The dielectric coefficients of gases.— Part I. The rare gases and hydrogen

The heterodyne beat method affords a means of measuring the dielectric coefficients of gases with a relative accuracy exceeding that of any of the older determinations, and in consequence it has been employed by a number of observers during recent years. The published results, however, in many cases, refer mainly to the method, and measurements are restricted to one or two gases apparently selected at random. Such determinations when made at different temperatures suffice to determine the electric moment, but owing to the great difficulty of measuring the absolute values, the figures for the dielectric coefficients themselves obtained by different observers cannot be co-ordinated.