that we
are not to look for the same law in every vortex, and it will,
therefore, appear as if the satellites of Jupiter, whose theory is so
well known, should render apparent any deviation between their periodic
times and the periodic times of the contiguous parts of the vortex,
which would obtain, if the density of the ether in the Jovian vortex
were not as the square roots of the distances directly. But, we have
shown how there can be a balance preserved, if the tangential resistance
of the vortex shall be equal and contrary at the different distances at
which the satellites are placed; that is, if these two forces shall
follow the same law. These are matters, however, for future
investigation.

LIGHT AND HEAT.

But will not the admission of a vorticose motion of the ethereal medium,
affect the aberration of light? It is well known that the question has
been mooted, whether the velocity of reflected light is the same as that
of direct light. The value of aberration having been considered 20".25,
from the eclipses of Jupiter's satellites, while later determinations,
from observations on Polaris, give 20".45. It cannot be doubted that
light, in traversing the central parts of the solar vortex, that is,
having to cross the whole orbit of the earth, should pass this distance
in a portion of time somewhat different to a similar distance outside
the earth's orbit, where the density is greater, and consequently induce
an error in the aberration, determined by the eclipses of Jupiter's
satellites. In the case of Polaris, the circumstances are more equal;
still, a difference ought to be detected between the deduced aberration
in summer and in winter, as, in the first case, the light passes near
the axis of the solar vortex, where (according to the theory) a change
of density occurs. This is an important practical question, and the
suggestion is worthy attention. Now, the question occurs, will light
pass through the rarefied space with greater velocity than through the
denser ether beyond? From recent experiments, first instituted by Arago,
it is determined that light passes with less velocity through water than
through air; and one result of these experiments is the confirmation
they give to the theory of Fresnel, that the medium which conveys the
action of light partly partakes of the motion of the refracting body.
This of itself is a strong confirmation of this theory of an ethereal
medium. It may also be remarked, that