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200 it has been attached to the solar system; and if it is really of cometic origin, the longer is the time that has elapsed since the catastrophe happened to the comet. As the Perseids are a very scattered group, perhaps they have been long in our system; but the Leonids and the Andromedes may be much more modern introductions if weight is to be attached to Le Verrier's conclusion that it was a rencontre of Tempel's Comet of 1866 (i.) with the planet Uranus, in the year 126, which brought that comet under the permanent influence and control of the Sun.

From what has gone before it will be readily realised that the two great meteor showers of November (12th and 27th as they may be summarily styled) are very certain in their cometary relations, but the same cannot be said in quite such positive terms of the Lyrid shower of April, nor of the Perseid shower of August. In the two first-named instances the periodical returns of the meteors yielding special displays have occurred at the predicted times, and the periods of revolution of comets and meteors respectively are clearly identical. But the same cannot be affirmed of the April and August systems, because the periods are open to considerable uncertainty owing to the orbits being of far greater eccentricity.

Kirkwood is responsible for the definite statement of another comet-meteor alliance. He says:—"The identity of the comets of 1866 [i.] and 1366, first suggested by Professor H. A. Newton, is now unquestioned. The existence then of a meteoric swarm, moving in the same track, is not the only evidence of the original comet's partial dissolution. The Comet of 1866 was invisible to the naked eye; that of 1366, seen under nearly similar circumstances, was a conspicuous object. The statement of the Chinese historian that 'it appeared nearly as large as a tow measure', though somewhat indefinite, certainly justifies the conclusion that its magnificence has greatly diminished during the last 500 years. The meteors moving in the same orbit are doubtless the products of this gradual separation."

How far we are justified in generalising on the whole