282 SCIENTIFIC RECORD FOR 1882. 



"weiglit is allowed to remain on the Ys in the various meridian circles of 

 the world. The reductions are i)urely difiereutial, as has been said. Tlie 

 refraction is computed by Bessel's tables, with the Greenwich modi- 

 fication. 



The probable error of a clock correction derived from one star is 

 ±0^052, and of a single determination of the equator-point ±0".55, or 

 from four stars it0".28. The resulting jj. e. of a single declination is, 

 above-lOo, ±0".G3, and from -I0oto-2(jo, i0".73. 



For comi)arison with this work we can refer to the Ann Arbor dec- 

 linations of 10.") stars, made with a circle of exactly the same size as 

 that of Dublin, and also by the same makers, published by the Wash- 

 burn Observatory (1881). 



This catalogue was observed by ]\Ir. Schoeberle in 1879, and the p. e. 

 •of a single night in declination is ±0".55; in R. A. iO^.OlO sec. (J. 

 Schjelleruj) at Coi>enhagen (10,000 stars, j). xvi), found between 0° and 

 H-Ioo^. e. in Dec. ±0".G9, and between Qo and —15^, ±0".95. 



The magnitudes of the stars have been assigned on Argelander's 

 scale, and a note of the color of each star is given for each observation. 



The main object of the work is to bequeath good determinations of 

 position of a large number of red stars, which maj' serve hereafter to 

 show if the red stars as a class have any peculiarities of proper motion. 



Besides this object, another has been attained, in that 321 red stars 

 have been observed for color and magnitude on three or four nights 

 each on the average. 



Dr. Dreyer has now undertaken the observation of a large number ot 

 aero stars for Schoenfeld's Dio'chmusterung with this circle, which, like 

 the large refractor of the observatory, is not destined to be idle. 



Double stars. — No. Gof "Publications of the Cincinnati Observatory" 

 lias been issued. It contains micrometrical measures of double stars 

 made with the 11-inch refractor in lS79-'80, consisting partly of obser- 

 vations preliminary to the formation of a general catalogue of known 

 double stars situated between the equator and 30° south declination, 

 and partly of observations of objects which Mr. Burnham has found to 

 need re-observing. The cases of notable differences from previous meas- 

 ures are collected in the introduction. The refractor appears to have 

 been much improved since the object-glass was refigured by Messrs. 

 Alvan Clark & Sons. 



The double star observations of Baron Dembowski are to be pub- 

 lished in the Atti della li. Accaclemia clei X. Lincei. They will till throe 

 to four of the (quarto) volumes, or about 1,500 pages in all, and are to 

 be edited by Professor Schiaparelli. 



Variable stars. — Prof. E. C. Pickering, of Harvard College Observa- 

 tory, has i^repared and published in pamphlet form a plan for securing 

 observations of the varial)le stars. It is well known to astronomers that 

 this observatory is doing systematic work in the study of the variable 



