64 SPECIAL RESULTS IN THE URANOLOGICAL 



of two reflecting telescopes which have raised to the highest 

 degree the expectation of astronomers. ( 123 ) With LasselFs 

 telescope, which has only 2 feet aperture and 20 feet focal 

 length, there have been already discovered a satellite of 

 Neptune and an eighth satellite of Saturn, besides the redis- 

 covery of two satellites of Uranus. Lord Rosse's new colossal 

 telescope has 6 feet clear aperture and 53 feet focal length. 

 It is placed in the meridian between two piers, each 12 feet 

 distant from the tube, and from 47 to 54 feet in height. 

 Many nebulae which no previous instrument could resolve, 

 have, by this magnificent telescope, been resolved into clusters 

 of stars, and the forms of other nebulae have now for the first 

 time been shown in their true outlines. The quantity of light 

 reflected from the surface of the mirror is truly wonderful. 



Morin, who, with Gascoigne, and before Picard and Auzout, 

 first combined the telescope with measuring instruments, con- 

 ceived, about 1638, the idea of observing stars telescopically 

 in full daylight. He says himself ( 124 ) that he " was led to 

 a discovery which may become important for the determina- 

 tion of longitudes at sea, not by Tycho Brahe's great labours 

 on the positions of the fixed stars, as, in 1582, and there- 

 fore twenty-eight years before the invention of the telescope, 

 he compared Venus with the sun in the day-time and with 

 the stars at night, but merely by the simple thought that it 

 might be possible, as with Yenus so also with Arcturus and 

 other fixed stars, once having them in the field of view of 

 the telescope before sunrise, to continue to follow them in 

 the heavens after sunrise." No one, he said, before him 

 " had been able to find the fixed stars in the broad daylight." 

 Since the establishment of great meridian telescopes by Romer 

 in 1691, day observations of the heavenly bodies have been 



