Measurements are made on the viscosity of, hydrogen-and deuteriumgas (purity 99.6% in weight) at room temperature, and at temperatures obtained with liquid oxygen and hydrogen.
At room temperature is found ~lh,/~ln.. = 1.39, which is in agreement with the classical theory of viscosity. At lower temperatures there is a gradual decrease of this ratio ; at temperatures of liquid oxygen it is equal to 1.35 and at liquid hydrogen temperatures to 1.24. We do not believe that this decrease can be attributed to the presence of the small quantity of H.. in the D~-gas. § 1. Introduction. Following our previous systematic investigations 1) on the viscosity of gases at low temperatures, we have now determined the viscosity of light and heavy hydrogen at room te mperature, and at temperatures obtainable with liquid oxygen and liquid hydrogen.
From a theoretical standpoint the investigation in question can be considered to be of great interest as is shown by the theoretical calculations made by U e h 1 i n g 2) on the transport phenomenon in gases at low temperatures.
Up to the present measurements on the viscosity of deuterium gas at temperatures obtained with liquid hydrogen are completely 1 acking. At room temperature measurements on the viscosity of deuterium have been carried out by A n d u r 3), T o r r e y 4) and lastly by v a n C 1 e'a v e and M a a s s 5). The results of all these investigators show that at room temperature the ratio between the viscosity of deuterium and hydrogen is equal to a/2, within the limits of experimental errors. This is in agreement with the well known class---938 --*) Prof. K e e s o m tells us that measurements on the viscosity of hydrogen vapour will be repeated.