Measurements of thermal and ordinary diffusion in gas mixtures (H₂ — N₂, H₂ — O₂ and H₂ — He) by using ultrasonic

Measurements are carried out on thermal diffusion of H₂-He, H₂—N₂ and H₂—O₂ mixtures whereby the change of the concentration is determined from sound velocity measurements. Using the method formulated by Jones and Furry, measurements are made on the change of sound velocity caused by the change of concentration as a function of time and from this the mutual diffusion coefficient D ₁₂ can be determined for the different mixtures as a function of temperature. A good agreement is obtained with the values calculated from the equations of Hirschfelder.