CHAP, vii.j DEEP-SEA TEMPERATURES. 309 



perature of 0< 8 C., showing that we had passed 

 the boundary, and were in the 6 cold area. 5 



At this point we requested Captain Calver to take 

 a serial sounding, ascertaining the temperature at 

 depths progressively increasing by 50 fathoms, which 

 was done with the following result : 



Surface 11-8C. 



50 fathoms 9 2 



100 8-4 



150 . 8-0 



200 7-5 



250 3-5 



300 0-6 



384 (Bottom) 0'8 



We thus ascertained that the minimum tempera- 

 ture was at the bottom; and this we have found to be 

 universally the case over the whole of the area which 

 we have examined, whatever the bottom temperature 

 might be. And we also ascertained that the decrease 

 in heat from the surface downwards was by no means 

 uniform, but that while after passing the surface 

 layer it was tolerably regular for the first 200 

 fathoms, there was an extraordinary fall amounting 

 to upwards of 7C. from 200 to 300 fathoms, at 

 which latter depth the minimum is nearly gained. 



The next few observations, Stations 53 to 59, were 

 all within the limits of the cold area, the bottom tem- 

 perature at depths ranging from 360 to 630 fathoms, 

 nowhere reaching the freezing-point of fresh water; 

 and "at one point, Station 59, lat. 60 21' N., long. 

 5 41' W., at a depth of 580 fathoms, the index stand- 

 ing so low as -13 C. On Saturday the 21st we took 

 a sounding in 187 fathoms, on the edge of the F&roe 



