465 JSxpcrmenls on the Chemical ProduSion 



ncr, with wealc folutions of nitrons acid, or nitrate of atn- 

 moniac, and falphuret of potaHi, gives pretty ftrong fliocks, 

 rapidly evolves gas from water, and afl'ods the condenfing 

 deftrometer. 



It does not lofe its power of action for many hours ; and, 

 uhen this power is loft^ it may be reftored by the addition 

 of fmall quantities of concentrated fohitions of the propef 

 chemical agents to the fluids in the diiVcrcnt cells. 



from two experiments made on copper and filver, it would 

 appear, that the fingle metallic batteries aft equally well, 

 when the metals made ufe of are {lightly alloyed, and when 

 they are in a Itate of purity. 



XXXVI. Expcriniejits -on the chemical Pro<lu£lion and Ageni^ 

 of EkSirici/j. By WiLLiAM Hyde Wollaston, 

 M. D. F. R. S.* 



N. 



OTWiTHSTANniNG the powcr of Mr. Volta's eleftric 

 pile is now known to be proportional to the difpofition of 

 one of the metals to be oxidated by the fluid interpofed, a 

 tloubt has been entertained by many perfons, whether this 

 power arifcs from the chemical aftion of the fluid on the 

 metal ; or, on the contrary, whether the oxidation itfelf may 

 not be occafioned by ele6lricitv, fet in motion by the conta<it: 

 of metals that have dilTcrent conducting powers. 



That the oxidation of the metal is the primary caufe of 

 the eleilric phsenomena obferved, is, I think, to be inferred 

 from the following experiments, which exhibit the galvanic 

 procefs reduced to its moft fimplc ftate. 



Exper. I. If a piece of zinc and a piece of filver have each 

 one extremity immerfed in the fame veilel, containing ful- 

 phuric or muriatic acid diluted with a large quantity of water, 

 the zinc is diflToIved, and yields hydrogen gas, by decom- 

 pofition of the water : the iilver, not being afted upon, ha* 

 no power of decompofing water 5 but, whenever the zinc and 

 filver are made to touch, or any metallic communication is 

 made between them, hydrogen gas is alfo formed at the fur- 

 face of the filver. 



Any other metal bcfide zinc, which by affiftance of the 

 acid employed is capable of decompofing water, will fuc- 

 ceed equally, if tlie other wire confifls of a metal on which 

 the acid has no efieft. 



Exper. 2. If zinc, iron, or copper, are employed with gold, 



* f rjim the fame. 



