on the Subject of Heat. 2 1 7 



iron, on being forged, is thus increased by a twentieth 

 part. 



" Hence it appears that the experiment of Count 

 Rumford is far from explaining satisfactorily a property 

 which is well known, and called in question by no 

 one. 



" It is easy, it is true, to arrange side by side in 

 an imposing manner the phenomena of heat ; if, how- 

 ever, you were to say to one who has little or no 

 knowledge of chemical speculations, * Count Rumford's 

 cylinder has, in the course of two hours, by means of 

 a violent friction, afforded all the heat required to dis- 

 solve in water, without changing its temperature, 15 

 kilogrammes of ice, or as much as 2 hectogrammes (6| 

 ounces) of oxygen would require [sic] in its combina- 

 tion with phosphorus,' I do not know at which of 

 these phenomena he would be most astonished. 



" The slight changes which can take place in the 

 amount of combined caloric have so inconsiderable an 

 influence on the capacity for work of the caloric within 

 the narrow limits of the thermometric scale, that it 

 cannot be computed. Moreover, we have not, as 

 yet, adequate data for determining the nature of the 

 changes in this respect which take place in a solid body 

 in consequence of the particular condition of condensa- 

 tion into which it has been brought by means of a cer- 

 tain mechanical force, and by degrees of heat differing 

 greatly from each other. 



" Besides, Rumford, in the experiment to determine 

 the specific heat of the filings of bell-metal thus ob- 

 tained, heated them to the temperature of boiling 

 water. But this extremely elastic metal would very 

 naturally as soon as left to itself, and especially dur- 



