178 THE ATLANTIC. [ CHAP. IIL. 
When at length it settles, it forms a perfectly smooth red- 
brown paste, without the least feeling of grittiness between the 
fingers, as if it had been levigated with extreme care for a proc- 
ess in some refined art. On analysis it is almost pure clay, a 
silicate of alumina and the sesquioxide of iron, with a small 
quantity of manganese. 
The weight beneath the dredge had certainly the desired ef- 
fect in this case of bringing the dredge rapidly to the bottom. 
The stem of the “ Hydra” machine had gone deep into the 
mud, and was bent, apparently by the weight falling upon it. 
The dredge had taken a deep scoop of mud, and the line had 
entangled itself in a coil of 20 or 80 fathoms over the second 
weight, showing that it had not been exposed to any current. 
On the 27th we proceeded steadily on our course, and on the 
28th we sounded in the morning in 2720 fathoms with No. 1 
line, to which were attached a “ Hydra” machine with 4-ewt. 
disengaging weights, a slip water-bottle, and two thermometers. 
At a distance of 500 fathoms from the bottom a stop-cock wa- 
ter-bottle was bent on to the line. The tube of the “ Hydra” 
was filled with a red mud containing a considerably larger pro- 
portion of carbonate of lime than in the previous sounding, and 
a few shells of calcareous foraminifera. As the bottom pre- 
sented so little difference from the former, which we had found 
so nearly destitute of animal life, it was thought unnecessary to 
spend the time and great labor necessarily involved in dredg- 
ing, and we proceeded under sail, after taking a series of tem- 
perature observations : 
Surfaces. .e. aun tee ws 80 fathoms... 5-65 ece Lopes 
HOPEATHOME coe eco ee 90 Bee” a chad A See ima 
20 ee Fa eae ee ORO 100 BORE FORS cay Lt) aa) 
30 “6 stds seas Ree 200 ss notte AS eee aes 
40 & RR aA code 7 300 BES feroy ics at Sc eaten tien ARLE 
50 sow seater ener ee acai Pl os! . 400 se 4c 2d (nea 
60 s NAS OR ee eS 500 S were etalsiararn eer chen ORRD 
70 We hortcicrer terete 21 °4 600 - 5 2 
