On the Properties of Liquefied Gases

Abstract

M. E. MATHIAS has just published in the form of an inaugural thesis (Gauthier-Villars, Paris), an important investigation on the latent heat of vaporization of liquefied gases. The value of this coefficient for sulphurous acid, carbonic acid, and nitrous oxide was determined experimentally throughout a considerable range of temperature by the following method. The gases were first liquefied in a small copper cylinder, 9 cm. in height, 3 cm. in diameter, with walls 0˙38 cm. in thickness. The cylinder was then weighed and introduced into an ordinary Berthelot calorimeter, and the liquefied gas was allowed to evaporate slowly, the pressure being constantly read off on a Bourdon gauge and regulated by means of two conical screw taps. The calorimetrical method employed was a null one (devised by the author), the heat absorbed by the evaporation of the liquid being compensated for by adding sulphuric acid of known strength to the water in the calorimeter, at such a rate as to keep its temperature approximately constant. The total amount of heat absorbed was thus easily determined, while the correction for cooling was reduced to a minimum. When necessary the laboratory was heated by means of regulated gas-burners, so that the liquid in the calorimeter and the surrounding atmosphere were at the same temperature in all cases. Seven experiments on liquid sulphurous acid between the temperatures of + 5°˙74 and + 19°˙95 gave values for L, the latent heat of vaporization, which may be expressed by the empirical formula—