Rime Cloud observed in a Balloon

Abstract

IN his letter, inserted in NATURE, vol. xxv. p. 507, Dr. Hermann Kopp says that “when Kratzenstein (1744) advocated the opinion anticipated by Halley (1686), that water-vapour may be condensed in a vesicular state, he availed himself of the observation that in clouds and mists and condensed steam over boiling water, a rainbow is not to be observed in reflected light.” I have good grounds to suppose these negative observations were made only because the intensity of reflected light was not sufficient, as a white rainbow is produced under these circumstances. In support of these assumptions, I may be allowed to quote an observation published by M. Faye in vol. xxviii. of the Comptes rendus, 1849, p. 244, where the celebrated astronomer says:—