1883.] Soundings and Temperatures in the Faeroe Channel. 207 



traced flowing across the ridge, and gradually increasing in tempera- 

 ture as it moved to the southward, until at a distance of 15 miles 

 from the axis of the ridge, it was of the usual normal temperature of 

 the warm area in that locality. 



This outflow of cold water seems to affect all the bottom tempera- 

 tures to the westward of Section C ; for, whilst to the eastward of 

 that section they are from 45° to 46° at depths of 500 fathoms, to the 

 westward they are from 42° to 48°, that is 3° lower. 



There is then apparently a regular interchange of the waters across 

 the. Wyville Thomson ridge, the Atlantic water flowing north-east 

 into the Arctic basin on the surface, and as far down as the ridge 

 permits, over the greatest portion, whilst over the deepest part of the 

 ridge there is a small outflow of Arctic water into the Atlantic, which 

 although of infinitely less volume than the water moving to the north- 

 east, yet appears to be sufficient to enable the bottom water of the 

 Arctic basin, immediately adjacent to the ridge, to retain its low 

 temperature. Were there no other outlet to the Arctic basin, it is 

 probable the outflow over the ridge at the bottom would equal the 

 inflow at the surface, but, as before remarked, we know the surface 

 water on the western side of the Arctic basin has a steady flow to the 

 southwards along the coast of Greenland. 



The existence of the Wyville Thomson ridge in the locality pre- 

 dicted, tends to prove the general correctness of the theory formed in 

 the " Challenger," but farther observations in other localities where 

 the same phenomenon exists, are requisite to determine its absolute 

 correctness, more especially when we remember that in nearly every 

 instance where the bottom temperatures differ materially in adjoining- 

 areas, the minimum temperature in one of those areas, the warm, is 

 found at a considerable height from the bottom ; whereas in the other 

 area, the cold, the temperature decreases with the depth, the minimum 

 being at the bottom. In the Faeroe Channel, however, the tempera- 

 ture in the warm area decreases as the depth increases, whilst in the 

 cold area it remains almost constant at 30^-° F. at depths exceeding 

 350 fathoms, thus reversing the rule which obtains elsewhere. For 

 instance, in the Mediterranean the temperature of the sea is constant 

 at 55° F. at depths exceeding 100 fathoms, whereas in the Atlantic, 

 the only sea in communication with the Mediterranean, the tempera- 

 ture outside the Straits of Gibraltar decreases as the depth increases. 

 In the Red Sea the temperature is constant at 70° F., at depths 

 exceeding 100 fathoms, whereas in the Indian Ocean it decreases with 

 the depth. In the Sulu Sea the temperature is constant at 50° "5 F. 

 at depths exceeding 400 fathoms, whereas in the adjacent seas the 

 temperature decreases to 39°, and there are also considerable areas in 

 the Atlantic, as well as the Pacific, where a minimum temperature is 

 reached at a certain depth, whilst in adjoining areas the temperature 



