224 CARNEGIE INSTITUTION OF WASHINGTON. 



OBSERVATIONS. 



During the year 17,422 observations were taken on 131 nights. 

 The observations were distributed among the observers as follows: 

 S. Albrecht, 7,333; .\rthur J. Roy, 6,224; W. B. Varnum, 3,865. The 

 circle-readings for zenith distance showed the followmg distribution; 

 S. B. Grant, 4,137; H. Jenkins, 7,111; H. Raymond, 6,017. In 

 respect to the four positions of the instrument these observations were 

 distributed— .\E 6,176, AW 6,856, BE 2,409, BW 1,981. In spite of 

 some very bad periods in the weather, notably three consecutive weeks 

 in June, considerable progress has been made with the fundamental 

 program. The near completion of parts of the miscellaneous list has 

 facilitated varying the hours of observing to cover other portions 

 needing double transit of polar stars and 12-hour groups of clock 

 stars. Open places have been utilized to obtain more material for 

 detennination of personal equation of the observers, particularly 

 feet-N minus feet-S. Mr. Roy has begun accumulating material to 

 show the effect of brightness upon the zenith distances, but the result 

 is still inconclusive. 



REDUCTIONS. 



With the decrease in the number of observations, the preluninaiy 

 steps m the reductions have been brought more nearly up to date. 

 These include reduction of transits to mean whe, computation of 

 means of microscope readings, application of corrections for division 

 error and runs, transcription to computation sheets and there entering 

 corrections for inclination of zenith distance wire, curvature of path, 

 and combined telescope and circle flexure. Computation of apparent 

 place reductions and of refractions, and the critical examination of 

 Albany microscope readings are well advanced. 



Duplicate copies of reduced transits have been checked with the 

 original, and duplicate sets of sheets containing the fundamental stars 

 have been drawn off. The definitive collimations, levels, and azimuth 

 of the mire are prepared for appUcation as far as May 1915. As has 

 been stated in former reports, there is an effect similar to lost motion 

 influencing the collimations; this has been elhninated by grouping the 

 collimations over considerable periods between breaks. After the 

 application of a temperature coefficient of — « 002 the resulting prob- 

 able error of a single determination amounts to ± ?009. Employing the 

 investigations of 1905, 1908, 1909, and 1911, pivot corrections have 

 been computed, tables laid out, and they are now being applied to the 

 observations of the fundamental stars. 



It has been possible to devote more time to the General Catalogue, 

 particularly in collecting material from new catalogues and comparing 

 the observations of each star with the approxunate ephemeris, pre- 

 liminary to the precise determination of the proper-motion. 



