The electric potential of metals, thermo-electro-positive in weak
liquids, was usually about 3.87 times, and in strong ones 1.87 times,
as great as of those which were negative. The potential of the
strongest thermo-electric couple, viz., that of aluminum in weak
solution of sodic phosphate, was 0.66 volt for 100 deg. F. difference of
temperature, or about 100 times that of a bismuth and antimony couple.
Heating one of the metals, either the positive or negative, of a
voltaic couple, usually increased their electric difference, making
most metals more positive, and some more negative; while heating the
second one also usually neutralized to a large extent the effect of
heating the first one. The electrical effect of heating a voltaic
couple is nearly wholly composed of the united effects of heating each
of the two metals separately, but is not however exactly the same,
because while in the former case the metals are dissimilar, and are
heated to the same temperature, in the latter they are similar, but
heated to different temperatures.
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