Binary Stars. 135 



given an account of this in the " Connexion of the 

 Physical Sciences," so I shall only mention here that 

 in one or two of the binary systems the revolving 

 star has been seen to make more than one revolution, 

 and that the periodical times and the elliptical ele- 

 ments of a great many other orbits have been calcu- 

 lated, though they are more than 200,000 times 

 farther from the sun than we are. 



After Sir John Herschel was married, we paid 

 him a visit at Slough ; fortunately, the sky was 

 clear, and Sir John had the kindness to show me 

 many nebulae and clusters of stars which I had 

 never seen to such advantage as in his 20 ft. tele- 

 scope. 1 shall never forget the glorious appearance 

 of Jupiter as he entered the field of that instru- 

 ment. 



For years the British nation was kept in a state of 

 excitement by the Arctic voyages of our undaunted 

 seamen in quest of a north-west passage from the 

 Atlantic to the Pacific Ocean. The idea was not 

 new, for a direct way to our Eastern possessions had 

 been long desired. On this occasion the impulse 

 was given by William Scoresby, captain of a whaler, 

 who had sailed on the east coast of Greenland as 

 high as the 80th parallel of latitude, and for two suc- 

 cessive seasons had found that the sea between 

 Greenland and Spitzbergen was free of ice for 18,000 



