122 EECORD OF SCIENCE FOR 1886. 



a very interesting series of photometric observations of this comet and 

 of the comet discovered by Barnard on December 3, 1885. The observa- 

 tions extended over the months of March and April, 1886 j and both 

 comets were increasing in brightness. Eeducing the measures to a dis- 

 tance unity, the intrinsic brilliancy seems to have been tolerably con- 

 stant; from which it m^j be concluded that the comets shone almost en- 

 tirely with borrowed light. This conclusion is confirmed by Dr. Miiller's 

 spectroscopic observations, according to which the continuous spectrum 

 predominates. Trepied, on the other hand, found that in Fabry's comet 

 the proportion of reflected sunlight was small, gaseous elements pre- 

 dominating and the bands being much brighter than the continuous 

 spectrum. Dr. Miiller remarks that his observations show no effect of 

 phase, and he suggests that this may be due to a variation in the in- 

 herent light of the comet as it approaches the sun and earth, or we may 

 assume that the nucleus is made up of discrete particles by which the 

 phase phenomena must to a great extent be modified. 

 Comet 1886 II : I A brief account of this eomet was given last year, 



=Coiiiet e 1885. as it was discovered by Barnard on December 3, 



^Baruartrs comet. | ^^^^^ ^jj.|^ ^ G-inQh Cooke equatorial. A small tail 

 about 15' long was detected by Tempel as early as December 31. In 

 April and May the comet developed into quite a fine object with stellar 

 nucleus and fan-shaped tail, 2° or 3^ in length. It was seen with the 

 naked eye on May 7 and 12 by Mr. Barnard, at Nashx ille, and on May 

 31 and June 3 by Mr. Tebbutt, at Windsor, New South Wales. The 

 last observation published was made on July 19, at Cordoba. A care, 

 ful series of " extinction observations " is given by Dr. Holetschek in 

 the ISTach rich ten, No. 2739. The spectroscope showed the three ordi- 

 nary cometarj" bands, with faint, continuous spectrum of the nucleus. 



The latest elements computed by Thraen from observations between 

 December 5, 1885, and May 10, 1886, place perihelion passage on May 

 3, and give a slightly hyperbolic orbit (eccentricity=1.0004). Whether 

 the curve really differs from a parabola can not be decide 1 until all the 

 observations, including those from southern observatories, can be taken 

 into account. Morrison has obtained hyperbolic elements agreeing 

 tolerably well with those of Thraen. Earlier elements showed a slight 

 resemblance to comet 1785 ii, but it is not probable that the comets are 

 identical. 

 Comet 1886 III: 



=Comet h 1886. 



=Comet 1886 .... (Brooks 2) 



This was discovered by Mr. W. R. Brooks, 

 at Phelps, New York, on April 30, 1886, or 

 in civil reckoning on the morning of May 

 1 ; his second comet within four days. Mr. Brooks described it as hav- 

 ing a small but bright and star-like head, and a conspicuous tail. (Jn 

 May 4 there was a tail 10' or 12' long; very bright near the origin. 

 Engelhardt, on May 6, found the tail 40' long and nearly straight, while 

 8' from the nucleus there was a faint secondary tail bending towards 

 the south. Pechiile, observing from May 3 to May 12, detected two 



