sufficient to explain them, and requiring a vacuum for its mathematical
accuracy, rejected the notion of an ethereal medium. His successors,
following too closely in his footsteps, and forgetting the golden law,
have forced themselves into a position by no means enviable. The
short-period comet has driven them to a resisting medium, which, while
according to Encke's hypothesis of increasing density around the sun, it
explains the anomalies of one periodical comet, requires a different
law of density for another, and a negative resistance for a third.


OUTLINES OF THE PROBLEM.

From the position we now occupy, we can see the outlines of the problem
before us, viz.: To reconcile the existence of an ethereal medium with
the law of gravitation, and to show the harmony between them. We shall
thus occupy the middle ground, and endeavor to be just to the genius of
Descartes, without detracting from the glory of Newton, by demonstrating
the reality of the Cartesian vortices, and by showing that the ether is
not affected by gravitation, but on the other hand is _least dense_ in
the centre of our system. But what (it may be asked) has this to do with
the theory of storms? Much every way. And we may so far anticipate our
subject as to _assert_ that every phenomenon in meteorology where force
is concerned, is dependent on the motions of the great sea of electric
fluid which surrounds us, in connection with its great specific,
caloric. If we are chargeable with overweening pretensions, let it be
attributed to the fact that for the last fifteen years we have treated
the weather as an astronomical phenomenon, calculated by simple formulæ,
and that the evidence of its truth has been almost daily presented to
us, so as to render it by this time one of the most familiar and
palpable of all the great fundamental laws of nature. True, we have