28 THYSICAL GEOGRArny OF THE SEA, AND ITS METEOROLOGY. 



oif Bernini* to be two hundred fathoms, which are thought to be 

 "within limits, the above I'ates of breadtli and A'clocity will give 

 one hundred and fourteen fathoms for its depth off Hatteras. 

 The waters therefore, wliich in the Sti-aits are below the level of 

 the Hatteras depth, so far from descending, are actually forced up 

 an inclined plane, whose submarine ascent is not less than ten 

 inches to the mile. 



84. The Niagara. — The Niagara is an " immense river descend- 

 ing into a plain." But instead of preserving its character in 

 Lake Ontario as a distinct and well-defined stream for several 

 hundred miles, it spreads itself out, and its waters are imme- 

 diately lost in those of the lake. Why should not the Gulf 

 Stream do the same ? It gradually enlarges itself, it is true ; but, 

 instead of mingling with the ocean by broad spreading, as the 

 " immense rivers" descending into the northern lakes do, its 

 waters, like a stream of oil in the ocean, preserve a distinctive 

 character for more than three thousand miles. 



85. A current counter to the Gulf Stream. — Moreover, while the 

 Oulf Stream is running to the north froijn its supposed elevated 

 level at the south, there is a cold current coming down from the 

 north ; meeting the warm waters of the Gulf midway the ocean, 

 it divides itself, and runs by the side of them right back into 

 those very reservoirs at the south, to which theory gives an 

 elevation sufficient to send out entirely across the Atlantic a jet 

 of warm water said (§ 75) to be more than three thousand times 

 greater in volume than the Mississippi Eiver. This current from 

 Baffin's Bay has not only no trade-winds to give it a head, but the 

 prevailing winds are unfavourable to it, and for a gi-eat part of 

 the ^vaj it is below the surface, and flxr beyond the propelling 

 reach of any wind. And there is every reason to believe that this, 

 with other polar currents, is quite equal in volume to the Gulf 

 Stream. Are they not the effects of like causes ? If so, what, 

 have the trade-winds to do with the one more than the other ? 



86. Bottle chart. — It is a custom often practised by seafaring 

 people to throw a bottle overboard, with a paper, stating the 

 time and place at which it is done. In the absence of other 

 information as to currents, that afforded by these mute little 

 navigators is of great value. They leave no tracks behind them, 



* Navy officers of the United States Coast Survey have sounded with the 

 deep-sea lead, and ascertained its depth here to be 370 fathoms (Januar}% 

 1850). 



