Page:The story of the comets.djvu/112

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74
The Story of the Comets.
Chap.

1884. discovered a small telescopic comet which was described by Tupman, a week later, as about 2' in diameter and possessing a stellar nucleus 3" in diameter; but it appears that Copeland, at Dunecht, found it by means of the spectroscope, independently, on Sept. 22. 1884.[1] At its next return this comet was probably first seen at Vienna by Spitaler on May 1, 1891, and certainly by Barnard at the Lick Observatory on May 3. Under the influence of Jupiter the orbit of this comet suffered a complete transformation in 1875, and we may now regard it as permanently attached to our system, for at its return in 1898 the error of the ephemeris of its movements computed beforehand was only 1" in R.A. and 4" in Declination. It was not seen in 1905, being unfavourably placed.

(10.) Holmes's Comet.

On Nov. 6, 1892, E. Holmes, at Islington, discovered a bright comet in Andromeda, which was also discovered independently on Nov. 9 by Davidson in Queensland. The comet was described by Holmes as 5' in diameter, and bright enough to be seen by the naked eye. The greatest theoretical brilliancy should have occurred in September, when the comet should have been rather brighter than on Nov. 6, and was well situated for observation in the Northern hemisphere. It is therefore remarkable that it should not have been detected sooner, but the explanation is no doubt to be found in the fact that the comet underwent great fluctuations of brilliancy during the time it was visible in the winter of 1892-3.

The most complete and interesting account of Holmes's Comet which we have is due to E. E. Barnard, whose observations and remarks[2] will now be given in a compressed form:—

"From several points of view it was one of the most remarkable comets ever observed.

At the time of discovery it was distinctly visible to the naked eye as a slightly ill-defined star of the 6th magnitude. The remarkable fact that
  1. Sid. Mess., vol. x, p. 288. June 1891. This would seem to be the only comet ever discovered by means of a spectroscope.
  2. Astrophysical Journal, vol. iii, p. 41. January 1896.