How great the privilege was we cannot even yet realize. For the uses of fire are by no means exhausted, and are multiplying from day to day. But the essential element of the change was that something came into the hands of man which did not exist in “Nature” at all, not, at least, in a manner ordinarily accessible to organic being. It was quite “unnatural” to use fire. Fire represented a state in which no organism could survive, in which all its functions were ruthlessly stopped, and its living tissues destroyed. No animal except man has ever attained to the use of fire. Its use represents the transcendence of man from the ordinary scheme of Nature and his ascent into a sort of supernatural, or at least super-organic realm.
From this step there has been no retreat, and there can be no retreat until the sun itself grows cold. Whatever our “back-to-Nature” cranks may say, mankind cannot repudiate and renounce its most precious acquisition and all that it involves in the present and the future. We may dislike the smoke of blast-furnaces, but the remedy is not to do away with them, but to stop their smoking. The bellows of Hephæstus are blowing and his fires are burning. The age of machinery, begun in far-off Palæolithic days, but only established within the last hundred years or so, has now gripped us in a scheme from which none may escape.
Taken in its narrower sense, the word “machine” means a contrivance for increasing the force we can bring to bear upon objects until it exceeds the limits imposed upon the tension of our muscles. As most of the 400 voluntary muscles of the human body are attached to the bones in a manner which diminishes the force exerted below the actual tension of the muscles, the adoption of machinery constitutes a reversal of the “natural” use of the system of levers which we call our skeleton. The Lever, the Inclined Plane, the Wedge, the Pulley, the Wheel and Axle, and the Screw, are all contrivances for slowing down the rate of work until the force required to perform it comes within the compass of our muscles. Our bones, on the other hand, are mostly levers “of the third order,” in which the force is applied between the fulcrum and the object to be moved. Thus it happens that in order to lift a weight of one pound, our muscles are strained by a force which may amount to as much as six pounds.
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]
[2] It is curious in this connection that among the legends of the Saints there is no record of a decapitated person being brought back to life. The angels or departed saints who came to heal the torn breasts of martyred Christian virgins were unable to put heads back on bleeding trunks, even though the tongues in some of those heads were empowered to testify for some time after they would, in the ordinary course of things, have become silent for ever.