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Stedman and Hutchinson, comps. A Library of American Literature:
An Anthology in Eleven Volumes. 1891.
Vols. IX–XI: Literature of the Republic, Part IV., 1861–1889

A Terse Statement of the Doctrine of Forces

By Edward Livingston Youmans (1821–1887)

TOWARD the close of the last century the human mind reached the great principle of the indestructibility of matter. What the intellectual activity of ages had failed to establish by all the resources of reasoning and philosophy, was accomplished by the invention of a mechanical implement, the balance of Lavoisier. When nature was tested in the chemist’s scale plan, it was first found that never an atom is created or destroyed; that though matter changes form with protean facility, traversing a thousand cycles of change, vanishing and reappearing incessantly, yet it never wears out or lapses into nothing.

The present age will be memorable in the history of science for having demonstrated that the same great principle applies also to forces, and for the establishment of a new philosophy concerning their nature and relations. Heat, light, electricity, and magnetism are now no longer regarded as substantive and independent existences—subtile fluids with peculiar properties, but simply as modes of motion in ordinary matter; forms of energy which are capable of mutual conversion. Heat is a mode of energy manifested by certain effects. It may be transformed into electricity, which is another form of force producing different effects. Or the process may be reversed; the electricity disappearing and the heat reappearing. Again, mechanical motion, which is a motion of masses, may be transformed into heat or electricity, which is held to be a motion of the atoms of matter, while, by a reverse process, the motion of atoms, that is, heat or electricity, may be turned back again into mechanical motion. Thus a portion of the heat generated in a locomotive is converted into the motion of the train, while by the application of the brakes the motion of the train is changed back again into the heat of friction.

These mutations are rigidly subject to the laws of quantity. A given amount of one force produces a definite quantity of another; so that power or energy, like matter, can neither be created nor destroyed: though ever changing form, its total quantity in the universe remains constant and unalterable. Every manifestation of force must have come from a preëxisting equivalent force, and must give rise to a subsequent and equal amount of some other force. When, therefore, a force or effect appears, we are not at liberty to assume that it was self-originated, or came from nothing; when it disappears we are forbidden to conclude that it is annihilated: we must search and find whence it came and whither it has gone; that is, what produced it and what effect it has itself produced. These relations among the modes of energy are currently known by the phrases Correlation and Conservation of Force.

The present condition of the philosophy of forces is perfectly paralleled by that of the philosophy of matter toward the close of the last century. So long as it was admitted that matter in its various changes may be created or destroyed, chemical progress was impossible. If, in his processes, a portion of the material disappeared, the chemist had a ready explanation—the matter was destroyed; his analysis was therefore worthless. But when he started with the axiom that matter is indestructible, all disappearance of material during his operations was chargeable to their imperfection. He was therefore compelled to improve them—to account in his result for every thousandth of a grain with which he commenced; and as a consequence of this inexorable condition, analytical chemistry advanced to a high perfection, and its consequences to the world are incalculable. Precisely so with the analysis of forces. So long as they are considered capable of being created and destroyed, the quest for them will be careless and the results valueless. But the moment they are determined to be indestructible, the investigator becomes bound to account for them: all problems of power are at once affected, and the science of dynamics enters upon a new era….

The law characterized by Faraday as the highest in physical science which our faculties permit us to perceive, has a far more extended sway; it might well have been proclaimed the highest law of all science—the most far-reaching principle that adventuring reason has discovered in the universe. Its stupendous reach spans all orders of existence. Not only does it govern the movements of the heavenly bodies, but it presides over the genesis of the constellations; not only does it control those radiant floods of power which fill the eternal spaces, bathing, warming, illumining, and vivifying our planet, but it rules the actions and relations of men, and regulates the march of terrestrial affairs. Nor is its dominion limited to physical phenomena; it prevails equally in the world of mind, controlling all the faculties and processes of thought and feeling. The star-suns of the remoter galaxies dart their radiations across the universe; and although the distances are so profound that hundreds of centuries may have been required to traverse them, the impulses of force enter the eye, and impressing an atomic change upon the nerve, give origin to the sense of sight. Star- and nerve-tissue are parts of the same system—stellar and nervous forces are correlated. Nay, more; sensation awakens thought and kindles emotion, so that this wondrous dynamic chain binds into living unity the realms of matter and mind through measureless amplitudes of space and time.

And if these high realities are but faint and fitful glimpses which science has obtained in the dim dawn of discovery, what must be the glories of the coming day? If indeed they are but “pebbles” gathered from the shores of the great ocean of truth, what are the mysteries still hidden in the bosom of the mighty unexplored? And how far transcending all stretch of thought that Unknown and Infinite Cause of all to which the human spirit turns evermore in solemn and mysterious worship!