A text-book of general astronomy : for colleges and scientific schools (1888)
Young, Charles A. (Charles Augustus), 1834-1908 · Boston ; London : Ginn & Company · leaf 214
ions stated are due to suchsubstances only. Observation needs to be directed to the special point todetermine whether all of the dark lines are reversed at the edge of the sun,or only a few ■ and if so, what ones. 321. Sun-Spot Spectrum. — This is like the general solar spectrum,except that certain…
Astronomy
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