208 G. H. KNIBBS. 



Stars of large proper motion. 

 fi£ Weight. R.A. D. R"' 



All magnitudes 644 10 276-°9 31-°4 ? 



R'" here denotes centennial 1 parallactic motion, at the mean 

 distance of the group. 



In these six results, if we accept Kapteyn's parallax-magnitude 

 theory, see (122) above, adopt the constant 0""106, and also the 

 mean magnitudes 2, 3J, 4J, 5J, 6J, 7J, which are probably suffici- 

 ently near the actual means, — not given by Newcomb — the 

 resulting velocities will be respectively 3-6, 5*2, 4-6, 5-9, 7*7, 10-7, 

 miles per second. 



Pointing out that Stumpe's mean positions, weighted according 

 to the number of stars, when classed by proper motions, and by 

 magnitudes were respectively 



R.A. = 281-°8, D.= +40-°7 

 283-1 38-7 



and that Boss' declination would, by correction to the new standard 

 be D.= +42 ,0 9 instead of 44 ,0 1, Newcomb gives the following 

 table of results : — 



Authority. *£* R.A. D. 



Newcomb from Bradley's stars, small P.M. 2,527 272-°5 31 °3 



large P.M. 644 276-9 31-4 

 Stumpe, mean two preceding results 995 282-4 39-7 



Boss, stars of Albany Zone 279 283-3 42-9 



from which he concludes that the most probable position is 



R.A. = 277-°5, D.= +35-°0, Y. = 3-5E. 

 V denoting the velocity per annum, and E the mean radius of the 

 earth's orbit. 



The third and fourth parts of the paper are respectively the 

 " Parallactic motion of the fainter stars " — giving 0-"0039 for 

 stars of magnitude 8-5 — and "The mean parallax of the Vogel 

 stars." The paper closes with the fifth part, "Summary of Con- 

 clusions." Kapteyn's speed of V = 35 E, and parallax formula 

 sr m = k m 7r with the constants previously given, are, Newcomb 



