ll gun-vessel, at the disposal of a small
committee to sound and dredge in the North Atlantic between Shetland and
the Farue Islands.

In the "Lightning," with the help of a donkey-engine for winding in,
dredging was carried on with comparative ease at a depth of 600 fathoms,
and at that depth animal life was found to be still abundant. The
results of the "Lightning's" dredgings were regarded of so great
importance to science that the Royal Society pressed upon the Admiralty
the advantage of continuing the researches, and accordingly, during the
years 1869 and 1870, the gun-boat "Porcupine" was put under the orders
of a committee consisting of Dr W. B. Carpenter, Dr Gwyn Jeffreys, and
Professor (afterwards Sir Charles) Wyville Thomson, one or other of whom
superintended the scientific work of a series of dredging trips in the
North Atlantic to the north and west of the British Islands, which
occupied two summers.

In the "Porcupine," in the summer of 1869, dredging was carried down
successfully to a depth of 2435 fathoms, upwards of two miles and a
half, in the Bay of Biscay, and the dredge brought up well-developed
representatives of all the classes of marine invertebrates. During the
cruises of the "Porcupine" the fauna of the deep water off the western
coasts of Great Britain and of Spain and Portugal was tolerably well
ascertained, and it was found to differ greatly from the fauna of
shallow water in the same region, to possess very special characters,
and to show a very marked relation to the faunae of the earlier Tertiary
and the later Cretaceous periods.

In the winter of 1872, as a sequel to the preliminary cruises of the
"Lightning" and "Porcupine," by far the most considerable expedition in
which systematic dredging had ever been made a special object left Great
Britain. H.M.S. "Challenger," a corvette of 2306 tons, with auxiliary
steam working to 1234 h.p., was despatched to investigate the physical
and biological conditions of the great ocean basins.

The "Challenger" was provided with a most complete and liberal
organization for the purpose; she had powerful deck engines for hauling
in the dredge, workrooms, laboratories and libraries for investigating
the results on the spot, and a staff of competent naturalists to
undertake such investigations and to superintend the packing and
preservation of the specimens reserved for future study. Since the
"Challenger" expedition the use of wire rope has enabled f