STARS IN COMA BERENICES. 



461 







Table X. 



— True 



Scale Values. 





Plate. 

 I 



I 



+/• 



Corr. 



for Aberr. 



Corr. Scale Value. 



Tel. Ther. 



Focus. 



+1 



000240 



+0 



000062 



52.'886o 



53 



8.4 



II 



+ 



238 



+ 



062 



52.8859 



53 



8.4 



III 



-1- 



308 



+ 



063 



52.8896 



58 



8.5 



IV 



+ 



233 



+ 



088 



52.8870 



60 



7-7 



V 



_}_ 



265 



+ 



08S 



52.8887 



60 



7-7 



VI 



-l- 



260 



+ 



088 



52.8884 



60 



7-7 



VII 



-L 



210 



+ 



088 



52.885S 



70 



7.6 



VIII 



+ 



215 



+ 



088 



52.8860 



70 



7.6 



IX 



+ 



290 



+ 



086 



52.8899 



60 



7-7 



X 



+ 



283 



+ 



086 



52.8895 



60 



7-7 



XI 



+ 



307 



+ 



086 



52.8908 



60 



7-7 



XII 



+ 



266 



+ 



086 



52.8885 



60 



7-7 



XIII 



+ 



307 



+ 



086 



52.8908 



65 



7.65 



XIV 



^" 



30+ 



+ 



086 



52.8906 



65 



7-65 



The mean scale-value is : 



52^^8884. 



In forming the above table no account has been taken of the 

 temperature at which the plate was exposed, nor of the reading 

 of the " focus " and " telescopic thermometer " (which are copied 

 from Table I). A discussion of the effects of these causes on 

 the scale-value must be postponed until a much larger number 

 of Rutherfurd plates have been independently reduced. 



Separate Results. — Employing the constants of Table IX 

 as explained in Sect. Ill, we obtain the " projected " right ascen- 

 sions and declinations, a^ and o^, given on the succeeding pages. 

 From them we can find the final coordinates, a. and o, and the 

 proper motions. The latter were deduced from my results, in 

 connection with Chase's (cf p. 343, foot-note, of the present pa- 

 per) positions, for all those stars which he observed. Only two 

 others were found on a sufficient number of plates to war- 

 rant an investigation for proper motion. The method em- 

 ployed for all cases when the observations were distributed 

 over more than two distinct dates, was that fully explained in 

 Part I, Sect. II, " Formulae for Adjustment." The epoch 

 being 1875, Chase's positions were reduced from 1892 to that 

 date, using his geometric precessions. A systematic correction 



(121) 



