46 W. Ferrel—Cyclones, Tornadoes and Waterspouts. 
The draught of the ascending current, as we have seen, is 
mostly near the earth’s surface. en the base of the gyrat- 
ing column of air strikes the mountain side, this draught is 
somewhat cut off, and the whole system somewhat broken up, 
and the power of the tornado destroyed. Hence the whole 
accumulation of water is sometimes poured down, almost at 
once, on the side of the mountain, tearing up rocks and trees, 
and causing a great ravine. 5 
Hail-storms.—As in tornadoes, there is a stratum of air ~ 
a 
ean fall to the earth, and as they may fall very slowly and 
1 
become suddenly weakened, or the whole system broken up, 
all this hail would fall rapidly to the earth, and hence the 
almost incredible amounts of hail] which are said to fall some- 
times in a very short space of time. 
A considerable amount of rain may be carried some distance 
up into the snow region before it has time to freeze. By the 
mixture of rain and snow, small balls of very moist snow are 
formed, which, being carried out where the strength of the 
ascending current permits them to fall slowly, they continue to 
grow until they become heavily coated with solid ice, and 
finally reach the earth. It is in this way that the large hail- 
stones with a snowy kernel within are formed. But these in 
falling are sometimes carried by the indrawing current below 
