nter the field of its action in no way diminishes the
attraction it exercises on each of them respectively, a thing which is
seen nowhere else in nature.

Nevertheless it is possible, by means of certain hypotheses, to
construct interpretations whereby the appropriate movements of an
elastic medium should explain the facts clearly enough. But these
movements are very complex, and it seems almost inconceivable that the
same medium could possess simultaneously the state of movement
corresponding to the transmission of a luminous phenomenon and that
constantly imposed on it by the transmission of gravitation.

Another celebrated hypothesis was devised by Lesage, of Geneva. Lesage
supposed space to be overrun in all directions by currents of
_ultramundane_ corpuscles. This hypothesis, contested by Maxwell, is
interesting. It might perhaps be taken up again in our days, and it is
not impossible that the assimilation of these corpuscles to electrons
might give a satisfactory image.[28]

[Footnote 28: M. Sagnac (_Le Radium_, Jan. 1906, p. 14), following
perhaps Professors Elster and Geitel, has lately taken up this idea
anew.--ED.]

M. Cremieux has recently undertaken experiments directed, as he
thinks, to showing that the divergences between the phenomena of
gravitation and all the other phenomena in nature are more apparent
than real. Thus the evolution in the heart of the ether of a quantity
of gravific energy would not be entirely isolated, and as in the case
of all evolutions of all energy of whatever kind, it should provoke a
partial transformation into energy of a different form. Thus again the
liberated energy of gravitation would vary when passing from one
material to another, as from gases into liquids, or from one liquid to
a different one.

On this last point the researches of M. Cremieux have given
affirmative results: if we immerse in a large mass of some liquid
several drops of another not miscible with the first, but of identical
density, we form a mass representing no doubt a discontinuity in the
ether, and we may ask ourselves whether, in conformity with what
happens in all other phenomena of nature, this discontinuity has not a
tendency to disappear.

If we abide by the ordinary consequences of the Newtonian theory of
potential, the drops should remain motionless, the hydrostatic
impulsion forming an exact equilibrium to their mutual attraction. Now
M. Cremieux remarks that, as a matter of fact, they