Ritter published an account of a curious appendage to Volta's pile, which he called the secondary pile, and which has been frequently called the idle of Ritter. It is a kind of electric apparatus, which may be charged by the voltaic pile, or may be made to retain the electricity that is per petually flying off from this instrument. He perceived that a body, which had formed part of the galvanic circle in the pile of Volta, when the pile was removed, became itself electiical ; but it exhibited an electricity opposite to that which it had previously possessed. Thus, if two wires terminating in water, and connected with the pile, were discharging, one oxygen, and the other hydrogen, when they were removed from it, they would still continue to discharge the gases, but the operation would be revers ed. These wires, in this state, may be considered as charged, and if a greater number of similar wires he placed between the ends of the pile, they will all become charged. The nature of the experiment will not be affected, if, in stead of wires terminating in water, plates of metal be substituted, with wet cards interposed. An instrument will thus be formed, which of itself cannot produce any signs of electricity, but which may be rendered electrical, by being placed in contact with the primary pile. When the two piles are connected, the action of the ends of each are reversed to each other, and as, when they are separated, the ends of the secondary pile are again reversed, conse quently the ends of both the piles will now act in the same manner. It is necessary for the pile of Hitter to remain for some time in contact with the pile of Volta, in order that it may be sufficiently charged. It is stated that the chemical effect of Ritter's pile, that is, its effect in decom posing water, does not bear a regular ratio to its physiolo gical effect, that is, its effect in giving shocks. The au thor observes, with respect to the voltaic pile, that its ten 'sion is the greatest, and it produces the strongest effects on the sensations :ininedi:itely alter it is constructed, but that its chemical elncts are the most powerful after it has been acting for some hours. See Journ. de Phys. Ivii. 345.
Shortly after the publication of the account of the se condary pile, Ritter made a number of experiments with the pile of Volta, which arc original and curious. Ile ob served, that when a communication was formed between the positive end of the voltaic pile and the earth, the whole instrument became negatively electrified, and ivhen the communication was made with the negative end, the in strument became positive. These changes do not, how ever, destroy the chemical action of the pile, which goes on in the same manner as before the communication was formed. He supposes that the decomposition of water is effected in consequence of the positive end disengaging oxygen, and the negative end hydrogen, and that the two ends have also a tendency to dispose metals to unite with oxygen and hydrogen respectively. He says, if the posi tive end be armed with gold leaf, and the negative with charcoal, and these substances be then brought into con tact, the gold will be burned ; but if the position of the substances be reversed, the charcoal will be burned.
When the extremities of a pile do not commmiicate, it is said that the action exercised between the different plates is very unequal ; the zinc, which is nearest the positive end, is the most oxidated. it is also asserted, that if a pile be broken into separate parts, by a number of wires insert ed between every fifth pair of plates, those wires nearest the positive end will be the most oxidated ; while, on the contrary, those wires near the negative end will be less oxidated than if they had been simply plunged in water. Hence he infers, that at the negative end an action has taken place, or a state has been induced, the reverse of oxidation. He goes so far as to say, that different sensa tions arc excited by the two ends of the pile, the one ex panding, and the other contracting, the muscular fibre; the positive end strengthens the pulse, and produces heat ; the negative weakens it, and produces cold. See Journ. de Phys. lvii. 401.
So far as we have been able to learn, few, if any, of the experiments of Ritter have been repeated, either in Eng land or in France ; a circumstance which is not a little re markable, when we consider that many of them are quite original, and would lead to important theoretical deduc tions. His language and manner of writing are, however, unfortunately obscure ; and he abounds so much in hypo thesis, that he has not obtained that degree of attention to which he would seem to be entitled, from his industry and ingenuity. It is scarcely to be supposed that he could have been mistaken respecting the effect of the secondary pile, or that he would have invented a series of facts, the fallacy of which might be so easily detected. With respect to the experiments on the voltaic pile, their authority is more doubtful ; they seem to have been peeformed with a mani fest view to a particular hypothesis ; sonic of them are of an indeterminate nature, and we may imagine that many are exaggerated, or even inaccurately stated.
The attention of the different experimentalists was now much occupied with the comparative merits of the two hypothesis, the electrical and chemical ; generally speak ing, the English seemed to incline to the latter, and the continental writers to the former. Biot drew up a candid and judicious Memoir, in which he compares the merits of the two opinions, and endeavours to shew how far either of them is supported by acknowledged facts. Electricity, he observes, is certainly excited, but it is not certain whether we ought to regard it as cause or effect. He proceeds to inquire, whether the action of the instrument depends en tirely upon the oxidation of the water, entirely upon the influence of the metals, or whether it is not produced by the two in conjunction. This he decides to be the case ; and yet, at the same time that he makes this decision, he appears to have a leaning towards the chemical hypothesis. See Ann. de Chinz. xlvii. 1.