10 THE PHYSICAL GEOGRAPHY OF THE SEA. 



bears it along — the evaporation at the equator causing a deficit, 

 the melting and accumulation of the ice in the frigid zone giving 

 rise to an excess of accumulation, which tends, along with the 

 action of the air and other causes, to institute and maintain the 

 transporting current. These stupendous masses, which have been 

 seen at sea in the form of church spires, and gothic towers, and 

 minarets, rising to the height of from 300 to 600 feet, and ex- 

 tending over an area of not less than six square miles, the masses 

 above water being only one tenth of the whole, are often to be 

 found within the tropics. 



32. " But these, though among the most regular and magnifi- 

 Mountain ranges, ccut, arc but a Small uumbcr of the contrivances by 



which the vast and beneficent ends of nature are brought about. 

 Ascent from the surface of the earth produces the same change, 

 in .point of climate, as an approach to the poles ; even under the 

 torrid zone mountains reach the line of perpetual congelation 

 at nearly a third less altitude than the extreme elevation which 

 they sometimes attain. At the poles snow is perpetual on the 

 ground, and at the different intervening latitudes reaches some 

 intermediate point of congelation betwixt one and 20,000 feet. 

 In America, from the line south to the tropics, as also, as there is 

 now every reason to believe, in Africa within similar latitudes, 

 vast ridges of mountains, covered with perpetual snow, run north- 

 ward and southward in the line of the meridian right across the 

 path of the trade-winds. A similar ridge, though of less mag- 

 nificent dimensions, traverses the peninsula of Hindoostan, in- 

 creasing in altitude as it approaches the line, attaining an eleva- 

 tion of 8500 feet at Dodabetta, and above 6000 in Ceylon. The 

 Alps in Europe, and the gigantic chain of the Himalayas in Asia, 

 both far south in the temperate zone, stretch from east to west, 

 and intercept the aerial current from the north. Others of lesser 

 note, in the equatorial or meridional, or some intermediate direc- 

 tion, cross the paths of the atmospherical currents in every direc- 

 tion, imparting to them fresh' supplies of cold, as they themselves 

 obtain from them warmth in exchange ; in strictness the two op- 

 erations are the same. 



33. " Magnificent and stupendous as are the effects and results 

 Water. of thc watcr and of air acting independently on 



each other, in equalizing the temperature of the globe, they are 



