. absorbing atom or molecule is plotted against frequency. The absorption intensities in the individual tables were obtained by taking heights off the microphotometer curve recorded on logarithmic paper and correcting these heights with a photographic characteristic curve to give very approximate values of the optical density associated with the absorbing material. These values can be used as an indication of the distribution of intensities in a band, The width and height of the microphotometer slit was kept the same for all traces. 15 JE