge is represented by the spear, the arrow, and the sword, while the hammer and the club acted as crushers rather than cutters. Observe, then, this puny but formidable creature emerging from his tropical forest. In his hand he carried the means of annihilating that continuity of the organism which is essential to its existence. He was able to drive a powerful and irresistible wedge into the body of his antagonist and thus end the co-ordination of its natural functions. It was thus that, later in history, the Macedonian phalanx split up the armies of the Persian kings. By a different but essentially similar process the 15-inch naval gun drives a wedge clean through the armour of its opponent, in the shape of a shell which does not explode until it is right inside the enemy ship. Man’s war of conquest against the animal world had begun. He brought to them a death more sudden than had existed up to his time. For he had the power of driving his wedge into the most vulnerable and essential part of his enemy’s body. A clean cut inflicted at the appropriate point would mean his final end. Man was not long in discovering his enemy’s weaknesses. And when his enemy was a human one, he made assurance complete by bringing home his head.[2]