124 RECORD OF SCIENCE FOR 1886. 



in diameter, with some central condensation, and no tail." The pos- 

 sible identity with " De Vico's lost comet," 1844 I, (for which Briiu- 

 now found a j^eriod of 5.5 years), immediately attracted attention, and 

 elliptic elements have been calculated by Boss, Krueger, Oppenheim, 

 and Holetschek. The computation of the orbit presents some difficul- 

 ties, and it is impossible to settle the question of identity until all ob- 

 servations -at this return have received a thorough discussion — if it can 

 be settled then. The last set of elements obtained by Professor Boss 

 (Astron. Journ., v. 3, p. 43) place perihelion passage on November 22, 

 188G, and give an approximate period of 6.675 years. With this period 

 the comet, if undisturbed, should return to the sun in Jul}', 1893, under 

 conditions quite favorable for observation. It is still visible, nearly 

 live months after discovery. 



Comet 188G YIII: A faint, telescopic comet was fouud by Barnard 

 = Comet c lSd7.- at Nashville on January 23, 1887 (the morning of 



=: Barnard's comet. , January 24 in civil reckoniug), which proved to 

 have passed perihelion on November 25, 1886, and it therefore takes 

 a place preceding the comet discovered by Barnard on October 4. As 

 it was receding from the earth and the sun, it mpidly grew fainter. 

 Perihelion distance obtained by Weiss was 1.4 times the mean distance 

 of the earth from the sun. 



Comet 1886 IX: 

 = Comet/ 1886. 



=^ Comet 1886/ (Barnard, October 4). 

 = Comet 1886.. ..(Barnard-Hart wig). 



This comet was discovered by E. 

 E. Barnard, at Nashville, Tenn., on 

 October 4, 1886 (or morjiing of Oc- 

 tober 5). It was also discovered in- 

 dependently by Dr. E. Hartwig at the Bamberg Observatory on Octo- 

 ber 5, and by Dr. C. F. Pechiile, at Copenhagen, on October G. It 

 was an easy object in the telescope, and developed a tail early in 

 October. By October 29 the nucleus was as bright as a star of the 

 eighth magnitude, and the comet was visible to the naked eye as an ill- 

 defined spot. Two distinct tails were detected about this time, and 

 Barnard fouud a third on November 23. The comet was now easily 

 seen witb the naked eye, as conspicuous as a star of the fourth magni- 

 tude, with a slender train traceable for 7° or 8°. The tail seems to 

 hav^e reached a maximum length of about 10° during the first week of 

 December, the theoretical brightness of the comet being then about 

 twenty-five times that at discovery. 



Eicco, of Palermo, found the spectrum composed of the three hydro- 

 carbon bands, of which the middle one (green) was longest and bright- 

 est. The spectrum of the nucleus was continuous, but re-enforced at 

 the bright bands. 



Elements computed by Lieutenant Allen from observations reaching 

 to December 10 show that perihelion was passed on December 16, 1886. 

 No deviation from a parabola is indicated. 



