10 THE OCEAX. 



diminish the width of the Atlantic more tlian lialf, would leave the 

 Gulf of Mexico completely dry, and only leave an elongated lake in 

 the central part of the Caribbean Sea. If the jiresent level were 

 lowered by 2187 fathoms, a continent separated from Europe and 

 America by two narrow channels, and extending over a space of 

 from about 1550 to 18G0 miles, would stretch into the torrid zone ; 

 and, by a remarkable coincidence, would affect that peninsular con- 

 formation and southerly direction, presented by Greenland, Scan- 

 dinavia, Spain, Italy, Greece, Arabia, India, and the three great 

 continents of the South.* A lowering of 8280 fathoms would com- 

 pletely unite Newfoundland to Ireland, and consequently form a 

 bridge between the Old and New Worlds. Even of the central 

 Atlantic there would only remain a narrow '* Mediterranean " sea in 

 front of the Antilles and Guiana. Finally, let the waters be lowered 

 by 4375 fathoms, and the northern part of the Atlantic would be 

 reduced to a small triangular " Caspian," situated between the Azores, 

 the bank of Newfoundland, and the Bermudas. 



In the present state of science, it is impossible to draw an approxi- 

 mate chart of the depths of the South Atlantic, similar to that which 

 one can construct of the bottom of the northern part. It even ap- 

 pears that many of the soundings made in this part of the ocean must 

 be considered null, because the explorers have not taken into account 

 the deflection of the sounding-line occasioned by submarine currents. 

 The depth of 7600 fathoms obtained by Captain Denham, R.N., 

 is accepted by ]\1. Bischof and other geologists with all confidence, 

 because this explorer took care to raise the cord several times by 

 a hundred yards, and when thrown again it always stopped at the 

 same point. As to the sounding of 8695 fathoms, announced by 

 the American Parker, it is certainly erroneous ; since later, in the 

 same latitudes, they have found the bottom at 3007 fathoms only. 

 Not knowing the depth of water in the difterent parts of the South 

 Atlantic, mathematicians have tried at least to calculate the mean 

 depth of the entire basin by the swiftness of the translation of 

 the tidal waves. They have estimated the mean force of the bed of 

 water in the Atlantic Ocean from the 50th degree south to the 50th 

 degree north latitude to be about 7330 yards. Now, the mean depth 

 of the north basin being very nearly 2187 fathoms, the depth of the 

 southern basin must be estimated, according to this calculation, at 

 about 4920 fathoms. f However, these figures rest on the very 



* Sir John Herschel, Thysical Geography, p. 35. 

 t Sir John Herschel, Physical Geography, p. 72, 



