THE STELLAR UNIVERSE. 



by Sir J. Herschel from Struve's catalogue, as remarkable exam- 

 ples of each class well adapted for observation by amateurs, who 

 may be disposed to try by them the efficiency of telescopes. 



54. One of the characters observed among the double stars is 

 the frequent occurrence of stars of different colours found together. 

 Sometimes these colours are complementary ; and when this occurs, 

 it is possible that the fainter of the two may be a white star, which 

 appears to have the colour complementary to that of the more 

 brilliant, in consequence of a well-understood law of vision, by 

 which the retina being highly excited by light of a particular 

 colour is rendered insensible to less intense light of the same 

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