THE SPECIFIC GRAVITY OF TEE SEA, ETC. 203 



tions upon the specific gravity of the water there at the surface 

 and at various depths would indicate to us not only the extent 

 to which the water there is diluted by the rivers and the rains, 

 ijut it would }aeld other highly interesting results. Now this 

 salt and hea\7' water, whose specific gravity at 27^.2 would have 

 been 1.0303, is the very water which Kodgers observed in the 

 Gulf Stream on its vfay to the arctic regions. This is the water 

 which, after passing the Grand Banks, and meeting the diluted 

 water as an ice-bearing current from the north, dips down, but 

 continues its course as an under current. It is protected from 

 farther loss of heat, after the manner of our own littoral waters, 

 by the colder but lighter and upper cmxent from the north, imtil 

 it enters the Arctic Ocean, there to rise up hke a boihng spring 

 in the centre of an open sea. 



428. Eelying upon a process of reasoning like this, and the de- 

 De Haven'3 water ductious flowiug tlicrefrom. Lieutenant De Plaven, 

 ^^^- when he went in command of the American expedi- 



tion in search of Sir John Frankhn and his companions, was 

 told in his letter of instructions, to look, when he should get well 

 up into Wellington Channel, for an open sea to the northward 

 and westward. He looked, and saw in that direction a "water 

 sky." Captain Penny afterwards went there, found open water,' 

 and sailed upon it. The open sea in the Arctic Ocean is proba- 

 bly not always in the same place, as the Gulf Stream (§ 126) is 

 not always in one place. It probably is always where the v^^aters 

 of the under currents are brought to the surface ; and this, we may 

 imagine, would depend upon the freedom of ingress and egress for 

 the currents. Their course may perhaps be modified more or less by 

 the ice on the surface, by changes, from whatever cause, in the 

 com^se or velocity of the surface cmTent, for obviously the mider 

 current could not bring more water into the frozen ocean than the 

 sm-face cm-rent would carry out again, either as ice or water. Ex- 

 ploring parties may have been near this open sea without perceiving 

 the warmth of its climate, for every winter, an example of how very 

 close wann water in the sea and a 'very severe climate on the land 

 or the ice may be to each other is aflbrded to us in the case of the 

 Gulf Stream and the Labrador-like climate of New England, Nova 

 Scotia, and Newfoundland. In these countries, in winter, the ther- 

 mometer frequently sinks far below zero, notwithstanding that the 

 tepid waters of the Gulf Stream may be fomid with their summer 

 temperature v/ithin one day's sail of these veiy, very cold places. 



