Comets of Short Period

Abstract

IT is now generally accepted that the periodic comets of our system did not originate in it, but are bodies captured from outer space by one of the planets, the parabolic orbits in which they approached the system being transformed into elliptical ones. On account of the perturbing action of Jupiter, however, the orbits of short-period comets are liable to considerable modifications, and it is practically impossible to identify two apparitions of the same cornet without laborious computations of the perturbations which it must have been subjected to be tween the two epochs. But even such computations may lead to a negative result, for frequently comets quite distinct have elements very much alike, probably because they are parts of an old comet travelling along the same orbit at greater or less intervals.