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VI. being visible. But it is possible that this failure may have been due to the faintness of the nucleus at that apparition. The observations did not favour the probability of the comet being identical with Lexell's, as was first thought. In 1903 this comet was again in perihelion and was discovered by Aitken at Lick on Aug. 20. The greatest diameter was about 3', and the brilliancy that of a 14th mag. star. The steady diminution in the brightness of this comet is so marked that it is hazardous to predict its future. At its last return in 1903 it was so much more faint than at its previous apparitions that it was only visible in some of our largest telescopes. It is due to return in 1910 and again in 1917. Shall we see it? Perhaps we shall: perhaps we shall not. But if we do see it on either of these 2 occasions it will still be leading a threatened life, for in 1921 it will again approach very close to Jupiter, and very likely that may end its career; or if not, it will certainly lead to a serious transformation of its orbit.

After Encke's Comet, Faye's may be regarded as the best-known and most regular of the short-period comets. It was discovered by Faye at the Paris Observatory on Nov. 22, 1843, in the constellation Orion. It exhibited a bright nucleus with a short tail, but was never sufficiently brilliant to be seen by the naked eye. That the comet's path was an ellipse, and the comet itself therefore a periodical one, seems to have been soon suspected by several astronomers, but to Le Verrier is due the credit of having exhaustively investigated its orbit. He showed that the comet came into our system at least as far back as the year 1747, when it suffered much perturbation from Jupiter; and that its next perihelion passage would occur on April 3, 1851. It was rediscovered by Challis on Nov. 28, 1850. O. Struve described it under the date of Jan. 24, 1851, as having a diameter of 24". During the whole of this apparition it scarcely exhibited any signs of nucleus or tail. Faye's Comet returned in due course, and was seen in 1858, 1866, 1873, 1880, 1888, and 1895, but it was missed in