the real cause of the voltaic current. The results of them are
contained in twenty tables; and by comparing them with each other, and
also by means of additional experiments, the following general
conclusions and chief facts were obtained.

When metals in liquids are heated, they are more frequently rendered
positive than negative in the proportion of about 2.8 to 1.0; and
while the proportion in weak solutions was about 2.29 to 1.0, in
strong ones it was about 3.27 to 1.0, and this accords with their
thermo-electric behavior as metals alone. The thermo-electric order of
metals in liquids was, with nearly every solution, whether strong or
weak, widely different from the thermo-electric order of the same
metals alone. A conclusion previously arrived at was also confirmed,
viz., that the liquids in which the hot metal was thermo-electro-positive
in the largest proportion of cases were those containing highly
electro-positive bases, such as the alkali metals. The thermo-electric
effect of _gradually_ heating a metal in a liquid was sometimes
different from that of _suddenly_ heating it, and was occasionally
attended by a reversal of the current.

Degree of strength of liquid greatly affected the thermo-electric
order of metals. Increase of strength usually and considerably
increased the potential of metals thermo-electro-negative in liquids,
and somewhat increased that of those positive in liquids.

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° F. difference of