The aerial currents - cyclones, anti-cyclones and dry S.E.
The Atlantic cyclones penetrate to the Russian plains, mitigating to some extent the cold of winter, and in summer bringing with them their moist winds and thunderstorms. Their influence is chiefly felt in W.
The laws and relations of the cyclones and anti-cyclones in Russia are not yet thoroughly understood.
It appears, however, that in January the cyclones mostly travel across N.W.
In July they are pushed farther towards the N., and cross the Gulf of Bothnia, while another series of cyclones sweep across middle Russia, between 50° and 55° N.
Nor are the laws of the anti-cyclones established.
Among the more remarkable phenomena of the hotter seas of Asia must be noticed the revolving storms or cyclones, which are of frequent occurrence in the hot months in the Indian Ocean and China Sea, in which last they are known under the name of typhoon.
The cyclones of the Bay of Bengal appear to originate over the Andaman and Nicobar islands, and are commonly propagated in a north-westward direction, striking the east coast of the Indian peninsula at various points, and then often advancing with an easterly tendency over the land, and passing with extreme violence across the delta of the Ganges.
The cyclones of the China Sea also occur in the hot months of the year, but they advance from north-east to south-west, though occasionally from east to west; they originate near the island of Formosa, and extend to about the 10th degree of N.
The forms of these flocculi show that all sun-spots are vortical in nature, and are probably analogous to terrestrial cyclones or tornadoes.
At the close of the dry season (end of February) cyclones from the N.E., usually accompanied by rain and thunder, burst over the land.
From January to the middle of April, Mauritius, in common with the neighbouring islands and the surrounding ocean from 8° to 30° of southern latitude is subject to severe cyclones, accompanied by torrents of rain, which often cause great destruction to houses and plantations.
While these are tracks frequently followed by the centres of barometric depressions, individual cyclones may and do cross the country in all directions, though very rarely indeed from east to west or from north to south.
The rainfall of England, being largely due to passing cyclones, can hardly be expected to show a very close relation to the physical features of the country, yet looked at in a general way the relation between prevailing winds and orographic structure is not obscure.
In the face of great natural catastrophes, such as river inundations, famines, tidal waves and cyclones of the lower provinces of Bengal, the religious instinct works with a vitality unknown in European countries.
The south-east winds blow from the arid lands and carry rising temperatures across the state; and the winter anti-cyclones from the north-west carry low temperatures even to the southern border.