THE SURFACE OF THE EARTH. 



the Archipelago is called the Dardanelles, the ancient Hellespont ; 

 and that which is next the Black Sea, the Bosphorus ; the inter- 

 mediate water being called the Sea of Marmora. 



56. The Black Sea is nearly enclosed by land, but com- 

 municating throughthe Bosphorus with the Archipelago and 

 the Mediterranean, it cannot properly be considered as a lake. 

 Its water is, nevertheless, much less salt than that of the ocean, 

 and it is consequently more readily frozen. Its depth near the 

 shore varies from 24 to 220 feet, and in the middle is more than 

 1000 feet. 



57. Sea of Azof. This sea communicates with a smaller one 

 north of it, called the Sea of Azof, by a narrow neck of water, 

 called the Strait of Yenekali. A tract of land nearly surrounded 

 by the waters of the Black Sea and the Sea of Azof, and connected 

 with the continent by a narrow neck of land, is called the Crimea; 

 the connecting neck being called the Isthmus of Perikop. This 

 peninsula has been celebrated for the fortress of Sebastopol erected 

 by Russia near its southern extremity, and destroyed in 1855 by 

 the allied armies of France and England. 



58. The Caspian. Near the southern confines of Europe and 

 Asia is the largest lake in the world, called the Caspian Sea. Its 

 water is salt, but much less so than the ocean, and it is shallow, 

 even at its centre, the depth not exceeding 300 feet. That it can 

 have no immediate and uninterrupted subterranean communication 

 with the Black Sea, which is near it, is proved by the fact that 

 the level of its surface is 82 feet below that of the latter sea. 



59. Africa is an immense triangular- shaped tract of land, the 

 base of which is presented towards the north, and the point to the 

 south. Its coast is everywhere nearly uniform, and entirely 

 destitute of those indentations for which Europe is so remarkable. 

 It projects southwards into the great ocean, which it divides into 

 two regions, of which the western is called the Atlantic, and the 

 eastern the Indian Ocean. As has been already stated, Africa is 

 separated from Asia by the Red Sea, except at the point where 

 they are connected by the narrow isthmus of Suez. 



This division of the great continent is, beyond all comparison, 

 the most uncivilised and desert portion of the globe. It includes 

 a vast range of country, extending from the northern to the 

 southern tropic, and lying, therefore, altogether in the torrid zone, 

 By reason of the great extent of desert of which it consists, the 

 insalubrity of its climate, and the barbarous character of its 

 inhabitants, it is little known to Europeans. 



60. Its Climatological Zones. It may be considered as con- 

 sisting of a succession of zones, separated by parallels of latitude, 

 having different physical characters. 



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