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    Naturevolume 101pages9394 (1918) | Download Citation



    INFRA-RED SOLAR SPECTRUM.—By the use of plates stained with dicyanin, Mr. W. F. Meggers, of the Washington Bureau of Standards, has obtained, an excellent series of photographs of the solar spectrum in the region from 6800 A to 9600 A (Astrophysical Journal, vol. xlvii., p. 1). These photographs thus provide material for accurate determinations of wavelengths in continuation of the classic tables of Rowland, which did not extend further than the approximate limit of the visible spectrum at 7300 A. Photographs in the same part of the spectrum of more than forty of the chemical elements have also been taken, and nearly 400 of the solar lines have been identified with lines in the spectra of eighteen elements. Two hundred lines are accounted for by iron, sixty-three by nickel, twenty-seven by titanium, twenty-two by cobalt, and smaller numbers by chromium, silicon, manganese, calcium, and other elements. One thousand six hundred lines remain for the present unidentified. In addition to the well-known bands due to terrestrial oxygen, there are others which appear to be due to water vapour. The separation of the solar and telluric lines has been undertaken at the Allegheny Observatory by the solar rotation method. Publication of the wavelengths is postponed, but reproductions of the solar photographs, with wave-length scales, are included in the paper.

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