Experiments on heavy hydrogen.―Part I

With the exception of those investigation in which spectroscopic or massspectrographic methods were applicable, earlier workers on the heavy hydrogen isotope (deuterium of diplogen denoted by H2 or by D) have determined the ratio H to D from measurements of the specific gravity of the water obtained from the heavy hydrogen. One per cent. of diplogen causes an increase of about one part in 1000 in the specific gravity. The density measurement may be made with great accuracy, but at least 3-4 mg. of water are required for every determination. A convenient and reliable determination can be made with a very much smaller quantity of material, both accurately and rapidly, utilizing the thermal conductivity of the gas to indicate its composition in the following manner.