his 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, 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
10,000 feet, or two miles, by the help of this sounding apparatus. The
specimens were sent for examination to Ehrenberg of Berlin, and to
Bailey of West Point, and those able microscopists found that this
deep-sea mud was almost entirely composed of the skeletons of living
organisms--the 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
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 a