41 



connected by mutual attraction ; and further, that neither of these 

 stars have any visible proper motion, as it is very unlikely that they 

 should both have exactly the same proper motion. 



Now among the numerous double stars there are several other 

 pairs that seem not to have changed their position relatively to each 

 other. For instance, ^ Ursae Majoris and its attendant have pre- 

 served the same relative positions. Such stars, therefore, probably 

 have no proper motions. This conjecture appeared to me nearly 

 if not altogether confirmed, when on examination I found that the 

 distance between the Pole Star and ^ Ursae Majoris remains by my 

 latest observations the same that it was found by Bradley in 1755, 

 and by Piazzi in 1 800. 



Distance between a Polaris and ^ Ursae Majoris, 



By Greenwich Ob. 1755 - 3S°46' 37",7 



Palermo Ob. 1800 - - 37,4. 



Ob. T. C. Dublin, 1824 - - 38,5 



^ Ursas Majoris being nearly opposite in right ascension to Polaris, 

 this distance does not depend on any accurate determination of the 

 right ascensions, but only on the accurate determination of the polar 

 distances. The right ascensions of Dr. Bradley have not been 

 observed with equal accuracy as the declinations, except perhaps 

 for about fourteen stars. 



Pursuing this enquiry as to other stars, several were found that 

 appeared to me fixed. Wherever I found two stars of nearly the 

 same right ascension remaining at the same distance from each 

 other, I have suspected that both were altogether or nearly fixed. 

 In this way I was led to conjecture that a Cassiopeae, Rigel, /S 

 Aurigae, a Orionis, « Cygni, and /3 Cephei, and several others, 

 have had no sensible proper motion for nearly seventy years. 



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