IN GALVANISM AND ELECTRICITY. 



179 



c cur- 



IV. 



Extract of a Letter Mr. J. B. Van Mons to Mr. Sue, on 

 different subjects relating to Galvanism and Electricity. 



\JtN repeating the experiments of Paechiani on the pre- Galvani 



tended decomposition of water into muriatic acid, I satisfied rent I conduc - 



,£•!,,. . tor of heat, 



myself, that the galvanic current is a conductor of heat like- 

 wise; by interposing between the plates pieces of pasteboard 

 moistened with oximuriatic acid, nitric acid, or oximuriates, 

 nitrates, &c. ; which, during their action on the metal of the 

 pile, setting caloric free, thefluid experimented on, or through 

 which the current passes, is heated considerably. 



The substances transferred by the action of the pile are Substances 

 partly resolved into their ultimate elements. This resolu- carnedaway 



j re 01 by its current, 



tion does not appear to be effected by means of chemical and their ele. 



affinity, or an attraction of composition, but in consequence ™"' s se P ara * 



of the different degree in which these elements are conduc- acted on with 



tible by the galvanic current; which conductibility is mea- m ° re or less 



. velocity. 



sured by the rapidity of the transmission, and the distance 



beyond the point of the two currents, the positive and the 

 negative, at which it takes place. So that we cannot mea- This no t con . 

 sure the degree of chemical affinity of a body by that of its nected with 

 decomposability by the pile ; but a substance not being de- £ emicalaffi. 

 composable by this apparatus affords a strong presumption, 

 that it is not decomposable by other substances. Substan- 

 ces have not been sufficiently subjected to the immediate 

 action of the pile, or to the effects of the plates on the sub- 

 stance used for impregnating the fluid, with a view to ef- 

 fect their decomposition. Few decomposable substances Almost all sub" 

 would escape being decomposed: even the carbonates are stances decom- 

 then resolved into their ultimate elements, or set free car- i^ c y 

 bon. When I say carbonates, I speak only of the carbonate 

 of ammonia, for the others appear only to have their base 

 separated from the acid. It would seem as if the activity 

 of the pile were satisfied with the first effect of decornposi- ammonia, 

 tion it exerts, and that the decomposition of the carbonic 

 acid in the carbonate of ammonia is the effect of a secon- 

 N 2 dary 



