PHOSPHORESCENCE. 55 
son, who states that during a storm on the 30th 
July, 1797, at about five in the morning, certain 
clouds were observed to shine first with a red, and 
afterwards with a blue, light. 
De Luc affirms also, that one winter’s night, in 
the neighbourhood of London, he observed a lwma- 
nous cloud extending east and west across the 
southern meridian of the place, about 30 or 40 
degrees from the zenith. The atmosphere was 
clear but not cold, and “there were no signs of 
electricity.’”’* 
One of the most authentic and curious observa- 
tions of lwminous fogs was lately communicated in 
a letter to M. Elie de Beaumont by M. L. F. 
Wartmann,t of Geneva. The strange phenomenon 
was observed during nine successive foggy nights, 
from the 18th to the 26th of November, 1859. The 
moon being new, was invisible and absent from 
the heavens of Geneva. But avast fog, not damp 
enough to wet the earth, but so opaque as to 
render invisible the borders of the river Leman 
and the mount Salése, hovered permanently over 
Geneva and its environs. ‘This foe diffused so 
much phosphoric light, that M. Wartmann could 
easily distinguish books, etc., upon his table, with- 
* For more ample details on some of these phenomena, see 
Beccaria, ‘ Dell’ Elettricismo terrestre atmosferico;’ Delue, ‘ Idées 
sur la Météorologie, and Arago, in the ‘Annuaire’ for 1838. 
+ Comptes-Rendus of the Academy of Sciences, Paris, 25 De- 
cember, 1859. 
