B. TERRESTRIAL PHYSICS AND METEOROLOGY. 65 



the map has been considerably changed, as it has been shown 

 to reach north to latitude 77, and east to longitude 69, and 

 Cape Nassau lies twenty-two miles farther southwest than 

 the position given to it hitherto. 



A very interesting discovery is that of the Gulf Stream 

 islands, in the exact place where the examinations of the 

 Dutch expeditions in 1594 to 1597 located a sand-bank with 

 eighteen fathoms of water over it, the depth of water between 

 it and the coast being fifty to sixty fathoms. This would in- 

 dicate that the sea-bottom in that region has risen more than 

 110 feet in three hundred years, a very remarkable fact. Ac- 

 cording to Mack, these islands are six miles from the coast, 

 the north point being in latitude 76 22', longitude 63 38'. 

 They consist of sand and rock, being bare, with no trace of 

 vegetation. Petrified shells are found on the firmer parts of 

 the surface. Notice, No. 89, Hydrographic Office. 



DISCUSSION OF DEEP-SEA TEMPERATURES. 



Professor Mohn, of Christiania, discussing in Petermann's 

 Mittheilungen the results of the deep-sea temperature obser- 

 vations in the waters between Greenland, North Europe, and 

 Spitzbergen, remarks that the deep basin of the polar sea is 

 filled from bottom to top with an enormous mass of cold 

 water, which on the southeast is encompassed by the warm 

 w T aters of the Gulf Stream, and penetrates below its current 

 to the coast of Europe. The principal discharge of the polar 

 ocean takes place into the lower strata of the Atlantic, through 

 the deep channel between Greenland and Iceland ; while the 

 shallow seas between Iceland and the Faroes hinders any 

 further outflow, which is only permitted through the narrow 

 lower portion of the Faroe-Shetland channel. The banks 

 around the British Islands (the shallow North Sea and the 

 Norwegian banks) prevent any other outflow southward; 

 and those between the Bear Islands and Norway answer the 

 same purpose to the east. On the other hand, an immense 

 mass of warm water extends from the deep abyss of the At- 

 lantic northward over the shallow sea between Iceland and 

 the Faroe Islands, as also above the Faroe-Shetland, chan- 

 nel. Thence some part of the current passes the Norwegian 

 coast and continues in two different arms, the narrower but 

 deeper reaching to the north coast of Spitzbergen, while the 



