454 Additional Remarks on Galvanic EleBricity. 



References to the Figures of the glafs Globe, isfc. mentioned in SeBion VII. 



A, (PI. VII. of the prefent volume) a ball or globe of glafs, nearly half an inch thick, and 

 feven inches in diameter. It has two necks, on which are cemented the brafs caps, B, C, 

 each being perforated with a female fcrew, to receive the male ones D, E : through the 

 ■former a fmall hole is drilled ; the latter is furniflied with a perforated ftud or fhank G. By 

 jncans of a leather collar H, the neck C can be air-tightly clofed. When a portion of the 

 powder is to be exploded, it muft be placed on a piece of paper, and a fmall wire laid acrofs 

 the paper, through the midft of the powder : the paper being then clofed, is to be tied at 

 each end to the wire, with a Glken thread, as fliewn at I. One end of this wire is to be 

 faftened to the end of the fliank G, and the fcrew D inferted to half its length into the 

 brafs cap B ; the other end of the wire, a, by means of the needle K, is to be drawn 

 through the hole F. The fcrew E being now fixed in its place, and the wire drawn tight, 

 it is to be fecured, by pufliing the irregular wooden plug L into the aperture of the fcrew D, 

 taking care to leave a paflage for air. The Hop-cock M, the feftion of which is fliewn at N, 

 is now to be fcrewed on to the part D, which is made air-tight by the leather collar ^i. The 

 glafs tube O is, bent, that it may more conveniently be' introduced under the receiver of a 

 pneumatic apparatus. P, fliews the manner of connecting the glafs tube with the ftop-cock. 



IV. 



Additional Remarks on Galvanic EUSricily. By Mr. TV. Cruickshank, Woolwich. 



Communicated by the Author. 



B, 



^EING defirous to afcertain with fome degree of precifion, the nature and relative 

 proportions of the gafes obtained from water and other fluids by this influence, I procured 

 feme wires of gold, and alfo fomc of filver gilt. On trial, I found that thefe wires were 

 not by any means fo much a£ted upon as filver, at leaft where water alone was.decom- 

 pofed ; I likewife obferved, that the quantity of oxigen in the mixed gas was much greater, 

 and amounted to nearly one third of the whole j the gas from the zinc wire was alfo more 

 copious, than when filver or copper wires were employed. 



I took a wide mouthed phial capable of containing 3 ounces, and filled it with very pure 

 lime water, a cork was then loofely introduced into i^s mouth, and two gold wires pafled 

 through it; the phial being inverted in a fmall bafon containing pure water, the other ex- 

 tremities of the wires were conned^ed with thofe of the pile in the ufual way ; a very co- 

 pious production of gas immediately took place, more efpecially from the filver wire, and 

 in about four hours the phial was completely filled. This gas was fubmitted to tlis fol- 

 lowing experiments : 



One meafure of it being mixed with two of nitrous gas, 3 diminution of one meafure 

 iook place, the refiduura contained nitrous gas, mixed with hydrogen. 



Four 



