Note on the Equivalent Absorption Coefficient for Diffused Resonance Radiation

It is shown that the ideas expressed in the preceding theoretical paper by Kenty when applied to the diffusion of resonance radiation in a layer of gas of finite thickness provide a method of calculating an equivalent absorption coefficient of the gas for all the frequencies due to the Doppler effect that are present in the diffusing radiation. This average absorption coefficient is calculated and compared with a similar quantity calculated on the basis of a different point of view by Samson. Both average absorption coefficients are discussed in connection with the author's experiments (1927) on the rapidity of escape of resonance radiation emitted from a slab of mercury vapor after the cut-off of the excitation.