364 GREENLAND A'OYAGE. 
mass of vapour, neither varying in size nor form, 
for a quarter of an hour together, it was in reality 
changing the whole of the particles of which it 
consisted, perhaps every minute. The cause of 
this phenomenon is to be looked for either in elec¬ 
tricity or temperature. In the case before us, 
however, the agent is most probably electricity. 
Thus damp air, otherwise transparent, when it 
comes in contact with elevated peaks, or rather 
within the sphere of its electric atmosphere, be¬ 
comes obscure from the deposition of moisture: 
this obscurity continues during its passage through 
the sphere of electrical influence, and then is im¬ 
mediately redissolved, and disappears. 
This doctrine, substituting changes of tempera¬ 
ture or changes of humidity, for changes in the 
electrical action, will enable us, I conceive, to ex¬ 
plain the phenomenon of the suspension of clouds, 
without resorting to the uuphilosophical opinion 
of the existence of vesicular vapour lighter than 
air. We shall suppose two portions of perfectly 
humid air, of different temperatures, to be com¬ 
bined, no matter by what cause, in that part of 
the atmosphere usually occupied by clouds. The 
effect, on the principle of Dr Hutton’s ingenious 
theory of rain, must be a condensation of a portion 
of moisture in the form of vapour. This vapour, 
however fine its particles, or whether its particles 
