THE SUN'S MOTION IN SPACE. 205 



[n] denoting the arithmetical mean of the components of the star's 

 absolute velocities, taken at right angles to the line of sight, and 

 V the absolute velocity of the sun's motion in space; so that \n~\j V 

 denotes the ratio of the former to the latter. Kapteyn concluded 

 that no change of velocity with increase of distance from the sun 

 is indicated by this result. The stars were next divided into two 

 series, all the stars of spectral type II. being put into one, and 

 the remaining ones into the other. These two series were again 

 subdivided into ten groups, containing in each group an equal 

 number, in the following manner, viz: — The stars were divided into 

 sub-groups according to the value of the angle formed between the 

 direction of the stars " total proper motion " and the great circle 

 through the antiapex, these angles being 0° to ±9°, ±10° to ±19° 

 and so on, closing with ± 170° to ± 180°. These greater groups 

 (1) contained the series of stars of the least proper motion through- 

 out the sub-groups, the second group (2) those of the next greater 

 value, and so on to the last, i.e., (10), which contains the stars of 

 greatest proper motion. The result was as follows : — 



Spectral Type 



II. 



Other Stars. 



Group. 



No. of 

 Stars. 



[n]/V 



No. of 

 Stars. 



[n]/V 



1 



103 



1-37 



139 



1-58 



2 



103 



1-30 



140 



1-38 



3 



104 



1-59 



139 



1-42 



4 



103 



1-50 



139 



1-31 



5 



103 



1-36 



139 



1-41 



6 



103 



1-44 



140 



1-52 



7 



103 



1-52 



139 



1-44 



8 



103 



1-62 



140 



1-40 



9 



103 



1-69 



139 



1-43 



10 



105 



1-55 



140 



1-40 



Total 1,033 1-494 1,394 1-429 



This shews no distinct evidence of a progression of the ratio, 

 with magnitude of proper motion ; and the inclusion of other stars 

 not embraced in the above result did not vary this result. The 

 finally deduced motions were 



[n] = 1*46 FMean velocity perpendicular to line of sight. 



[s] = 1*86 rMean actual linear velocity. 



[t ] = 0-93 V Mean velocity (considered as positive) in line of sight. 



