A HISTORY OF SCIENCE 



Herschel himself had proved that the sun shares this 

 motion with the other stars. Here was another shift 

 of place, hitherto quite unsuspected, to be reckoned 

 with by the astronomer in fathoming sidereal secrets. 



Double Stars 



When John Herschel, the only son and the worthy 

 successor of the great astronomer, began star-gazing in 

 earnest, after graduating senior wrangler at Cambridge, 

 and making two or three tentative professional starts in 

 other directions to which his versatile genius impelled 

 him, his first extended work was the observation of his 

 father's double stars. His studies, in which at first he 

 had the collaboration of Mr. James South, brought to 

 light scores of hitherto unrecognized pairs, and gave 

 fresh data for the calculation of the orbits of those 

 longer known. So also did the independent researches 

 of F. G. W. Struve, the enthusiastic observer of the 

 famous Russian observatory at the university of Dor- 

 pat, and subsequently at Pulkowa. Utilizing data 

 gathered by these observers, M. Savary, of Paris, 

 showed, in 1827, that the observed elliptical orbits of 

 the double stars are explicable by the ordinary laws of 

 gravitation, thus confirming the assumption that New- 

 ton's laws apply to these sidereal bodies. Henceforth 

 there could be no reason to doubt that the same force 

 which holds terrestrial objects on our globe pulls at 

 each and every particle of matter throughout the visi- 

 ble universe. 



The pioneer explorers of the double stars early found 

 that the systems into which the stars are linked are by 

 no means confined to single pairs. Often three or four 



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