CHAP. IV.] THE VOYAGE HOME. 219 



of the previous day. All the isotherms from that of 1°'5 C. 

 had risen palpably, most of them, between 100 and 200 fath- 

 oms. Even the surface participated in the fall of temperature, 

 liaving sunk from 21°-6 C. to 19°-9 C. This is evidently a space 

 in the Brazil Current occupied by cold water, like the peculiar 

 cold interdigitations which are so marked in the Gulf-stream. 

 The position of this sounding was lat. 37° 3' S., long. 44° IT W. 

 A serial temperature sounding on the following day, at a dis- 

 tance of 80 miles to the eastward, where the depth was 2900 

 fathoms and the bottom temperature — 0°*3 C, showed by the 

 sinking of all the isotherms that we had again entered the nor- 

 mal flow of the Brazil Current. 



On the 6th of March it was blowing hard from the south- 

 west with a heavy sea. We sounded in 2000 fathoms, with a 

 bottom of gray mud, and a bottom temperature of — 0°'3 C ; 

 but the weather was too boisterous to admit of a serial temper- 

 ature sounding. On the Tth the sea was more moderate, and 

 we sounded in 2675 fathoms, with a bottom temperature of 

 — 0°"6 C, and took a series of temperatures. The bottom was 

 again a fine gray or slightly reddish mud, almost free from 

 calcic carbonate. Samples of water were obtained for spe- 

 cific-gravity determinations and analysis down to 2000 fath- 

 oms. 



On the 8th of March we sounded in 2440 fathoms, with a 

 bottom of light-red mud and a bottom temperature of — 0°-3 C. ; 

 and on the 9th, somewhat to our surprise, we sounded in 1715 

 fathoms, with a bottom of globigerina ooze and a temperature 

 of l°-3 C. The sea was heavy, and trawling operations conse- 

 quently difficult. The trawl was lowered, however, on account 

 of the remarkable shallowness of the sounding ; but it unfortu- 

 nately came up foul, and the observation was lost. It seems 

 that this sounding was on the central meridional rise which 

 separates the western from the eastern trough of the Atlantic 

 at a depth apparently nowhere much beyond 2000 fathoms, near 



