PROGRESS OF ASTRONOMY FOR 1891 A\D 1892. G99 



dor eoiulitioiis altcniatcly raAOrablc and unfavorable tor oh.st'rviitiou. 

 Jt was ori<;inally discovered byTeuipel hi ISIJU, was picked up a.i;aiu iu 

 1880 by Swift, and again yi\nm this refurii by liarnard. At its iuter- 

 inediate returns iu 187;> and 1885 it was so situated witli rel'erenee to 

 tlie earth and sun as to have been entirely iu\isible. A very carefully 

 ]U'ei)ared ephemeris by IJossert, taking account of the i)ertnrbations 

 from 188(>, enabled Barnard to lind the comet on September 27, 181)1, 

 and it was imlejiendently Ibund by IJenniug at Bristol on September 

 '•'A). It was <lescribed as a faint, shai)eless nebulosity, with slight con- 

 densation about the center, but even at its brightest, towards the end 

 of November, it was a difficult object for precise observation, a fact 

 all tlu' more to be regretted as its position would render it of especial 

 value for the determination of the distance of the sun. 



Comet \Vinnecke: Winnecke's well-known i^eriodic comet was picked 



=Coniet mj-2 IV. I ^p ^t this return, through the help o\' von [laerdtl's 



ephemeris, by Spitaler at Vienna on March 18,1892; it was then an 

 exceedingly faint and small nebulous mass with stellar nucleus of the 

 sixteenth magnitu(h'. It increased in brightness towards i)erihelion 

 (on dune 30), and after perihelion was observed in the southern hem- 

 isphere till the end of Septend)er. 



Comet 188o IV,* v.hich was discovered by Brooks on May 22, 188(5, 

 was expected to make its lirst return to perihelion in the latter part of 

 18!»2, but was not found. The orbit is somewhat uncertain. 



Comet 1889 V. — To quote from the lirst of a series of masterly papers 

 on the oibit published by Mr. Chandler in the Astronomical Jourmd: 

 "The vicissitudes in the history of this comet give it an interest 

 exceeded, perhaps, l>y no other in astronomical annals; and the settle- 

 ment of the problems connected therewith promises to illuminate our 

 knowledge of cometary mechanics in various important particulars. 



While the manner in which the comet became vSei)arated into several 

 l)arts, by its encounter with Jupiter in 188(1, may possibly recjuire for 

 its precise exposition the observaticuis which will be obtained at the 

 next ai)i)(nirauce in 189(», we ma\ hope lor an ai)i)roximate answer in 

 the careful dis(;ussion of those made in 1889 alone. . . 



'Vo begin with, it is necessary to notice some of the ]diysical phe- 

 nomena 1 (resented by the comi)anions. The notation used will be the 

 letters assigned by Barnaid, />' (' J) and U in order of the distances 

 from the main comet J. As is known, B and C weic detected by him 

 on August 1, witli the 12 inch, /> and Eon Auv!:ust I, with the 3(!-inch. 

 It is desirable to remark here that tlie reason for their not having been 

 discovered in the i)revious month, on July 8, 9 and 10, can iH)t have 

 been superposition by perspective, at least in the case of C aiul the 

 more distant companions; for the orbit of C . . . shows that 



* See Smithsonian Report 1887, p. 123. 



