232 Dr. W. B. Carpenter on Physical Investigations [June 15, 



case was very different with, tlie next much deeper sounding (Plate 2. 

 Station 7), which was taken about a degree further south, but still 

 towards the nfiddle of Davis Strait : for there was here (Plate 3. 

 No. yil.) a surface-stratum of 45°, but of such extremely small thickness, 

 that the isotherm of 40° was reached in about 15 fathoms ; from 40° to 

 38° the interval was nearly the same as in the previous souuding ; but 

 below 38° the descent was so slow that 37° was not reached until nearly 

 800 fathoms, and on the bottom at 1100 fathoms the temperature was still 

 36°-4. At the next station (Plate 2. Station 8), Lat. 62° 6' JST., Long. 55° 56' 

 W. (that is, another degree further south, and at about the same distance 

 from the Grreenland coast), a depth of 1350 fathoms was met with ; 

 the surface-temperature was still 45° ; but the bottom-temperature was 

 found to be 34°' 6, as in the 410 f athoms sounding. The next temperature- 

 sounding (Plate 2. Station 9, and Plate 3. Xo. IX.) was taken nearly 3 de- 

 grees further south and 5^ degrees to the west, namely in Lat. 59° 10' N., 

 Long. 50°25' W. ; that is, a little to the south of Cape Farewell, but still six 

 degrees to the west of it : here the surface-temperature was still 45° ; 

 but the bottom-temperature at 17 50 fathoms had sunk to 33°*4. Pinally, 

 a set of serial soundings (Plate 2. Station 10, Plate 4. No. X.) was taken 

 before rounding Cape Farewell, about a degree further south and 4 degrees 

 east : the surface-temperature had then risen to 49° ; but the isotherm 

 of 40° was reached at about 50 fathoms, that of 39° at about 90 fathoms, 

 and that of 38° at about 160 fathoms ; whilst below this the descent of 

 the thermometers was extremely slow down to the isotherm of 37°, which 

 lay at about 1050 fathoms — becoming more rapid, however, beneath this, 

 so that 36° was reached at about 1400 fathoms, 35° at about 1500, and 

 34°-3 on the bottom at 1660 fathoms. 



Now these phenomena seem to me to point very distinctly to the 

 existence (1) of a superheated layer, which is slowly moving up Davis 

 Strait, and gradually losing its excess of temperature as it proceeds 

 north, as shown by the gradual approach of the isotherms to the surface ; 

 (2) of a neutral intermediate layer, 1000 fathoms or more in thickness, 

 marked out by the extreme uniformity of its temperature, which indicates 

 its stationary condition ; and (3) of a deep cold layer, wbich as clearly 

 derives its low temperature from a northern source, as the uppermost 

 stratum does from a southern, and which must, therefore, be in 

 movement. 



The Temperatures at Station YI. (Plate 3.) seem at first sight rather 

 anomalous when compared with those of Stations VII.-X. — the iso- 

 therm of 37° here coming up within 200 fathoms of the surface, whilst 

 at only a degree further south it lies at nearly 800 fathoms; and a 

 bottom-temperature of 34°-6 being found at 410 fathoms at Station VI., 

 whilst at Station YIII. it is only reached at 1350 fathoms. But the ano- 

 maly disappears when the rapidly increasing depth and the tendency of 

 the coldest water to gravitate to the bottom are taken into account : for 



