ix Climates of the World 141 



America and North -Western Europe. The monsoon 

 influence of North America is very slight, on account of the 

 position of these two high-pressure areas, and that of North 

 Africa is also remarkably feeble ( 185). The winds of the 

 Indian Ocean and Western Pacific are completely dominated 

 by the vast furnace flue of Western Asia, which attains its 

 maximum effect in July, and destroys the theoretical atmo- 

 spheric circulation of the northern hemisphere. 



198. Summer Monsoon of the Indian Ocean. Round 

 the coast of Asia the north-east wind falls off in February, 

 and gradually shifts to the south as the winter high pressure 

 over the continent is reduced, and gives place to the summer 

 low pressure. March and April are characterised by 

 variable winds and frequent storms. By May the north- 

 east wind has died away, and in its place south-west winds, 

 usually spoken of in India as The Monsoon, blow strongly 

 across the Arabian Sea and Bay of Bengal, and wheel round 

 along the foot of the Himalayas, blowing up the Ganges 

 valley as south-east winds. This state of matters lasts until 

 August or later. As the wind blows for a long distance over 

 the heated surface of the ocean it reaches land laden with 

 vapour, and, rising up the steep and almost unbroken slopes 

 of the Western Ghats, condenses in tremendous showers. 

 The first deluges of rain are known as the bursting of the 

 monsoon. A heavier rainfall reaches the western edge of 

 the Indo-Chinese peninsula, and the heaviest of all is 

 found in the converging valley of Assam, at one place over 

 500 inches a year. After August the south-west monsoon 

 diminishes in force and gradually dies away as the pressure 

 over the land increases. The monsoon "owes much of its 

 strength to the energy set free by the condensation of the 

 vapour it carries. On the coast of China the summer 

 monsoon blows from the south-east, and the winter monsoon 

 from the north-west. 



199. Yearly Swing of the Atmosphere. The disturb- 

 ing effect of land and sea on the normal arrangement and 

 movements of the atmosphere may be put briefly thus. In 

 winter the chilled land draws down the blanket of air which 

 the less-cooled sea is tossing off upward. In summer the 



