1870.] 



Deep-sea Researches. 



171 



Station. 



Depth, 



Surface- 



Bottom- 



No. 



in faths. 



temp. 



temp. 



41 



. . ! . . 730 



74-5 



55-0 



42 



790 



74-0 



54-0 



43 



162 



74-7 



55-0 



44 .. 



455 



70-0 



550 



45 .. 



207 



72-7 



54*7 



46 



493 



73-5 



55-5 



47 .. 



845 



69-5 



54-7 



It will be observed that the surface-temperature varied between 69°'5 and 

 74°* 5 ; and that whilst the highest temperatures were shown at Stations 

 near the African Coast, the lowest presented itself between Cape de Gat 

 and Cartagena. Now the Gibraltar inflow is very sensibly felt at Cape 

 de Gat, where the current usually runs at the rate of a mile an hour ; and 

 of the strength of this current we had unpleasant experience. For on the 

 19th of August, as we were crossing from Station 46 towards the Spanish 

 coast, we encountered a strong N.E. breeze, which, meeting the current, 

 worked up a considerable swell ; this prevented us from taking even a 

 Temperature-sounding on that day, and gave our Ship a peculiar twisting 

 or screwing movement, from which we were glad to escape by the subsi- 

 dence of the breeze during the following night. During this day the 

 Surface-temperature of the Sea came down from the average of 72°" 2, which 

 it had maintained on the 18th, to 66°*9. Had the weather been calm we 

 might have attributed this reduction to the colder Gibraltar in-current ; 

 but as the average temperature of the Air also fell from 73°*8 to 69°*8, and 

 as the strong N.E. breeze must have had a cooling effect upon the surface 

 of the sea, we should have deemed it probable that the reduction of Surface- 

 temperature was due at least as much to the latter as to the former of these 

 causes, had it not been that a set of Serial soundings which we took at 

 Station 47 showed that the reduction extended very far down, as will be 

 apparent on comparing the following results with those given in § 45 : — 



Fahr. 



Surface 69'5 



10 fathoms 59*0 



20 „ 57'5 



30 „ 56-5 



40 „ 557 



50 „ 55-3 



100 „ 547 



845 „ (bottom) , 547 



It will be seen hereafter that the observations made on our return voyage 

 gave more distinct evidence of the cooling influence of the Gibraltar in- 

 current(§ 86). 



48. At most of these Stations we explored the bottom by means of the 

 Dredge, with results much less profitable than we had anticipated. Except 



