“PHOTOGRAPHIC MAP OF THE SOLAR SPECTRUM / MADE BY PROF. H. A. ROWLAND, JOHNS HOPKINS UNIVERSITY.” This is from the first series, and extends from 30.75 to 37.1 units .
Henry A. Rowland, the first professor of physics at Johns Hopkins University in Baltimore, Md., produced a photographic map of the solar spectrum using concave diffraction gratings made with his own ruling engine. The first edition, published in 1886, covered the region from wave-length 3100 to 5790. The scale of these maps was much greater than the maps of Angstrom or Rutherfurd, and they showed many more spectral lines.
According to “Photographs of the Solar Spectrum,” American Journal of Science 31 (1886): 319, "Seven plates on heavy albumen paper are offered for sale. Six contain two strips of the spectrum, and one contains three. The price for the set is $10, or $12 if mounted on cloth."
Ref: “Photograph of the Normal Solar Spectrum. Made by Professor H. A. Rowland,” Johns Hopkins University Circular 5 (1886).
Rowland, 'A Discussion of the Wavelengths of Lines in the Solar Spectrum,' American Journal of Science 33 (1887): 182-190.
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