ELECTllOMOTIVE FOllCES IN THE VOLTAIC CluI.L. 



igs, and 



ing HCl 



He also 

 at there 

 d with ii 

 3CS oil to 

 responds 

 ordinury 

 c plate is 

 itive. If 

 station ol" 

 lierc is no 

 gas pvo- 

 m on the 

 3 probably 

 surface of 



condenseil 

 svhieh may 

 these iilra-^ 

 11 is ncces- 

 )lta cftect is 

 touched all 

 r, he lays it 

 mieal action 

 at once tlic 

 lim, but liiii 



,n— the very 

 Volt a ciTcot 

 ;, or whether 

 icnta on tlm 

 those points 

 For if hy 

 Ave result or 

 |es, of course, 

 or chloride, 



ythii)'-?.' 1'' 

 istitule sorao 

 you hiivpn't 

 png ?i:indirg' 

 [mfthat youv 

 h yos, it 1^ 



Las •('"'(■■'' esta- 



fetal /iiir' con- 



[jrras contact 



force on tlic 

 teality. ""■'■^; 



dancer' ; <"»' 



Itact force at 



any given locality lias the value ordinarily assigned to it as the I'csult of 

 experiment. 



The earliest attempt made to examine the question as {n whether the 

 \'olta effect deijcnded on the atmosphere wiis made by I'i'all ' in IS'lV, who 





Fig. ;t.--rcllat's Apparatus for oxpeninenting in different Ga.-cs ;in(l ;it diU'oicrit 



rrcssurcs. 



he. lins sinto nuide a smaller nrran^eiuciit cf 1 litre ciipiU'ity, with pl.itcs D'ceiitiiiu'tns 

 •liaineter, nnd, what is luoic iinportnnt, with the elect riniia;:int outside, and iKithiui; iii.-iili> 

 Imt j^lass, iniea, and metal. In this the jjressure j^oes down to a niillinu'tre. ifut even 

 this is not all that eouUl he wished. Moreover tlic cxiicriuients de-seribed li;id heeu made 

 with the larii;er apparatus. 



ua'd dry and damp air, oxygen, nitrogen, liydrogen.carbu retted liydrogen, 

 and carbonic acid, and ho found that there was no difference so lone as 

 no visible chemical action occurred; but it must be noted that the oppo-siii-r 

 faces of his plates were varnished. De la Hive, on the other hand, asserted 



' I'fivff : An». de Chlm., 2 .scr. xli. 23C. The metals be employed were copper, tin, 

 and zinc. 



