Abstract: The invention is related to a method of measuring the ratio .gamma. of the specific heats of a fluid at a given constant pressure C.sub.P and a constant volume C.sub.V corresponding to a given temperature T.sub.o and a given pressure P.sub.o. This method comprises the steps of adiabatically compressing a predetermined mass of the fluid to be examined, detecting the maximum pressure value P.sub.S, measuring said maximum pressure value, measuring the stabilization pressure P.sub.T and computing the specific heat ratio according to the equation:.gamma.=(P.sub.S -P.sub.o)/(P.sub.T -P.sub.o) .

Abstract: Improved device for dispersing into the atmosphere exhaust gases in the form of mixtures having a controlled composition. The device, consisting of a mixing duct provided with an axial injector extending from a supply tube for gas under high pressure, the ratio of the square roots of the areas of the sections of the duct and the injector lying between 30 and 300, is characterized in that it comprises, positioned on the supply tube of the injector, a control mechanism delivering to the injector a flow of gas under a pressure intermediate between the high initial supply pressure and the pressure prevailing in the mixing duct, the control mechanism being provided with means for fixing the maximum value of the pressure at which the gas is delivered to the injector. This improvement in devices for dispersing exhaust gases renders them more efficient when they are used to purge or evacuate the chamber which is not being supplied.

Abstract: This invention concerns a method of analysis by liquid-phase chromatography with programmed elution gradient.According to this method, two chromatography columns, of at least approximately similar porous volume and permeability, are each fed with a mixture of two solvents, in such a way that at any point in time the concentration of one of the solvents at the inlet to the first column is the same as the concentration of the other solvent at the inlet to the second column; the substance for analysis is injected into the inlet of one of the two columns; and the fluids leaving both columns are added to each other to form a mixture for analysis in a concentration detector.The main purpose of the method is to ensure better analysis of petroleum cuts.