12 6 Sir H. Davy on the formation of mists. 
May 31st and June 2d and 3d, the nights being very clear, 
the same phenomenon of the formation of mists was observed, 
precisely under the same circumstances ; but as I could exa- 
mine the temperature of the air and of the river only close to 
the banks, and in two or three situations, my observations 
were less precise and less numerous; the mist formed later in 
the evening, and disappeared sooner in the morning than on 
the Danube ; which was evidently owing to the circumstances 
of the atmosphere being warmer and the river colder, the 
temperature of the one being from 66° F. to 73° F. during 
the day, and that of the river, where I examined it, from 59 0 
to 6o° F. 
July 11th. I examined the temperature of the Raab near 
Kermond in Hungary, at 7 o’clock, P. M. and found it 65° F. 
that of the atmosphere being 72 0 F. During the whole 
evening there were some thin fleecy clouds in the western 
sky, which being lighted up by the setting sun, greatly inter- 
fered with the cooling by radiation from the earth, and at half 
past nine the thermometer, in the atmosphere, was still 6g° F. 
and at half past ten 67° F., when there was not the slightest 
appearance of mist. In the morning, before sun-rise, the 
temperature of the atmosphere on the banks was 6i° F., that 
of the river 64° F., and now the bed of the river was filled 
with a white thin mist, which entirely disappeared half an 
hour after sun-rise. 
I made similar observations on the Save in Carniola, in the 
end of August; on the Izonzo in the Friul, in the middle of 
September ; on the Po near Ferrara, in the end of September ; 
and repeatedly on the Tiber and on the small lakes in the 
Campagna of Rome in the beginning of October; and I have 
never in any instance observed the formation of mist on a 
