264 RUDOLF JULIUS EMANUEL CLAUSIUS. 



called the diagregation, and regarded as determined by the positions 

 of the elementary parts of the body without reference to their veloci- 

 ties. In this respect it differed from the entropy. An immediate 

 consequence of these relations is that for any reversible cyclic process 



1?=' 



and therefore that H, the molecular vis viva of the body, must be 

 a function of the temperature alone. This important result was 

 expressed by Clausius in the following words : " Die Menge der in 

 einem Korper wirklich vorhandenen Warme ist nur von seiner 

 Temperatur und nicht von der Anordnung seiner Bestandtheile 

 abhangig." 



To return to the equation 



= tdZ. 



This expresses that heat tends to increase the disgregation, and that 

 the intensity of this tendency is proportional to the absolute tempera- 

 ture. In the words of Clausius: "Die mechanische Arbeit, welche 

 die Warme bei irgend einer Anordnungsanderung eines Korpers thun 

 kann, ist proportional der absoluten Temperatur, bei welcher die 

 Aenderung geschieht." 



Such in brief and in part were the views advanced by Clausius in 

 1862, in his memoir, "Ueber die Anwendung des Satzes von der 

 Aequivalenz der Verwandlungen auf die innere Arbeit." i Although 

 they were advanced rather as a hypothesis than as anything for 

 which he could give a formal proof, he seems to have little doubt of 

 their correctness, and his confidence seems to have increased with the 

 course of time. 



The substantial correctness of these views cannot now be called in 

 question. The researches especially of Maxwell and Boltzmann have 

 shown that the molecular via viva is proportional to the absolute 

 temperature, and Boltzmann has even been able to determine the 

 precise nature of the functions which Clausius called entropy and 

 disgregation. t But the anticipation, to a certain extent, at so early a 

 period in the history of the subject, of the ultimate form which the 

 theory was to take, shows a remarkable insight, which is by no 

 means to be lightly esteemed on account of the acknowledged want of 

 a rigorous demonstration. The propositions, indeed, as relating to 

 quantities which escape direct measurement, belong to molecular 

 science, and seem to require for their complete* and satisfactory 

 demonstration a considerable development of that science. This 



* Pogg. Ann., vol. cxvi, p. 73. See also vol. oxxvii, p. 477 (1866). 

 \Sitzungaberichte Wien. Akad., vol. Ixiii, p. 728 (1871). 



