Count Rumford Identifies Heat 



cylinder for the purpose of introducing a small 

 mercurial thermometer. The weight of the 

 cylinder was 113.13 pounds avoirdupois. 



The borer was a flat piece of hardened steel, 

 o . 63 of an inch thick, four inches long, and nearly 

 as wide as the cavity of the bore of the cylinder, 

 namely, three and one-half inches. The area 

 of the surface by which its end was in contact 

 with the bottom of the bore was nearly two and 

 one-half inches. At the beginning of the experi- 

 ment the temperature of the air in the shade, 

 and also that of the cylinder, was 60 Fahr. At 

 the end of thirty minutes, and after the cylinder 

 had made 960 revolutions round its axis, the 

 temperature was found to be 130. 



Having taken away the borer, he now removed 

 the metallic dust, or rather scaly matter, which 

 had been detached from the bottom of the cylin- 

 der by the blunt steel borer, and found its weight 

 to be 837 grains troy. "Is it possible," he ex- 

 claims, "that the very considerable quantity of 

 heat produced in this expemnent a quantity 

 which actually raised the temperature ,of above 

 113 pounds of gun-metal at least 70 of Fahren- 

 heit's thermometer could have been furnished 

 by so inconsiderable a quantity of metallic dust 

 and this merely in consequence of a change in its 

 capacity of heat?" 



" But without insisting on the improbability of 

 this supposition, we have only to recollect that 

 from the results of actual and decisive ex- 

 periments, made for the express purpose of as- 

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