The Poetry of Science; or, Studies of the Physical Phenomena of Nature

by Robert Hunt

Although the world of science looks back to Volta as the man who gave the first true interpretation of this discovery, yet the ordinary world will never disconnect this important branch of physical science from the name of Galvani, and chemical electricity in all its forms will for ever be known under the familiar name of Galvanism. And it must not be forgotten, that the phenomena of the manifestation of electricity, in connection with the conditions of vitality, are entirely due to Galvani.

Let us examine the phenomena of Galvanism in its most simple phases:—

If we place a live flounder upon a plate of zinc, put a shilling on its back, and then touch both metals with the ends of a metallic wire, the fish will exhibit painful convulsions. The zinc becomes oxidized by the separation of oxygen from the fluid on the surface with which it is in contact, whilst hydrogen gas is liberated at that surface touched by the other metal. Here we have, in the first place, a chemical change effected, then a peculiar muscular disturbance. Each successive combination or decomposition, like a pulsation, is transmitted along the circuit from one extremity to the other. How the impulse which is derived from the zinc is transmitted through the body of the animal, or the tongue, to the silver or copper is the next consideration.

We can only understand this upon the supposition that a series of impulses are communicated in the most rapid manner along the connecting line; the idea of a current, although the term is commonly employed, tends to convey an imperfect impression to the mind. It would seem rather that a disturbance throughout the entire circuit is at once set up by a series of vibrations or impulses communicated from particle to particle, and along the strange net-work of nerves. One set of chemical elements have a tendency to develope themselves at that point where vibration is first communicated to the mass from a better conductor than it is, and another set at the point where it passes from the body to a better conductor than itself. The cause of this is to be sought for in the laws which regulate molecular constitution—by which chemical affinity is disturbed,—and a new attractive force exerted, in obedience to which the vital energy is itself agitated. We must not, however, forget that it is probable after all, although not yet susceptible of proof, that the electricity does nothing more than disturb or quicken the unknown principles upon which chemical and vital phenomena depend; being, indeed, a secondary agent.[141]

Notwithstanding our long acquaintance with the phenomena of galvanism, there are but few who entertain a correct idea of the enormous amount of electricity which is necessary to the existing conditions of matter. To Faraday we are indebted for the first clear set of deductions from a series of inductive researches, which are of the most complete order. He has proved, by a series of exceedingly conclusive experiments, that if the electrical power which holds a grain of water in combination, or which causes a grain of oxygen and hydrogen to unite in the right proportions to form water, could be collected and thrown into the condition of a voltaic current, it would be exactly the quantity required to produce the decomposition of that grain of water, or the liberation of its elements, hydrogen and oxygen.[142]

By direct experiment it has been proved that one equivalent of zinc in a voltaic arrangement evolves such a quantity of electricity in the form of a current, as, passing through water, will decompose exactly one equivalent of that fluid. The law has been thus expressed:—The electricity which decomposes, and that which is evolved by the decomposition of a certain quantity of matter, are alike. The equivalent weights of bodies are those quantities of them which contain equal quantities of electricity; electricity determining the equivalent number, because it determines the combining force.[143]

The same elegant and correct experimentalist has shown that zinc and platinum wires, one-eighteenth of an inch in diameter, and about half an inch long, dipped into water in which is mixed sulphuric acid so weak that it is not sensibly sour to the tongue, will evolve more electricity in one-twentieth of a minute than is given by thirty turns of a large and powerful plate electrical machine in full action, a quantity which, if passed through the head of a cat, is sufficient to kill it as by a flash of lightning. Pursuing this interesting inquiry yet further, it is found that a single grain of water contains as much electricity as could be accumulated in 800,000 Leyden jars, each requiring thirty turns of the large machine of the Royal Institution to charge it,—a quantity equal to that which is developed from a charged thunder-cloud. “Yet we have it under perfect command,—can evolve, direct, and employ it at pleasure; and when it has performed its full work of electrolisation, it has only separated the elements of a single grain of water.”

It has been argued by many that the realities of science will not admit of anything like a poetic view without degrading its high office; that poetry, being the imaginative side of nature, has nothing in common with the facts of experimental research, or with the philosophy which generalises the discoveries of severe induction. If our science was perfect, and laid bare to our senses all the secrets of the inner world; if our philosophy was infallible, and always connected one fact with another through a long series up to the undoubted cause of all—then poetry, in the sense we now use the term, would have little business with the truth; it would, indeed, be lost or embodied, like the stars of heaven, in the brightness of a meridian sun. But to take our present fact as an example, how important a foundation does it offer upon which to build a series of thoughts, capable of lifting the human mind above the materialities by which it is surrounded,—of exalting each common nature by the refinement of its fresh ideas to a point higher in the scale of intelligence,—of quickening every impulse of the soul,—and of giving to mankind the most holy longings.

What does science tell us of the drop of water? Two gases, the one exciting life and quickening combustion, the other a highly inflammable air, are, by the influence of a combination of powers, brought into a liquid globe. We can, from this crystal sphere, evoke heat, light, electricity, and actinism in enormous quantities; and beyond these we can see powers or forces, for which, in the poverty of our ideas and our words, we have not names; and we learn that each one of these principles is engaged in maintaining the conditions of the drop of water which refreshes organic nature, and gives gladness to man’s dwelling-place.