STELLAR SYSTEMS AND NEBULA. 199 



When his mother died Sir John Herschel 

 decided to sail to the Cape of Good Hope to 

 make an investigation of the stars of the 

 southern hemisphere, which until then had been 

 much neglected. He was offered a free passage 

 in a ship of war, but declined. In November 

 1833 he left England, taking with him his great 

 telescopes. In two months he arrived at Cape 

 Town, and erected his astronomical instruments 

 at Feldhausen, a short distance off. In October 

 1835 he informed his aunt that he had almost 

 completed his survey of the southern hemisphere. 

 During his "sweeps" of the heavens he dis- 

 covered 1202 double stars, and 1708 nebulae 

 and star-clusters. In 1838 he returned to Eng- 

 land, and devoted the remainder of his life to 

 the publication of his results, as well as to 

 other branches of science. He died at Colling- 

 wood, in Kent, on May 11, 1871, at the age of 

 seventy-nine. 



John Herschel's favourite objects of study 

 were double stars, of which he discovered 3347 

 in the northern hemisphere, and 2102 in the 

 southern. He also computed several stellar 

 orbits ; but the first calculation of a stellar 

 orbit was made by the French astronomer Felix 

 Savary (1797-1841), who computed the orbit of 

 f Ursae Majoris, and found the period to be 



