452 THE URANOLOGICAL PORTION OF THE COSMOS. 



Tliese -elements of stability, elements as it were of the 

 preservation and continuance of the " life" of the planets, 

 are attached to the condition of mutual action within the 

 interior of a circumscribed circle. If by the arrival from 

 the regions of exterior space of a cosmical body not pre- 

 viously belonging to the system, this condition cease (Laplace, 

 Expos, du Syst. du Monde, p. 309 and 391), then, indeed, 

 there might ensue, as the result either of new forces of at- 

 traction or of a shock, consequences injurious or destructive 

 to that which now exists, until at last, after a long conflict, 

 a new equilibrium should be produced. The consideration 

 of the possible arrival of a -comet in a hyperbolic path from 

 remote regions, even though the smallness of its mass should 

 be compensated by an enormous velocity, could only occasion 

 uneasiness to an imagination which should be inaccessible to 

 the reassuring deductions of the calculus of probabilities. 

 Those travelling clouds, the interior comets of our system, 

 are as far from being dangerous to the stability of the 

 system, as are he great inclinations of the orbits of some of 

 the small planets situated between Mars and Jupiter. That 

 which must be designated as a mere possibility lies beyond 

 the domain of a Physical Description of the Universe. 

 Science ought not to pass from its true domain into the 

 misty land of cosmological dreams. 



