The ratio of the specific heats of hydrogen

The investigation of the ratio of the specific heats,cp /cv =γ , of hydrogen described in the present communication was undertaken during the summer of 1923 by the method previously used with air, carbon dioxide, oxygen and nitrogen. The gas used was electrolytic hydrogen, supplied by the British Oxygen Company, and was purified in the same way as the oxygen in the previous experiments, except that the four U-tubes now contained quicklime, caustic soda, and two tubes of calcium chloride, in the order given. Phosphorus pentoxide was, as before, used for the final drying of the gas. The globe A, fig. 1 in the paper of 1924, was, before the commencement of the experiments, filled with pure nitrogen from previous measurements. The purified hydrogen was passed directly into the globe until the nitrogen had been completely displaced, and there was thus no danger that an explosive mixture of hydrogen and oxygen could be formed, which might have been ignited by contact with the thin platinum wires of the bolometer, or, at least, might have formed moisture by slow reaction in contact with the platinum.