From The British Quarterly Review. spoken as a "splendid generalization, to have added which to the sum of human knowledge is a glorious distinction." THE results of the deep-sea explorations recently carried out by Dr. CarNo stronger testimony could have been penter, Mr. J. Gwyn Jeffreys, and Pro- given to the opinion entertained by the fessor Wyville Thomson have excited so most competent judges, as to the great much interest, not only among men of value of the work already done, and the science, but also among the general pub-probability that a far richer harvest would lic and this not less in other countries be gathered by the prosecution of similar than in our own - that we feel sure researches on a more extended scale, of our readers' welcome to an endeavour than the fact that our late Government, to place before them a general account of certainly not unduly liberal in its enthe most important of them; chiefly di-couragement of Science, unhesitatingly recting their attention to those new ideas adopted the proposal for a scientific cirwhich these researches have introduced cumnavigation expedition submitted to into science, since without such any mere the Admiralty by Dr. Carpenter on the accumulation of facts remains a rudis in- part of himself and his colleagues, fitted digestaque moles, not animated and quick-out the Challenger with every appliance ened by any vital force. On two of these ideas we shall especially dwell — viz., the doctrine advocated by Dr. Carpenter, of a General Oceanic Circulation sustained by thermal agency alone, characterized by Sir Roderick Murchison* as which, "if borne out by experiment," would "rank amongst the discoveries in physical geography, on a par with the discovery of the circulation of the blood in physiology;" and Professor Wyville Thomson's doctrine of the Continuity of the Chalk-formation on the bed of the one, Atlantic, from the Cretaceous epoch to the present time, of which Mr. Kingsley has * (1.) The Depths of the Sea. An account of the General Results of the Dredging Cruises of H.M.SS. Porcupine and Lightning during the Summers of 1868, 1869, and 1870, under the Scientific Direction of Dr. Carpenter, F.R.S., J. Gwyn Jeffreys, F.R.S., and &c., Regius Professor of Natural History in the Uni- don. (2.) Reports of Deep-Sea Explorations carried on in H.M.SS. Lightning, Porcupine, and Shearwater, in the years 1868, 1869, 1870, and 1871. “Proceedings of the Royal Society," Nos. 107, 121, 125, and 138. Nares, R.N., with Abstracts of Soundings and Dia grams of Ocean Temperature in the North and South Atlantic Oceans. Published by the Admiralty: 1873. (4.) Lecture on The Temperature of the Atlantic," delivered at the Royal Institution on March 20th, 1874. By WILLIAM B. CARPENTER, M.D., LL.D. "Proceedings of the Royal Geographical Society," January, 1871. asked for by the committee of the Royal Society to which the scientific direction of the expedition was entrusted, and sent her forth fully equipped for her work, under the command of one of the ablest surveying officers in the naval service, together with a complete civilian scientific staff, under the experienced direction of the distinguished naturalist by whom the inquiry was initiated, and who had taken an active share in the earlier prosecution of it. Professor Wyville Thomson's beautitifully illustrated volume, entitled “The Depths of the Sea," which made its appearance on the eve of the departure of the Challenger expedition, gives a highly interesting account of the explorations carried on by Dr. Carpenter and himself in the tentative Lightning cruise of 1868, and by the same gentlemen, with the cooperation of Mr. J. Gwyn Jeffreys, in the Porcupine exploration which extended over the four summer months of 1869. In the work of the following year, which extended into the Mediterranean, Professor Wyville Thomson was prevented by illness from participating, and its results are but slightly noticed in his volume. And of the results of Dr. Carpenter's second visit to the Mediterranean in 1871, no mention whatever is made, as they had not long been published when "The Depths of the Sea" made its appearance. They constitute, however, the subject of two very elabo The sea covers nearly three-fourths of the surface of the earth, and until within the last few years very little was known with anything like certainty about its depths, whether in their physical or their biological relations. The popular notion was, that after arriving at a certain depth the conditions became so peculiar, so entirely different from those of any portion of the earth to which we have access, as to preclude any other idea than that of a waste of utter darkness, subjected to such stupendous pressure as to make life of any kind impossible, and to throw insuperable difficulties in the way of any attempt at investigation. Even men of science seemed to share this idea, for they gave little heed to the apparently well-authenticated instances of ani rate reports in the "Proceedings of the Royal Society," in which Dr. Carpenter fully develops his doctrine in regard to Oceanic Circulation, meets the objections which had been raised to it, and discusses the question of the Gulf Stream (necessarily mixed up with it) on the basis of the most recent information. And, as his views have received very striking confirmation from the observations made during the survey of the North and South Atlantic Oceans by the Challenger, of which the results have been recently published by the Admiralty as the first fruits of the circumnavigation expedition, we shall treat this portion of the subject in accordance with Dr. Car-mals, comparatively high in the scale of life, penter's doctrine, rather than with that having been brought up on sounding lines from great depths, and welcomed any suggesof Professor Wyville Thomson. The tion of the animal having got entangled when latter, while devoting a special chapter swimming on the surface, or of carelessness of his work to "The Gulf Stream," seems on the part of the observers. And this was to have proceeded on a foregone conclu-strange, for every other question in physical sion in regard to the extent of its agency, geography had been investigated by scientific which weakens the value of his argument; and hence, while cordially commending every other portion of Professor Wyville Thomson's book to the attention of our readers, we would ask them in perusing this chapter to suspend their judgment, until they have acquainted themselves with the arguments which may be advanced on the other side. men with consummate patience and energy. Every gap in the noble little army of martyrs striving to extend the boundaries of knowledge in the wilds of Australia, on the Zambesi, or towards the North or South Pole, was struggled for by earnest volunteers; and still the covered a region apparently as inaccessible to great ocean slumbering beneath the moon man as the Mare Serenitatis. (p. 2.) We propose, in the following sketch of Thanks, however, to the enterprise of the results of these inquiries, to dwell on the scientific men who commenced the the generalizations to which they point, inquiry, to the support which they rerather than on any of the multitudinous ceived from the Royal Society, and to details which they have added to our the efficient means placed at their disphysical and biological knowledge. A posal year after year by the Admiralty, it very interesting selection of these has has been shown that with sufficient been made by Professor Wyville Thom-power and skill, an ocean of three miles' son; and there is not one of his admira-depth may be explored with as much cerble figures and descriptions, which will not be deeply interesting to every one who is possessed of but an elementary knowledge of Zoology, as showing what manner of creatures they are which dwell in those depths which were previously deemed uninhabitable. tainty, if not with as much ease, as what may now be considered the shallows around our shores, lying within 100 fathoms of the surface. The bed of the deep sea, the 140,000,000 of square miles which we have now added to the legitimate field of natural history research, is not a barren waste. It is inhabited by a fauna more rich and varied on account of the enormous extent of the area; and with the or The state of our previous knowledge, or rather of our ignorance, in regard to the condition of the deep sea, is thus graphically described by Professor Wy-ganisms in many cases apparently even more ville Thomson : elaborately and delicately formed, and more exquisitely beautiful in their soft shades of pact of the weight upon the bottom, even colouring and in the rainbow tints of their if it really strikes the ground, should be wonderful phosphorescence, than the fauna of perceptible above; and thus the quantity the well-known belt of shallow water teeming of rope which runs out, may afford no with innumerable invertebrate forms, which indication of the actual depth of the seafringes the land. And the forms of these bed. Hence all those older "soundings" hitherto unknown living beings, and their mode of life, and their relations to other orwhich were supposed to justify the stateganisms, whether living or extinct, and the ment that the bottom of the ocean lies in phenomena and laws of their geographical some places at not less than six or eight distribution, must be worked out. (p. 4.) miles depth, still more, those which represented it as absolutely unfathomable, are utterly untrustworthy. Various methods have been devised for The first point to be determined in the exploration of what are often called the "fathomless abysses" of the ocean, is their actual depth. This, it might be obtaining more correct measurements, of supposed, would be very easily ascer- several of which illustrated descriptions tained by letting down (as in ordinary will be found in Professor Wyville Thom"sounding") a heavy weight attached to son's pages. One principle may be said a line strong enough to draw it up again, to be common to them all; namely, that until the weight touches the bottom; the regard should be had, not so much to the length of line carried out giving the recovery of the plummet or sinker," as measure of the depth. But this method to securing the vertical direction of the is liable to very great error. Although a line to which it is attached, so that the mass of lead or iron thrown freely into measurement of the amount run out may the sea would continue to descend at an give as nearly as possible the actual increasing rate (at least until the aug- depth of water through which the sinkers mented friction of its passage through have descended. Now, as it is by the the water should neutralize the accelerat- friction of the line through the water that ing force of gravity), the case is quite the rate of descent of the plummet is inaltered when this mass is attached to the creasingly retarded, it is obvious that the end of a thick rope, of which the im-size of the line should be reduced to a mersed length increases as the weight descends. For the friction of such a rope comes to be so great, when a mile or two has run out, as seriously to reduce the rate of descent of the weight, and at last almost to stop it; and since the upper part of the rope will continue to descend by its own gravity (which, when the rope has been wetted throughout, so as to hold no air between its fibres, considerably exceeds that of water), any quantity of it may be drawn down, without the bottom being reached by the weight at its extremity. Further, if there should be a movement, however slow, of any stratum of the water through which it passes, this movement, acting continuously against the extended surface presented by the rope, will carry it out horizontally into a loop or "bight," the length of which will depend upon the rate of the flow and the time during which the line is being acted on by it. Under such circumstances it is impossible that the im minimum; but since, for the purposes of scientific exploration, it is requisite to send down and bring up again thermometers and water-bottles, as well as to obtain samples of the bottom, it is now found desirable to employ, not the fine twine or silk thread of the earlier instruments constructed on this plan, but a line about the thickness of a quill, which, if made of the best hemp, will bear a strain of more than half a ton. plummet being disengaged by a simple mechanical contrivance, and being left on the sea-bed, the instruments only are drawn up by the line. The The trustworthiness of the modern method of sounding is shown by the coincidence of the results obtained by different marine surveyors. Thus the Porcupine soundings taken about 200 miles to the west of Ushant, which reached to a depth of 2,435 fathoms, correspond very closely with the soundings previously taken in the same locality for the French obliterate a large part of the North Sea, which (with the exception of a narrow channel along the coast of Norway and Sweden) would become a continuous plain, connecting our present eastern coast with Denmark, Holland, and Belgium; would in like manner wipe out the British Channel, and unite our southern Atlantic cable; and the soundings taken ney and Shetland Islands, but would by the Porcupine and the Shearwater in the Strait of Gibraltar, bear an equally exact correspondence with those previously laid down in the Admiralty charts, on the authority partly of our own and partly of French surveyors; though the deeper and narrower part of this Strait, in which the current runs the strongest, had been formerly pronounced "unfath-coast with the present northern shores of omable." Hence it may be said that the France; and would carry the coast-line ocean depths, on areas that have been of Ireland a long distance to the west carefully examined, are known with al- and south-west, so as to add a large area most the same exactness as the heights of what is now sea-bottom to its land-surof mountain ranges. Until very re-face. Even an elevation not greater than cently there was reason to believe that the height of St. Paul's would establish a the depth of the North Atlantic nowhere free land communication between Engexceeds about 2,800 fathoms (16,800 land and the Continent, as well as befeet); but the Challenger has recently met with the extraordinary depth of 3,800 fathoms (more than four miles), a little to the north of St. Thomas's; and that this result did not proceed from an accidental error, is shown by the fact that two thermometers, protected in the manner to be hereafter described, which had been tested under a hydrostatic pressure of three tons and a half (corresponding to a column of 2,800 fathoms) were crushed by the excess. tween England and Ireland. And thus we see how trifling a change of level, by comparison, would have sufficed to produce those successive interruptions and restorations of continuity, of which we have evidence in the immigrations of the Continental mammalia, on each emergence that followed those successive submergences of which we have evidence in our series of Tertiary deposits.* Many of our readers, we doubt not, have been in the habit - as we formerly Before proceeding to inquire into the were ourselves — of looking at the Medrelation which the depth of the ocean iterranean as only a sort of British Chanbears to its temperature, and to the dis- nel on a larger scale; whereas it is a tribution of animal life on the sea-bed, we basin of quite another character. For may stop to point out how important is a whilst the separation between Great knowledge of the exact depth of the sea- Britain and the Continent may be pretty bottom to the geologist. It is only by certainly attributed to the removal, by such knowledge that he can judge what denudation, of portions of stratified dedepartures from the present distribution posits that were originally continuous, of land and sea would have been pro- the extraordinary depth of the Mediterduced by those changes of level, of which ranean basin can scarcely be accounted he has evidence in the upheaval and sub- for on any other hypothesis than that of mergence of the stratified deposits that the subsidence of its bottom; which was, formed the ocean-bed of successive geo- perhaps, a part of that "crumpling" of logical periods; or that he can obtain the earth's crust, which occasioned the the clue to the distribution of the animal elevation of the high mountain chains in and vegetable forms, by which he finds its neighbourhood. This great inland sea those periods to have been respectively may be said to consist of two basins; the characterized. For example, a knowl- western extending from the Strait of edge of the comparative shallowness of Gibraltar to the "Adventure" and the Seas that surround the British Is-"Skerki" banks, which lie between lands, enables us readily to understand the former connection of our islands, not merely with each other, but with the Continent of Europe. For they stand upon a sort of platform, of which the depth is nowhere greater than 100 fathoms; so that an elevation of 600 feet (only half as much again as the height of St. Paul's) would not only unite Ireland to Great Britain, and extend the northern boundary of Scotland so as to include the Ork Sicily and the Tunisian shore; while the eastern extends from the Adventure bank to the coast of Syria. Now, over a large part of the former area, the depth ranges to between 1,000 and 1,500 fathoms, being often several hundred fathoms within sight of land; and over a large part of the latter, it ranges from See Professor Ramsay's "Physical Geology and Geography of Great Britain," chap. xii. 1,500 to 2,000 fathoms, the descent being | lars of Hercules," the evidence is equally so rapid that a depth of upwards of 2,000 clear of a depression of the south-western fathoms (above 12,000 feet) is met with at portion of France at no remote geologinot more than fifty miles to the east of cal period; so that a wide communicaMalta. But the ridge between Capes tion would have existed between the Bay Spartel and Trafalgar, which constitutes of Biscay and the Gulf of Lyons, along the "marine watershed" between the the course of the present canal of LanMediterranean and the Atlantic basins, guedoc. And certain very curious conis nowhere more than 200 fathoms in formities between the marine fauna of depth; and as the Adventure and Skerki the Mediterranean and that of the Arctic banks, which lie between Sicily and the province, are considered by Mr. Gwyn Tunisian coast, are within that depth Jeffreys as indicating that Arctic species (some of their ridges being not more than which migrated southwards in the cold fifty fathoms from the surface), it is ob- depths congenial to them, found their vious that an elevation of 1,200 feet, by way into the Mediterranean through this closing the Strait of Gibraltar, and unit- channel. We shall presently see what ing Sicily with Africa, would convert the very important modifications in the conMediterranean into two great salt-water dition of this great Inland Sea, affecting lakes, still of enormous depth, and of its power of sustaining animal life, would but slightly reduced area, as is shown result from any considerable increase in in regard to the Western basin, in Plate the depth of its channel of communicav. of "The Depths of the Sea." That tion with the great oceanic basin, from such a partition did at one time exist, is which all but its superficial stratum is evident from the number and variety of now cut off. the remains of large African mammalia Another most interesting example of entombed in the caves of Sicily and in the importance of the information supthe Tertiary deposits of Malta. Thus in plied by exact knowledge of the depth of caverns of the hippurite limestone, not the sea, is furnished by the inquiries of far from Palermo, there is a vast collec- Mr. A. R. Wallace in regard to the geotion of bones of the hippopotamus, asso- graphical distribution of the fauna of the ciated with those not only of Elephas Eastern Archipelago. For while Java, antiquus, but of the living African ele- Sumatra, and Borneo clearly belong to phant. And in Malta there have been the Indian province, Celebez, the Mofound remains of several species of luccas, and New Guinea no less clearly elephants; amongst them a pigmy of belong to the Australian; the boundaryabout the size of a small ass. It is not a line between them passing through the little curious that there is distinct evi-Strait of Lombok a channel which, dence of considerable local changes of though no more than fifteen miles in level, in various parts of the Mediterra- width, separates faunæ not less differnean area, within the human period. Thus ing from each other than those of the Captain Spratt has shown that the Island Old and the New Worlds. The explanaof Crete has been raised about twenty-tion of these facts becomes obvious, five feet at its western extremity, so that when we know that an elevation of no ancient ports are now high and dry above more than fifty fathoms would unite the sea; while at its eastern end it has Borneo, Sumatra, and Java with each sunk so much, that the ruins of old towns other, and with the peninsula of Malacca are seen under water. And on the and Siam; while an elevation of 100 southern coast of Sardinia, near Cagliari, fathoms (600 feet) would convert nearly there is an old sea-bed at the height of the whole of the bed of the Yellow Sea nearly 300 feet above the present level into dry land, and would reunite the of the Mediterranean, which contains Philippine Islands to the south-eastern not merely a great accumulation of ma-part of the continent of Asia. But even rine shells, but numerous fragments of the latter elevation would not connect the antique pottery - among them a flattened ball with a hole through its axis, which seems to have been used for weighting a fishing-net. It is doubtful, however, whether the western basin of the Mediterranean was ever cut off from the Atlantic; for though there is pretty clear evidence of former continuity between the two "Pil upraised area with the Australian province, the depth of the narrow dividing strait being greater than that of any part of the large Asiatic area now submerged. In some parts of the Australian portion of the Eastern Archipelago, indeed, there are some very extraordinary and sudden depressions, showing the activity of the changes which have taken place in the |