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hemisphere and found to be moving in almost the same orbit. The first sign which it gave of its approach was its long tail rising above the horizon. This was seen in the Argentine Republic, at the Cape of Good Hope, and in Australia. Not until the fourth of February did the head become visible. It swept around the sun, again passed to the south, and disappeared without observers in the northern hemisphere seeing it.

The question now arose whether this could possibly be the same comet that had appeared in 1843. Previously it had been supposed that when two such bodies moved in the same orbit with a long interval between they must be the same. In the present case, however, the hypothesis of identity seemed to be incompatible with the observations. The question was set at rest by the appearance in 1882 of a third comet moving in about the same orbit. This certainly could not be a return of the comet which had appeared a little more than two years before. The remarkable spectacle was therefore offered of three bright comets all moving in the same orbit at varying intervals of time. Possibly there were more even than these three, for, in 1680, a comet had passed very near the sun. Its orbit, however, was somewhat different from those of the three comets already mentioned.

The most probable explanation of the case seems to be that these comets were parts of some nebulous mass which gradually broke up, its different members pursuing their courses independently. The result would be that, for many ages, the objects would all continue in nearly the same orbit.