OCEAN DEPTHS.

Globe, Volume XXI, Issue 1660, 16 June 1879, Page 4

OCEAN DEPTHS.

The untrustworthiness of the vague and very varying estimates which are given in schoolbooks for the mean depths of the ocean has induced Dr. Otto Krummel, with the help of the rich material accumulated in recent years, to make a new and thoroughly careful calculation of the mean depths of the various ocean beds. Besides taking advantage of the material brought together by Berghaus and the late Dr. Petermann, Herr Krummel has himself collated the data' obtained by such expeditious as these of the Challenger, Gazelle, Hydra, and others. For the Antarctic and a large portion of the Arctic Oceans scarcely any materials exist, the whole area for which data are wanted being something like 10 million square miles. The result of calculations can therefore be only a series of approximate values, and as such Herr Krummel states them as follows: —1, Atlantic Ocean, mean depth in fathoms, 2013, area in square miles, 29,514,275; 2, Indian Ocean, 1829, 28,369,595 ; 3, Pacific Ocean, 3887,60,843,690; 4, South Ice Sea, 1800 (?), 7,930,000 (?); 5, North Ice Sea, 845, 5,264,600; 6, Australasian Archipelago, 487, 3,046,600 ; 7, Mexican GuK, 1001,1,765,910 ; 8, Mediterranean Sea, 729, 1,109,230; 9, Baltic Sea, 36,159,690; 10, Bed Sea, 243,170.820 ; 11, Persian Gulf, 20, 90,100; 12, North Sea, 48, 210,505; 13, the Channel, &c., 47, 78,416; 14, Gulf of St, Lawrence, 160, 101,075; 15, East Chinese Sea, 66, 472,210; 16, Japan Sea, 1200, 383,305; 17, Okhotsk Sea, 830, 553,080; 18, Behring Sea, 550, 864,555 ; the three open oceans (1 3), 2026,118,227,560 ; the Mediterranean seas, (5-11), 740, 11,606,950; the coast seas (12-18), 386, 2,663,046; the entire ocean (1-18), 1887 fathoms, 140,427,556 square miles. It thus appears that the mean depth of the great ocean which everywhere surrounds the land is 1877 fathoms, or 11,562 ft,, or about 2 l-sth miles. Herr Krummel remarks that he has apparently taken the total surface at 3,276,000 square miles too little, a result of the rough methods of measuring the areas which he was compelled to use. In his further calculations, therefore, ho takes the ocean area at, in round numbers, 143,703,000 square miles, and thus finds that the present proportion of land and water is as 1 to 2 75. Comparing with the mean ocean depths the mean height of the continents above sea level, he find* that the mean height of the land as a whole is 1377 feet, which is only about onooighth the mean depth of the ocean. Herr Krummel enters into a calculation as to the relative volume* of the water and the land above the ocean belt; in this respect the proportion of land and water is as Ito 22'4. On the other hand, the masses (volume multiplied by specific weight) of earth and ocean are very nearly the same.