432 HISTORY OF PHYSICAL ASTRONOMY. 



1736. But Newton was not unknown or despised in France till this 

 time. In 1699 he was admitted one of the very small number of 

 foreign associates of the French Academy of Sciences. Even Fonte- 

 nelle, who, as we have said, never adopted his opinions, spoke of him 

 in a worthy manner, in the Eloge which he composed on the occasion 

 of his death. At a much earlier period too, Fontenelle did homage to 

 his fame. The following passage refers, I presume, to Newton. In 

 the History of the Academy for 1V0S, which is written by the secre- 

 tary, he says, 10 in referring to the difficulty which the comets occasion 

 in the Cartesian hypothesis : " We might relieve ourselves at once 

 from all the embarrassment which arises from the directions of these 

 motions, by suppressing, as has been done by one of the greatest 

 geniuses of the age, all this immense fluid matter, w T hich we commonly 

 suppose between the planets, and conceiving them suspended in a 

 perfect void." 



Comets, as the above passage implies, were a kind of artillery which 

 the Cartesian plenum could not resist. When it appeared that the 

 paths of such wanderers traversed the vortices in all directions, it was 

 impossible to maintain that these imaginary currents governed the 

 movements of bodies immersed in them ; and the mechanism ceased 

 to have any real efficacy. Both these phenomena of comets, and many 

 others, became objects of a stronger and more general interest, in con- 

 sequence of the controversy betw r een the rival parties ; and thus the 

 prevalence of the Cartesian system did not seriously impede the prog- 

 ress of sound knowledge. In some cases, no doubt, it made men un- 

 willing to receive the truth, as in the instance of the deviation of the 

 comets from the zodiacal motion ; and again, when Romer discovered 

 that light was not instantaneously propagated. But it encouraged 

 observation and calculation, and thus forwarded the verification and 

 extension of the Newtonian system ; of which process we must now 

 consider some of the incidents. 



io Hist. Ac. Sc. 1708. p. 103. 



