322 ANNUAL OF SCIENTIFIC DISCOVERY. 



from the deep sea of the Straits of Gibraltar would at once settle this 

 question. 



DEEP SEA SOUNDINGS IN THE ARCTIC OCEAN. 



From a recent report of Lieutenant Maury to the Secretary of the Navy, 

 we derive the following extract relative to some observations made last year 

 by Com. Rodgers, in the U. S. ship Vincennes, on the temperature and 

 specific gravity of the water at the surface, midway, and at the bottom of 

 the Arctic ocean. These observations are highly interesting. He passed up 

 through Behring's Straits into that sea during the summer of 1855, and, 

 though he remained in it but a few days, he availed himself of the opportunity 

 to try the temperature and specific gravity of the water at various depths 

 and places ; and his observations show uniformly this arrangement or strati- 

 fication in the fluid mass of that ocean warm and light water on top, cold 

 water in the middle, and warm and heavy water at the bottom. These 

 observations, if extended, would go far towards the final settlement of the 

 question of an open sea in the Arctic ocean. It is likely that this warm 

 water went in as an under current ; that though warmer it was salter, and 

 for that reason it was heavier. It was made salter, we conjecture, by evapo- 

 ration ; and while it was subjected to this process it was in some latitude 

 where it received heat while it was giving off fresh water vapor. This sub- 

 stratum of heavy water was, therefore, probably within the tropics and at the 

 surface when it received its warmth. "Water, we know, is transported to 

 great distances by the under currents of the sea without changing its tempe- 

 rature but a few degrees by the way. Beneath the Gulf Stream, near the 

 tropic of Cancer, and in the month of August, with the surface of the ocean 

 above 80 degrees, the deep sea thermometer of the Coast Survey reports a 

 current of cold water only 3 degrees above the freezing point. That cold 

 current or the water that it bore must certainly have come from the polar 



regions. 



We know of numerous currents flowing out of the Polar basin and dis- 

 charging immense volumes of water into the Atlantic ; we know of but one 

 surface current, and that a feeble one, around the North Cape, that goes into 

 this basin. All these out-coming currents are salt water currents ; therefore 

 we cannot look for their genesis to the rivers of hyperborean America, 

 Europe, and Asia, and the precipitation of the Polar basin for all the water 

 from these sources is fresh water. The salt that these upper currents bring 

 out is sea salt ; hence we should be forced to conclude, were there no other 

 evidence to warrant the conclusion, that there must be one or more under 

 currents of salt and heavy water flowing into the Arctic basin. A consider- 

 able body of water at the temperature of 40 degrees rising to the surface 

 there as come to the surface it must, in order to supply the outgoing 'upper 

 currents would tend mightily to mitigate the severe cold of those hyper- 

 borean regions. 



This discovery of Rodgers furnishes the only link that seems to have been 

 wanting in the chain of reasoning to complete from known facts the theory of 

 an open water in the Arctic ocean; and this discovery, taken in connection 



