482 Life of Count Rumford. 



furnished by the air, for in one. set of the experiments, 

 the apparatus being immersed in water, the atmospheric 

 air was excluded. Nor yet was the heat furnished by the 

 water, because, first, the water was receiving heat from 

 the machinery, and therefore could not at the same 

 time be giving heat to it ; and, second, because there 

 was no chemical decomposition of the water. So con- 

 siderate and cautious had the Count's method been, that, 

 allowing for the possibility of this latter contingency, 

 he had been on the watch for any sign of the decom- 

 position of the water by the escape of either of its com- 

 ponent elastic fluids, and had even made preparations 

 for seizing and examining any air-bubbles which might 

 rise through it. It being evident that the heat was not 

 to be referred to either of these sources, and that the 

 source of it, as generated by friction, was inexhaustible, 

 the conclusion reached by Rumford is thus expressed in 

 his own clear language. 



" It is hardly necessary to add that anything which any in- 

 sulated body or system of bodies can continue to furnish with- 

 out limitation cannot possibly be a material substance ; and it 

 appears to me to be extremely difficult, if not quite impossible, 

 to form any distinct idea of anything capable of being excited 

 and communicated in the manner the Heat was excited and 

 communicated in these Experiments, except it be MOTION. 



" I am very far from pretending to know how, or by what 

 means or mechanical contrivance, that particular kind of mo- 

 tion in bodies which has been supposed to constitute Heat is 

 excited, continued, and propagated, and I shall not presume to 

 trouble the Society with mere conjectures ; particularly on a 

 subject which, during so many thousand years, the most en- 

 lightened philosophers have endeavored, but in vain, to com- 

 prehend. 



" But, although the mechanism of Heat should, in fact, be 



