Franks. Litteratur. 117 II. C. Vogel. Ueber Sternspectra. Vierteljahressehr. Astr. Ges. 22, 57—59. Beibl. 12, 104. Spectroscopic Astronomy in 1887. Monthl. Not. 48, 218. Photographie Study of Stellar Spectra. Ibid. 220 (Rep. R. A. S.) L. Elkin. Heliometer Determinations of the Relative Places of the Principal Stars of the Pleiades. (Trans. Astr. Obs. of the Yale Univ. 1887.) R e f. Naturw. Rundsch. 3, 60. Monthl. Not. 48, 210 (Rep. R. A. S.) 4. B . r