Masterpieces of Science 



BEING engaged in superintending the boring 

 of cannon in the workshops of the military arsenal 

 at Munich, Count Rumford was struck with the 

 very considerable degree of heat which a brass 

 gun acquires, in a short time, in being bored, 

 and with the still more intense heat (much 

 greater than that of boiling water) of the metallic 

 chips separated from it by the borer, he pro- 

 posed to himself the following questions: 



"Whence comes the heat actually produced 

 in the mechanical operations above mentioned? 



"Is it furnished by the metallic chips which 

 are separated from the metal ? " 



If this were the case, then the capacity for heat 

 of the parts of the metal so reduced to chips 

 ought not only to be changed, but the change 

 undergone by them should be sufficiently great 

 to account for all the heat produced. No such 

 change, however, had taken place, for the chips 

 were found to have the same capacity as slices 

 of the same metal cut by a fine saw, where heat- 

 ing was avoided. Hence, it is evident, that the 

 heat produced could not possibly have been 

 furnished at the expense of the latent heat of the 

 metallic chips. Rumford describes these experi- 

 ments at length, and* they are conclusive. 



He then designed a cylinder for the express 

 purpose of generating heat by friction, by having 

 a blunt borer forced against its solid bottom, 

 while the cylinder was turned around its axis by 

 the force of horses. To measure the heat de- 

 veloped, a small round hole was bored in the 

 156 



