268 HISTORY OF PHYSICAL ASTRONOMY. 



It has been said 12 that Bradley's discoveries 

 "assure him the most distinguished place among 

 astronomers after Hipparchus and Kepler." If his 

 discoveries had been made before Newton's, there 

 could have been no hesitation as to placing him 

 on a level with those great men. The existence 

 of such suggestions as the Newtonian theory offered 

 on all astronomical subjects, may perhaps dim, in 

 our eyes, the brilliance of Bradley's achievements ; 

 but this circumstance cannot place any other person 

 above the author of such discoveries, and there- 

 fore we may consider Delambre's adjudication of 

 precedence as well warranted, and deserving to be 

 permanent. 



Sect. 5. Discovery of the Laws of Double Stars. 

 The two Herschels. 



No truth, then, can be more certainly established, 

 than that the law of gravitation prevails to the 

 very boundaries of the solar system. But does it 

 hold good further? Do the fixed stars also obey 

 this universal sway ? The idea, the question, is an 

 obvious one, but where are we to find the means 

 of submitting it to the test of observation ? 



If the stars were each insulated from the rest, 

 as our sun appears to be from them, we should 

 have been quite unable to answer this inquiry. 

 But among the stars, there are some which are 



12 Delambre, Ast. du 18 Stec. p. 420. Rigaud, xxxvii. 



