OF ABTri AND SCIENCES. 393 



XVII. 



OBSERVATIONS OF VARIABLE STARS IN 1884. 

 By Edward C. Pickerixg. 



Communicated March 11, 1885. 



In the communication entitled -' Recent Observations of Variable 

 Stars," ^ it was stated that a similar circular would be published early 

 in 1885. The friendly co-operation of several astronomers interested 

 in the subject makes it practicable to present on this occasion a much 

 fuller view of the progress of observation, in Europe as well as in 

 America, than could be given last year. The various observers are 

 named below in alphabetical order, with the abbreviations employed to 

 designate them in the subsequent tabular statements. 



B. These observations were made by Mr. T. W. Backhouse, at 

 Sunderland, England. The instruments employed were a refracting 

 telescope by Cooke, aperture 4| inches, with magnifying powers 38 

 and 75 ; the finder of this telescope, power 9 ; a field-glass and an 

 opera-glass, with powers 4 and 2.2 respectively ; other observations 

 were made with the naked eye. The comparisons were made either 

 in grades, in fractions of the interval between two comparison stars, or 

 by approximate differences. A copy of the observations for 1884 has 

 been received at the Harvard College Observatory. 



C. These observations were made by Mr. S. C. Chandler, Jr., at 

 the Harvard College Observatory. The telescope is by Clacey ; aper- 

 ture 61 inches, magnifying power generally 45, sometimes 125 or 200. 

 The observations were made by Argelander's method. Most of them 

 were made before April 28, and they were discontinued after June 30, 

 owing to the requirements of other researches. They are not likely to 

 be resumed at present. 



D. Tliese observations were made by Dr. N. C. Duner, at the Ob- 

 servatory of Lund, Sweden, according to the method of Argelander. 



E. These observations were made by Mr. John IL Eadie, at Bay- 

 onne, New Jersey. The telescope employed was made by John 

 Byrne ; its aperture is SI inches, and the lowest magnifying power 



1 Proc. Amer. Acad, of Arts and Sciences, XIX. 296. 



