266 
NOTES FROM THE “CHALLENGER” 
V. 
O* Wednesday, March 26, we sounded (Station 
25) in lat. 19° 41’ N., long. 65° 7’ W., nearly go 
miles north of St. Thomas, in 3,875 fathoms. The 
bottom brought up in the hydra tube was reddish 
mud, containing, however, a considerable quantity 
of carbonate of lime, It is singular that the colour and 
composition of this mud were not uniform. The upper 
layer, that which had been forced farthest into the tube, 
was much redder than that which was nearest the mouth 
of the tube, and which had consequently come from a 
greater depth. 
I am inclined to attribute this to the 
> ( 
Fic. r.—Deidamia crucifer, vy. W.-S. 
steepness of the slope from the plateau of the Virgin 
Islands. It is easy to conceive that, under the influence 
of currents varying from time to time in force and direc- 
tion, the calcareous mud, the product of the disintegration 
of the coral reefs, may be washed down the incline in 
varying proportions. 
Two thermometers were sent down in this sounding, 
and aslip water-bottle. The thermometers were unable to 
bear the extreme pressure, and both were broken. I 
have already (vol. vili. p. 109) in a former report described 
the circumstances connected with the loss of these two 
NATURE 
[Fuly 31, 1873 
instruments. The water bottle appeared to have 
answered its purpose. Mr. Buchanan finds that the 
bottom water has a specific gravity slightly greater than 
usual at great depths, but not materially so. The 
amount of carbonic acid is somewhat in excess. 
As this was the deepest sounding which we had taken 
we were anxious to try whether the dredge would sti 
prove serviceable. The small @redge was accordingly 
lowered with the usual bar and tangles, and from the 
centre of the bar a “ hydra” sounding tube weighted with 
4 cwt. was suspended about two fathoms behind the dredge. 
A two-inch rope was veered to 4 400 fathoms ; a toggle 
was stopped on the rope 500 fathoms from the dredge, and 
when the dredge was well down two weights of one cwt. 
each were slipped down the rope tothe toggle. Wecom- 
menced heaving in about 1.30, and at 5 P.M. the dredge 
appeared, with a considerable quantity of reddish- 
grey ooze, mottled like the contents of the sounding-tube. 
lhe whiter portion effervesced freely with acids, the redder 
only slightly. The mud was carefully examined, but no 
animals were detected except a few small foraminfera, with 
calcareous tests, and some considerably larger of the 
arenaceous type. This dredging, therefore, only con- 
firmed our previous conviction, that very extreme depths, 
while not inconsistent with the existence of animal life, 
are not favourable to its development. In the afternoon 
a series of temperatures were taken at intervals of 100 
fathoms from the surface to 1,500. The temperature at 
the surface was 24°°5 C,, and that at 1,500 2%4C. The 
curve constructed from this series indicates a very rapid 
and uniform fall of about 20 C. during the first 600 
fathoms, and generally a distribution of temperature 
almost identical with that of some of the later stations 
on the section from Santa Cruzto Sombrero. . In this way 
we pursued our course northwards under all plain sail. 
On the following day we sounded in much shallower 
water—2,800 fathoms. The bottom was much of the 
same character, and on the 28th in 2,960 fathoms with a 
like result, but at our next sounding in 2,850 fathoms on 
the 29th, the calcareous element in the mud had almost 
entirely disappeared, and the contents of the tube seemed 
to be identical with the “red clay” which occupied so 
large a portion of our first section. 
this clay is a large and important phenomenon. In the 
section of the Atlantic, from the Canaries to the West 
Indies, it occupies about 1,900 miles, a distance twice as 
great as that occupied by the globigerina mud. What its 
lateral extension from that line may be, we do not know; 
but we now find that it extends more or less from over 
the greater part of the distance between St. Thomas and 
Bermudas. The nature and source of this deposit, and 
the causes of its peculiar distribution in the deeper parts 
of the ocean, are therefore questions of the highest 
interest, 
On the 2nd of April, at a distance of 134 miles from 
Bermudas, a series of temperature soundings was taken 
at intervals of 20 fathoms from the surface to 300 
fathoms. ( 
The pilot came on board in the afternoon of April 4 
and we passed through the narrows, the reefs which make, 
the navigation of this singular little group of islands so 
dangerous spreading round us in rich purple patches, 
contrasting with the vivid pale green of the channels of 
deeper water between them. : 
The evening was falling as we anchored in Grassy Bay 
and received our first impressions of Bermudas. On the 
Monday following we moved from Grassy Bay to the 
Camber, in the great Dockyard. We remained there till 
the 21st of April, and employed the interval in taking such 
a general survey of the natural beauty of the island as 
our time allowed. 
As Bermudas, on account of its isolated position, its 
structure, and its peculiar conditions of temperature, pre- 
sents many points of great interest, I will defer giving a 
The occurrence of 
’ 
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