dN THE NEW SYSTEM OF CHEMISTRY. ]gj 



The fliock was tried of a column of twenty pairs of copper The ftocks not 

 and zinc of one inch and a half, and of another of the fame '/ the j ncrea f c 

 number of plates of five indies; and alfo of another of ten of Airfare. 

 inches fquare ; but not the leaft difference could be per- 

 ceived. The laft mentioned pile (which, as well as the 

 others, was moiftened with muriate of ammonia), fufed five 

 inches of wire ; and the other of five inches fquare fufed four Fufion of wire 

 inches. Whence it feems to follow that the effecls of thefe tTkTLlhclf' 

 piles, as to the fufion of wire, do not increafe in the proper- but in a lefs 

 tion of their furfaces, but in a lefs ratio. ratl °* 



IV. 



A Reply to Mr. Cruikshank's Obfervations in Defence of 

 the New Syjlan of Chemiflry, in the Philofophical Journal*. By 

 Joseph Priestley, L. L.D. F. R. S. $c. Communicated 

 by the Author. 



JlXAVING propofed to philofophers the rc-confideration of Short preface 

 the doctrine of phlogifton, which for fome time has been aim oil a . nd reca P ltu,a " 

 univerfally exploded, I am happy to find fo truly ingenious 

 and candid a perfon as Mr. Cruiklhank has given fome atten- 

 tion to the fubject. That experiment of mine which he par- The heavy in- 

 Jticuiarly examines, is that in which I procured a very lar^e J amnt \ ab,e Mr m 



. " ■ . r Jo from finery cin- 



quantity of heavy inflammable air from finery cinder and der and charcoal, 



charcoal, both previoufly expo fed to fuch a degree of heat, as 



would have expelled from them all the air that mere heat 



could expel. This I afcribed to the water in the finery cinder afcribed to wa- 



uniting with phlogifton from the charcoal. Mr. Berthollet^^ * f ™ p ! e 



thinks, that this inflammable air comes from the decompofition 



of the water contained in the charcoal, and Dr. Woodhoufe, 



from that which he allows to be retained in the finery cinder. 



But Mr. Cruiklhank, not fatisfied, I prefumc, with either of but by Mr. 



thefe hypothefes, has fuggefted a very different one^fqrhe.^^^g 



allerts, that water is not at all necefjfary to the production of of caibonic acid. 



this inflammable air, maintaining that metals, and their calces, 



in a very high temperature, have the power of decompofing 



fixed air, and in this cafe the fixed air mutt be formed from 



fhe oxigen in the finery cinder, and the carbon in the charcoal, 



* Vol. V. Quarto Series, page 1. 



After 



