192 THE PHYSICAL GEOGRAPHY OF THE SEA. 



water generally is. The same phenomenon is repeated in the Bal- 

 tic, where (§ 423) an under current of salt water runs in, and an 

 upper current of brackish water (§ 37) runs out. 



532. Then, since there is salt always flowing out of the north 

 Polar basin, we infer that there must be salt always flowing into 

 it, else it would either become fresh, or the whole Atlantic Ocean 

 would be finally silted up with salt. 



533. It might be supposed, were there no evidence to the con- 

 trary, that this salt was supplied to the Polar seas from the At- 

 lantic around North Cape, and from the Pacific through Behring's 

 Straits, and through no other channels. 



534. But, fortunately, Arctic voyagers, who have cruised in the 

 direction of Davis's Straits, have afforded us, by their observations 

 (§ 478), proof positive as to the fact of this other source for sup- 

 plying the Polar seas with salt. They tell us of an under current 

 setting from the Atlantic toward the Polar basin. They describe 

 huge icebergs, with tops high up in the air, and of course the 

 bases of which extend far down into the depths of the ocean, rip- 

 ping and tearing their way with terrific force and awful violence 

 through the surface ice or against a surface current, on their way 

 into the Polar basin. 



535. Passed Midshipman S. P. Griffin, who commanded the 

 brig Rescue in the American searching expedition after Sir John 

 Franklin, informs me that, on one occasion, the two vessels were 

 endeavoring, when in Baffin's Bay, to warp up to the northward 

 against a strong surface current, which of course was setting to 

 the south ; and that while so engaged, an iceberg, with its top 

 many feet above the water, came " drifting up" from the south, 

 and passed by them "like a shot." Although they were stem- 

 ming a surface current against both the berg and themselves, such 

 was the force and velocity of the under current, that it carried the 

 berg to the northward faster than the crew could warp the vessel 

 against a surface but counter current. 



536. Captain Duncan, master of the English whale-ship Dun- 

 dee, says, at page 76 of his interesting little narrative :* 



* Arctic Regions ; Voyage to Davis's Strait, by Dorea Duncan, Master of the Ship 

 Dundee, 1826, 1827. 



