2 M. R. Clausius on the Moving Force of Heat, 



from a warm body to a cold one ; for example, the vapoui- which 

 is generated in tne boiler of a steam-engine, and passes thence 

 .to the condenser where it is precipitated, carries heat from the 

 fireplace to the condenser. This transmission Carnot regards as 

 the change of heat corresponding to the work produced. He 

 says expressly, that no heat is lost in the process, that the quan- 

 tity remains unchanged ; and he adds, " This is a fact which 

 has never been disputed ; it is first assumed without investigation, 

 and then confirmed by various calorimetric experiments. To 

 deny it, would be to reject the entire theory of heat, of which it 

 forms the principal foundation." 



I am not, however, sure that the assertion, that in the pro- 

 duction of work a loss of heat never occiu's, is sufficiently esta- 

 blished by experiment. Perhaps the contrary might be asserted 

 with greater justice ; that although no such loss may have been 

 directly proved, still other facts render it exceedingly probable 

 that a loss occurs. If we assume that heat, like matter, cannot 

 be lessened in quantity, we must also assume that it cannot be 

 increased ; but it is almost impossible to explain the ascension 

 of temperature brought about by friction otherwise than by 

 assiuning an actual increase of heat. The careful experiments 

 of Joule, who developed heat in various ways by the application 

 of mechanical force, establish almost to a certainty, not only the 

 possibiUty of increasing the quantity of heat, but also the fact 

 that the newly-produced heat is proportional to the work ex- 

 pended in its production. It may be remarked further, that 

 many facts have lately transpired which tend to overthrow the 

 hypothesis that heat is itself a body, and to prove that it con- 

 sists in a motion of the ultimate particles of bodies. If this be 

 so, the general principles of mechanics may be applied to heat ; 

 this motion may be converted into work, the loss of vis viva in 

 each particular case being proportional to the quantity of work 

 produced. 



These circumstances, of which Camot was also well aware, and 

 the importance of which he expressly admitted, pressingly de- 

 mand a comparison between heat and work, to be imdertaken 

 with reference to the divergent assumption that the production 

 of work is not only due to an alteration in the distribution of 

 heat, but to an actual consumption thereof; and inversely, that 

 by the consumption of work heat may be produced. 



In a recent memoir by Holtzmann*, it seemed at first as if the 

 author intended to regard the subject from this latter point of 

 view. He says (p. 7), " the effect of the heat which has been 

 communicated to the gas is either an increase of temperature 



* Ueber die Wdrme und Elasticit'dt der Gase und Diimpfe, von C. Holtz- 

 mann. Manheim, 1846. Also Taylor's Scientific Memoirs, Part XIV.p. 189. 



