62 ©ftt)e^ectjanicalflD|igine 



various vehement and inteftine com- 

 motion of the parts among them- 

 felves , and in fuch an one we for- 

 merly obferv'd the nature of Heat to 

 confift. 



EX PER. VII. 



IN the foregoing Experiment the 

 br'uk agitation of the parts of a 

 heated iron was made fenfible to the 

 touch } I mall now adde one of the 

 attempts, that I remember I made to 

 render it difcoverable to the eye it 

 felf. In order to this , and that I 

 might alfo (hew , that not onely a 

 fenfible but an intenfe degree of heat 

 may be produc'd in a piece of cold 

 iron by Local Motion, I caus'd a bar 

 of that metal to be nimbly ham- 

 mer'd by two or three lufty men ac- 

 cuftom'd to manage that Inftrument* 

 and thefe (hiking with as much 

 force , and as little intermiffion as 

 they could upon the iron, foon 

 brought it to that degree of Heat, 



that 



