Sixty-five Stars near 61 Gygni. 119 



whence is obtained by substitution of the constants and from the 

 figure : 



Att = 62°59 / i7 // -\- (y — Aj ) before epoch, 



= — 1 17° o / 43 // + (y — &x ) after epoch, 



and thus the total change of angle is 



Att + A'tt 



additive to the observed position-angle. These quantities are 

 printed in columns seven and eight of Table XIII. 



When these corrections for proper motion have been applied to 

 the preceding columns of Table XIII we get in the next-to-the- 

 last column of the Table the distance and angle of 61 2 good for 

 1873.546 corrected for all known motions of either star, except 

 for difference of parallax if there be any such difference. This 

 oint will be considered in the following Contribution, No. 13. 



