The ratios of the specific heats of nitrogen at atmospheric pressure and at temperatures between 10˚ C. and - 183˚C

Abstract

These measurements of the ratios of the specific heats of nitrogen, at room and at lower temperatures, have been made, and the results have been calculated, in exactly the same way as those obtained when air and hydrogen were used. The latter were described in a former paper, (1) in which will be found a description of the apparatus and an account of the method of dealing with the experimental results. In the work which follows the same apparatus was employed, the only changes being that a new platinum wire (from the same reel) was used on the thermometer, and, owing to breakage, a rather finer quartz suspension had been put on the galvanometer. However, as the apparatus had to be dismantled for transference to another laboratory I thought it desirable to confirm some of the effects and relationships previously noted; therefore, a full set of experiments with the four expansion vessels was made a t room temperature. It may be recalled that the method has been especially worked out, using small expansion vessels in order that values of the ratios of the specific heats can be readily obtained at different temperatures. Up to the present time work has been restricted to determinations at temperatures below that of the laboratory. Several vessels are used in order to allow a correction to be made for a systematic change in the apparent value of the ratio, which depends on the size of the vessel employed. The nitrogen was supplied by the British Oxygen Company, and was stated to contain less than ½ of 1 per cent, of impurity, mostly oxygen. I am indebted to Mr. D. Newitt for six analyses of gas taken from the apparatus at various times during the course of the experiments. All of these show that the percentage impurity was less than the amount stated above.