34^ Experiments in Galvanic EleBricitj :. 



the common fait is decompofed, and exhibits an efflorefcenc*. 

 of foda round the edges of the pile, extruded, moft probably^ 

 by the hydrogen: and that, on account of the corrofion of 

 the faces of the zinc, it is neceflary to renew them previoufly 

 to each conftruftion of the pile. This may be done by 

 fcraping or grinding." 



By fevera! accurate and well conduced experiments, Mr, 

 Nichqlfon afcertained that the electricity of the zinc was 

 plus, and that of the filver minus, which ever of them were 

 at the top of the pile. The eleclric fpark was even rendered 

 vifible ; fo that there can be no doubt of the identity of the 

 electric and Galvanic fluid. 



The decompofition of water, and oxydation of metallic 

 wire, fucgeftcd other experiments. Two fmall wires of pla- 

 lina were inferted, as before, in a fhort tube. When the 

 connexion with the piltj was fprmcd, the wire from the 

 filver gave a plentiful ftream of gas, and that from the zinc 4 

 fmaller one. In four hours, neither turbidnefs, oxydation, 

 nor tarniOi appeared. The larger Ilream was naturally fup- 

 pofed to be hydrogen, the fmaller oxygen. 



With thick gold leaf inflead of platina, the refult was the 

 fame, only the extremity of the flip conne6le{i with the zinp 

 acquired a coppery or purplifh tinge. 



A brafs wire was fubtHtuted for one of the (lips of gold. 

 W'hen the former was joined to the filver end, the two 

 ftreams were extricated as before; but when joined to the 

 zinc, it became oxyded^ as when both the wires were of 

 brafs. 



The fimple decompofition of water by platina wires, with- 

 out oxydation, offered a means of obtaining the gafes fepa- 

 rate from qach other. This was tried with a pile of fixty- 

 eioht fets. A wire from each end of the pile paflTed under 

 fcparate phials full of water inverted in a faucer of water. 

 " A cloud of gas arofe from each wire, but moll from the 

 filver or minus fide. Bubbles were extricated from all parts 

 of the water, and adhered, to the whole internal furface of 

 the veflTels. The prpcefs was continued for thirteen hours, 

 alter which the wires were difengaged, and the gafes decanted 

 juto feparate bottles. On meafuriug the quantities, which 



\\a£ 



