cHaP. vil.] DEEP-SEA TEMPERATURES. 393 
350 fathoms 9°-5C. lessthan 300 fathoms. 0°: 3C. 
400, 25-47 , 350, 0-3 
eae 8-7 ; oe sO 5 
500, 8-55 E 450 , . 0°15 
550, 8-0 2 500, 0-55 
600, 7:4 : ee oe 
650, 6-83 a ene 66 
MG? ee 4h, 650, 0-4 
50 , -Med- 83 = 700, 0-6 
300... ,,. utr aD DS e 750 0-3 
862 (Bottom) 4°3 f 800 1-25 
The general result of these two series of soundings 
_ is very important. The high temperature reduced by 
7°5 C. in the first series at 250 fathoms is undoubtedly 
due to superheating by direct solar radiation. This 
is shown still more clearly in the second series, where 
nearly 4° C. are seen to be lost between the surface and 
30 fathoms, and somewhat above 2° C. more between 
30 and 100 fathoms. From 100 to 500 fathoms the 
temperature is still high and tolerably uniform, and 
it falls rapidly between 500 and 1,000 fathoms. A 
reference to the second series shows that this rapid 
fall is between 650 and 850 fathoms, in which inter- 
val there is a loss of more than 3°C. ‘This second 
stage of elevated temperature from 250 to 700 
fathoms, which is represented graphically by the 
singular ‘hump’ on the temperature curves in Fig. 
61 and Plate VI. would seem to be caused by the 
north-easterly reflux under peculiar conditions, which 
will be referred to in next chapter, of the great 
equatorial current. From 1,000 fathoms down- 
wards, the loss of temperature goes on uniformly at 
the rate of about 0°38 C. for every 250 fathoms. 
The most singular feature in this decrease of tem- 
y 2 
