M. De Luc then examined the action of the pile, when dissected according to the second arrangement, where the metals were placed together, and the wet cloth in contact with the zinc, or the most oxidable of the metals ; the ter nary groups being separated from each other by the wire frames. The extremities of the pile indicated to the elec trometer the same states of positive and negative, as in the former instance, but no shock was experienced ; when the wiles of the interrupted circuit were placed in water, al though it appeared that there was a communication es tablished through the fluid, yet no decomposition took place, nor did there appear to be the retardation of the elec tric current upon its entering the fluid, as in the former case. Hence the author concludes, that the electi ical and chemical effects originate from different causes, because in this state of the instrument the electrical effects continue, although the chemical effects are suspended. The third dissection of the pile was now made, i. e. it was divided into ternary groups, consisting of the metals contiguous to each other, and the wet cloths in contact with time silver ; the groups being separated as before, by wire supports. Here there was no effect perceptible, either electrical or chemi cal.
In the above experiments, the cloths which were em ployed to retain the fluid were moistened with water : A second set of experiments was now performed, in which a strong solution of muriate of soda was employed. The pile, whether moistened with water or the saline solution, had the same effect upon the electrometers, both as to quality and quantity ; but when the salt was used, there was a more powerful effect upon the sensations. He ob served, that a new shock was experienced every time either of the hands was brought into contact with the apparatus, or removed from it ; but that no effect took place as long as they remained in contact. When the interrupted circuit was applied between the extremities of the pile, the shock might be felt, but it was rendered less violent ; and the chemical effects were diminished, but not suspended, while the contact of the body was preserved : hence it may be inferred, that the body is about an equally good conduc tor with water. The retardation of the current appeared to be rather greater in this case, than where the apparatus was supplied with pure water.
The pile was now dissected in the same three ways as before, muriate of soda in solution being employed instead of water. In the first dissection, i. e. with the moistened cloths between the plates, the same electric effects were exhibited by the electrometers, the same shock was felt,, and the same chemical effects were produced, only in ra ther a less degree than in the continuous pile, with muriate of soda. The second and third dissections of the pile pro duced exactly the same effect, as when the same dissec tion were employed with pure water.
The author afterwards enters upon a number of specu lations respecting the manner in which the electric fluid circulates through the apparatus, and upon the immediate cause of the electrical and chemical phenomena. He con ceives, that when no cause of retardation exists, the elec tric fluid circulates so rapidly through the pile, as not to exhibit any of its effects, or indeed not to indicate its pre sence ; and that NI hen these are manifested, it always de pends upon some retarding cause. The electrical and che
mical effects are supposed to originate from different parts of the pile, or from different groups, considered in their re lation to the parts contiguous to them. The electrical ef fects consist simply in the combination of the two metals, each pair being separated by a non-metallic conductor ; while for the chemical effects, ternary groups are neces sary, the two metals with a fluid between them. This dis tinction between the two sets of properties, or the two modes of action, is supposed to be proved by the different effects which are produced by the pile in its three states of dissection. In the pile dissected in the first manner, which indeed may be regarded as equivalent to the instrument in the continuous state, both the electrical and chemical ac tion takes place : for here are the two metals, either in con tact, or connected by the wire frames, for the electrical effects ; and for the chemical effects, there are the two me tals with the wet cloth interposed. In the pile as dissected in the second manner, there are the binary groups, i. c. the metals in contact, and accordingly they produce the elec trical effects ; but we have no chemical effects, because they have no fluid between them. In the third dissection, no effects are produced ; we have not the chemical effects, because the metals have not the wet cloth between them, and we have no electrical effects, because the zinc has the copper plate on one side, and the wire frame on the other, which have the same electrical relation to the zinc, and therefore counteract each other.
The different effects which seemed to ensue, between the pile when furnished with pure water, and with the so lution of a neutral salt, induced M. De Luc to examine what connexion existed between the oxidation of the zinc, and the chemical action of the instrument. For this pur pose he formed a pile of silver and pewter, the pewter be ing selected for the experiment, because it has an electri cal relation with silver, and is oxidable by muriatic acid, at the same time that it is not much affected by pure water. In the first instance, water was interposed between the plates; the extremities of the pile, as indicated by the elec trometer, became electric, the pewter side negative, and the silver positive ; but there was no shock, nor any decompo sition of the water in the interrupted circuit.' A pile was then formed of such a number of zinc and silver plates, that its electrical energy might be the same with the pewter pile ; but here there was both the shock produced, and the decomposition of water. The pile of pewter and silver was then fitted up with muriatic acid ; and in this case, when the pewter plates became oxidated, the shock and the de composition of water were both produced. From these ex periments, the author deduces the following conclusions. When the metal is not oxidated, no chemical effect is pro duced on the water in the interrupted circuit. When the oxidation is produced by means of pure water, there is no shock, although the chemical effects take place; and lastly, when either of these effects are produced, the current of electricity is retarded in its passage across the water in the interrupted circuit.