On the Electromotive Force of Alloys. 435 
between successive kinetic foci, in the absence of reflecting or 
refracting- surfaces, and so forth. Nevertheless he who has 
realized the omnipresence and all-powerfulness of a maximum- 
principle in one form or another, both in the physical and the 
moral sciences, and who is persuaded of the harmony of those 
sciences, will not hastily abandon the conjecture that in the 
correspondence between maximum energy and greatest pos- 
sible happiness is to be sought the first principle of Psycho- 
Physics. 
LXIII. On the Electromotive Force of Alloys. 
By John Tkowbbidge and E. K. Stevens.* 
THE best study of alloys and the most thorough work on 
them has been done by Matthiessen, who proved con- 
clusively that alloys were neither mechanical mixtures nor 
chemical compounds, but what he terms, in a general way, 
" a solidified solution of one metal in another." He also 
showed that, with reference to the formation of alloys, metals 
were divided inlx) two classes — the first class being those 
which, when alloyed with each other, give a conductivity in 
proportion to the respective volumes of the two metals ; and 
the second those which, when alloyed with each other, give 
a conductivity which is less than that of the respective volumes 
of the two metals. 
The aim of this investigation has been to note the variation 
of electromotive force in different alloys of the same metals 
and to deduce, if possible, some general law which governs 
the variation. 
Two sets of alloys were used — one set of lead and tin, and 
the other of copper and zinc. The first set was made by 
taking the proportional weights of lead and tin, and melting 
them together in a crucible, and then pouring them out on a 
flat surface and allowing them to cool. The second set was 
made by melting a weighed amount of copper in a Fletcher 
gas-furnace, and, when in a molten state, adding more than 
the required amount of zinc, in order to make allowance for 
volatilization. Pure metals were obtained, in order that the 
results might be as accurate as possible. 
It was deemed sufficient, as far as the lead and tin alloys 
were concerned, to weigh out carefully the required amounts 
of each metal, and to take those weights as showing tb.3 com- 
position. This could not be. done with the copper- and zinc 
alloys, as it is impossible to determine how much of the zinc 
* Proceedings of the American Academy of Arts and Sciences, vol. xviii. 
(May 29, 1883). 
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