Regnault's Experiments on the Joule-Thomson Effect

Abstract

THAT Regnault made a number of experiments similar to some of those described by Joule and Kelvin in their papers on the thermal effects of fluids in motion does not seem to be commonly known; at all events, the numerical results of his work on this subject are not often mentioned. After experimenting on the flow of gases through small holes in thin plates, and through long capillary tubes, he followed the example of Joule and Kelvin in using porous bodies, especially discs and tubes of soft; unglazed porcelain. He found great difficulty in getting definite results, especially in the regard that the temperature observed in the stream of gas issuing from the porous wall depended on the position of the thermometer. He concludes the account of his experiments in the following words:—“Après ces tentatives infructueuses et beaucoup d'autres dont je ne parlerai pas, j'ai renoncé à l'espoir d'obtenir quelque chose de précis, d'expériences fondées sur la mesure de températures dans les courants gazeux, et il ne m'est resté que le regret d'avoir consacré beaucoup de temps à des recherches stédies” (Regnault, “Relation des Experiences,” vol. iv., p. 707, 1870).