The sector or fan, so well seen in the comet which lately (1861) burst upon us with such astonishing brilliancy, is the form which the gush of luminous particles assumes under some unknown repelling power. The revolution of the comet is determined by the laws of gravitation, but there are perplexing movements in the tail and nucleus, which likely will receive an explanation from this rocket-like action.
We have, however, to do at present, not with the theory of the constitution of the comet, but with its character, as a vehicle for surveying the solar system. We may be pardoned in using it as a vehicle for our imagination, when some advocates for the plurality of inhabited worlds have gravely argued, that the most ethereal comets may have their inhabitants—that even each particle may have its adhering element of life. An inexorable logic has driven them to this conclusion, from the assumed position, that the very matter of planets, apart from their proved adaptation, implies life. The densest comet would afford but insecure footing to beings of almost spiritual essence, as the matter of which it is composed must be so light that the atmosphere of our earth is as lead compared to it. But we shall overlook this difficulty, and venture, in thought, to follow the fortunes of some cometic wanderer. The difficulty of reaching some suitable comet, is lessened by the consideration that the comet may come to us. It has been surmised that the above comet touched at our earth, as one of its stations, in
