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 these different classes of objects. Those who hold this view urge that a shower of shooting- stars is merely the aggregation on a grand scale of the isolated or sporadic shooting- stars which are always more or less to be seen, and they affirm that between these occasional shooting stars and the mightiest fire-ball there is a perfect continuity, exhibited by the fact that shooting-stars of every gradation of lustre are from time to time observed. They are thus led to regard meteorites as congenerous with the objects which appear in shooting-star showers. In this inference I am convinced that a serious mistake has been made.

One of the most important results of the great shower of 1866 was the demonstration that the swarm of little bodies to which that shower owed its origin was connected with a comet. The swarm was found in fact to follow the exact track which the comet pursued round the sun. So remarkable a coincidence could not reasonably be accounted for on any other supposition than that the meteors, if not themselves actual fragments of the comet, were at all events so closely connected with it, that they could not have come from any source very different from that in which the comet itself took its rise. This remarkable discovery made with regard to the Leonids may be illustrated and confirmed by similar discoveries of a cometary association in the case of other notable meteoric displays. Probably one of the most remarkable episodes in the whole of this branch of astronomy is connected with Biela's comet. It was known that the body so named revolved in a certain orbit, and a highly dramatic proof was rendered that a shoal of meteors were its fellow-travellers along the same path. As, however, I have discussed this episode