Prominences represented in their natural colors, as seen through a large telescope when the slit of the spectroscope was open wide and directed on to the red C-line. These prominences are characteristic of the a nebulous form.
Schellen, Heinrich. “Solar Prominence Observed by Young.” Spectrum Analysis in Its Application to Terrestrial Substances, and the Physical Constitution of the Heavenly Bodies. London, England: M. & N. Hanhart (Printers), 1872. https://digital.sciencehistory.org/works/3197xn19c.