Abstract
REVISION OF ROWLAND'S WAVE-LENGTHS.—In view of the extreme importance to workers in astrophysics of having a perfectly trustworthy system of standard wave-lengths, Prof. Hartmann reviews, in No. 3, vol. xviii., of the Astrophysical Journal, the methods used by Rowland in constructing his wave-length tables, and points out their sources of error. He shows that Rowland made the metallic arc wave-lengths given in his “New Table of Standard Wave-lengths” coincide with those of the solar spectrum by applying purely empirical corrections which cannot now be found. In a series of tables Prof. Hartmann also shows that differences, amounting in some cases to 003 unit, exist between the solar and metallic wave-lengths, and suggests that further experiments should be performed, on similar lines to those pursued by Michelson and Fabry and Perot, for the purpose of determining a general factor—the F of Fabry and Perot;—by which the whole of Rowland's table might be reduced to a rationalised standard from the equation λ=(F and P)Fo, where (F and P) is the absolute wave-length found by the French observers, and Fo is the factor mentioned above. This would produce an errorless wave-length on Rowland's scale for each of the thirty-three lines measured by Fabry and Perot, which would vary but little from Rowland's values, and yet be free from their systematic errors.
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Our Astronomical Column . Nature 69, 37–38 (1903). https://doi.org/10.1038/069037a0
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DOI: https://doi.org/10.1038/069037a0