Page:Reflections on the Motive Power of Heat.djvu/35

Rh  des corps entre lesquels se fait, en dernier résultat, le transport du calorique.”

“Lorsqu'un gaz passe, sans changer de température, d'un volume et d'une pression déterminés à une autre pression également déterminée, la quantité de calorique absorbée ou abandonnée est toujours la méme, quelle que soit la nature du gaz choisi comme sujet d'expérience.”

Perhaps as remarkable a discovery as any one of the preceding (and one which, like those, has been rediscovered and confirmed by later physicists; one which was the subject of dispute between Clausius, who proved its truth by the later methods which are now the source of his fame, and the physicists of his earlier days, who had obtained inaccurate measures of the specific heats of the gases;—values which were finally corrected by Regnault, thus proving Carnot and Clausius to be right—is thus stated by Carnot, and is italicized in his manuscript and book:

“La différence entre la chaleur spécifique sous pression constante et la chaleur spécifique sous volume constant est la même pour tous les gaz.”

He bases his conclusion upon the simplest of thermodynamic considerations. He says that the increase of volumes with the same differences of temperature are the same, according to Gay-Lussac