The four outstanding meteor radiants are those named, but there are very many others. Mr. Denning, to whom this branch of science owes so much, estimates the number of distinct radiants known at about 4,400; and it seems likely that every one of these showers, some of them, of course very feeble, represents some comet deceased. The history of a meteor shower would appear to be something like this: When the comet, whose executor it is, has but recently deceased, it will appear as a very brilliant periodic shower, occurring on only one or two nights exactly at the point where the comet in its journeying would have crossed the earth's track, and appearing only at the time when the comet itself would have been there. Gradually the meteors get more and more tailed out along the orbit, as runners of unequal staying powers get strung out over a track in a long race, until the displays may be repeated, with somewhat diminished splendour, year after year for several years before and after the time when the parent comet is due. At last they get thinly spread out over the whole orbit, and the shower becomes an annual one, happening each year when the earth crosses the orbit of the comet. This has already happened to the Perseid shower; at least 500,000,000 miles of the orbit of Biela's comet are studded with representatives of the Andromedes; and the Leonid shower had already begun to show symptoms of the same process at its appearance in 1866. Readers will remember the disappointment caused by the failure of the Leonid shower to come up to time in 1899, and it seems probable that the action of some perturbing cause has so altered the orbit of this shower that it now passes almost clear of the earth's path, so that we shall not have the opportunity of witnessing another great display of the Leonid meteors. So far as is known, no member of one of these great showers has ever fallen to the earth. There are two possible exceptions to this statement, as in 1095 a meteor fell to the ground during the progress of a shower of Lyrids, and in 1885 another fell during a display of the Andromedes. In neither case, however, was the radiant point noted, and unless it was the same as that of the shower the fall of the meteor was a mere coincidence. It seems probable that this is the case, and the absence of any evidence that a specimen from a cometary shower has reached the earth points to the extreme smallness of the various members of the shower and also to the fine division of the matter of the original comet.