60 On the Laws which Regulate the 



mouths. The different aspects of these rivers may be com- 

 pared on the map. The rivers of North Asia look like cer- 

 tain trees, such as palms, with a long single stem, and a 

 few fronds at the top, from whence they derive nourishment 

 from the air ; the Amazon or the Danube resembles those 

 mighty trees of the forest that send out boughs from every 

 part of the trunk, the more completely to nourish their stately 

 forms. 



After passing the Ural Mountains, the watershed of North- 

 ern Europe becomes very low. It is nothing more than a 

 dome-shaped elevation of the great northern plain of Russia, 

 with a height of 550 feet ; but towards the centre of Europe 

 it curves more southward, and rises into the mountain ridges 

 of the Carpathians and Alps, and finally terminates in the 

 Pyrenees and the table-land of Spain. The rivers of Europe 

 are by this means separated into two great divisions, — those 

 that flow north into the Atlantic and Arctic Oceans, and 

 those which discharge their waters into the Mediterranean, 

 the Black Sea, and the Caspian. Into the vast hollow basin 

 of Central Asia other rivers from the eastern slopes also empty 

 their waters, as the Oxus, Jaxartes, Helmund. 



The great southern watershed is formed by the Kouen- 

 lun range, forming the north boundary of Tibet and the 

 Himalaya, Hindoo Koosh, and Taurus and Iranian chains, 

 which stretch in a direction from east to west, between 

 the parallels of 30° and 40° north. The Euphrates, Indus, 

 Ganges, Brahmapootra, and Chinese rivers, flow south and 

 south-east from this, the most elevated watershed of the 

 globe. The elevated range of the Himalaya intercepts the 

 south-west and south-east winds blowing from the Indian 

 Ocean, and loaded with its moisture ; and this moisture is de- 

 posited at the different seasons of the year, partly in copious 

 rain, and partly in snow, which latter accumulating in nu- 

 merous glaciers, affords the summer supply of the great rivers 

 which have their sources in these elevated regions. So ex- 

 tensive and almost complete is this interception of the mois- 

 ture coming from the south, that, on the table-lands of Tibet 

 to the north, rain is almost unknown, and snow is only 



