Cloud shadow, noon

Study of a lighting effect caused by atmospheric dust and gases ejected by the 1883 volcanic eruption on the island of Krakatoa (Krakatau, Indonesia). Shadows cast by a cloud observed in the midday sun at Jena, Germany, 10 September 1887. Plate 4 from the book Untersuchungen uber Dämmerungserscheinungen zur Erklarung der nach dem Krakatau-ausbruch beobachteten atmospharisch-optischen Storung, by J. Kiessling (Hamburg, Leopold Voss, 1888). The plate is inscribed above: ‘Kiessling, Dämmerung-Untersuchungen. Taf. IV.’ Inscribed below: ‘WOLKENSCHATTEN NACH DER STORUNGSPERIODE. (MITTAG). [Cloud shadow after a disturbed period]. Pechuel-Loesche. Jena, Sept. 10 1887. Chromolithographie von Leo Kempner & Co. in Hamburg. Verlag von Leopold Voss in Hamburg (und Leipzig).’ Karl Johann Kiessling (1839-1905) German physicist, replicated twilight glow phenomena in the laboratory.