."iOS 



RErouT — 1884. 



tit!" 



■dj' 



i^tibtract Pol tier forces fi-om tlio observed numbers before comparing tbcm 

 with theory, but those forces are too small to mako any appreciable 

 <i'.i (Terence. 



Vol ill Effects in Air. 



The alternative calculated nnmbor sometimes given is merely to show 

 I lie kind of variation probable in those cases from uncertainty of data. 

 in each case of agreement the calculated number is a little higher than 

 the observed, as -was to bo expected. Xo i-cason occurs to me for the 

 breakdown, and apparent interchange, iu the case of lead and iron but 

 such vague guesses as may occur to everyone. 



Measurements of the E.M.F. between clean metals plunged into dis- 

 tilled water or weak acid have been made by Clifton and by Bcetz.' I 

 suppose one is justified in calling them — 



Volta Effects in Water. 



I do not wish to blink the fact that some of the numbers in the former 

 •of the above tables afford a rather poor sui)port to my theory; but it must 

 be remembered, on the other hand, that they are not relative numbers 

 ■only that we have calculated, but aKsolate; and the fact that the heats of 

 •combustion reduced to volts are numbers of the same order of magni- 

 tude as the Volta effects, is of itself a strong confirmation of the belief 

 that chemical strain at the air contacts is the real cattse of the apparent 

 "Contact force at the junction of two metals. 



" Beetz, Ann. dvr r/uj.v/.; x. :U8, 1880. 



