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 an eruptive form.
Schellen, Heinrich. “Solar Prominence Observed by Zollner.” Paper. 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/wh246t32z.