OF
ELECTRICITY.
DIVISION III.
CHAP. I.
Introductory Observations to the theory of Electricity.
There is scarcely any thing to which an inquisitive mind, such as a philosopher possesses, submits with more reluctance, than to the inability of assigning the causes of the most interesting appearances or phenomena of nature. That every effect has a cause, is a first or self evident principle, and the mind is not easily brought to acquiesce in its utter ignorance of the cause, when the effect is visible and striking.—From this circumstance proceeded the numerous wild, fanciful, and delusive systems of natural philosophy, which existed before the time of the great Lord Bacon.—His penetrating and discriminating mind saw that nothing solid could ever be achieved in that noble science, unless such a procedure were relinquished;—unless men would consent to confess their ignorance of causes which were actually unknown;—unless they would cease to rely on hypotheses, however plausible, until they were verified by experiment;—consent to take facts as they are found, and by experiments alone endeavour to ascend to their causes. On this immoveable base the Newtonian philosophy is founded, and it will of course prove as durable as nature herself.
Two things, however, in regard to this subject, are of some importance to be remarked.—The first is, that experiments may sometimes be supposed to ascertain causes which will afterwards be found not to exist, or to be wrongly assigned; because the experiments had not been accurately or extensively made.
The second remark is, that though hypotheses are not to be taken for philosophy, till they have stood the test of experiment; yet in the process of the mind in making discoveries, hypothesis is perhaps always used, where the discovery is not merely accidental. No man can rationally make experiments till he has conceived a notion, supposition, or hypothesis in his mind, which he imagines experiment may serve to verify.—It is this which prompts him to his researches and guides him in conducting them.
In regard to electricity, it is remarked by Dr. Priestley, that “no other part of the whole compass of philosophy affords so fine a scene for ingenious speculation. Here the imagination may have full play, in conceiving of the manner in which an invisible agent produces an almost infinite variety of visible effects. As the agent is invisible every philosopher is at liberty to make it whatever he pleases, and ascribe to it such properties and powers as are convenient for his purpose. And, indeed, if he can frame his theory so as really to suit all the facts, it has all the evidence of truth, that the nature of things can admit.”
For ourselves we are by no means satisfied that there is yet any theory of electricity which will “suit all the facts;” and therefore if this be requisite to entitle a theory philosophy, as contra-distinguished from hypothesis, we must think that the best theory of electricity is yet hypothesis, and not philosophy. We believe that the Franklinian theory accounts for more facts, and is far more plausible, than any other. But, as we have already had occasion to remark in a former chapter, it does not appear to us fully and satisfactorily to account for all the phenomena of electric attraction and repulsion. Dr. Franklin always spoke with great diffidence of his own theory, and always denominated it an hypothesis.
“Every appearance, says he, which I have seen, in which glass and electricity are concerned, are, I think explained with ease by this hypothesis. Yet, perhaps, it may not be a true one, and I shall be obliged to him who affords me a better.” In like manner Æpinus, who adopted the theory of Franklin, and who has illustrated its leading principles in a far more masterly and scientific manner than any other writer, still denominates the theory which he maintains an hypothesis. Why should pupils affect to go farther than their masters? We think that the theory of electricity is still an hypothesis. We are however clearly of opinion that the hypothesis of Franklin is preferable to every other. We have therefore adopted it in the whole of our system, and mean to close this division of our subject by giving it, somewhat in detail, with the leading facts and considerations by which its claim to superiority appears to us to be supported. In the mean time, as every student of electricity may wish to know, and ought to know, what other theories have been adopted, we shall fill the following chapter with a brief and compendious recital of some of the principal of them.—It would be endless to recite them all. We shall, however, enter into no extensive argument to prove their fallacy, as this would be inconsistent with our plan, as well as unprofitable in itself. We shall afterwards say what we can to confirm the theory of Franklin, and if we succeed, every thing opposed to it, must, of course, appear to be unsupported.