VOL. XXXV.J VHILOSOPHICAL TllANSACTIONS. SIQ 



difficult to judge when they are exactly on the middle of the wire, fixed in the 

 common focus of the glasses of the telescope. 



Mr. B. confesses, that the agreement of the observations with each other, 

 as well as with the hypothesis, is much greater than he expected to find, before 

 comparing them ; and it may possibly be thought to be too great, by those who 

 have been used to astronomical observations, and know how difficult it is to 

 make such as are in all respects exact. But if it would be any satisfaction to 

 such persons, he could assure them, that in above 70 observations made of this 

 star in a year, there is but one (and that is noted as very dubious on account of 

 clouds) which differs from the foregoing hypothesis more than 1", and this does 

 not differ 3". 



This therefore being the fact, he cannot but think it very probable, that the 

 phaenomena proceed from the cause he has assigned, since the foregoing obser- 

 vations make it sufficiently evident, that the effect of the real cause, whatever 

 it is, varies in this star, in the same proportion, that it ought according to the 

 hypothesis. 



But least y Draconis may be thought not so proper to show the proportion, 

 in which the apparent alteration of declination is increased or diminished, as 

 those stars which lie near the equinoctial colure ; he gives also the comparison 

 between the hypothesis and the obsesvations of r\ Ursae Majoris, that which was 

 farthest south about Jan. 17, 1728, agreeable to the hypothesis. The follow- 

 ing table shows how much more northerly it was found by observation in several 

 parts of the year, and also what the difference should have been according to 

 the hypothesis. 



The difference The difference The difference The difference 



Mr. B. finds, on examination, that the hypothesis agrees altogether as exactly 

 with the observations of this star, as the former ; for in about 50 that were 



