86 MILLER— PARALLAXES OF FIFTY STARS. 



cordance with the scheme described in Sproul Pubhcation No. 4, (p. 

 10 et seq.). Other fields have been selected in the usual way, i.e., 

 the comparison stars were selected because of their location and 

 brightness, the ideal being in every case to select stars of approxi- 

 mately the same brightness and to reduce the parallax star to the 

 same magnitude by the occulting disc. In the final table of this 

 paper, which contains a summary of the preceding results, I have 

 marked with an asterisk those stars whose comparison fields were 

 selected by the first method. I propose a little later to discuss more 

 fully our experience with this method. In the detailed results which 

 follow there is given for each star its B.D. number together with 

 some other ordinarily used designations ; its position for the epoch 

 of 1900; its magnitude; its proper motion; and its spectrum. The 

 magnitude and spectrum are taken if possible from the Annals of 

 the Harvard College Observatory, Volume 50. The proper motions 

 are taken, with few exceptions from Boss' Preliminary General 

 Catalogue, or from the Cincinnati publications. 



Two tables are given in connection with each star. The first con- 

 tains the necessary observational data, and the quantities needed for 

 reduction. The initials in columns 2 and 9, have the following sig- 

 nification : B. denotes Barton ; Be., Bender ; M., Miller ; Ma., Matos ; 

 P., Pitman ; S., Miss Steele ; Sm., Miss Smedley. T., in column 4, is 

 the time of observation given in 100 days from the mean date of the 

 series ; m., in column 6, is the " solution " of the plate given in quar- 

 ter-milhmeters ; p., in column 7, is the weight of the plate assigned 

 by the person who measures it. The second table contains the data 

 for the position of the comparison stars measured in equatorial co- 

 ordinates, the diameter of the stars in quarter-millimeters, and their 

 B.D. numbers. Following this table are the normal equations and 

 their solutions. The quantity fx in these equations is the proper 

 motion given in seconds of arc per hundred days. The quantity, tt, 

 is the relative parallax. 



An appropriation made from the income of a fund given by 

 James C. Watson for Astronomical Research, has been made to me 

 by the National Academy of Sciences for three successive years. 

 These appropriations have been used to aid in the measurements and 

 reduction of these plates. It is a pleasure to acknowledge these gen- 

 erous contributions from the x\cademy. 



