S6 ESSAYS AND OBSERVATIONS 



all experience ; and they would do well 

 to inform, the world, in what manner 

 this idea was fuggefted to them. 



The paffive nature of body is abun- 

 dantly manifeft, from its yielding to the 

 l&ifl conceivable adlion. The leg of a fly 

 moves the whole globe of the earth. A 

 man indeed cannot roll a tun fo fail as 

 he can a tennis-ball \ And we may find a 

 horfe able to draw a loaded cart two miles 

 in the hour> who cannot be prevailed up- 

 on to draw it four miles in the fame 

 time. But are not fueh common phae- 

 nomena as thefe more naturally account- 

 ed for from the fluggifhnefs or inadivity 

 of matter, than from its fuppofed adivi- 

 ty ? A great body fet in motion is one ef- 

 itdi : A little body moved with the fame 

 velocity is another. A given body mo- 

 ved with a gr^at velocity, is one efFedl ; 

 and when moved with a lefs velocity, it 

 is a different effedl. The oM principle 

 feems to apply well enough in this cafe, 

 that efledls are proportional to their caufes. 



It muft be confeffed, that authors, in 

 treating of the inertia of matter, and of 



its 



