28 ESSAYS AND OBSERVATIONS 



tlons which may appear not to be very 

 confiflent: Yet both are true in fadl. 

 And the difficulty will vanifh, by attend- 

 ing to the 'uis inertiae or reftflentui€^ that 

 it is not meafured merely by the fize or 

 bulk of the body in which it is inherent, 

 but has a relation to the momentum of the 

 impinging body. The lead force will puc 

 the greateft body in motion: But from 

 this it does not follow, that matter does 

 not refill a change from reft to motion. 

 It only follows, that this refiftance is al- 

 ways lefs than the ins matrix. To calcu- 

 late the proportion betwixt the 'vis matrix 

 and the refiftance bf a body at reft, fhall 

 be the fubjecfl of the next chapter. 



Of 



