Bürgel, Bruno Hans, 1875-, Bloch, Stella · London, New York, [etc.] Cassell and company, ltd. · leaf 239
Fig. 152.—The Black Drop. Fig, 15 3.-Venus, according to theAuthors observation. … Fig. 154.—Irregularities at the Light border of the Venus Sphere, which are supposed to be mountains.
Astronomy
Internet Archive · California Digital Library · Public Domain Mark 1.0. Free to use for anything.
