. On the Chemical Effe&s of the Pile of Volta. 515 



which fcem fufficlent to account for the phsenomenon. The laws of cryftalllzation will 

 apply to explain why the lead aflumes a regular figure, as other metals, for inftance tin, 

 affume their own forms. You may alfo have remarked that, when a metal is diflblving in 

 an acid, the folution defcends through the folvent (as happens in the oxidation of copper 

 by wires of that metal in water, and connefted with the pile) according to the increafed 

 fpecific gravity of the newly formed compound. It is alfo known, that there arc different 

 degrees of faturation between metals and acids, which may take place as the heavier fluid 

 defcends; for you will obferve that the vegetations generally take place downwards. I 

 have obferved that, when zinc is placed in a faturated folution of lead or tin, 2 very con- 

 fufed mafs of precipitated metal forms very foon around it, and that, in order to produce 

 fine cryflallizations, it is necefTary to add a large proportion of water : this feems to fhew 

 that the defcent of the new metallic folution has fome {hare in producing the efFeft. But 

 in thefe experiments continuity is preferved, and the fame effefts are produced in every 

 cryftallization of any falls. 



It appears to me therefore that the reparation of the two gafes from the connexion with 

 the pile of Volta, is an anomalous efFedl in chemiftry, as yet unexplained according to the 

 dodlrine of the decompofition of water. It has been a long time known that pofitive and 

 negative ele£tricity have different properties ; it is now clearly (hewn that they produce 

 different chemical efFe£ts. I do not fee how, in ftrift philofophy, we are warranted in 

 faying more of the experiment with the pile, than that one kind of ele£tricity and water 

 produce one kind of gas, and the other another gas. Is it not an afTumption in this ex- 

 periment to fay, that the bafes of the gafes are the component parts (if water ? I could 

 ftart other difficulties even where there appears to be a clearer proof of the decompofition 

 of water, but, fearful left I fhould have already too much impofed upon your kindnefs, I 

 haften to fubfcribe myfelf. 



Your obedient humble Servant, 



AN EXPERIMENTALIST. 



January 2o, 1801. 



X. 



AnalyJisoftheMellite, or in German, Honigfldn. By Cit. Vauq^uelin*. 



T. 



HE anal'yfes which MefTrs. Abich and Lampadius have given of this interefting foffil 

 are well known. The firft obtained from one hundred parts, 16 carbonate of alumine, 

 4 carbone, 3 oxyde of iron, 40 carbonic acid, 28 water of cryftallization, having a fmell 

 of bitter almonds, and 5.5 of Naptha. 



* Annales de Chimie XXXVI. zoj, 



3U2 The 



