THE ATMOSPHERE. 97 



truly astonisHng. Here, then, are not only the conditions for 

 causing more rain, now on the west, now on the east side of this 

 mountain range, Ibut the conditions also for the most copious pre- 

 cipitation. Accordingly, when we come to consult rain gauges, 

 and to ask meteorological observers in India about the fall of rain, 

 they tell us that on the western slopes of the Ghauts it some- 

 times reaches the enormous 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 he truly astonish- 

 ing; for the water which the Amazon and the other majestic 

 streams of South America return to the ocean would still be pre- 

 cipitated between the sea-shore and the crest of these mountains. 



202. 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 temperature than that to which they were ex- 

 posed 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 basins, as well as the course of the prevailing winds, 

 are shown, these facts will become obvious. 



203. The Regions of Greatest Precipitation. — We shall now 

 be enabled to determine, if the views which I have been endeav- 

 oring to present be correct, what parts of the earth are subject to 

 the greatest fall of rain. They should be on the slopes of those 

 mountains which the trade-winds first strike, after having blown 

 across the greatest tract of ocean. The more abrupt the elevation, 

 and the shorter the distance between the mountain top and the 

 ocean (§ J99), the greater the amount of precipitation. 



If, therefore, we commence at the parallel of about 30° north in 

 the Pacific, Avhere the northeast trade-winds first strike that ocean, 

 and trace them through theu' circuits till they first strike high land, 

 we ought to find such a place of heavy rains. 



* Keith Johnston. 



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