10 PHYSICAL GEOGKAPHY OF THE SEA, AXD ITS METEOROLOGY. 



tliem to sea, wliere the beautiful law wliicli renders ice lighter than 

 the warmest water, enables it to float, and drifts southward a vast 

 magazine of cold to cool the tepid water which bears it along — the 

 evaporation at the equator causing a deficit, the melting and accu- 

 mulation 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 extending 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 rarges. ccut, are but a Small number of the contrivances 



by which the vast and beneficent ends of natm'e 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 v/hich 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 evers' 

 reason to believe, in Africa within similar latitudes, vast ridges of 

 mountains, covered with perpetual snow, run northward and south- 

 ward in the line of the meridian right across the path of the trade- 

 winds. A similar ridge, though of less magnificent dimensions, 

 traverses the peninsula of Hindoostan, increasing in altitude as it 

 approaches the line, attaining an elevation of 8500 feet at Doda- 

 betta, and about 6000 in Ceylon. The Alps in Eiu'ope, and the 

 gigantic chain of the Himalayas in Asia, both far south m the 

 temperate zone, stretch fi'om east to west, and intercept the aerial 

 current from the north. Others of lesser note, in the equatorial or 

 meridional, or some intermediate direction, cross the paths of the 

 atmospherical currents in every direction, imparting to them fresh 

 supplies of cold, as they themselves obtain from them warmth in 

 exchange ; in strictness the two operations are the same. 



33. " Magnificent and stupendous as are the efi^ects and results 

 Water. qi the Water and of air acting independently on 



each other, in equalizing the temperatm-e of the globe, they are 

 «till more so when combined. One cubic inch of water, when in- 



