s8o Experi/nenls with ike Galvanic Apparatus. 



it. But Httlc gas was given out in the filver tube, the acid in it was clouded with a white 

 fubftance, which was evidently fulphur ; it was perpetually produced round the point of 

 the wire. 15 meafures of gas were evolved, which gave rather greater diminution, fired 

 with oxygen, than pure hydrogen ; hence they might poffibly have been partially fulphu- 

 lated hydrogen. 



When folution of cauftic pot-afli was put into the filver tube, and fulphuric acid into 

 the zinc tube, pure hydrogen was difengaged in the filver tube, and pure oxygen in the 

 zinc tube ; the fame phenomena took place when water was employed inftead of folution 

 of pot-afli. 



When water was connefted with the zinc, and fulphuric acid with the filver, the pro- 

 dufts were the fame as when pure fulphuric acid was ufed in both tubes. When very 

 diluted fulphuric acid was employed in both tubes, oxygen and hydrogen, nearly in the 

 proportions required to form water, were feparately evolved. 



d. The tubes were filled with pure folution of muriatic acid, and the communication 

 made as before. No gas was given out in the zinc tube, and the gold in it was very much 

 cortoded; 30 meafures of pure hydrogen were coUefted in the filver tube, the gold in 

 which was not perceptibly a6led upon. When water was made to communicate with the 

 zinc, and muriatic acid with the filver, neither of the gold wires were adled upon, and 

 22 meafures of oxygen were colledled from the water, and 41 of hydrogen from the mu- 

 riatic acid. When water was connefted with the filver, and muriatic acid with the zinc, 

 the fame phsenomena took place, as when pure muriatic acid was ufed in both tubes. 



e. Concentrated folutions of nitric acid were galvanifed in the tubes, 19 meafures of 

 pure oxygen were produced in the zinc tube. A globule of gas only, not equ^l to half a 

 meafure, was produced in the filver tube, and the acid became green on the top. The 

 globule of gas did not diminifli with oxygen, it was too fmall to be tried by other tefts. 

 The gold wires were not a£ted upon. 



When nitric acid was conne£i:ed with the zinc, and water with the filver, oxygen and 

 hydrogen were feparately produced. When water was conne£led with the zinc, and 

 nitric acid with the filver, oxygen was given out from the water; no gas was given out 

 from the acid, and It became green. 



In the experiments on the fulphuric and nitric acids, it is moft probable, that the acids 

 were decompofed by the nafcent hydrogen in the filver tube. In the experiments on the 

 muriatic acid and ammoniac, the deficiency of the oxygen in the gold tube moft probably, 

 partly arbfe from the oxydation of the gold, in confequence of what may be' called pre- 

 difpofing affinity. In thefe procefi^es, none of the compound bodies appear to have been' 

 immediately decompofed by the galvanic influence. 



The difference between my refults and thofe of Mr. Henry, may be accounted for from 

 the difference between our modes of operating; I fufpeft, however, that on repeating his 

 experiment on the folution of pot-afli under new circumltances, that ingenious chemift 

 will find rcafons for altering his concluGons witli regard to the decompofition of the alkali. 



Judging 



