COSMIC PHILOSOPHY 



case of two bodies which are moving in inde- 

 pendent directions. For the sake of simplicity, 

 let us suppose that the second body, b, is so 

 much heavier than the first body, a, that the 

 common centre of gravity of the two lies within 

 b's periphery. What now will be the result ? 

 The direction of a's motion, instead of remain- 

 ing unaltered, will be at each instant deflected 

 from a straight line in such a way that a will 

 continually approach nearer and nearer to a 

 point somewhere in advance of b, upon the line 

 in which b is moving : instead of a straight line 

 we shall have a curve of which the coordinates 

 will bear to each other a ratio equal to the ratio 

 between a's momentum and b's tractive force. 

 The velocity of a will also cease to be uniform. 

 For as soon as a has passed on beyond b, a 

 portion of its momentum will be at each instant 

 consumed in neutralizing b's tractive force, so 

 that the velocity due to the remaining momen- 

 tum will be at each instant diminished. Now, 

 unless a's momentum be infinite, this process 

 cannot go on forever. By the time that a has 

 arrived at the point directly in advance of b, so 

 much momentum will have been lost that b's 

 attraction will begin to overbalance it, and the 

 curve in which a is moving will begin to turn 

 back toward b. But now b's tractive force be- 

 gins to augment at each instant the velocity 

 of a, until, by the time that a has reached a 

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