120 THE PHYSICAL GEOGRAPHY OF THE SEA. 



west monsoons. The forces of diurnal rotation assist (§ 113) to 

 give these winds their westing. Thus the southeast trades, in 

 certain parts of the Indian Ocean, are converted, during the sum- 

 mer and early autumn, into southwest monsoons. These then 

 come from the Indian Ocean and Sea of Arabia loaded with 

 moisture, and, striking with it perpendicularly upon the Ghauts, 

 precipitate upon that narrow strip of land between this range and 

 the Arabian Sea an amount of water that is truly astonishing. 

 Here, then, are not only the conditions for causing more rain, 

 now on the west, now on the east side of this mountain range, but 

 the conditions also for the most copious precipitation. Accord- 

 ingly, when we come to consult rain gauges, and to ask meteoro- 

 logical observers in India about the fall of rain, they tell us that 

 on the western slopes of the Ghauts it sometimes reaches the enor- 

 mous depth of twelve or fifteen inches in one day."^ Were the 

 Andes stretched along the eastern instead of the western coast of 

 America, we should have an amount of precipitation on their 

 eastern slopes that would be truly astonishing; for the water 

 which the Amazon and the other majestic streams of South 

 America return to the ocean would still be precipitated between 

 the sea-shore and the crest of these mountains. These winds of 

 India then continue their course to the Himalaya range as dry 

 winds. In crossing this range, they are subjected to a lower tem- 

 perature than that to which they were exposed in crossing the 

 Ghauts. Here they drop more of their moisture in the shape of 

 snow and rain, and then pass over into the thirsty lands beyond 

 with scarcely enough vapor in them to make even a cloud. 

 Thence they ascend into the upper air, there to become counter- 

 currents in the general system of atmospherical circulation. By 

 studying Plate VIII., where the rainless regions and inland ba- 

 sins, as well as the course of the prevailing winds, are shown, these 

 facts will become obvious. 



299. The Regions of Greatest Precipitation. — "We shall now be 

 The regions of sreat- Guablcd to determine, if the views which I have 

 Ser?aponjie'^^^'^a^ bccu endcavoring to present be correct, what parts 

 Patagonia. of the carth are subject to the greatest fall of rain. 



They should be on the slopes of those mountains which the trade- 

 winds or monsoons first strike after having blown across the 



* Keith Johnston. 



