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ascertain with precision the depths of the waters they traversed。
Out of this necessity grew the use of the lead and sounding line；
and； ultimately； marine…surveying； which is the recording of the
form of coasts and of the depth of the sea； as ascertained by the
sounding…lead； upon charts。
At the same time； it became desirable to ascertain and to indicate
the nature of the sea…bottom； since this circumstance greatly
affects its goodness as holding ground for anchors。 Some ingenious
tar； whose name deserves a better fate than the oblivion into which
it has fallen； attained this object by 〃arming〃 the bottom of the
lead with a lump of grease； to which more or less of the sand or
mud； or broken shells； as the case might be； adhered； and was
brought to the surface。 But； however well adapted such an
apparatus might be for rough nautical purposes； scientific accuracy
could not be expected from the armed lead； and to remedy its
defects （especially when applied to sounding in great depths）
Lieut。 Brooke；＇61＇ of the American Navy； some years ago invented
a most ingenious machine； by which a considerable portion of the
superficial layer of the sea…bottom can be scooped out and brought
up from any depth to which the lead descends。
In 1853； Lieut。 Brooke obtained mud from the bottom of the North
Atlantic； between Newfoundland and the Azores； at a depth of more
than ten thousand feet； or two miles； by the help of this sounding
apparatus。 The specimens were sent for examination to Ehrenberg ＇62＇
of Berlin； and to Bailey of West Point；＇63＇ and those able
microscopists found that this deep…sea mud was almost entirely
composed of the skeletons of living organismsthe greater proportion
of these being just like the Globigerinae already known to occur
in the chalk。
Thus far； the work had been carried on simply in the interests of
science； but Lieut。 Brooke's method of sounding acquired a high
commercial value； when the enterprise of laying down the telegraph…
cable ＇64＇ between this country and the United States was undertaken。
For it became a matter of immense importance to know； not only the
depth of the sea over the whole line along which the cable was to
be laid； but the exact nature of the bottom； so as to guard against
chances of cutting or fraying the strands of that costly rope。 The
Admiralty consequently ordered Captain Dayman； an old friend and
shipmate of mine； to ascertain the depth over the whole line of the
cable； and to bring back specimens of the bottom。 In former days；
such a command as this might have sounded very much like one of the
impossible things which the young prince in the Fairy Tales is
ordered to do before he can obtain the hand of the Princess。
However； in the months of June and July； 1857； my friend performed
the task assigned to him with great expedition and precision
without； so far as I know； having met with any reward of that kind。
The specimens of Atlantic mud which he procured were sent to me to
be examined and reported upon。*
* See Appendix to Captain Dayman's 〃Deep…sea Soundings in the North
Atlantic Ocean； between Ireland and Newfoundland； made in H。M。S。
Cyclops。 Published by order of the Lords Commissioners of the
Admiralty； 1858。〃 They have since formed the subject of an
elaborate Memoir by Messrs。 Parker and Jones； published in the
Philosophical Transactions for 1865。
The result of all these operations is； that we know the contours
and the nature of the surface…soil covered by the North Atlantic；
for a distance of seventeen hundred miles from east to west； as
well as we know that of any part of the dry land。
It is a prodigious plainone of the widest and most even plains in
the world。 If the sea were drained off； you might drive a wagon
all the way from Valentia； on the west coast of Ireland； to Trinity
Bay； in Newfoundland。 And； except upon one sharp incline about two
hundred miles from Valentia； I am not quite sure that it would even
be necessary to put the skid on； so gentle are the ascents and
descents upon that long route。 From Valentia the road would lie
down…hill for about 200 miles to the point at which the bottom is
now covered by 1700 fathoms of sea…water。 Then would come the
central plain； more than a thousand miles wide； the inequalities of
the surface of which would be hardly perceptible； though the depth
of water upon it now varies from 10；000 to 15；000 feet； and there
are places in which Mont Blanc might be sunk without showing its
peak above water。 Beyond this； the ascent on the American side
commences； and gradually leads； for about 300 miles； to the
Newfoundland shore。
Almost the whole of the bottom of this central plain （which extends
for many hundred miles in a north and south direction） is covered
by a fine mud； which； when brought to the surface； dries into a
greyish…white friable substance。 You can write with this on a
blackboard； if you are so inclined； and； to the eye； it is quite
like very soft； greyish chalk。 Examined chemically； it proves to
be composed almost wholly of carbonate of lime； and if you make a
section of it； in the same way as that of the piece of chalk was
made； and view it with the microscope； it presents innumerable
Globigerinae embedded in a granular matrix。
Thus this deep…sea mud is substantially chalk。 I say
substantially； because there are a good many minor differences； but
as these have no bearing on the question immediately before us；
which is the nature of the Globigerinae of the chalk；it is
unnecessary to speak of them。
Globigerinae of every size； from the smallest to the largest； are
associated together in the Atlantic mud； and the chambers of many
are filled by a soft animal matter。 This soft substance is； in
fact； the remains of the creature to which the Globigerina shell；
or rather skeleton； owes its existenceand which is an animal of
the simplest imaginable description。 It is； in fact； a mere
particle of living jelly； without defined parts of any kind
without a mouth； nerves； muscles； or distinct organs； and only
manifesting its vitality to ordinary observation by thrusting out
and retracting from all parts of its surface； long filamentous
processes； which serve for arms and legs。 Yet this amorphous
particle； devoid of everything which； in the higher animals； we
call organs； is capable of feeding； growing and multiplying； of
separating from the ocean the small proportion of carbonate of lime
which is dissolved in sea…water； and of building up that substance
into a skeleton for itself； according to a pattern which can be
imitated by no other known agency。
The notion that animals can live and flourish in the sea； at the
vast depths from which apparently living Globigerinae have been
brought up； does not agree very well with our usual conceptions
respecting the conditions of animal life； and it is not so
absolutely impossible as it might at first appear to be； that