If the body is heavier than water its motion is less than that of the
liquid, and, consequently, relatively to the vibrating body, it is of
like phase; and if it is lighter, the contrary takes place, and the
phases are in discordance. These effects may be very well verified by
the aid of the little apparatus shown in Fig. 5, and which carries two
bars, one of them lighter and the other heavier than water. On
presenting to them the vibrating body, one presents its extremity and
takes an axial direction, while the other arranges itself crosswise
and takes the equatorial direction. These experiments may be varied in
different ways that it is scarcely necessary to dwell upon in this
place, as they may be seen at the Electrical Exhibition.

[Illustration: FIG. 5.]

Very curious effects are also obtained with the arrangement shown in
Fig. 6. Between the two drums there is introduced a body sustained by
a float such as represented at a, Fig. 4. Various results may, then,
be obtained according to the combinations adopted. Let us suppose that
the phases are alike, and that the interposed body is heavier than
water; in this case it is repelled as far as the circumference of the
drums, at which point it stops. If the phases are different, the
influenced body behaves in the opposite manner and stops at the
center. If the body is lighter than water the effects are naturally
changed. Placed between two like phases, it is attracted within a
certain radius and repelled when it is placed further off; if the
phases are unlike, it is always repelled. We may easily assure
ourselves that these effects are analogous to those which are produced
on bodies placed between the poles of wide and powerful magnets. It
is useless to repeat that the analogies are always inverse.