ASTRONOMY FOR 1889, 1890. 133 



A remarkable star of the Algol type, having- the shortest period 

 iciiown, was discovered iu 1888 by Prof. U. M. Paul, of tbe IT. S. Naval 

 Observatory. The star is 12 Autlia^ of Gould's LJrauouietria Argentina, 

 a=9'^ 20™ 00% 0= — 28° 4.7 (1875.0). The rauge of magnitude is 6.7 to 

 7.3, and acjcording to Oliandier it }i;oe3 tlirough its changt-s iu o'' 20'". 



From au examiuatiou of one of the photographic phites takeu by the 

 Harvard observatory party, at the Chosica station iu Peru, Professcu' 

 Pickering' has anuounced the discovery of a long-period variable in 

 Caelum of the same chiss as O Ceti, R Hydr;e, and U Leonis. The 

 spectra show bright hydrogen lines. 



A number of other uew variabh\s have beeu detected in the exami- 

 uatiou of the ])hotogra[)hic plates taken at the observatory, and have 

 beeu auuouuced by Professor Pickering iu the Astroncmiisiihe Nacli- 

 richteu. iSome atteution has also beeu paid to tliissul)ject by Dr. J. C. 

 Kapteyu iu measuring the phites takeu at the Ca()e of Good Hope for 

 the formation of Dr. Gill's photographic southern .Durvhmuslerun</, and 

 also by Mr. Roberts iu the prosecution of his work iu astronomical pho- 

 tography. 



A general index to observations of variable stars, prepared under 

 the direction of Prof, E. C. Pickering, forms No. 8 of Vol. 18 of the Har- 

 vard Annals. A large nutuber of unpublished observations are referred 

 to, particularly three extensive series of observations by Argelander, 

 Heis, and Schmidt, to whose manuscripts access was given. 



A new edition or rather revision of BirmiiKjhani's Red Star Catalogue 

 has beeu printed iu No. v of the Cunningham Memoirs of the lioyal 

 Irish Academy. The work of revision was uudertakeu by Pev. T. E. 

 Espin in 1880, with the 17:^-inch equatorial reflector, and iu the course 

 of the work a number of uew red stars, new variables, aud stars with 

 bright lines in their spectra were discovered. There is also au addi- 

 tional list of 029 " ruddy stars." 



STELLAR SPECTRA. 



Spectrum of C, Ursw Majoris. — Professor Pickering has reported a re- 

 markably interesting peculiarity in the spectrum of this star. It was 

 noticed that the Kline was double in the photographs taken March 21), 

 1887, May 17, 1889, and August 27 aud 28, 1889, while on many other 

 dates the line appeared hazy as if the components were slightly sepa- 

 rated, and at other times the line was well defined and single. It was 

 concluded that the line was double at intervals of 52 days beginning 

 March 27, 1887, and it Avas pjedicted that the doubling would occur 

 again on December 9, 1889, aud this prediction was confirmed by each 

 of three photographs on the latter date. Professor Pickering says : 



"Theoidy satisfactory exi)lanatiou of this phenomenon as yet pro- 

 posed is that the brighter component of this star is itself a double star 

 having components nearly equal in brightness and too close to have been 

 separated as yet visually. Also that the time of revolution of the sys- 



