«^S Jddilim&l Remarks en Galvanic EkBridty. 



oxygen, it feizes their oxygen, and becomes oxygenated; but when it paffes from the 

 fluid to the metal again, it affumes its former ftate, and becomes deoxygenated. Now 

 when water is the fluid interpofed, and the influence enters it from the filver fide deoxyge- 

 nated, (and we fuppofe that it always paiTes from the deoxygenated to the oxygenated 

 fide) it feizes the oxygen of the water, and difengages the hydrogen, which accordingly 

 appears in the form of gas ; but when the influence enters the zinc wire, it parts with the 

 oxygen, with which it had formerly united, and this either efcapes in the form of gas, 

 unites with the metal to form an oxyde, or, combined with a certain portion of water, &c. 

 may, according to the German chemifts, form nitrous acid. When a metallic folutlon is 

 the interpofed fluid, the efFe£l produced may be explained in two ways*, but the fimpleft 

 is to fuppofe, that the influence in pafling from the filver wire, feizes the oxygen of the 

 metallic calx, and afterwards depofits it on entering the zinc ont ; in this cafe no gas fliould 

 appear at the filver wire, but when a perfect metal is employed, oxygen (hould be difen- 

 gaged from the zinc wire ; and this, as has been already mentioned, is exactly what takes 

 place. What I confider, however, as the flrongeft argument in favour of this hypothefis, 

 is, that all fluids which do not contain oxygen, are incapable of tranfmitting the galvanic 

 fluid, fuch as alcohol, sether, the fat, and eflential oils, as I have proved by direft experi- 

 ment -, but on the contrary, that all thofe which do contain oxygen condudl it more or lefs 

 readily, as all aqueous fluids, metallic folutions, and acids, more efpecially the concentrated 

 fulphuric acid ; which it decompofes. In this laft inftance, the oxygen produced can hardly 

 be afcribed to the decompofition of water ; for this acid, when properly concentrated, 

 does not contain any fenfible quantity. By this theory alfo, we can readily explain the 

 oxydation of the zinc plates in the machine ; where the fluid in pafling from the different 

 pairs of plates, appears to be alternately oxygenated and deoxygenated. Although I am 

 not by any means intirely fatisfied with this hypothefis, yet, as it is the only one by which 

 I can explain the different phenomena, it was thought advifeable to throw it out, merely 

 with a view to induce others to reafon upon the fubjeft, and to incite them to make expe- 

 riments, by which alone truth can be afcertained. 



A coBvenient and powerful machine is at prefent a great defidcratum in galvanifm ; the 

 common pile, although at firft fufEciently fl;rong, very foon lofes its power; it is befides 

 very troubiefome to be conftantly repiling it, and clearing the different pieces from oxida- 

 tion, &c. which muft necefTarliy be done, if it is intended that the apparatus fhould pro- 

 duce the full efFeft. The contrivance whiph has fucceeded befl: with me is as follows : I 

 con(lru£ted a kind of trough of baked wood, 26 inches in length, 1.7 inches deep, and 1,5 

 inches wide ; in the fides of this trough grooves were made oppofite to each other, about 

 the tenth of an inch in depth, and fufficiently wide to admit one of the plates of zinc and 

 filver when foldered together ; three of thefe grooves were made in the fpace of one inch 

 and three tenths, fo that the whole machine contained 60 pairs of plates. A plate of zinc 



• Ste the former paper on thi» fubjeft, 



and 



