OP ARTS AND SCIENCES. 297 



obviously be lost by waiting for the reduction and publication of the 

 observations. It is intended to publish another circular early in 1885, 

 giving, so far as practicable, the results obtained during 1884 by all 

 observers of variable stars. The value of this circular will depend 

 upon the amount of assistance which the various astronomers inter- 

 ested in the subject may be inclined to afford. Those who have 

 already undertaken to communicate their observations to this Observa- 

 tory will, no doubt, continue their co-operation. If the greater part 

 of the results obtained by independent observation elsewhere are also 

 communicated in a form so far condensed that they can be furnished 

 with little trouble to the observers themselves, the proposed circular will 

 exhibit a statement of the course of observation during the year suffi- 

 ciently complete to form a highly useful guide for subsequent work. 

 It is therefore hoped that observers of variable stars, whether profes- 

 sional astronomers or amateurs, will be generally disposed to furnish 

 the information necessary to the completeness of the circular. This 

 information relates to the following subjects : — 



1. Method of observation. If photometric, some account of the 

 instrument and the manner of using it. If not photometric, whether 

 the observations are made by Argelander's method, by the division 

 into tenths of the interval in brightness between two comparison stars, 

 one slightly brighter and the other slightly fainter than the star ob- 

 served, or by direct estimation of magnitude. 



2. Stars observed during 1884, and the number of nights on which 

 each was observed. In naming the stars, it may be convenient to 

 use the numbers given in the first column of Table I. below. 



3. The time and form of publication of the observations now con- 

 templated by the observer. 



4. Plans for 1885, with regard to the stars selected for observa- 

 tion, and the number of nights on which it is proposed that each shall 

 be observed. 



Further information, although not directly required for the purpose 

 of the circular, will be gratefully received. If the observations are 

 not to be published by the observer, a copy of them would be most 

 acceptable. If they are, any results already reached, as, for example, 

 the times and magnitudes of the maxima and minima of the stars, the 

 dates of the separate observations, or the number of nights in each 

 month of the year upon which a given star was observed, would be 

 of much service. 



Table I. exhibits the results of observation of variable stars for 

 1883, so far as they are at hand, in order to show the nature of the 



