56 



THE ATLANTIC. 



[chap. I. 



same very characteristic globigerina 

 deposit, and a temperature of 2°-0 C. 

 The bottom temperatures in this sec- 

 tion show some irregularities ; but as 

 these do not extend beyond 0°"2 C, 

 they may arise from errors of obser- 

 vation, due to the somewhat unsatis- 

 factory mode of registering of Six's 

 thermometers. 



On the 14tli we sounded in 2400 

 fathoms ; and a serial temperature 

 sounding (Fig. 15) indicated an al- 

 most total disappearance of the upper 

 stratum of abnormally warm water; 

 but, on the other hand, the isotherms 

 between three and eight hundred 

 fathoms showed very distinctly the 

 excess of heat in a deeper layer, to 

 which reference has already been 

 made, and which, becoming more 

 marked a little to the northward, 

 gives so peculiar a character to the 

 temperature soundings in the Bay of 

 Biscay. In Fig. 13 the curves con- 

 structed from the serial soundings be- 

 tween Bermudas and Madeira show 

 very clearly the gradual disappear- 

 ance of the upper Avarm layer in pass- 

 ing to the eastward ; and the appear- 

 ance of the second deeper hump near 

 the coast of Africa. The curve mark- 

 ed with the asterisk constructed from 

 the Porcupine., LigJdnijig, and Shear- 

 water soundings is introduced for 

 comparison. 



