Chemical FfftEls of Galvanic EkSricity. 223 



which manifcfted no fmcll of any kind, and could not, therefore, be fufpe£l:ed to contain 

 either arfenic or antimony : I fuppofe it to be muriate of lead, as notwithftanding its great 

 fufibility, and its fuppofed fixity, it is, in fadl, in fome degree volatile, as I have re- 

 peatedly obferved on other occafions. 



No more than twenty-two parts of water arc neceflary to diflblve one of muriate of 

 lead, and the diflblving power is much encreafed by the prefence of an acid, yet we fee in 

 the cafe before us it could refill the aftion of a much greater quantity, even when aided by 

 a confiderable portion of nitric acid in excefs ; fuch examples are not rare in natural fub- 

 ftances, compared with the flight aggregation of thofe which art can produce. 



The exiftence of a natural muriate of lead has been fufpedted more than once. Ferber 

 examined a fpecimen found at Meis and Bleylladt, in Bohemia, which he imagined to 

 contain muriatic acid ; but the Baron de Born aflures, that Kbproth, upon an accurate 

 analyfis, had determined thofe fame grey hexaedral cryftals, which Ferber had procured, to 

 be merely phofphate of lead, a variety then well known. Monf. Sage had likewife afferted 

 as much ; but the fpecimens which he had tried, being further fubmitted to inveftigation 

 by Mr. Laborie, and by fome members of the Royal Academy of Paris, were found to 

 be totally void of muriatic acid, and are now univerfally acknowledged as pure carbonated 

 leads. 



The authorities here mentioned are too refpe£table for me to difcufs their merits. I 

 fhall only add, that after the experiments above defcribed, and which were performed 

 in the prefence of Monf. de Bournon, he no longer refufes his aflent to this new fpecies 

 of lead ore, now firft proved, if not difcovered, but has added it to thofe varieties already 

 admitted in the fyftem of mineralogy. 



VII. 



Experiments en the Chemical Effe&s of Galvanic EUSricity, By Mr. JViiliam Henrt. 



To Mr. NICHOLSON. 

 S I R, 



Manchejleff July 20, i8oo. 



An addition to the interefting fa£ls, refpe£ling the chemical adlion of galvanifm, which 

 appeared in the laft Number of your Journal, I beg leave to communicate the following 

 experiments. The apparatus, which I employed, needs no further defcription than that 

 it confided of half crowns and fimilar pieces of zinc, varying in number as occafion 

 required, with pieces of woollen cloth interpofed, foaked in a faturated folution of common 

 fait. I tried muriate of lime, as a fubftitute for common fait, but without any better 



I. To 



