METEOROLOGY. 219 
of February. The rain drops of these and other tropical regions are 
remarkable for their magnitude, and produce a very unpleasant sensation on 
the naked skin. In the East Indies, where monsoons blow instead of trade 
winds, there are varying conditions of rain, the rainy season on the eastern 
coast occurring at the time of the north-east monsoon ; that on the west coast 
at the time of the south-west monsoon. The rainy region of the calms does 
not possess any periodical rain. In some regions of the earth rains seldom, 
if ever, occur ; among these are Egypt, the desert of Sahara, the high plains 
of Persia, northern Arabia, a part of Thibet, of Mongolia, &c. This is 
especially the case with the extensive arid and barren plains out of the 
tropics. The great heat and dryness of the countries is to be considered as 
the cause of this deprivation. Even on the high seas in those countries, 
where the trade winds blow regularly, rain is very rare, and the sky almost 
always clear. Rainis more abundant in the vicinity of mountain ranges on 
the warm plains of Asia and Africa. When, for instance, the vapors of the 
Mediterranean are carried south and east by a north wind, they become 
heated in their passage, and are thereby further removed from the condition 
of saturation. To this they again approximate by rolling up the slopes of 
the high mountains, and thereby coming into colder regions. Mountains 
everywhere exert a great influence on rain, the gathering of clouds about a 
mountain top being generally the precursor of approaching rain. 
With regard to the condition of Europe in respect to rain, we find in 
Portugal a country where this is almost entirely absent during summer. 
North of the Pyrenees, however, copious showers occur in greater or 
less abundance throughout the whole year. To the north then of the 
Pyrenees and the Alps, we may distinguish two groups of climate, called by 
Kaemtz the middle European and the Swedish. In the former rain 
generally accompanies westerly winds, in the latter easterly, the westerly 
winds losing their water in crossing the crests of the Scandinavian moun- 
tains. St. Petersburgh and Moscow appear to lie on the confines of the 
two regions of climate, since there is a prevalent wind at neither of these 
places. In passing from the western coast of England to the interior of 
Europe, we shall find the annual amount of rain, as also the number of 
rainy days, to decrease continually. Calling the annual amount of rain at 
St. Petersburg unity or one, then on the coast of England this same 
amount is 2.1, in the interior of England 1.4, on the plains of Germany 1.2; 
although particular places may present considerable deviations from these 
proportions. Thus in western and southern England the annual fall of rain 
amounts to thirty-five inches, while in Kendall it is fifty, in Dover forty-four, 
in Bristol twenty-two inches; in middle and eastern England it is on an 
average a little over twenty-five, in Dumfries thirty-four, and in Glasgow 
only twenty inches. In France and Holland it is about twenty-four, and 
in Brussels only eighteen inches. In Tegernsee it is forty-four, in Augs- 
burg thirty-seven, in Carlsruhe, Ulm, and Géttingen, twenty-five, in 
Manheim and Ratisbon twenty-one, in Prague fifteen, in Wurzburg 
fourteen, in Erfurt only twelve and a half inches. In St. Petersburg it is 
seventeen, in Abo twenty-four, in Buda sixteen, in Copenhagen seventeen, 
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