iia ESSAYS and OBSERVATION^ 



many examples. Let us fuppofe a board 

 fet nearly upright on its end, and £6 

 flightly fupported, that a bullet thrown 

 againft it, out of a man's hand, will 

 tumble it over j if the fame bullet be dif- 

 charged from a guti, it will go through 

 the board without moving it out of its 

 place. In the fame way, a bullet has 

 been known to go through a man's body, 

 an arm has been taken off by a cannon- 

 ball, or even by the fail of a wind-mill^ 

 without any vifible motion produced in 

 the other parts of the body ; though a 

 much lefs force would be fufEcient to drag 

 the whole body forwards. The better to 

 illuftrate the manner in which thefe ef- 

 fecls are performed, let it be obferved^ 

 that, by means of a fmall thread or aload- 

 flone, a confiderable mafs of matter may 

 be gently pulled along a table ; whereas, 

 if a fuddentug be given, or a greater force 

 applied, the thread breaks, or the load- 

 ftone feparates, without feemipg at all to 

 move the body. The nature of hertii^ 

 and refiftance has been fo much mifun- 

 derilood, or mifreprefented, that it was 



ncceflary 



