THE SUN S MOTION IN SPACE. 



209 



thinks, probably near the truth : the latter at least as far as the 

 ninth magnitude. 



(124) Kobold, 1899 (Sept.)— In 1899 Kobold returned to the 

 problem of determining the solar motion by the Besselian method, 1 

 discussing very fully the distribution over the surface of the 

 celestial sphere of the differences between the purely parallactic 

 motion, and the observed motion of the star, (<£ — \p). Using a 

 still larger number of stars, and as before dividing them into 

 classes according to the magnitude of their proper motions, he 

 obtained the following results : — 



Epoch 

 1810-0 



•oper Motion. 



No. of 

 Stars. 



R.A. 



T>. 



dp 



>.l-6 



13 



271°7 



+ 10-4 



0-9931 



1-6 to 0-8 



23 



267-5 



+ 3-7 



- -0425 



0-8 „ 0-4 



85 



267-3 



-1-7 



+ -0055 



0-4 „ 0-2 



242 



269-7 



-1-7 



- -0007 



0-2 „ 0-1 



542 



270-1 



+ 0-1 



+ -0034 



> 0-1 Total 905 269-6 -0-4 + -0034^ 



Again, taking all stars with proper motions ranging from 0'"02 

 to 0-"l, and dividing them into two series, the results were 

 Proper Motion. 



0-1 to 0-05 

 0-05 „ 0-02 



No. of 

 Stars. 



583 



774 



0-1 to 0-02 Total 1357 



No. of 

 Stars. 



R.A. D. 



dp 





267-6 -3-9 



+ 0-0045] 





270-8 - 3-0 



-0-0048 



Epoch 



- 





[1810-0 



269-6 -3-3 



-0-0031 



j 





result from a total of 2,262 stars 



R.A. D. 



dp Epoch 



269-°6 -2-°3 



- 0-"002 



1810-0 



Proper Motion. 



^0-02 2,262 



Kobold pointed out that the mean error of the observed direc- 

 tions is not greater for stars of small than for those of large proper 

 motion, a point which, he affirms, demands peculiar attention. 

 The effect of an error in the precession-constant was shewn to be 

 negligible, and also that one must conclude either that the influence 

 of the motus peculiares becomes less as the proper motions become 



1 Die Constante der Praecession und die Bewegung des Sonnensystems 

 untersucht auf Grundlage der Methode von BesseL— Astr. Nach., Bd. cl., 

 pp. 257 - 296, 1899. 



N— Nov. 7, 1900. 



