RHYTHM 



last illustration, from the succession of forms 

 of life upon the earth, suggests still another su- 

 premely important aspect in which the general 

 principle must be viewed, before we leave it. 



As we saw in our initial illustration, from the 

 movements of heavenly bodies, where a rhyth- 

 mical motion is dependent on only two com- 

 pounded forces, the result is a closed curve. 

 Though each planet is, strictly speaking, sub- 

 jected to a great number of variously com- 

 pounded forces exerted on it by all its compan- 

 ion planets, yet these forces are so insignificant 

 in quantity, compared to the two chief forces 

 of solar gravity and the planet's own momen- 

 tum, that they do not essentially alter the re- 

 sult. They prevent the curve in which any 

 given planet moves from being perfectly regular, 

 but they do not prevent its being a closed curve 

 so far as the solar system alone is concerned ; 

 so that, at the end of each rhythm, the distri- 

 bution of forces is very nearly the same as at 

 its beginning. If there were only two bodies 

 concerned, it would be exactly the same : every 

 rhythm would end in bringing about precisely 

 the same state of things with which it started. 

 But where there are a vast number of forces at 

 work, as in the evolution of the earth and of 

 life upon its surface, the probability is infinitely 

 small that any pair of forces can so far predomi- 

 nate over all the rest as to reduce their effects 

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