Lessons in astronomy including uranography. A brief intoductory course without mathematics (1896)
Young, Charles A. (Charles Augustus), 1834-1908 · Boston, London, Ginn and company · leaf 139
sary for this purpose,the spectroscope must be so arranged that the observer canconfront the spectrum of sunlight with that of the substanceto be tested. In order to do this, half of the slit is coveredby a little reflector or comparison prism, which reflects intothe tube the light of the sun,… … Fig. 34. — Comparison of the Spectrum of Iron with the Solar Spectrum. From aNegative by Professor Trowbridge. made by sunlight, while the upper half is made by light com-ing from an electric spark between two metal points, say ofiron. This latter spectrum will show the bright lines of ironvapor,…
Astronomy
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