262 | THE ATLANTIC. [omap. rv. 
the “ Hydra” tube was reddish mud, containing, however, a con- 
siderable quantity of carbonate of lime. The color and compo- 
sition of the mud were not uniform. The upper layer—that 
which had been forced farthest into the tube—was much red- 
der than that which was nearest the mouth of the tube, and 
which had consequently come from a greater depth. 
This is a phenomenon with which we are now very famil- 
iar, particularly among the red clays from great depths. It 
seems to be due to some deoxidizing process taking place 
slowly, and consequently visibly affecting only those deeper 
layers which have been deposited for a considerable length of 
time. 
As to the determination of depth, this sounding was perfect- 
ly satisfactory. Being still near the Islands, we did not expect 
the depth to be nearly so great as it was, and the “ Hydra” tube 
was weighted with 3 ewt. only; but the sea was smooth and 
the weather fine, and it was easy to keep the ship nearly sta- 
tionary. The following table gives the time-intervals in the 
running-out of the line: 
Fathoms. Time. Interval. Fathoms. Time. Interval. 
H. M S: M Ss. Hs MM: Ss. M. S; 
500 62536" i NW oar 2400 7 9 38 2 Mia: 
600 Gres 16 0 59 2500 Wee Ub Re Pelt 
4700 (Ro BRE We) ts: 2600 ia eal 2 8 
800 6 89 48 i a9 2700 i Ge 26 2) lb 
900 (fo) etl Sil le 224 2800 We is Bi7/ 2oreil 
1000 6 42 48 Bie 2900 if 20) 959 2 322. 
1100 Go 44 337 3000 fe, BBS Be 2 Par 
1200 6 46 8 1 ae 3100 if PAs Us 2 ND 
1300 6 47 45 42 3200 te tte al 2 26 
1400 Gus Omeoe ery 3300 A sd), BS Dy sO 
1500 o bil 20 1 48 *3400 Sse 2. "25 
1600 6 58 22 2 3500 fl S40) idl BESS 
1700 GeoD 7 1 55 3600 i Geb XM) 2 40 
1800 Ge bie eab 1 58 *3700 AG We a 62 
1900 6 59 2 Set 8800 7 BG 99): |e 
2000 a 1 6 2 4 3900 8 Oo 19 Ot 
- A { At the 
2100 7 8 2 Lae. OA MERE eerges paratie 
2200 5 5 as 2 5 38925 8 eas 3 56 
2300 a 24. Olt 3950 8 De 4 ~ 
