J-iacriodciivifi/ of Metals generally. 



349 



Denoting the metal effect for zinc by x iind tluit for copper 

 by y, and the Volta effect for the two metals by V, we have 



Limiting Potential 

 (millivolts). 



V + ./; = 527, 



V - ^ = 304, 



X = 160, 

 ^= 73, 



from which we obtain the values 367 and 377 millivolts for 

 the contact difference of potential for the metals zinc and 

 copper, an agreement sufficiently close to confirm our 

 hypothesis. 



Similar measurements have been made with all combinations 

 of the metals aluminium, zinc, lead, tin^ and copper, taken in 

 pairs, with uniformly close results, but the Volta effects obtained 

 in this way were in every case proportionately less than the 

 generally accepted values. 



As an additional illustration of these measurements, the 

 curves representing the results obtained v/ith an inner 

 cylinder of lead and an outer of each of the metals are 



560 



















!/«. 



^//?i 



"/^^^ 



1^ 



S20 









^ 



^-^ 

















•'^eo 







/ 



/ 



















^ 



Jk <:.«& 







/ 

























/ 

























/ 























520 





/ 























^50 





/ 

























] 



^^ 









,u 



^cf/ 



7 77/7 









2^^ 











\ 



/ 



y^ 







> Z< 



'<3k/; 



r?U 



<7C/ 









.a-- 



,/^ 









/CO 



k 



r 











./J 



'0^/> 



tZ'// 



*r 









/'/: 



■S"^ 









,.J 



!s///7 



A.J.' 



7//7//y 



77 





/-jj 











LJ 







\/ 























-fC 



i 























V 1 





















3 -/ 





shown in fig. 4. Combining the limiting potentials of 

 these with the metal effect for lead, 216 millivolts, the 



