Spectrum analysis in its application to terrestrial substances, and the physical constitution of the heavenly bodies / Familiarly explained by the late H. Schellen. Trans. from the 3d enl. and revised German edition by Jane and Caroline Lassell.

  • Heinrich Schellen
Date:
1885
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Licence: Public Domain Mark

Credit: Spectrum analysis in its application to terrestrial substances, and the physical constitution of the heavenly bodies / Familiarly explained by the late H. Schellen. Trans. from the 3d enl. and revised German edition by Jane and Caroline Lassell. Source: Wellcome Collection.

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    <j o a c/} . -1 u 'S (f) u Uh I ro d U^ To facilitate reference to any portion of the solar spectrum (Plate XIV., Nos. I, 9, IO), Fraunhofer, whose drawing is given in Fig. 31, designated e/g/it of the most prominent lines by the letters A, B, C, D, E, F, G, H ; of these lines A and B lie in the red, C in the red near the orange, D in the orange, forming a double line with a high power, E in the yellow, F on the borders of the green and blue, G in the dark blue or indigo, and FI in the violet. Besides these lines, there is a noticeable group a of fine lines between A and B, and also a group b, consisting of three fine lines,* between E and F. It may here be remarked that Fraunhofer found that the Posi- tion of the two dark lines in the solar- spectruni, designated by him D were coincident with the two bright lines, now known as the double sodium line, shown by the light of a lamp. The whole of the dark lines of the solar spectrum have been called, after their discoverer, the Fraunhofer lines. In forming the spectrum, if instead of a prism of crown glass one of flint glass is employed, the dispersion of the light will be greater and the length of the spectrum increased. ln consequence of this extension the * [Better marked even than E in the present state of the solar spectrum.]
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