trum Wave Lengths. Experience has shown that some lines of intensity -3 listed by Rowland do not appear on modern spectrograms, although the same plates bring out other weak lines not observed by him. This is particularly true near the ultraviolet limit of the solar spectrum. With regard to the line À 3122.78 of gold, the doubt may now be removed. Our solar spectrograms confirm the presence of a -3 line in the disk at % 3122.79, very near the limit of visibility, in good agreement with Rowland.

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... This observation by itself would not be conclusive, for reasons adduced by Moore and King, but our spectrograms of sunspots show that the line is moderately strengthened in spots, where we estimate its intensity as -2. Atmospheric and instrumental scattering are usually sufficient, in this region of the spectrum, to obscure all of the delicate distinctions between the spectra of disk and spot. It is therefore probable that the true intensity of this line in the spot is about -1. This moderate strengthening in the spot (typical behavior for a line of low excitation potential), together with the satisfactory correspondence in position of the solar and laboratory lines, would seem to justify the statement that gold is now identified in the sun.