the fact that the result of such motions was the production of regular
mechanical actions. He calculated the directions of these, and, along
about 1875, perceived the possibility of reproducing the effects of
permanent magnetism. More recently, in 1879, he saw that magnetism by
derivation might likewise be explained by those hypotheses, and
figured by actions of this kind. It was not till then that he
performed the experiments, and submitted a body to the results of
calculation.

The same process has led him to the conclusion that the action of
currents might be represented in the same manner; only, instead of
bodies in vibration, it would require bodies in alternating rotation.
The effects are much more difficult to ascertain, since it is
necessary to employ viscid liquids.

Meanwhile, the experiments have been performed. Up to the present time
attractions and repulsions have not been shown, and I do not know
whether Mr. Bjerknes has obtained them. But, by the process pointed
out, the lines of action (electric phantoms, if I may so express
myself) have been traced, and they are very curious. By supposing the
current perpendicular to the plate, and in the presence of the pole of
a magnet, the influences produced around it are very well seen, and
the figures are very striking, especially in the case of two currents.
Mr. Bjerknes does not appear as yet to have obtained from these
experiments all that he expects from them. And yet, such as they are,
they have already led him to important conclusions. Thus, calculation,
confirmed by application, has led him to renounce the formula proposed
by Ampère and to adopt that of Regnard as modified by Clausius. Is he
right? This is what more prolonged experimentation will allow to be
seen.