COSMIC PHILOSOPHY 



surface of our earth, it becomes legitimate to 

 inquire from what antecedent form of energy 

 proceeded all these motions. This inquiry we 

 shall make in due season. By our second cor- 

 ollary it appeared that where motion results 

 from the composition of two or more forces, it 

 must always take place in the line of least re- 

 sistance ; but that the difficulty of calculating 

 or predicting this resultant line must increase 

 very rapidly with each addition to the number 

 of forces which are concerned in producing it. 



Our third corollary has given us glimpses of 

 a truth, which, though less immediately obvious, 

 is equally necessary and equally important with 

 any of the foregoing. We have seen that, in 

 the hypothetical case of a single moving body 

 in an otherwise empty universe, the direction 

 of motion would be in a straight line, and the 

 velocity would be uniform. In the hypotheti- 

 cal case of a single pair of mutually attracting 

 bodies moving in independent directions in an 

 otherwise - empty universe, the motion would 

 be rhythmical both in direction and in velocity, 

 but it would take place in closed curves, and 

 the distribution of forces at the end of each 

 rhythm would be the same as at the beginning. 

 In the simplest of actual cases, however, — in 

 the case of our planetary system, — such a re- 

 sult, though apparently realized so long as we 

 eliminate from the problem all factors save the 

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