CURRENTS OF THE OCEAN. 29 



area equal in extent to the IMississippi Valley ; it is so thickly matted 

 over with the Gulf Weed {Sargassum bacciferuni), that the speed of 

 vessels passing through it is actually retarded, and to the companions 

 of Columbus it seemed to mark the limits of navigation ; they became 

 alarmed. To the eye at a little distance it seemed sufficiently sub- 

 stantial to walk upon." These moving vegetable masses, always 

 of a brownish green, which tail off to a steady breeze, serving as 

 an anemometer to the mariner, afford an asylum to multitudes of 

 molluscs and crustaceans. 



The Gulf Stream plays a grand part in the Atlantic system. It 

 carries the tepid water of the equinoctial regions into the high lati- 

 tudes ; beyond the fortieth parallel the temperature is 16" Centi- 

 grade. Urged by the south-west winds which predominate in that 

 zone, its tepid waters mix with those of the Northern Sea, softening 

 the rigour of the climate in these regions. To the south of the great 

 bank of Newfoundland, the wann current, in vast volume, rushing 

 from the Florida Straits meets the cold currents descending from the 

 Arctic Circle through Baffin's Bay and the Sea of Greenland, running 

 with equal velocity towards the south. A portion of these waters 

 re-ascend towards the pole along the western coast of Greenland. It 

 is to this conflict of the polar and equatorial waters, that the formation 

 of the Banks of Newfoundland is ascribed. Each of these great 

 currents having unceasingly deposited the debris carried in its bosom, 

 the bank has been tKus formed bit by bit in the concourse of ages. 



The difference of temperature between the Gulf Stream and the 



waters it traverses gives birth ine\atably to tempests and cyclones. In 



1780 a terrible storm ravaged the Antilles, in which 20,000 persons 



perished. The ocean quitted its bed and inundated whole cities ; 



the trunks of trees, mingled with other debris, were tossed into the 



air. Numerous catastrophes of this kind have earned for the Gulf 



Stream the title of the " King of the Tempests." In consequence of 



the numerous nautical documents which have been placed at the 



command of the National Observatory of Washington, and the 



admirable use made of them by the late Naval Secretary and his 



assistants, the directions and range of these cyclones engendered by 



the Gulf Stream may be foreseen, and their most dangerous ravages 



turned aside. As an example of the utiHty of Dr. Maury's labours 



in settling the direction of storms in the trajet of the Gulf Stream, 



we quote a well-known instance : In the month of December, 1859, 



the American packet San Francisco was employed as a transport to 



convey a regiment to California. It was overtaken by one of these 



sudden storms, which placed the ship and its freight in a most 



