18'i ACCOUNT OF THE ARCTIC REGIONS. 



SECT. II. 



Temperature, Depth, and Pressure of the Green- 

 land Sea, with a Description of an Appai^atus 

 for bring ijig up Water from great Depths, and 

 an Accmint of Experiments made xcith it. . 



In a sea perpetually covered with ice, the tem- 

 perature of the surface might he supposed to be at 

 or near the freezing point, in all seasons. This is 

 no doubt generally tlie case ; but it is remarkable 

 that, in some situations, even in the keenest frost, 

 and in the midst of ice, the temperature of the sea, 

 in latitude 76° to 78°, is sometimes as high as 36° or 

 38° of Fahrenheit. 



As far as experiments have hitherto been made, 

 the temperature of the sea has generally been found 

 to diminish on descending. But, in the Greenland 

 Sea, near Spitzbergen, the contrary is the fact. For 

 determining this interesting point, I first made use 

 of a cask, capable of containing about ten gallons of 

 water, composed of two-inch fir plank, as being a 

 bad conductor of heat. Each end of the cask was 

 furnished with a valve, opening and shutting simul- 

 taneously, by means of a connecting wire. With 

 the top of the upper valve, moveable with it, was 

 connected a horizontal lever, having a flat circular 

 extremity projecting beyond the chime, or edge of 



