SIR WM. AND CAROLINE HERSCHEL. 101 



He made a catalogue of double stars, and found 

 by laborious calculations that such stars have a 

 common centre of gravity ; that one sun revolves 

 about another. He found that our solar system 

 has a motion of its own ; a grand orbit round some 

 as yet unknown centre, and that other systems 

 have a like motion. 



What this centre may be, whether a great sun 

 like Sirius, one hundred times larger than ours, 

 with unknown powers and unknown uses, is of 

 course only conjecture. 



Herschel gave much attention to nebulae, discov- 

 ering and describing twenty-five hundred new neb- 

 ulae and clusters. He gave his life to the study 

 of the construction of the heavens. Concerning 

 his statement of the general construction, Profes- 

 sor Holden, himself a brilliant astronomer, says : 

 " It is the groundwork upon which we have still 

 to build. ... As a scientific conception it is perhaps 

 the grandest that has ever entered into the human 

 mind. As a study of the height to which the 

 efforts of one man may go, it is almost without a 

 parallel. ... As a practical astronomer he remains 

 without an equal. In profound philosophy he has 

 few superiors. By a kindly chance he can be 

 claimed, as the citizen of no one country. In very 

 truth his is one of the few names which belong to 

 the whole world." 



The distinguished man, though unassuming and 

 gentle in manner, must have had a realizing sense 

 of the greatness of his work, for he said, " I have 



