ses are the hydrodynamic analogues of magnets having their opposite
poles presented to one another, and that bodies pulsating in opposite
phases are analogous to a presentation of similar magnetic poles; but
it will be seen at once that this cannot be the case if three magnetic
poles or three pulsating bodies be considered instead of only two. It
is clear, on the one hand, that three similar magnet poles will all
repel one another, while, on the other, of three pulsating bodies,
two of them must always attract one another, while a third would be
repelled; and, moreover, two similarly pulsating bodies set up around
them the same lines of force as two similar magnetic poles, and two
oppositely pulsating bodies produce lines of force identically the
same as those set up by two magnets of opposite polarity. Thus it
will be seen that there is a break in the analogy between the
hydrodynamical and the magnetic phenomena (if a uniform inversion
of the effects can be called a break, for it is, as far as Professor
Bjerknes' experiments go, without an exception); and if by any means
this inversion could be reinverted, all the phenomena of magnetism and
diamagnetism could be exactly reproduced by hydrodynamical analogues;
there would thus be grounds for forming a theory of magnetism on the
basis of mechanical phenomena, and a very important link in the chain
of the correlation of the physical forces would be supplied.

While the experiments of Professor Bjerknes upon pulsating and
rectilinearly vibrating bodies and their influence upon one another
illustrate by very close analogies the phenomena of magnetism, those
upon circularly vibrating bodies and their mutual influences bear a
remarkable analogy to electrical phenomena; and it is a significant
fact that exactly as in the case of magnetic illustration, the
analogies are direct as regards the phenomena of induction, and
inverse in their illustration of direct electrical action.

If we examine the figure produced by the field of force surrounding a
conductor through which a current of electricity is being transmitted
(see Fig. 1), we see that iron filings within that field arrange
themselves in more or less concentric circles around the conductor
conveying the current. From this fact Professor Bjerknes and his
son, reasoning that, to produce a similar field of energy around a
vibrating body, the vibrations of that body must partake of a
circular or rotary character, constructed