ANNIYEESAET ADDRESS OP THE PEESIDENT. lix 



PoTiillet * briefly discusses ocean temperatures, and concludes 

 that, although all the difficulties of the case are not solved, it seems 

 certain that there is generally an upper current carrying the 

 warm tropical waters towards the polar seas, and an undercurrent 

 carrying the cold waters of the arctic regions from the poles to the 

 equator. 



The early evidence on the subject was necessarily contradictory, as 

 the instruments were often imperfect, and the temperature in the 

 early experiments was often taken by means of water or mud 

 brought to the surface. Off the coast of Greenland, Scoresby al- 

 ways found the temperature in descending to increase, in some 

 cases, to 36° or 38° F., while the surface-temperature was only from 

 28° to 30°. He mentions, however, that in lat. 72° 7' N., long. 

 19° 11' "W., where the temperature was 34° F. at the surface, it was 

 29° at a depth of 700 feet. Sir Edward Parry found the surface-tem- 

 perature off Spitzbergen to vary from 28° to 31°, and at depths of 

 from 400 to 600 feet to be from 30° to 28°. Sir John Eoss found the 

 temperature at a depth of 2520 feet in Melville Bay to be 29|° ; 

 in Lancaster Sound, depth 7900 feet, 29° ; and in lat. 72° 33' N. 

 and long. 73° 7' W. the surface-temperature was found to be 35°, 

 decreasing gradually to 28f° at a depth of 6000 feet. More lately 

 the carefully made observations of M. Chas. Martins in the Spitz- 

 bergen seas led him to the following conclusions : — 



1st. In the months of July and August the temperature of the 

 surface, although near freezing-point, is always somewhat 

 above it, 



2nd. From the surface to a depth of 240 feet, the temperature 

 here increases, there decreases. 



3rd. From 240 feet to the bottom the temperature always de- 

 creases. 



4th. The mean temperature of the water at the bottom of the 

 sea is 28-84° F. (- 1-75° C). 



The greatest depths of the soundings seem to have been from 2000 

 to 2800 feet. 



These low deep-sea temperatures have not only been found to pre- 

 vail in high northern latitudes, but to extend, though in some- 

 what diminished force, to the equator, and thence to the Antarctic 

 regions. 



* Elem. de Phys. vol. ii. p. 667, 1847. 



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