cuar. vi]  DEEP-SEA TEMPERATURES. eal 
At this point, therefore, the ice-cold water of the 
Arctic current filling up the bottom of the trough 
is nearly 2,000 feet deep, while the temperate water 
above has nearly an equal depth. The lower half of 
the latter, however, has its temperature considerably 
reduced by intermixture and diffusion, Fig. 55 
represents diagrammatically the general result of 
temperature observations in the cold area. ‘The 
depth at the next Station, No. 65, was 354 fathoms, 
showing that the channel had begun to shoal towards 
Shetland; the temperature was, however, still low, 
almost exactly 0° C. The next Station, No. 66, 
eighteen miles further on towards the Shetland 
banks, gave a depth of 267 fathoms, with a bottom 
temperature of 7° 6 C., the temperature at the surface 
being 11°3C. We had therefore got beyond the 
edge of the trough filled by the cold stream, and 
passed into lesser depths occupied from the surface 
to the bottom by the warm southern stratum. 
The next series of soundings, Nos. 67 to 75, are 
either in shallow water round Shetland, or in water 
on the shelving edge of the plateau, not deep enough 
to reach the frigid stream. It is of some interest 
that the two soundings, Nos. 68 and 69, in 75 and 67 
fathoms respectively, to the east of Shetland, show a 
bottom temperature of 6°6 C., while a serial sounding 
in the warm area at the western entrance of the 
Fwéroe Channel gives for the same depth a tempera- 
ture of about 8°8 C. This circumstance, along with 
others to be mentioned hereafter, would seem to show 
that a considerable indraught of cold water spreads 
over the bottom of the shallow north sea. 
At Stations 76 to 86, which are along the southern 
