bottom of the porous vessel gets above the jets, the internal
diffusion ceases and the hydrogen becomes diffused externally, the
internal pressure diminishes, and the vessel descends. The vessel then
comes opposite the jets of hydrogen and the same motion occurs again,
and soon indefinitely. The work produced by this motor, which has
purely a scientific interest, is very feeble, and much below that
assigned to it by theory. In order to obtain a maximum, it would be
necessary to completely surround the porous vessel each time with
hydrogen, and afterward remove the jets to facilitate the access of
air. All the mechanical arrangements employed for obtaining such a
result have failed, because the friction introduced by the maneuvering
parts also introduces a resistance greater than the motor can
overcome. There is therefore a waste of energy due to the continuous
flow of hydrogen; but the apparatus, for all that, constitutes none
the less an original and interesting device.--_La Nature._

* * * * *




SOME RELATIONS OF HEAT TO VOLTAIC AND THERMO-ELECTRIC ACTION OF METALS
IN ELECTROLYTES.[1]

[Footnote 1: Read before the Royal Society, Nov., 1883.]

By G. GORE, F.R.S., LL.D.


The experiments described in this paper throw considerable light upon