CHAP. VU.] DEEP-SEA TEMPERATURES. BLE 
continuous with the general basin of the North 
Atlantic. 
The temperature of this ocean valley was investi- 
gated with great care during the first and second 
eruises of the ‘ Porcupine’ in 1869, and the results 
were so very uniform throughout the area that it 
will be needless to describe in detail the slight 
differences in different localities. These differences, 
in fact, only affected the surface layer of the water, 
and depended merely upon differences of latitude. 
The temperatures in deep water may be said to 
have been practically the same everywhere. The 
first chain of soundings, taken by Captain Calver 
during the first cruise under the scientific direction 
of Mr. Gwyn Jeffreys, was between Lough Swilly 
and Rockall. The greatest depth, 1,380 fathoms, is 
in the middle of the channel, and a sounding at 
that depth, lat. 56° 24’ N., long. 11° 49’ W., gave 
a bottom temperature of 2°8 C. A depth of 6380 
fathoms, No. 28, a little to the south of Rockall, 
gave a temperature of 6°4 C., almost exactly the 
same as the temperature of a like depth in the warm 
area off the entrance of the Féroe Channel; and a 
temperature at 500 fathoms, one of a series taken 
at Station 21 with a bottom temperature at 1,476 
fathoms of 2°°7 C., was 8°5 C., rather less than a 
degree higher than the temperature at a correspond- 
ing depth at Station 87. At Station 21 the tempera- 
ture was taken at every 250 fathoms. 
SUDRYGO. 6 Soe ig a og b0 5 Pe a Oe 
DAVIN 6 ceo 6 oe 8 oe eon oS 9:0 
500 Way oc, 5, ee es, 8 Sirs 
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HO one Be i lor ES EO) on 2 OR 
