METEOROLOGY. 20% 
of weakness and relaxation. In spring it furthers the progress of vegetation 
in a remarkable degree, and causes the snow to melt very rapidly. It is 
most violent on the Lake of the Four Cantons, where it sometimes tears up 
nets lying deep in the water. It lasts generally but for a few hours, 
occasionally, however, for eight or more days; it blows with greatest 
intensity in spring and autumn, rarely in winter, and very seldom in 
summer. This wind was very remarkable in its appearance on the 18th 
of July, 1841, when it extended at the same time over a‘ great part of 
Germany, even reaching as far as the Black Forest and the Odenwald. 
The Mistral of South France cannot be considered as a wind allied to 
the sirocco and f6éhn; it is rather a very violent north-west wind, 
generally dry and cold, extending as a north wind as far as Algiers. 
The hot winds in the south-eastern part of New Holland are very 
remarkable ; these come from the high mountains in the north and 
north-east, and hardly yield to the hottest winds of Africa in their’ 
temperature. 
Cold winds are less conspicuous and frequent than warm. They are felt 
in long valleys, and come from northern side valleys, and are especially cold 
when these contain ice and snow the year round. Winds of this character 
are principally found in Thibet, and are called Burana when they are 
stormy. In the deserts of Beloochistan they are accompanied during the 
summer months by copious falls of rain. The cold storms of the Russian 
Steppes, called Wiuga, are exceedingly devastating, being accompanied by 
snow squalls, and lasting generally three days. 
Whirlwinds arise from the meeting of two winds blowing from opposite 
directions ; these sometimes, even on calm days, set sand, dust, &c., into a 
whirling motion, frequently lifting these objects to a considerable height. 
Very violent whirlwinds produce the so-called trombs or weather columns, 
also called wind or water spouts, as they occur on land or over the water. 
The name tromb (French) is borrowed from the trumpet-shape of the 
object. In every phenomenon of this nature there is a kind of cloud which 
descends in a hollow column from the clouds above to the earth. or to the 
surface of water. This progresses with varying velocity, rotating on a 
vertical axis, and taking up water as well as dry substances, which it 
sometimes elevates to the height of several hundred feet. These spouts 
generally form a hollow, straight, or curved double cone, whose upper part, 
with the point downwards, proceeds from a cloud; the lower part, with the 
point directed upwards, consisting of water, sand, and other substances. 
The color is generally grey, dark blue, dark brown, and sometimes fiery 
red ; the middle portion is frequently transparent.’ The force exercised by 
these spouts is, in many cases, truly enormous ; they uproot trees. unroof 
houses. hurl men and other objects to a great distance, &c. The motion 
of the spout is often very rapid and tempestuous, some traversing seven or 
eight miles in an hour, while others can readily be followed on foot; they 
rarely, however, stand still. Horner asserts the following propositions with 
regard to water-spouts proper. They arise for the most part only in the 
vicinity of land where inconstant winds blow and the temperature is very 
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