Page:The story of the comets.djvu/117

January 24. On the moonlit sky, the comet, in the 12-inch, appeared to be about 1' in diameter—its greater portion being lost in the brightness of the sky. There was no nucleus. With the finder the comet appeared rather bright and cometary—like a large and conspicuous nebula. After this, absence from the Observatory prevented the comet from being followed further."

Photographs of the comet were made: the most interesting and important of these was the one made on November 10. but Barnard remarks:—

"That the central, well-defined body of the comet has been lost in the half-tone, the outline shown being that of the diffused haze surrounding the comet proper. The nebulous appendage, however, is fairly well shown. . . .

There is one other thing that this photograph shows (and which seems to have been generally overlooked) that must sometime be of the highest importance in the solution of the mystery surrounding this extraordinary object. To the south-east of the comet, distant about one degree or so, is shown a large irregular mass of nebulosity covering an area of one square- degree or more, and noticeably connected with the comet by a short hazy tail. Evidences of this diffused nebulosity had been seen when examining the region about the comet with a low power on the 12-inch. This very extraordinary appendage deserves the earnest attention of those who are at all interested in this comet."

On Jan. 18, 1893, Palisa found the comet to shine as a star of the 8^th mag. surrounded by a nebulosity no more than 20" in diameter. The striking variations which this comet under- went would seem to explain the fact that it had remained undetected at previous apparitions, for it is now a recognised short-period comet fully entitled to a place on the regular list. It returned in 1899, passing through perihelion on April 13, and discovered by Perrine at the Lick Observatory on June 10, shining as a star of the 6^th mag. It returned again in 1906, passing perihelion about the middle of March, but it was very faint, and seen only in some of the largest telescopes in the world. It has been thought that Holmes's Comet not improbably belongs to a family of which the lost Di Vico is a member. Its sudden outburst of brilliancy at the time of its first discovery in Nov. 1892 would seem to have been an incident in the comet's history without precedent, so far as we know, and one which has never been repeated. Holmes's Comet has the least eccentric orbit of any of the comets moving in elliptic