458 



Messrs. Carpenter, Jeffreys, and Thomson [Nov. 18, 



98. This result comes out even more strikingly in another Series (No. 64) 

 taken about 180 miles to the N.E. of the preceding, in the deep channel 

 between the Faroe and Shetland Islands. For we observe (1) that the 

 surface-temperature is here 49°* 7, or 2°*4 below that of No. 52; (2) that 

 this difference is maintained with slight variation down to 150 fathoms; 

 (3) that a rapid descent of the thermometer here begins, a fall of 3° 7 

 taking place between 150 and 200 fathoms, and a further fall of 5° 3 be- 

 tween 200 and 250 fathoms, making a reduction of 9° in 100 fathoms, 

 and bringing down the temperature at 250 fathoms to 34 0, 3 ; whilst (4) 

 the fall between 250 and 300 fathoms is only 1°*9, and between 300 and 

 350 fathoms is 1°, bringing down the temperature at the latter depth to 

 31 0, 4; and (5) that in descending through the lowest 290 fathoms, the 

 temperature is reduced to 30°* 1 at 500 fathoms, and stands as low as 29°"6 

 on the bottom at 640 fathoms. The relation between Depth and Tempe- 

 rature in the Cold area is represented diagrammatically in the accompanying 

 Figure ; in which, for the sake of better comparison with the preceding, 

 the upper portion is constructed from Series 52 (so as to commence from 

 the surface-temperature of 52°), and the lower portion from Series 64, 

 each line marking a descent of 1° Fahr. 



Diagram IT. 



TatA Si* Tath 



99. Hence it is evident that a temperature of 32° would have been reached 

 at something more than 300 (say 320) fathoms ; so that the lower half 

 of the icater occupying the deepest part of this channel forms a stream 

 nearly 2000 feet in depth, having a temperature below the freezing-point 

 of fresh water ; and this notwithstanding that the temperature of its surface 

 and of its first 150 fathoms' depth does not differ more from the tempera- 

 ture of the surface and of the first 150 fathoms in the Warm area (Series 

 87) than is accounted for by the difference of Latitude (nearly 2°) between 

 the two stations. — These remarkable facts are expressed by the two lower 

 curves in Diagram III., which are constructed from the Serial soundings in 

 the Cold area, as the upper curve is from the Serial sounding in the Warm 

 area. 



