INEQUALITY OF JUPITER AND SATURN. 327 



equally striking diminution of the mean motion of Saturn. 

 These variations led to conclusions of the most singular 

 nature. 



In accordance with the presumed cause of these per- 

 turbations, to say that the velocity of a body increased 

 from century to century was equivalent to asserting that 

 the body continually approached the centre of motion ; 

 on the other hand, when the velocity diminished, the 

 body must be receding from the centre. 



Thus, by a strange arrangement of nature, our plane- 

 tary system seemed destined to lose Saturn, its most 

 mysterious ornament. to see the planet accompanied by 

 its ring and seven satellites, plunge gradually into un- 

 known regions, whither the eve armed with the most 



9 



powerful telescopes has never penetrated. Jupiter, on 

 the other hand, the planet compared with which the earth 

 is so insignificant, appeared to be moving in the opposite 

 direction, so as to be ultimately absorbed in the incandes- 

 cent matter of the sun. Finallv. the moon seemed as if 



^ ' 



it would one day precipitate itself upon the earth. 



There was nothing doubtful or speculative in these 

 sinister forebodings. The precise dates of the approach- 

 ing catastrophes were alone uncertain. It was known, 

 however, that they were very distant. Accordingly, 

 neither the learned dissertations of men of science nor 

 the animated descriptions of certain poets produced any 

 impression upon the public mind. 



It was not so with our scientific societies, the members 

 of which regarded with regret the approaching destruc- 

 tion of our planetary system. The Academy of Sciences 

 called the attention of geometers of all countries to these 

 menacing perturbations. Euler and Lagrange descended 

 into the arena. Never did their mathematical genius 



