178 C J. MERFIELD. 



Signor Cerulli succeeded in making several comparisons on the 

 date 1899 July 31, which is one of the latest observations published. 

 The comet was, on this date, described by the observer as a faint 

 nebula having a nucleus of about the 14th magnitude. 



Physical Aspects. 1 — During 1899 March, the comet appeared as 

 a nebulous mass some four or five minutes of arc in diameter, 

 with a central condensation. After perihelion passage however, 

 some interesting changes were noticeable. Mr. Perrine of the 

 Lick Observatory, saw the nucleus double and obtained measures 

 of their distance apart, during the period 1899 May 11 to May 14 

 the distance between the components increased from 12" to 18". 

 This increasing distance would appear to be partly due to an actual 

 separation of the two portions, but the writer has not examined 

 the question critically. Prof. Barnard of the Yerkes Observatory 

 also observed this aspect of the comet on May 20, and obtained 

 several measures until May 23, the distance between the com- 

 ponents increasing during this interval from 29 to 38 seconds of 

 arc. A photograph taken by this observer shews a slender tail 

 some eight degrees in length. 



On June 5th a considerable increase in brightness took place, 

 which was observed by many. Prof. Hartwig says, that there 

 was no doubt that the comet had increased in brightness about 

 this date, the magnitude of the nucleus being about 9*5, 

 while the comet as a whole being of the 5th magnitude, the 

 diameter of the coma being some 12 minutes of arc. Dr. Schorr 

 also says that on the same date the nucleus appeared to be excen- 

 trically placed, the magnitude being 6 5, whole comet 5th magnitude, 

 the diameter being 9 minutes of arc. Part of this increased 

 brightness may have been due to some physical change in the 

 mass, but it may be mentioned that the comet was nearest to the 

 earth on the date 1899 May 29, and the distance was not increas- 



1 Astronomische- Nachrichten, 3572-74-86. Astronomical Journal, 464. 

 Publications of the Astronomical Society of the Pacific.. 1899 August. 

 Bulletin de la Societe Astronomique de France 1899. Comptes Eendus, 

 1899. 



