NEWTON S PRINCIPIA. 327 



velocity would decrease, and therefore the earth would 

 return to its original form. So also, by similar reasoning? 

 the same would occur if the earth were to become less el 

 liptical. 



If e be small, it is easy to see that the preceding equa 

 tion leads us to 



since 2e 2 = e, when the powers of e higher than the second 

 are neglected. 



Y 4 



