An English translation of this paper is given in the Astrophysical Journal, xxiv.
The ably the most perfect yet proposed for modern astrophysical research.
In 1875 he was appointed director of the new astrophysical observatory established by the French government at Meudon, and set on foot there in 1876 the remarkable series of solar photographs collected in his great Atlas de photographies solaires (1904).
Descriptions of spectroheliographs by Hale, Deslandres, Newall and others, may be found in various papers in Astronomy and Astrophysics, Astrophysical Journal, Comptes rendus, Bulletin astronomique, and other periodicals.
He was director of the Kenwood Astrophysical Observatory, in Chicago, from 1890 to 1896.