178 . G. H. KNIBBS. , 



adopted, Gould's in the Uranometria Argentina; and the stellar 

 parallax that given by Peters. 3 The result according to the two 

 suppositions previously referred to, the latter of which was the 

 probable one, was, when Galloway's stars only were used : — 



(a) R. A. = 276-0, D.= +2-7, R. = 1-470 



(b) 262-7, -1-5, 0-724 



R denoting as previously the angular value of the motion viewed 

 from a first magnitude star. The differences from the positions 

 computed by Galloway himself were so remarkable, that a further 

 investigation was undertaken in which all the Cape catalogue stars 

 whose proper motions were greater than 0'"1 annually were 

 included. The results from the 274 available stars were 



(a) R.A. = 281-°3, D.= +25-°8, R. = : 772 



(b) 270-1, 20-3, 1-690 



The deviation from other results being still great, and an 

 examination of the influence of certain stars shewing that four 

 greatly affect the result, suggested the adoption of a change in 

 the manner of grouping them. Relying upon the results of 

 Safford's discussion, which apparently shewed that stellar distances 

 should be approximately in the inverse ratio of the proper motions, 

 a reinvestigation was undertaken on the assumption that the 

 distances of the stars were as shewn in the following table : — 



Proper Motion 2 + 2-1 l'-0 - 8 -8 - -6 -6 - 4 4- -2 -2 - -1 *1 - 

 Distance ... \ 1 1*67 2-14 3 5 10 15 

 No. of Stars... 7 16 7 9 16 72 112 35 



The computation now gave for the place of the point to which 

 the solar motion was directed, and for the quantity of the motion 

 R.A.==276-°1, D.= +26-°5, R. = 0-"926 



A close criticism of the general result convinced Plummer that 

 Safford's doctrine as to the relation of distance and proper motion 

 had some degree of probability. On the other hand there did not 

 appear to be any decisive evidence of change of distance with 



3 Struve's Etudes d'Astrononrie stellaire, p. 106. 



