56 METEOROLOGICAL 
out having recourse to any other ight. Moreover, 
he questioned a person who had gone on foot from 
Geneva to Annemasse, in Savoie, on the 22nd of 
November: he had started at half-past ten at 
night, and declared that he saw his way the whole 
distance as if it had been a moonhght might. M. 
Auguste de la Rive was, that same night, at some 
distance from Geneva, and was also surprised at 
the distinctness with which he saw his road and 
the objects around him. 
The celebrated dry fog of 1783 was described 
by M. Verdeil, a physician of Lausanne, as having 
diffused at night, a lwminosity sufficiently intense 
to render distant objects visible, and this hght was 
equally spread in all directions. It resembled the 
light of the moon seen through the clouds. 
This dry fog, m which objects could be seen at 
night at a distance of 600 feet, lasted a whole 
month ; it made its appearance nearly at the same 
time in many distant places, spreading from the 
north of Africa to Sweden; it was likewise ob- 
served over a great portion of North America, 
but was not seen to spread over the sea. It ap- 
peared to reach higher than the summits of the 
highest mountains, and neither wimds nor rain 
had any power to disperse it. In Europe this fog 
exhaled a disagreeable odour, was remarkably dry, 
did not affect the hygrometer, and possessed the 
remarkable phosphoric quality I mentioned above. 
