16 Matter and Motion* 



and so to be taken as a principle in na* 

 tural philosophy. 



Supposing then the earth the sole bo- 

 dy in the universe, and at rest ; if God 

 should create the ir.oon, at the same dis- 

 tance that it is now from the earth, the 

 earth and the moon would presently be- 

 gin to move one towards another in a 

 straight line, by this motion of attraction 

 or gravitation. 



If a body, that by the attraction of 

 another would move in a straight line 

 towards it, receives a new motion any 

 ways oblique to the first, it will no longer 

 move in a straight line, according to ei- 

 ther of those directions, but in a curve, 

 that will partake of both ; and this curve 

 will differ, according to the nature and 

 quantity of the forces that concurred to 

 produce it; as, for instance, in many ca- 

 ses it will be such a curve as ends when* 

 it began, or recurs into itself; that is, 

 make up a circle, or an ellipsis, or oval 

 very little differing from a circle. 



Attraction may be divided, with res- 

 pect to the law it observes, into two kinds. 

 That which takes place at a sensible, dis- 

 tance^ and that which does not extend to 



