540 



Dr. W. B. Carpenter on the 



[June 13, 



3. On the 19th of August we took another deep Sounding in Lat. 

 36° 47' N. and Long. 9° 39' W.,— about 60 miles to the S.W. of Cape St. 

 Vincent. The surface-temperature being here 68°, the temperature of the 

 bottom at 1560 fathoms was 37|°. A series of Temperature-soundings at 

 intervals of 10 fathoms down to 100 fathoms having been then taken by 

 Capt. Nares at my request, the results given in the Table, p. 539, were ob- 

 tained, which it may be well to compare with the temperatures obtained at 

 corresponding depths, and nearly under the same latitude, within the Me- 

 diterranean (Report for 1870, § 87, Series II.). 



4. The continuity of the surface-temperature through the uppermost ten 

 fathoms' stratum, with even a slight increase, was a phenomenon which I 

 have not myself met with in any other instance, the temperature at 10 

 fathoms' depth being generally at least 3 degrees below that of the surface. 

 But Capt. Chimmo, in his "Soundings and Temperatures in the Gulf- 

 stream" (Proceedings of the Royal Geographical Society, vol. xv. 1871, 

 p. 99) states that out of 45 carefully obtained observations between 

 Halifax and the Mid-Atlantic, 26 gave a temperature at 12 fathoms 

 wanner than the surface, — sometimes as much as 1|°, — 10 colder, and 9 

 of the same temperature ; whilst he further states that in the Pacific, off 

 the Isalcos Mountains on the west coast of America, the temperature has 

 been found not less than 10° or 1 1° higher at 12 or 15 feet below the sur- 

 face than at the surface. This he presumes to be due to excessive evapo- 

 ration, as he has often there found the difference between the wet- and the 

 dry-bulb thermometer to be 9°, and on one occasion 11°. From this it 

 seems probable that the marked differences observable between the rates of 

 descent of the thermometers in the subsurface-stratum are partly referable 

 to the hygrometric condition and movement of the air above, which will 

 have an influence even more potent than Temperature per se upon the rate 

 of evaporation from the surface. 



5. Having been led to believe, by the bottom-soundings taken last year, 

 that the temperature of the upper stratum of the Atlantic from 100 

 fathoms down to the " stratum of intermixture " would here fall pretty 

 regularly to about 50° at 700 fathoms, I did not think it needful that time 

 should be spent in carrying Serial soundings continuously downward, if the 

 temperature at that depth should be found to accord with my expectations ; 

 and this it did in a very satisfactory manner, the thermometers sent down 

 to 700 fathoms giving 50°*5. I therefore requested Capt. Nares to take 

 successive temperature-soundings from 700 fathoms downwards, at in- 

 tervals of 100 fathoms ; and these also gave the result I had anticipated, 

 the thermometer falling to 46° at 800 fathoms, to 42° at 900 fathoms, and 

 to 38° at 1000 fathoms. From 1000 fathoms to the bottom at 1560 

 fathoms, the further reduction was only from 38° to 37j°. 



6. Thus, then, this set of Serial soundings fully confirmed the deduc- 

 tion I had ventured to draw last year (Report for 1870, § 81), from the 



