INEQUALITY OF JUPITER AND SATURN. 3827 
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 eye armed with the most 
powerfnl 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. Finally, 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 
