The history of science proves how few have practically respected the
adage of the ancients, which we have chosen for our motto; words which
ought to be written in letters of gold in every language under the sun.
Descartes, by considering the mechanical impulse of the ether sufficient
to explain the planetary motions, failed to detect the force of gravity
in the heavens. Newton, on the other hand, feeling that his law was
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.