PHYSICAL AND LITER ARV. 91 



a(£^ivity to body r What fiiould determine 

 the body to ftop, if there be nothing 

 to oppofe its motion ? Is there any 

 experiment pointing that way? Yes, "we 

 " may be defired to reflect: on what a per- 

 " fon feels within himfelf in walking, du- 

 " ring which a repeated acfhivity is exert- 

 *' ed to continue the motion *." But this, 

 furely, can only ^ intended as an illuftra- 

 tion of what is meant by the fuppofed 

 adlivity of matter in motion, and not as 

 a proof of its reality, For, every day's 

 experience muft teach us, on the contrary, 

 that it requires a great adivity, fome- 

 times more than we are mailers of, to 

 Aop a begun motion in our bodies. How 

 doth it appear, that the fame efFo^t is ne- 

 cefTary to be continually exerted, which 

 was employed at the beginning of the 

 motion ? We find a certain effort neceffary 

 to begin a motion in our own bodies ; bur, 

 we fhould find no occafion for repeating 

 it, were it not confumed or wafted upon 

 j|_ pthcr bodies, When we give ourfelves 



^H * EHay I, p, 22^ 



I 



