Would not it be possible to increase the intensity of the Voltaic battery till it should equal that of the common machine?
MRS. B.
It can actually be increased till it imitates a weak electrical machine, so as to produce a visible spark when accumulated in a Leyden jar. But it can never be raised sufficiently to pass through any considerable extent of air, because of the ready communication through the fluids employed.
By increasing the number of plates of a battery, you increase its intensity, whilst, by enlarging the dimensions of the plates, you augment its quantity; and, as the superiority of the battery over the common machine consists entirely in the quantity of electricity produced, it was at first supposed that it was the size, rather than the number of plates that was essential to the augmentation of power. It was, however, found upon trial, that the quantity of electricity produced by the Voltaic battery, even when of a very moderate size, was sufficiently copious, and that the chief advantage in this apparatus was obtained by increasing the intensity, which, however, still falls very short of that of the common machine.
I should not omit to mention, that a very splendid, and, at the same time, most powerful battery, was, a few years ago, constructed under the direction of Sir H. Davy, which he repeatedly exhibited in his course of electro-chemical lectures. It consists of two thousand double plates of zinc and copper, of six square inches in dimensions, arranged in troughs of Wedgwood-ware, each of which contains twenty of these plates. The troughs are furnished with a contrivance for lifting the plates out of them in a very convenient and expeditious manner.[*]
CAROLINE.
Well, now that we understand the nature of the action of the Voltaic battery, I long to hear an account of the discoveries to which it has given rise.
MRS. B.
You must restrain your impatience, my dear, for I cannot with any propriety introduce the subject of these discoveries till we come to them in the regular course of our studies. But, as almost every substance in nature has already been exposed to the influence of the Voltaic battery, we shall very soon have occasion to notice its effects.
[*] This mode of explaining the phenomena of the Voltaic pile is called the chemical theory of electricity, because it ascribes the cause of these phenomena to certain chemical changes which take place during their appearance. In the preceding edition of this work, the same theory was presented in a more elaborate, but less easy form than it is in this. The mode of viewing the subject which is here sketched was long since suggested by Dr. Bostock, of whose theory, however, this is by no means to be considered as a complete statement.