338 On the Caufes of the Galvanic Phenofnena. ' - 



^ The piles that I employed for afcertaining the influence of factitious airs on the galvanic 

 phenomena, were eredled horizontally in the ufual mode ; but to prevent the plates from 

 feparating when in an oblique pofition, their fides were joined together by refinous cement 

 nt two or three points, fufEcient interftice being preferred to admit of a free circulation of 

 air. The gafes, when any were produced, were received in fmall tubes filled with diftilled 

 water, containing wires covered externally with wax, and communicating with the ends of 

 the pile. The piles were introduced into the airs through water *, and elevated above the 

 water by a metallic plate cemented to their lower extremities. 



1 . Zinc, nvhether connected with Silver in ftngle Galvanic Circles^ cr conjlituiing the Plates 

 of the Galvanic File, feerrn to undergo no Oxidation at common Temperatures, as long as the 

 Water in conlbEi ivith it is pure. 



By pure water, is more immediately meant water holding In folution no oxygen gas, no 

 nitrous gas, and no acids. It has long been known that certain metallic bodies, which 

 oxidate flowly in water expofed to the atmofphere, efFe£l: no change in pure water f: this 

 I have obferved is particularly the cafe with regard to zinc. That zinc, when in contadl 

 with filver in the atmofphere, and forming with it a circuit by means of water, becomes 

 oxidated much more rapidly than when fimply in contact with water, was obferved by 

 Dr. Aft X' 



Suppofing the more rapid oxidation to be the efFe£t of a peculiar ele£lrical influence pro- 

 educed by the contaft of the metals, it would be reafonable to conclude, that zinc in fingle 

 circles with filver and pure water, or at leaft in the galvanic pile erefted with cloths 

 moiftened in pure water, would undergo oxidation. Fabroni §, however, has advanced 

 that fingle galvanic circles do not oxidate in water, unlefs it be expofed to the atmofphere. 

 That the zinc of the galvanic pile does not oxidate in contadt with pure water, will appear 

 from the following obfervations : 



a. A fmall pile of filver and zinc, having its pafteboards moiftened with water, that 

 had been juft boiled, was introduced into a veflel of water that had been long boiling, and 

 was yet warm. Refinous cement was poured upon the furface of the water, and faftened 

 to the glafs as it cooled, to preferve it efieflually from the contact of air H. The apparatus, 

 after remaining for two days, was examined ; the zinc plates were fcarcely at all tarniflied ; 

 no oxide was depofited in the water, and no gas had been evolved through it. A Cmilar 



• Before thefe experiments were made, I had found, by numerous trials, that a pile afled m the atmof- 

 phere immediately after its immerfion in water without being wiped, though more feebly than before : I 

 had likewife found that after the firft immerfion, the powers were not diminished by fubfequeat ones. 



f See Fabroni, Phil. Journ. III. 309. 



J And Humboldt, fee Refearches Chem, & Phil, page 568. 



§ Phil. Journ. III. 309. 



I Oil of turpentine, and even common oil, a$ will be feen hereafter, is ineffejlual for this purpofe, 



4 pile 



