SUCCESSORS OF NEWTON IN ASTRONOMY 



ha ve^ done, if the earth's axis had retained the same 

 inclination to an invariable plane." 2 



FRENCH ASTRONOMERS 



Meanwhile, astronomers across the channel were by 

 no means idle. In France several successful observers 

 were making many additions to the already long list 

 of observations of the first astronomer of the Royal 

 Observatory of Paris, Dominic Cassini (1625-1712), 

 whose reputation among his contemporaries was 

 much greater than among succeeding generations of 

 astronomers. Perhaps the most deserving of these 

 successors was Nicolas Louis de Lacaille (1713-1762), 

 a theologian who had been educated at the expense 

 of the Duke of Bourbon, and who, soon after com- 

 pleting his clerical studies, came under the patronage 

 of Cassini, whose attention had been called to the 

 young man's interest in the sciences. One of Lacaille's 

 first undertakings was the remeasuring of the French 

 arc of the meridian, which had been incorrectly meas- 

 ured by his patron in 1684. This was begun in 1739, 

 and occupied him for two years before successfully 

 completed. As a reward, however, he was admitted 

 he academy and appointed mathematical professor 

 in Mazarin College. 



In 1751 he went to the Cape of Good Hope for the 

 purpose of determining the sun's parallax by observa- 

 the parallaxes of Mars and Venus, and inci- 

 dentally to make observations on the other southern 

 hemisphere stars. The results of this undertaking 

 were most successful, and were given in his Ca-lnm 

 anstrale stelligerum, etc., published in 1763. In this he 



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