us, the _cyclostat_
(Fig. 4), which, opposite the prism, has a second plate whose
actuating wheel is mounted upon the same axis as the first, the
gearing being so calculated that the prism shall revolve with twice
less velocity than the second plate. This latter, observed through the
prism, will be always seen at rest, and be able to serve as a support
for the object that it is desired to examine.

[Illustration: FIG. 4.--THE CYCLOSTAT.

1. General view of the apparatus.
2. Section of the ocular, O.]

The applications are multitudinous. In the first place, in certain
difficult cases, it may serve for the observation of a swinging
thermometer, which is then read during its motion. Then it may be
employed for the continuous observation of a body submitted to
centrifugal force. Apropos of this, we desire to add a few words. Most
of the forces at our disposal, applied to a body, are transmitted from
molecule to molecule, and produce tension, crushing, etc. Gravity and
magnetic attraction form an exception; their point of application is
found in all the molecules of the body, and they produce pressures and
slidings of a peculiar kind. But these forces are of a very limited
magnitude; but it might nevertheless be of great interest to amplify
them in a strong measure. Let us, for example, suppose that a magician
has found a means of increasing the intensity of gravity tenfold in
his laboratory. All the conditions of life would be modified to the
extent of being unrecognizable. A living being borne in this space
would remain small and squat. All objects would be stocky and be
spread out in width or else be shattered. Viscid or semi-solid bodies,
such as pitch, would rapidly spread out and take on a surface as
plane and smooth as water under the conditions of gravity upon the
earth. On still further increasing the gravity, we would see the soft
metals behaving in the same way, and lead, copper and silver would in
turn flow away. These metals, in fact, are perfectly moulded under a
strong pressure, just like liquids, through the simple effect of the
attraction of the earth applied to all their molecules. Upon causing
an adequate attractive force to act upon the molecules of metals they
will be placed under conditions analogous to those to which they are
submitted in strong presses or in the mills that serve for coining
money. The sole difference consists in the fact that the action of
gravity is infinitely more regular, and p