<< Tee “VU, ar as ors Vv ee Ea . iv if: Mitad Bee bir ne Woe ae vet ue SAT RRA A AA aR Eni wv Ab yr ae q a Ki. Sh { } + oe | t,~ ‘i A i, WITH NUMEROUS RATIONS AND MAPS. Pondon : MEAG ME PAN AONE CO: Lois: LONDON: . R, CLAY, SONS, AND TAYLOR, PRINTERS, BREAD STREET HILL. ae TO VAD VEE, ERO a EN Chis Volume is dedicated, IN GRATEFUL REMEMBRANCE OF THE PLEASANT TIMES SPENT BY HIMSELF AND HIS COMRADES AT THE GOVERNOR'S HOUSE IN THORSHAVN, BY THE AUTHOR. << oeee e PREFACE. Av the close of the Deep-sea Dredging Expeditions which had been undertaken by the Admiralty at the instance of the Council of the Royal Society during the years 1868, 1869, and 1870, it was thought right that those who had been entrusted with their scien- tific direction should, in addition to their official reports, lay before the general public some account of their proceedings with the objects ;—first, of show- ing, if possible, that the value of the additions which had been made to human knowledge justified the liberality of Government in acceding to the request of the Council of the Royal Society, and placing means at their disposal to carry out the desired researches; and, secondly, of giving such a popular outline of the remarkable results of our work as might stimulate general interest, and induce those who have the proclivities and the opportunity, to penetrate farther into the new and strange region on whose borders we have had the good fortune to have been among the first to encroach. Vill PREFACE. It was originally intended that the general account should have been a joint production, each of us con- tributing his part. There were difficulties, however, in the way of this arrangement. We were all fully occupied with other matters, and the amount of communication and correspondence between us, re- quired to carry out the plan of joint authorship, seemed likely to prove a cumbrous complication. It was therefore decided that quoad the popular exposition I should take upon myself the office of ‘reporter,’ and thus it comes about that I am indi- vidually and solely responsible for the opinions and statements contained in this book, save where they are included within quotation marks, or their sources otherwise acknowledged. Since we began these deep-sea investigations, inquiries have come in from all quarters, both at home and abroad, as to the implements and methods which we employ. 'To supply the desired informa- tion, I have described, in detail, the processes both of sounding and dredging; and I hope that the special chapters on these matters—the result of considerable experience—may be found useful to beginners. J pretend to no special knowledge of physics, and I should have greatly preferred confining myself to the domain of Biology, my own proper province; but certain physical questions raised during our late explorations have so great importance in relation to PREPACE. ix the distribution of living beings, and have of late been brought into so great prominence by Dr. Car- penter, that it has been impossible for me to avoid giving my earnest consideration to their general bearings on Physical Geography, and forming decided opinions, which, I regret to say, do not altogether coincide with those of Dr. Carpenter. The chief points on which my friend and I ‘agree to differ’ are discussed in the chapter on the Gulfstream. It was at first my intention that appendices should be added to the different chapters, containing lists and scientific descriptions of the animal forms which were observed. This it was found impossible to accomplish, chiefly on account of the large number of undescribed species which were placed in the hands of the experts who undertook the examination of the several groups. I am not sure that, even if it had been possible to furnish them in time, such lists would have been altogether an appropriate addition to what is intended merely as a popular preliminary sketch. The metrical system of measurement, and the centigrade thermometer scale, have been adopted throughout the volume. The metrical system is pro- bably familiar to most of my readers. In case the centigrade notation, which comes in very frequently owing to the frequent discussion of questions of the distribution of temperature, should not be equally familiar, a comparative scale, embodying those of Allman, F.R. PREPACE, Fahrenheit, Celsius, and Réau- mur, is introduced for com- parison. My various sources of infor- mation, and the friendly as- sistance I have received on all hands during the progress of our work, are acknowledged, so far as possible, in the text. I need here only renew my thanks to Staff-Commander May and the officers of the ‘Lightning,’ and Captain Cal- ver and the officers of the ‘Porcupine, without whose hearty sympathy and co-ope- ration our task could never have been satisfactorily accom- plished; to my colleagues, Dr. Carpenter, F.R.S., and Mr. Gwyn Jeffreys, F.R.S., who have cordially assisted me in every way in their power; and to the naturalists into whose hands the animals of various classes were placed for descrip- tion and study,—the Rev. A. Merle Norman, Professor K6l- liker,, Dr... Carter, -EUR.S:,0 Dr Professor Martin Duncan, F.R.S., PREFACE. X1 and Dr. M‘Intosh, for information courteously supplied. The whole of the illustrations in the book—with the exception of the vignettes of Froe scenery for which 1 am indebted to the accomplished pencil of Madame Holten—are by my friend Mr. J. J. Wild. I need scarcely thank him for the admirable way in which he has accomplished his task, for every figure was with him a labour of love, and I almost envy him the gratification he must feel in the result. To Mr. J. D. Cooper I owe my sincere thanks for the singularly faithful and artistic rendering of Mr. Wild’s beautiful drawings on the wood-blocks. On the return of the ‘Porcupine’ from her last cruise, so much interest was felt in the bearings of the new discoveries upon important biological geo- logical and physical problems, that a representation was made to Government by the Council of the Royal Society, urging the despatch of an expedition to traverse the great ocean basins, and take an out- line survey of the vast new field of research—the bottom of the sea. Rear-Admiral Richards, C.B., F.R.S., the Hydro- erapher to the Navy, warmly supported the pro- posal, and while I am writing a noble ship is lying at Sheerness equipped for scientific research under his wise and liberal directions, as no ship of any nation was ever equipped before. xu PREFACE. The scientific staff of the ‘Challenger’ are well aware that for some time to come their réle is to work and not to talk; but now, on the eve of depar- ture, I think it is only right to take this opportunity of saying that nothing has been left undone by the Government, to ensure the success of the undertaking, and that dire misfortune only ought to prevent our furnishing a valuable return. C. WYVILLE THOMSON. EDINBURGH, December 2nd, 1872. Slattaretindur ae i A == Slaw = eDon or CONTENTS: CHAPTER I. INTRODUCTION. The Question of a Bathymetrical Limit to Life-—The general Laws which regulate the Geographical Distribution of Living Beings.—Professor Edward Forbes’ Investigations and Views.—Specific Centres.—Repre- sentative Species,—Zoological Provinces.—Bearings of a Doctrine of Evolution upon the Idea of a ‘Species, and of the Laws of Distribution. —The Circumstances most likely to affect Life at great Depths : Pres- sure, Temperature, and Absence of Light ... ... 0... 0... + Page 1 CHAPTER II. THE CRUISE OF THE ‘LIGHTNING.’ Proposal to investigate the Conditions of the Bottom of the Sea.—Sugges- tions and Anticipations.—Correspondence between the Council of the Royal Society and the Admiralty.—Departure from Stornoway.—The Froe Islands.—Singular Temperature Results in the Froe Channel.— Life abundant at all Depths.—Brisinga coronata.—Holtenia carpentert. —General Results of the Expedition Be Aime a eA ea Oe Appenpix A.—Particulars of Depth, Temperature, and Position at the various Dredging Stations of H.M.S. ‘Lightning, in the Summer of 1868 ; the Temperatures corrected for Pressure... ... .... Page 81 CHAPTER III. THE CRUISES OF THE ‘ PORCUPINE.’ The Equipment of the Vessel.—The first Cruise, under the direction of Mr. Gwyn Jeffreys, off the West Coast of Ireland and in the Channel between Scotland and Rockall.— Dredging carried down to 1,470 fathoms. Xiv CONTENTS. —Change of Arrangements.—Second Cruise ; to the Bay of Biscay.— Dredging successful at 2,435 fathoms.—Third Cruise ; in the Channel between Féroe and Shetland.—The Fauna of the ‘Cold Area.’ Page 82 Appenpix A.—Official Documents and Official Accounts of preliminary Proceedings in connection with the Explorations in H.M. Surveying- vessel ‘ Porcupine,’ during the Summer of 1869... ... ... Page 133 AppENDIx B.—Particulars of Depth, Temperature, and Position at the various Dredging Stations of H.M.S. ‘ Porcupine, in the Summer of 1869: cee cee eee ws DIAGRAM OF THE~ RELATIVE PosITION OF THE VESSEL, THE WericHts, AND THE DREDGE, IN DREDGING IN DkEP WATER PREDGE- WITH *HEMPEN 'FANGLES’ { 3. > 20000 cee) eeu ee oes SET ‘OF DREDGING SIEVES:::... 0 cc. eevee : BD itt Tum MintEr-CasELLA Monmecation OF SIXx’s oo REGISTER- ING THERMOMETER~ «.. °°... -. fe Behe CoprerR CASE FOR ‘PROTECTING THE Erte tia: C JASELLA ‘Dern: MOMETER ... «3 . Ease AG alate Sou Mies eh Ose + aaa SERIAL SOUNDING, Station 64. SERIAL SOUNDING, Station 87 ene é ; ; CURVES CONSTRUCTED FROM SERIAL Soa MDINGE J IN THE Warw - AND *@onp-AREAS’ IN THE CHANNEL BETWEEN SCOTLAND AND FAROE wet ‘ ty : A Sf dieu Bienen ty: CURVES CONSTRUCTED FROM ee AND » Bomtow SouNDINGS IN THE CHANNEL BETWEEN SCUTLAND AND ROCKALL ... ... DIAGRAM REPRESENTING THE RELATION BETWEEN DEPTH AND TEMPERATURE OFF ROCKALL ... .:. ..- « eases DIAGRAM REPRESENTING THE RELATION BETWEEN Desi AND TEMPERATURE -IN THE ATLANTIC BASEN - ...> eis eer ose CURVES CONSTRUCTED FROM SERIAL AND Borrom TEMPERATURE SoUNDINGS IN THE ATLANTIC BASIN... ... tes, Sic ee DIAGRAM REPRESENTING THE RELATION BETWEEN Daprd AND TEMPERATURE, FROM THE TEMPERATURE OBSERVATIONS TAKEN BETWEEN CAPE FINISTERRE AND CAPE St. VINCENT, ATGUSTS US 7TON saan) tes MP rere tisa ache tance eee eae “RINE GRUSSERE CYTODE VON 7 Barey ios MIT EINGEBETTETEN Goecounwmmn oy GOO) vee see oh oc) eae. case \eesar ons ‘ CoccosrHERB’ (x. 1000) Ten Satay tite eases | iat ernie aera eee RossELLA VELATA (sp. n.). Natural size. (No. 32, 1870) HyALonemMA LUsITANICUM, Barboza du Bocage, Half the natural SIZEVEM NOs 00S LOOO)ie. ce conn y oes Seankeeee : ASKONEMA SETUBALENSE, Kent. One: cour the iatutal size, (No, 95, 1870). =... ; ect FLABELLUM DISTINCTUM. siietiad ihe aatbuwal’s size. (No. 2 28 -187 0) TireCOorsAMMIA SocrIALIs, Pourtales. Once and a half the cece See S TR IBOO) ROA ir Paid ike slur ae hue” tae Peyracrinus Asteria, Linneus. One-fourth the natural size ... PENTACRINUS WYVILLE-THOMSONI, Jeffreys. Natural size. (No. 17, 1870) XIX PAGE 83. 84. LIST OF ILLUSTRATIONS. RHIZOCRINUS LOFFOTENSIS, M, Sars. Once and a half the natural gize, (No. 43, 1869) ..., ct) cag. sts len: ee feaeh Secpeeee BATHYCRINUS GRACILIS = n.). Twice the natural size. (No, S75 L869) cones RAM Ane. OBS, Sone, oe ap beds See ARCHASTER BIFRONS (sp. co. Oral aspect. Three-fourths the natural size. (No, 57, 1869) ‘ cheater ge SoLASTER FURCIFER, Von Duben and re “ral aspect. Natural size: ACNo"50, 1869) 0c: ycve cae meet Ge eae vere Buccinopsis sTRIATA, Jeffreys. Fisroe Chennai ae Larirrus Asus, Jetireys. Twice the nema size, Fééroe Channel eee ete re eo ae PLEURONECTIA LUCIDA, Tetrere > ties the natural size. a, from the Eastern Ailantic- ; b, from the Gulf of Mexico Prcren nosxynsi, Forbes. Twice the natural size VENTRICULITES SIMPLEX, Toulmin Smith, Once anda half the natural size ... . tee VENTRICULITES SIMPLEX, ‘Tagimen Srnithi Owen satis : “tour times the natural size . VENTRICULITES SIMPLEX, Teale canis Beaean of the oiler wall, showing the structure of the silicious network (x. 50) C@LOsPH#RA TUBIFEX (sp.n.). Slightly enlarged. Off the Coast of Portugal ‘Cuoanites.’ In a flint from ie Si ae VIGNETTES. Tut Farozt IsLanps TINDHOLM THORSHAVN : THE GOVERNOR’S guee acai see Litte Dimon Meant Nousé6, FROM THE hea ABOVE tie eens Fret, FROM THE HASTERN SHORE OF VIDERO ... VaAay CHURCH IN SUDERO THE GIANT AND THE HaG Borpé, Kuné, anp KALs6, FROM THE seh eie OF amen aS Kuno, From Vaay 1x Borpo 485 486 xi 48 80 132 196 235 280 328 406 466 501 MAPS AND PLATES. To face PLATE page L—Track or H.M.S. ‘Lientnine’—1868 «0. we ve 59 Tl.—First Cruise or H.M.S. ‘PorcuPINE’—1869 ... «> 87 TII.—Serconp Cruise oF H.M.S. ‘ PorcuPINE = N869 we. as 95 TV.—Tuirp Cruise or H.M.S. ‘Porcupine ESTER: |. OE. ws LOG V.—Track or H.M.S. ‘ PorcuPINE PEACOT Rn cee i eda ees LOU VI.—D1Acram oF THE ‘PorcUPINE’ SOUNDINGS IN THE ATLAN- TIC AND IN THE F.#ron CHANNEL, SHOWING THE RELATION BETWEEN TEMPERATURE AND DepTH,—THE SERIAL SounpD- INGS REDUCED To Curves. THE NUMBERS REFER TO THE SraTions ON THE CHarts, Puiates II., IIIL., anp Aes VIl.—PuysicaL Cuart oF THE NortTH ATLANTIC: SHOWING THE DeEptH, AND THE GENERAL DISTRIBUTION OF TEMPERATURES FOR THE MONTH OF JULY 2.2 cee tee cee cee eee ete VIII.—Mar snowing THE GENERAL DISTRIBUTION OF THE TER- TIARY, THE CRETACEOUS, AND THE JurRAssic SysTEMS IN THE NorrH-West oF EUROPE WITH REFERENCE TO (GONTOUR «5. ot ly Res eee, Cepek wes open 20 oe 323 363 474 “3 - - rs Se ee ee ee See 8 whe ee sae ; PS EE atv am ll te oe Fa 5 =e? Pee ee ta - aie * 4 Ponte & SP dt et & ee Ee: bia =) = Fab Sate a N 4 = + - — - ‘ i ot THE DEPTHS UF THE six THE DEPTHS OF THE SHA. (OS 7s Oh 2 VE Si) ape INTRODUCTION. The Question of a Bathymetrical Limit to Life——The general Laws which regulate the Geographical Distribution of Living Beings.— Professor Edward Forbes’ Investigations and Views.—Specific Centres.—Representative Species.—Zoological Provinces.—LBear- ings of a Doctrine of Evolution upon the Idea of a ‘Species,’ and of the Laws of Distribution.—The Circumstances most likely to affect Life at great Depths: Pressure, Temperature, and Absence of Light. 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 lke 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, sub- jected to such stupendous pressure as to make life of any kind impossible, and to throw insuperable diffi- B 2 THE DEPTHS OF THE SEA. [CHAP. I. culties 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-authenti- cated instances of animals, comparatively high in the scale of life, having been brought up on sounding lines from great depths, and welcomed any suggestion of the animals having got entangled when swimming on the surface, or of carelessness on the part of the observers. And this was strange, for every other question in Physical Geography had been investi- gated by scientific men with consummate patience and energy. Every gap in the noble little army of martyrs striving to extend the boundaries of know- ledge in the wilds of Australia, on the Zambesi, or towards the North or South Pole, was struggled for by earnest volunteers, and still the great ocean slumbering beneath the moon covered a region apparently as inaccessible to man as the ‘mare serenitatis.’ A few years ago the bottom of the sea was required for the purpose of telegraphic communication, and practical men mapped out the bed of the North Atlantic, and devised ingenious methods of ascertain- ing the nature of the material covering the bottom. They laid a telegraphic cable across it, and the cable got broken and they went back to the spot and fished up the end of it easily, from a depth of nearly two miles. It had long been a questien with naturalists whether it might not be possible to dredge the bottom of the sea in the ordinary way, and to send down water- bottles and registering instruments to settle finally the question of a ‘zero of animal life,’ and to deter- CHAP. 1.] INTRODUCTION. o mine with precision the composition and temperature of sea-water at great depths. An investigation of this kind is beyond the ordinary limits of private enter- prise. It requires more power and sea skill than naturalists can usually command. When, however, in the year 1868, at the instance of my colleague Dr. Carpenter and myself, with the effective support of the present Hydrographer to the Navy, who is deeply interested in the scientific aspects of his pro- fession, we had placed at our disposal by the Admi- ralty sufficient power and skill to make the experiment, we found that we could work, not with so much ease, but with as much certainty, at a depth of 600 fathoms as at 100; and in 1869 we carried the operations down to 2,435 fathoms, 14,610 feet, nearly three statute - miles, with perfect success. Dredging in such deep water was doubtless very trying. Each haul occupied seven or eight hours ; and during the whole of that time it demanded and received the most anxious care on the part of our commander, who stood with his hand on the pulse of the accumulator ready at any moment, by a turn of the paddles, to ease any undue strain. The men, stimulated and encouraged by the cordial interest taken by their officers in our operations, worked willingly and well; but the labour of taking upwards of three miles of rope coming up with a heavy strain, from the surging drum of the engine, was very severe. The rope itself, ‘hawser-laid,’ of the best Italian hemp, 24 inches in circumference, with a breaking strain of 21 tons, looked frayed out and worn, as if it could not have been trusted to stand this extraordinary ordeal much longer. B2 4 THE DEPTHS OF THE SEA, (CHAP. 1. Still the thing is possible, and it must be done again and again, as the years pass on, by naturalists of all nations, working with improving machinery, and with ever-increasing knowledge. For 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 organisms in many cases apparently even more elaborately and delicately formed, and more exquisitely beautiful in their soft shades of colouring and in the rainbow-tints of their wonderful phosphorescence, than the fauna of the well-known belt of shallow water teeming with innumerable invertebrate forms which fringes the land. And the forms of these hitherto unknown living beings, and their mode of life, and their rela- tions to other organisms whether living or extinct, and the phenomena and laws of their geographical distribution, must be worked out. The late Professor Edward Forbes appears to have been the first who undertook the systematic study of Marine Zoology with special reference to the distribu- tion of marine animals in space and intime. After making himself well acquainted with the fauna of the British seas to the depth of about 200 fathoms by dredging, and by enlisting the active co-operation of his friends—among whom we find MacAndrew, Barlee, Gwyn Jeffreys, William Thompson, Robert Ball, and many others, entering enthusiastically into the new field of Natural History inquiry—in the year 1841 Forbes joined Capt. Graves, who was at that time in command of the Mediterranean Survey, as naturalist. CHAP. I.| INTRODUCTION. 5 During about eighteen months he studied with the utmost care the conditions of the Aigean and its shores, and conducted upwards of one hundred dredging operations at depths varying from 1 to 180 fathoms. In 1843 he communicated to the Cork meeting of the British Association an elaborate report on the Mollusca and Radiata of the Aigean Sea, and on their distribution considered as bearing on Geology.’ Three years later, in 1846, he published in the first volume of the ‘Memoirs of the Geological Survey of Great Britain,’ a most valuable memoir upon the Connection between the existing Fauna and Flora of the British Isles, and the geological Changes which have affected their Area, especially during the Epoch of the Northern Drift.2 In the year 1859 appeared the Natural History of the European Seas by the late Professor Edward Forbes, edited and continued by Robert Godwin Austen.’ In the first hundred pages of this little book, Forbes gives a general outline of some of the more important of his views with regard 1 Report on the Mollusca and Radiata of the Aigean Sea, and on their Distribution, considered as bearing on Geology. By Edward Forbes, F.L.S., M.W.S., Professor of Botany in King’s College, London. (Report of the Thirteenth Meeting of the British Association for the Ad- vancement of Science ; held at Cork in August 1843. London, 1844.) 2 On the Connection between the Distribution of the existing Fauna and Flora of the British Isles and the geological Changes which have affected their Area, especially during the Epoch of the Northern Drift. By Edward Forbes, F.R.S., L.S., G.S., Professor of Botany at King’s College, London; Palzontologist to the Geological Survey of the United Kingdom. (Memoirs of the Geological Survey of Great Britain, vol. i. London, 1846.) 3 The Natural History of the European Seas, by the late Professor Edward Forbes, F.R.S., &c. Edited and continued by Robert Godwin Austen, F.R.S. London, 1859. 6 THE DEPTHS OF THE SEA. [CHAP. I. to the distribution of marine forms. The remainder of the book is a continuation by his friend Mr. Godwin Austen, for before it was finished an early death had cut short the career of the most accomplished and original naturalist of his time. I will give a brief sketch of the general results to which Forbes was led by his labours, and I shall have to point out hereafter, that although we are now inclined to look somewhat differently on certain very fundamental points, and although recent inves- tigations with better appliances and more extended experience have invalidated many of his conclusions, to Forbes is due the credit of having been the first to treat these questions in a broad philosophical sense, and to point out that the only means of acquiring a true knowledge of the rationale of the distribution of our present fauna, is to make ourselves acquainted with its history, to connect the present with the past. This is the direction which must be taken by future inquiry. Forbes, as a pioneer in this line of research, was scarcely in a position to appreciate the full value of his work. Every year adds enormously to our stock of data, and every new fact indicates more clearly the brilliant results which are to be obtained by following his methods, and by emulating his enthusiasm and his indefatigable industry. Forbes believed implicitly, along with nearly all the leading naturalists of his time, in the immutability of species. He says (Natural History of the British Seas, p. 8), ‘‘ Every true species presents in its indi- viduals, certain features, specific characters, which distinguish it from every other species; as if the Creator had set an exclusive mark or seal on each CHAP. I.] INTRODUCTION. 7 type.’ He likewise believed in specific centres of distribution. He held that all the individuals com- posing a species had descended from a single pro- genitor, or from two, according as the sexes might be united or distinct, and that consequently the idea of a species involved the idea of the relationship in all the individuals of common descent; and the converse, that there could by no possibility be community of descent except in living beings which possessed the same specific characters. He supposed that the original individual or pair was created at a particular spot where the conditions were suitable for its existence and propagation, and that the species extended and migrated from that spot on all sides over an area of greater or less extent, until it met with some natural barrier in the shape of unsuitable conditions. No specific form could have more than a single centre of distribution. If its area appeared to be broken up, a patch not in connection with the original centre of distribution occurring in some distant locality, it was accounted for by the formation, through some geolo- gical change after the first spread of the species, of a barrier which cut off a part of its area; or to some accidental transport to a place where the conditions were sufficiently similar to those of its natural original habitat to enable it to become naturalized. No species once exterminated was ever recreated, so that in those few cases in which we find a species abundant at one period over an area, absent over the same area for a time, and recurring at a later period, it must be ac- counted for by a change in the conditions of the area which forced the emigration of the species, and a sub- sequent further change which permitted its return. 8 THE DEPTHS OF THE SEA. [CHAP. I. Forbes defined and advocated what he called the law of representation. He found that in all parts of the world, however far removed, and however completely separated by natural barriers, where the conditions of life are similar, species and groups of species occur which, although not identical, resemble one another very closely; and he found that this similarity existed likewise between groups of fossil remains, and between groups of fossils and groups of recent forms. Admitting the con- stancy of specific characters, these resemblances could not be accounted for by community of de- scent, and he thus arrived at the generalization, that in localities placed under similar circumstances, similar though specifically distinct specific forms were created. These he regarded as mutually repre- sentative species. Our acceptance of the doctrines of specific centres and of representation, or, at all events, the form in which we may be inclined to accept these, depends greatly upon the acceptance or rejection of the funda- mental dogma of the immutability of species; and on this point there has been a very great change of opinion within the last ten or twelve years, a change certainly due to the remarkable ability and candour with which the question has been discussed by Mr. Darwin‘ and Mr. Wallace,’ and to the genius of Pro- “ The Origin of Species by means of Natural Selection ; or, the Preservation of Favoured Races in the Struggle for Life. By Charles Darwin, M.A., F.R.S., L.S., G.S., &e. &. London, 1859, and subse- quent editions. 2 Contributions to the Theory of Natural Selection. A Series of Essays by Alfred Russel Wallace. London, 1870. CHAP. 1.] INTRODUCTION. 9 fessor Ernst Haeckel,! Dr. Fritz Miiller,? and others of their enthusiastic disciples and commentators. I do not think that I am speaking too strongly when I say that there is now scarcely a single competent general naturalist who is not prepared to accept some form of the doctrine of evolution. There is, no doubt, very great difficulty in the minds of many of us in conceiving that, commenc- ing from the simplest living being, the present state of things in the organic world has been produced solely by the combined action of ‘atavism,’ the ten- dency of offspring to resemble their parents closely ; and ‘variation,’ the tendency of offspring to differ individually from their parents within very narrow limits: and many are inclined to believe that some other law than the ‘survival of the fittest’ must regulate the existing marvellous system of extreme and yet harmonious modification. Still it must be admitted that variation is a vera causa, capable, within a limited period, under favourable circum- stances, of converting one species into what, accord- ing to our present ideas, we should be forced to recognize as a different species. And such being the case, it is, perhaps, conceivable that during the lapse of a period of time—still infinitely shorter than eternity—variation may have produced the entire result. * Generelle Morphologie der Organismen. Allgemeine Grundziige der organischen Formen-Wissenschaft mechanisch begriindet durch die von Charles Darwin reformirte Descendenz-Theorie. Von Ernst Haeckel. Berlin, 1866.—Natiirliche Schépfungsgeschichte. Von Dr. Ernst Haeckel, Professor an der Universitit Jena. Berlin, 1870. ? Fiir Darwin. Von Dr. Fritz Miiller. Leipzig, 1864. Translated from the German by W. S. Dallas, F.L.S., London, 1869. 10 THE DEPTHS OF THE SEA. [CHAP. I. The individuals comprising a species have a definite range of variation strictly limited by the circum- stances under which the group of individuals is placed. Except in man, and in domesticated animals in which it is artificially increased, this individual variation is usually so slight as to be unappreciable except to a practised eye; but any extreme variation which passes the natural limit in any direction clashes in some way with surrounding circum- stances, and is dangerous to the life of the indivi- dual. The normal or graphic line, or ‘line of safety,’ of the species, lies midway between the extremes of variation. If at any period in the history of a species the conditions of life of a group of individuals of the species be gradually altered, with the gradual change of circumstances the limit of variation is contracted in one direction and relaxed in another; it becomes more dangerous to diverge towards one side and more desirable to diverge towards the other, and the position of the lines limiting variation is altered. The normal line, the line along which the specific characters are most strongly marked, is consequently slightly deflected, some characters being more strongly expressed at the expense of others. This deflection, car- ried on for ages in the same direction, must eventually carry the divergence of the varying race far beyond any limit within which we are in the habit of admitting identity of species. But the process must be infinitely slow. It is diffi- cult to form any idea of ten, fifty, or a hundred mil- lions of years; or of the relation which such periods bear to changes taking place in the organic world. CHAP. I.] INTRODUCTION. Tt We must remember, however, that the rocks of the Silurian system, overlaid by ten miles’ thickness of sediment entombing a hundred successive faune, each as rich and varied as the fauna of the present day, themselves teem with fossils fully representing all the existing classes of animals, except perhaps the highest. If it be possible to imagine that this marvellous manifestation of Eternal Power and Wisdom involved in living nature can have been worked out through the law of ‘descent with modification’ alone, we shall certainly require from the Physicists the longest row of cyphers which they can afford. Now, although the admission of a doctrine of evolu- tion must affect greatly our conception of the origin and rationale of so-called specific centres, it does not practically affect the question of their existence, or of the laws regulating the distribution of species from {heir centres by migration, by transport, by ocean currents, by elevations or depressions of the land, or by any other causes at work under existing circum- stances. So far as practical naturalists are con- cerned, species are permanent within their narrow limits of variation, and it would introduce an element of infinite confusion and error if we were to regard them in any other light. The origin of species by descent with modification is as yet only a hypothesis. During the whole period of recorded human observa- tion not one single instance of the change of one species into another has been detected ; and, singular to say, in successive geological formations, although new species are constantly appearing and there is abundant evidence of progressive change, no single case 12 THE DEPTHS OF THE SEA. [ CHAP. I. has yet been observed of one species passing through a series of inappreciable modifications into another. Every species appears to have an area of maximum development, and this has been called the metropolis of the species; and practically we must employ the same methods in investigating the laws of its distri- bution as if we still regarded it as having been specially created in its metropolis. It is the same in dealing with the law of represen- tation. Accepting an evolution doctrine, we should certainly regard closely allied or ‘ representative’ species as having descended comparatively recently from a common ancestry, and as having diverged from one another under somewhat different conditions of life. It is possible that as our knowledge increases we may be able to trace the pedigree of our modern species, and some attempts have already been made to sketch out the main branches of the universal genealogical tree ;* but practically we must continue to accord a specific rank to forms which exhibit characters to which we have been in the habit of assigning specific value. “Every species has three maxima of develop- ment,—in depth, in geographic space, in time. In depth, we find a species at first represented by few individuals, which become more and more numerous until they reach a certain point, after which they again gradually diminish, and at length altogether disappear. So also in the geographic and geologic distribution of animals. Sometimes the genus to which the species belongs ceases with its disappear- ance, but not unfrequently a succession of similar 1 Ernst Haeckel, op. cit. CHAP. 1. | INTRODUCTION. 13 species are kept up, representative as it were of each other. When there is such a representation, the minimum of one species usually commences before that of which it is representative has attained its correspondent minimum. Forms of representative species are similar, often only to be distinguished by critical examination.” * As an illustration of what is meant by the law of ‘representation,’ I may cite a very curious case men- tioned by Mr. Verril and Mr. Alexander Agassiz. On either side of the Isthmus of Panama the Echinoderm order Hehinidea, the sea-urchins, are abundant; but the species found on the two sides of the Isthmus are distinct, although they belong almost universally to the same genera, and in most cases each genus is represented by species on each side which resemble one another so closely in habit and appearance as to be at first sight hardly distinguishable. I arrange a few of the most marked of these from the Carib- bean and Panamic sides of the Isthmus in parallel columns. Eastern Fauna. WESTERN Fauna. Cidaris annulata, GRAY. Cidaris thouarsii, VAL. Diadema antillarum, Putt. Diadema mexicanum, A. Ac. Echinocidaris punctulata, DEsMi. Echinocidaris stellata, Aa. ichinometra michelini, Drs. Echinometra van brunti, A, Ac. 3 viridis, A. AG. i rupicola, A. AG. Lytechinus variegatus, A. Ac. Lytechinus semituberculatus, A. AG. Tripneustes ventricosus, AG. Tripneustes depressus, A. AG. Stolonoclypus ravenellii, A. Ac. Stolonoclypus rotundus, A. AG. Mellita testudinata, Ku. Mellita longifissa, Micu. 1 Edward Forbes, Report on Augean Invertebrata, op. cit. p. 173. 14 THE DEPTHS OF THE SE4A. [cHAP. I. EasTERN Fauna. Western Fauna. Mellita hexapora, A. Aa. Mellita pacifica, V Er. Encope michelini, Ac. Encope grandis, AG. » emarginata, AG. » mucropora, AG. Rhyncholampas caribbearum, Rhyncholampas pacificus, A. AG. A. Aa. Brissus columbaris, AG. Brissus obesus, VER. Meoma ventricosa, LUTK. Meoma grandis, GRAY. Plagionotus pectoralis, AG. Plagionotus nobilis, A. AG. Agassizia excentrica, A. AG. Agassizia scrobiculata, V AL. Mera atropos, Micu. Mera clotho, Micu. Supposing species to be constant, this singular chain of resemblances would indicate simply the special creation on the two sides of the Isthmus of two groups of species closely resembling one another, because the circumstances under which they were placed were so very similar; but admitting ‘ descent with modification,’ while gladly availing ourselves of the convenient term ‘ representation,’ we at once come to the conclusion that these nearly allied ‘ re- presentative species’ must have descended from a com- mon stock, and we look for the cause of their diver- gence. Now on examining the Isthmus of Panama we find that a portion of it consists of cretaceous beds containing fossils undistinguishable from fossils from the cretaceous beds of Europe; the Isthmus must therefore have been raised into dry land in tertiary or post-tertiary times. It is difficult to doubt that the rising of this natural barrier isolated two portions of a shallow-water fauna which have since slightly diverged under slightly different conditions. I quote Alexander Agassiz :—‘‘ The question naturally arises, have we not in the different Faunze on both sides of the Isthmus a standard by which to measure the CHAP. I.| INTRODUCTION. 15 changes which these species have undergone since the raising of the Isthmus of Panama and the isolation of the two Faunze?’’? Edward Forbes distinguished round all seaboards four very marked zones of depth, each characterized by a distinct group of organisms. The first of these is the littoral zone, the space between tide-marks, distinguished by the abundance of sea-weeds, on the European shores of the genera Lichina, Fucus, Enteromorpha, Polysiphonia, and Laurencia, which severally predominate at different heights in the zone, and subdivide it into subordinate belts like a softly-coloured riband border. This band is under very special circumstances, for its inhabitants are periodically exposed to the air, to the direct rays of the sun, and to all the extremes of the climate of the land. Animal species are not very numerous in the littoral zone, but individuals are abundant. The distribution of many of the littoral species is very wide, and some of them are nearly cosmopolitan. Many are vegetable feeders. Some characteristic genera on the coast of Europe are Gammarus, Tatitrus, and Balanus among Crustacea, and Lit- torina, Patelia, Purpura, and Mytilus among Mol- lusea, with, under stones and in rock-pools, many stragglers from the next zone. The Laminarian zone extends from low-water mark to a depth of about fifteen fathoms. This is specially * Preliminary Report on the Echini and Starfishes dredged in Deep Water between Cuba and the Florida Reef, by L. F. de Pourtales, Assistant U.S. Coast Survey; prepared by Alexander Agassiz. Communicated by Professor B. Peirce, Superintendent U.S. Coast Survey, to the Bulletin of the Museum of Comparative Zoology, Cambridge, Mass., 1869. 16 THE DEPTHS OF THE SEA. [CHAP. 1. the zone of ‘tangles’ for the first few fathoms, and in deeper water of the beautiful scarlet sea-weeds (floridee). It is always under water except at the very lowest ebb of spring tides, when we get a glimpse of its upper border. The laminarian zone produces abundance of vegetable food, and, like the littoral zone, may be divided into subordinate bands distinguished by differently tinted alge. Animals swarm in this zone, both as to species and _ indi- viduals, and are usually remarkable for the bright- ness of their colouring. The molluscan genera Trochus, Lacuna, and Lottia are characteristic of this belt in the British seas. The Laminarian zone is succeeded by the Coralline zone, which extends to a depth of about fifty fathoms. In this belt vegetation is chiefly represented by coral- like millipores, and plant-like hydroid zoophytes and bryozoa abound. All of the higher orders of marine invertebrates are fully represented, principally by animal feeders. The larger crustaceans and echino- derms are abundant; and the great fishing-banks frequented by the cod, haddock, halibut, turbot, and sole, belong properly to this zone, although they sometimes extend into water more than fifty fathoms deep. Characteristic molluscan genera are Buccinwn, Fusus, Ostrea, and Pecten; and among echinoderms in the European seas we find Antedon sarsii and cellicus, Asteracanthion glaciale and rubens, Ophio- thrix fragilis, and on sand, Ophioglypha lacertosa and albida. The last belt defined by Forbes as extending from about fifty fathoms to an unknown lower limit is the zone of deep-sea corals. ‘‘ In its depths the number CHAP. I.] INTRODUCTION. 17 of peculiar creatures are few, yet sufficient to give a marked character to it, whilst the other portions of its population are derived from the higher zones, and must be regarded as colonists. As we descend deeper and deeper in this region, its inhabitants become more and more modified, and fewer and fewer, indicating our approach towards an abyss where life is either extinguished, or exhibits but a few sparks to mark its lingering presence.”’! Forbes pointed out that the groups of animals having their maximum development in these several zones are thoroughly characteristic, and that groups of representative forms occupy the same zones all over the world, so that on examining an assemblage of marine animals from any locality, it is easy to tell from what zone of depth they have been procured. At all periods of the earth’s history, there has been the same clear definition of zones of depth, and fossil animals from any particular zone are in some sense representative of the fauna of the corresponding zone at the present day. We can, therefore, usually tell with tolerable certainty to which zone of depth a par- ticular assembiage of fossils is to be referred. Although we must now greatly modify our views with regard to the extent and fauna of the zone of deep-sea corals, and give up all idea of a zero of animal life, still we must regard Forbes’ investiga- tion into the bathymetrical distribution of animals as marking a great advance on previous knowledge. His experience was much wider than that of any other naturalist of his time; the practical difficulties in the way of testing his conclusions were great, and 1 Edward Forbes, Natural History of the European Seas, p. 26. C 18 THE DEPTHS OF THE SEA. [CHAP, I. they were accepted by naturalists generally without question. The history of discovery bearing upon the extent and distribution of the deep-sea fauna will be discussed in a future chapter. It will suffice at present to mention in order the few data which gradually prepared the minds of naturalists to distrust the hypothesis of a zero of animal life at a limited depth, and led to the recent special investigations. In the year 1819 Sir John Ross published the official account of his voyage of discovery during the year 1818 in Baffin’s Bay.’ At page 178 he says, “In the meantime I was em- ployed on board in sounding and in trying the cur- rent, and the temperature of the water. It being perfectly calm and smooth, I had an excellent oppor- tunity of detecting these important objects. Sound- ings were obtained correctly in 1,000 fathoms, consisting of soft mud, in which there were worms, and, entangled on the sounding line, at the depth of 800 fathoms, was found a beautiful Caput Meduse (Fig. 1). These were carefully preserved, and will be found described in the appendix.” This was in lat. 73° 87’ N., long. 77° 25’ W., on the 1st of September, 1818, and it is, so far as I am aware, the first recorded instance of living animals having been brought up from any depth approaching 1,000 fathoms. General Sir Edward Sabine, who was a member of Sir John Ross’s expedition, has kindly furnished Dr. 1 A Voyage of Discovery made under the Orders of the Admiralty in His Majesty’s ships ‘Isabella’ and ‘ Alexander,’ for the purpose of exploring Baffin’s Bay, and inquiring into the Possibility of a North-west Passage. By John Ross, K.G., Captain Royal Navy. London, 1819. CHAP. I. | INTRODUCTION. 19 Carpenter with some more ample particulars of this Fia. 1.—Asterophyton linckii, MULLER aud TroscHEL. A young specimen slightly enlarged. No. 75. occurrence :'—‘‘ ‘ The ship sounded in 1,000 fathoms, mud, between one and two miles off shore (lat. * Preliminary Report, by Dr. William B. Carpenter, V.P.R.S., of Dredging Operations in the Seas to the North of the British Islands, carried on in Her Majesty’s steam-vessel ‘Lightning,’ by Dr. Carpenter and Dr. Wyville Thomson. (Proceedings of the Royal Society, 1868, p. 177.) C2 20 THE DEPTHS OF THE SEA. [CHAP. I. 73° 87 N., long. 77° 25’ W.); a magnificent Asterias (Caput Meduse) was entangled by the line, and brought up with very little damage. The mud was soft and greenish, and contained specimens of Lawm- bricus tubicola. So far my written journal; but I can add, from a very distinct recollection, that the heavy deep-sea weight had sunk, drawing the line with it, several feet into the soft greenish mud, which still adhered to the line when brought to the surface of the water. The star-fish had been entangled in the line so little above the mud that fragments of its arms, which had been broken off in the ascent of the lne, were picked up from amongst the mud.” Sir James Clark Ross, R.N., dredging in 270 fathoms, lat. 73° 3’°S., long. 17676" EH. reports: “ Corallines, Flustre, and a variety of invertebrate animals, came up in the net, showing an abundance and great variety of animal life. Amongst these I detected two species of Pycnogonum ; Idotea baffini, hitherto considered peculiar to the Arctic seas; a Chiton, seven or eight bivalves and univalves, an un- known species of Gammarus, and two kinds of Serpula adhering to the pebbles and shells . . . It was interest- ing amongst these creatures to recognize several that I had been in the habit of taking in equally high northern latitudes; and although, contrary to the general belief of naturalists, I have no doubt that, from however great a depth we may be enabled to bring up the mud and stones of the bed of the ocean, 1 A Voyage of Discovery and Research in the Southern and Antarctic Regions during the Years 1839-43. By Captain Sir James Clark Ross, R.N. London, 1847. CHAP, 1.] INTRODUCTION. i] we shal] find them teeming with animal life; the ex- treme pressure at the greatest depth does not appear to affect these creatures; hitherto we have not been able to determine this point beyond a thousand fathoms, but from that depth several shell-fish have been brought up with the mud.” On the 28th of June 1845, Mr. Henry Goodsir, who was a member of Sir John Franklin’s ill-fated expedition, obtained in Davis’ Strait from a depth of 300 fathoms, “a capital haul,—mollusea, crustacea, asterida, spatangi, corallines, &e.”' The bottom was composed of fine green mud like that mentioned by Sir Edward Sabine. About the year 1854 Passed-midshipman Brooke, U.S.N., invented his ingenious sounding instrument for bringing up samples from the bottom. It only brought up a small quantity ina quill. These trophies from any depth over 1,000 fathoms were eagerly sought for by naturalists and submitted to searching micro- scopic examination; and the result was very surpris- ing. All over the Atlantic basin the sediment brought up was nearly uniform in character, and consisted almost entirely of the calcareous shells, whole or in fragments, of one species of foraminifer, Globigerina bulloides (Fig. 2). Mixed with these were the shells of some other foraminifera, and particularly a little perforated sphere, Orbulina universa (Fig. 3), which in some localities entirely replaces Globigerina ; with a few shields of diatoms, and spines and trellised skeletons of Radiolaria. Some soundings from the Pacific were of the same character, so 1 Natural History of the British Seas. By Professor Edward Forbes and R. Godwin-Austen. P. 51. bo 2, THE DEPTHS OF THE SEA. [cHAP. I. that it seemed probable that this gradual deposition of a fine uniform organic sediment was almost universal. Then the question arose whether the animals which secreted these shells lived at the bottom, or whether they floated in myriads on the surface and in the upper zones of the sea, their empty shells falling after death through the water in an incessant shower. Specimens of the soundings were sent to the eminent Fic. 2.—Globigerina bulloides, D'OrBicNy. Highly magnified. microscopists Professor Ehrenberg of Berlin and the late Professor Baily of West Point. On the moot question these two naturalists gave opposite opinions. Ehrenberg contended that the weight of evidence was in favour of their having lived at the bottom, while Baily thought it was not probable that the animals live at the depths where the shells are found, but that they inhabit the water near the CHAP. I. ] * INTRODUCTION. 23 surface, and when they die their shells settle to the bottom.’ The next high authority who expressed an opinion was Professor Huxley, and he was very guarded. The samples procured by Capt. Dayman in the ‘Cyclops,’ Fia. 3.—Orbulina wniversa, D’OrBIGNY. Highly magnified. in 1857, were submitted to him for examination, and in his report to the Admiralty’ in 1858 he says :— 1 Explanations and Sailing Directions to accompany the Wind and Currents Charts. By M. F. Maury, LL.D., Lieut. U.S.N., Super- intendent of the National Observatory. 6th Edition. Philadelphia, L364 P.299: * Appendix A to Deep Sea Soundings in the North Atlantic Ocean between Ireland and Newfoundland, made in H.M.S. ‘Cyclops,’ Lieut.-Commander Joseph Dayman, in June and July 1857. Pub- lished by order of the Lords Commissioners of the Admiralty, London, 1858. 24 THE DEPTHS OF THE SEA. [ciar, 1. “ How can animal life be conceived to exist under such conditions of light, temperature, pressure, and aération as must obtain at these vast depths? Tothis . one can only reply that we know for a certainty that even very highly-organized animals do contrive to live at a depth of 300 or 400 fathoms, Inasmuch as they have been brought up thence, and that the difference in the amount of hight and heat at 400 and at 2,000 fathoms is probably, so to speak, very far less than the difference in complexity of organization between these animals and the humble Protozoa and Proto- phyta of the deep-sea soundings. I confess, though, as yet, far from regarding it proved that the Glc- bigerine live at these depths, the balance of proba- bilities seems to me to incline in that direction.” In 1869 Dr. Wallich accompanied Captain Sir Leopold McClintock in H.M.S. ‘Bulldog’ on her sounding expedition to Iceland, Greenland, and New- foundland, as naturalist. During the cruise soundings were taken, and specimens of the bottom were brought up from depths from 600 to 2,000 fathoms; many of these were the now well-known grey ‘Globigerina ooze, while others were voleanic detritus from Iceland, and clay and gravel the product of the disintegration of the metamorphic rocks of Greenland and Labrador. On the return voyage, about midway between Cape Fare- well and Rockall, thirteen star-fishes came up from a sounding of 1,260 fathoms, ‘‘ convulsively embracing a portion of the sounding-line which had been payed out in excess of the already ascertained depth, and rested for a sufficient period at the bottom to permit of their attaching themselves to it.” On his return Dr. Wallich published in 1862, an extremely valuable CHAP. I.] INTRODUCTION. 95 work which will be frequently referred to hereafter, upon ‘The Atlantic Sea-bed.’* He warmly advocated the view that the conditions of the bottom of the sea were not such as to preclude the possibility of the existence of even the higher forms of animal life, and discussed fully and with great ability the arguments which had been advanced on the other side. The first part only of Dr. Wallich’s book appeared, in a some- what costly and cumbrous form, and it scarcely came into the hands of working naturalists, or received the attention which it deserved. At the time, however, it was merely an expression of individual opinion, for no new facts had been elicited. Star-fishes had come up on several previous occasions adhering to sounding- lines, but the absolute proof was still wanting that they had lived upon the ground at the depth of the sounding. Dr. Wallich referred the star-fishes procured to a well-known littoral species, and complicated their history somewhat irrelevantly with the disappearance of the ‘Land of Buss.’ Fortunately the artistic if not very satisfactory figure which he gives of a star- fish clinging to the line does not bear out his deter- mination either in appearance or attitude, but suggests one or other of two species which we now know to be excessively abundant in deep water in the North Atlantic, Ophiopholis aculeata, O. F. MULLER, or Ophiacantha spinulosa, Mutter and TROSCHBL. 1 The North Atlantic Sea-bed : comprising a Diary of the Voyage on board H.M.S. ‘Bulldog,’ in 1860; and Observations on the presence of Animal Life, and the Formation and Nature of Organic Deposits at great Depths in the Ocean. By G. C. Wallich, M.D., F.LS., F.G.8., &c. Published with the sanction of the Lords Com- missioners of the Admiralty. London, 1862. 26 THE DEPTHS OF THE SEA. [CHAP. I. Dr. Wallich’s is the only book which discusses fully and systematically the various questions bearing upon the biological relations of the sea-bed, and his conclusions are in the main correct. In the autumn of the year 1860 Mr. Fleeming Jenkin, C.E., now Professor of Engineering in the University of Edinburgh, was employed by the Mediterranean Telegraph Company to repair their cable between Sardinia and Bona on the coast of Africa, and on January 15, 1861, he gave an interest- ing account of his proceedings at a meeting of the Institution of Civil Engineers.’ This cable was laid in the year 1857. In 1858 it became necessary to repair it, and a length of about 30 miles was picked up and successfully replaced. In the summer of 1860 the cable completely failed. On taking it up in comparatively shallow water on the African shore, the cable was found covered with marine animals, greatly corroded, and injured appa- rently by the trawling operations in an extensive coral fishery through which it unfortunately passed. It was broken through in 70 fathoms water a few miles from Bona. The sea-end was however recovered, and it was found that the cable which thence traversed a wide valley nearly 2,000 fathoms in maximum depth, was perfect to within about 40 miles of Sar- dinia. It wasthen picked up from the Sardinian end, and the first 39 miles were as sound as when it was first laid down. At this distance from the shore there was a change in the nature of the bottom, evidenced by the different colour of the mud, and the wires were 1 Minutes of Proceedings of the Institution of Civil Engineers, with Abstracts of the Discussions. Vol. xx. p. 81. London, 1861. cHap. I. ] INTRODUCTION. rat much corroded. Shortly afterwards the cable gave way in a depth of 1,200 fathoms, at a distance of one mile from the spot where the electrical tests showed that the cable had been previously broken. With these 40 miles of cable much coral and many marine animals were brought up, but it did not appear that their presence had injured the cable, for they were attached to the sound as well as to the corroded portions. On his return, Mr. Fleeming Jenkin sent specimens of the animals which he had himself taken from the cable, noting the respective depths, to Pro- fessor Allman, F.R.S. for determination. Dr. Allman vives a list of fifteen animal forms, including the ova of a cephalopod, found at depths of from 70 to 1,200 Fic. 4.—Caryophyllia borealis, FLeminc. Twice the natural size. No. 45. fathoms. On other portions of the cable species of Grantia, Plumularia, Gorgonia, Caryophyllia, Alcy- onium, Cellepora, Retepora, Kschara, Salicornaria, Ascidia, Lima, and Serpula, I observe from Professor 28 THE DEPTHS OF THE SEA. [CHAP. I. Fleeming Jenkin’s private journal, which he has kindly placed in my hands for reference, that an example of Caryophyllia, a true coral (Fig. 4), was found naturally attached to the cable at the point where it gave way; that is to say, at the bottom in 1,200 fathoms water. Some portions of this cable subsequently came into the custody of M. Mangon, Professor at the Ecole des Ponts et Chaussées in Paris, and were examined by M. Alphonse Milne-Edwards, who read a paper upon the organisms attached to them, at the Academy of Sciences, on the 15th of July, 1861. After some introductory remarks which show that he is thoroughly aware of the value of this observation as a final solution of the vexed question of the existence of animal life at depths in the sea greatly beyond the supposed ‘zero’ of Edward Forbes, M. Milne- Edwards gives a list of the animals which he found on the cable from the depth of 1,100 fathoms. The list includes Murex lamellosus, CRISTOFORI and JAN, and Craspedotus limbatus, PuitipPi, two univalve shells allied to the whelk; Ostrea cochlear, Pout, a small oyster common below 40 fathoms throughout the Mediterranean; Pecten teste, BIVONA, a rare little clam; Caryophyllia borealis, FLEMING, or a nearly allied species, one of the true corals; and an unde- scribed coral referred to a new genus and species under the name of Zhalassiotrochus telegraphicus, A. Mitnr-Epwarps. 1 Observations sur I’Existence de divers Mollusques et Zoophytes & de trés grandes profondeurs dans la Mer Méditerranée: Annales des Sciences Naturelles; quatritme série—Zoologie. Tome xv. p. 149. Paris, 1861. CHAP. I.] INTRODUCTION. 29 It is right, however, to state that Prof. Fleeming Jenkin’s notes refer to only one or two species, and especially to Caryophyllia borealis, as attached to the cable at a depth of upwards of 1,000 fathoms. From this depth he took examples of Caryophyilia with his own hands, but he suspects that specimens from the shallower water may have got mixed with those from the deeper in the series in the possession of M. Mangon, and that therefore M. Milne-Edwards’ list is not entirely trustworthy. Up till this time all observations with reference to the existence of living animals at extreme depths had been liable to error, or at all events to doubt, from two sources. ‘he appliances and methods of deep- sea sounding were imperfect, and there was always a possibility, from the action of deep currents upon the sounding line or from other causes, of a greater depth being indicated than really existed; and again, although there was a strong probability, there was no absolute certainty that the animals adhering to the line or entangled on the sounding instrument had actually come up from the bottom. They might have been caught on the way. - Before laying a submarine telegraphic cable its course is carefully surveyed, and no margin of doubt is left as to the real depth. Fishing the cable up isa delicate and difficult operation, and during its progress the depth is checked again and again. ‘The cable lies on the ground throughout its whole length. The animal forms upon which our conclusions are based are not sticking loosely to the cable, under circum- stances which might be accounted for by their having been entangled upon it during its passage through the 30 THE DEPTHS OF THE SEA. (crap. 1. water, but they are moulded upon its outer surface or cemented to it by calcareous or horny excretions, and some of them, such as the corals and bryozoa, from what we know of their history and mode of life, must have become attached to it as minute germs, and have grown to maturity in the position in which they were found. I must therefore regard this observation of Mr. Fleeming Jenkin as having afforded the first absolute proof of the existence of highly-organized animals living at depths of upwards of 1,000 fathoms. During the several cruises of H.M. ships ‘Light- ning’ and ‘ Porcupine’ in the years 1868, 1869, and 1870,' fifty-seven hauls of the dredge were taken in the Atlantic at depths beyond 500 fathoms, and sixteen at depthsbeyond 1,000 fathoms, and in all cases life was abundant. In 1869 we took two casts in depths greater than 2,000 fathoms. In both of these life was abun- dant; and with the deepest cast, 2,435 fathoms, off the mouth of the Bay of Biscay, we took living, well- marked and characteristic examples of all of the five invertebrate sub-kingdoms. And thus the question of 1 Preliminary Report, by Dr. William Carpenter, V.P.RS., of Dredging Operations in the Seas to the north of the British Islands, carried on in Her Majesty’s steam-vessel ‘ Lightning’ by Dr. Carpenter and Dr. Wyville Thomson, Professor of Natural History in Queen’s College, Belfast. (Proceedings of the Royal Society of London, 1868.) Preliminary Report of the Scientific Exploration of the Deep Sea in H.M. surveying-vessel ‘ Porcupine,’ during the Summer of 1869. Conducted by Dr. Carpenter, V.P.R.S., J. Gwyn Jeffreys, F.R.S., and Professor Wyville Thomson, LL.D., F.R.S. (Proceedings of the Royal Society of London, 1870.) Report of Deep Sea Researches carried on during the months of July, August, and September 1870, in H.M. surveying-ship ‘ Porcu- pine,’ by W. B. Carpenter, M.D., F.R.S., and J. Gwyn Jeffreys, F.B-S. (Proceedings of the Royal Society of London, 1870.) CILAP. 1.] INTRODUCTION. 31 the existence of abundant animal life at the bottom of the sea has been finally settled and for all depths, for there is no reason to suppose that the depth any- where exceeds between three and four thousand fathoms; and if there be nothing in the conditions of a depth of 2,500 fathoms to prevent the full develop- ment of a varied fauna, it is impossible to suppose that even an additional thousand fathoms would make any great difference. The conditions which might be expected principally to affect animal life at great depths of the sea are pressure, temperature, and the absence of light which apparently involves the absence of vegetable food. After passing a zone surrounding the land, which is everywhere narrow compared with the extent of the ocean, through which the bottom more or less abruptly shelves downwards and the water deepens; speaking very generally, the average depth of the sea is 2,000 fathoms, or about two miles; as far below the surface as the average height of the Swiss Alps. In some places the depth seems to be considerably greater; possibly here and there nearly double that amount ; but these abysses are certainly very local, and their existence is even uncertain, and a vast por- tion of the area does not reach a depth of 1,500 fathoms. The enormous pressure at these great depths seemed at first sight alone sufficient to put any idea of life out of the question. There was a curious popular notion, in which I well remember sharing when a boy, that, in going down, the sea-water became gradually under the pressure heavier and heavier, and that ali the loose things in the sea floated at different levels. 32 THE DEPTHS OF THE SEA. [CHAP. I. according to their specific weight : skeletons of men, anchors and shot and cannon, and last of all the broad gold pieces wrecked in the loss of many a galleon on the Spanish Main; the whole forming a kind of ‘false bottom’ to the ocean, beneath which there lay all the depth of clear still water, which was heavier than molten gold. The conditions of pressure are certainly very extra- ordinary. At 2,000 fathoms a man would bear upon his body a weight equal to twenty locomotive engines, each with a long goods train loaded with pig iron. Weare apt to forget, however, that water is almost incom- pressible, and that therefore the density of sea-water at a depth of 2,000 fathoms is scarcely appreciably increased. At the depth of a mile, under a pressure of about 159 atmospheres, sea-water, according to the formula given by Jamin, is compressed by the riz of its volume; and at twenty miles, supposing the law of the compressibility to continue the same, by only ; of its volume—that is to say, the volume at that depth would be ? of the volume of the same weight of water at the surface. Any free air suspended in the water, or contained in any compressible tissue of an animal at 2,000 fathoms, would be reduced to a mere fraction of its bulk, but an organism supported through all its tissues on all sides, within and without, by incom- pressible fluids at the same pressure, would not necessarily be incomimoded by it. We sometimes find when we get up in the morning, by a rise of an inch in the barometer, that nearly half a ton has been quietly piled upon us during the night, but we expe- rience no inconvenience, rather a feeling of exhilara- tion and buoyancy, since it requires a little less exer- CHAP. 1. | INTRODUCTION. oo tion to move our bodies in the denser medium. Weare already familiar, chiefly through the researches of the late Professor Sars, with a long list of animals of all the invertebrate groups living at a depth of 300 to 400 fathoms, and consequently subject to a pressure of 1,120 lbs. on the square inch; and off the coast of Portugal there is a great fishery of sharks (Centros- cymnus coelolepis, Boc. and CaP.), carried on beyond that depth. If an animal so high in the scale of organization as a shark can bear without inconvenience the pressure of half a ton on the square inch, it is a sufficient proof that the pressure is applied under circumstances which prevent its affecting it to its prejudice, and there seems to be no reason why it should not tolerate equally well a pressure of one or two tons. At all events if is a fact that the animals of all the invertebrate classes which abound at a depth of 2,000 fathoms do bear that extreme pressure, and that they do not seem to be affected by it in any way. We dredged at 2,485 fathoms Scrobicularia nitida, MULLER, a_ species which is abundant in six fathoms and at all inter- mediate depths, and at 2,090 fathoms a large Fusus, with species of many genera which are familiar at moderate depths. Although highly organized animals may live when permanently subjected to these high pressures, it is by no means certain that they could survive the change of condition involved in the pres- sure being suddenly removed. Most of the mollusca and annelids brought up in the dredge from beyond 1,000 fathoms were either dead or in a very sluggish state. Some of the star-fishes moved for some time D 34 THE DEPTHS OF THE SEA. [CHAP. I. feebly, and the spines and pedicellarize moved on the shells of the urchins, but all the animals had evi- dently received from some cause their death-shock. Dr. Perceval Wright mentions’ that all the sharks brought up by the long lines from 500 fathoms in Setubal Bay are dead when they reach the surface. Various methods have been proposed to test the actual pressure at great depths, but as all the elements in the calculation are well known, it is easier to work out the question in the study than in the field. A neat instrument was constructed for the American Coast Survey. > |e = pee / 9L ee O04 say IPCs 657 Lt i 618 6 : p eae k N atipewer \ { SL as ce / LN Bee bee i fof L ii aa 802 = 0£9 oger 10s) Stl oF. : £8. yi OST @) © P| i | | | | 4 US | (e) 4 H i i ae he 9" Se © 7 j hat wa i> i i f ? i ' * ‘ i fi f * ” id @. "eV" igee ec ‘ one ee’ DMA jf 7 ree ” hn sits sf ‘ew Bl ve ‘eer " 7] pe) OLLNWTLY HLMON| ae is\. I—,, emdnasog ,, SHH fo eensy potyy—TI FivId CHAP. III. ] THE CRUISES OF THE ‘ PORCUPINE’ 87 weather, off Valentia and between Valentia and Galway, at depths varying from 80 to 808 fathoms (Station 2), with a temperature at the latter depth of 5°2C. ‘The general character of the fauna was that which we have hitherto been in the habit of regarding as Northern. Several interesting things were met with— Nucula tumidula, Maum.; Leda frigida,TORELL; Verticordia abyssicola, JEFFREYS ; and Siphonodenta- lium quinquangulare, Forses. Among the echino- derms a multitude of the large form of Lehinus norve- Fie. 8.—Gonoplax rhomboides, FaBRicivs. Young. Twice the natural size. (No. 3.) gicus, D. and K., which I am now inclined to regard, along with several of its allies, as a mere variety of E. flemingti, Batu; and the fine asterid already mentioned, Brisinga coronata, G. O. Sars. Some interesting crustaceans, including Gonoplax rhom- boides, Fax. (Fig. 8), a well-known Mediterranean species, and a young specimen of Geryon tridens, Kroyer (Fig. 9), a rare Scandinavian form, and the only known North European brachyurous crustacean §8 THE DEPTHS OF THE SEA. [CHAP. III. which had not previously been taken in the British seas. Here the Miller-Casella thermometers were tried for the first time and compared with those of the ordinary construction. The minimum recorded by one of the former was 5°°2 C., while that recorded by one of the best ordinary instruments of the Hydro- graphic Office pattern was 7°3C. As this difference of 2° C. was almost exactly what the results of the ex- periment previously made had indicated as the effect \ Fic. 9.—Geryou tridens, KRovER. Young. Twice the natural size, (No. 7.) of a pressure of 1 ton on the square inch, which is about equal to the pressure of a column of sea-water of 800 fathoms, this close coincidence gave great confidence in the practical working of the protected instrument, a confidence which all subsequent ex- perience has fully justified. Mr. Gwyn Jeffreys and his companions next pro- ceeded to examine the sea-bed between Galway and Poreupine Bank, a shoal discovered during one of CHAP. LI. ] THE CRUISES OF THE ‘ PORCUPINE’ 89 the previous cruises of our little vessel under the command of Lieut. Hoskyn, R.N. The deepest dredging of this excursion was 1,230 fathoms, with a minimum temperature of 3°2C., and a bottom of fine grey mud with a considerable admixture of sand. Animals were abundant even at this great depth: among the mollusca several new forms allied to Arca; Trochus ninutissimus, MicuEL, a North American species; and several others; several crus- taceans, and many interesting foraminifera. As in previous dredgings in deep water, the miltolines were of very large size, and the large cristellarians showed every gradation in their axis of growth from the rectilineal to the spiral. In the shallower dredgings of this cruise the general character of the fauna was much the same as before. It had what we have been in the habit of considering a northern ‘facies,’ but probably, as already explained, because the largely extended deep-water fauna at a temperature of 0° to + 3°C., of which it forms a part, has hitherto only been investigated off the coast of Scandinavia, where it crops up within reach of observation. Limopsis aurita, Broccu1; Arca glacialis, GRAY ; Verticordia abyssicola, JEFFREYS; Dentalium abys- sorum, Sars; Trochus cinereus, DA Costa; fusus despectus, L.; F. islandicus, CuEM.; I’. fenestratus, Turv; Columbella haliweti, JEFFREYS ; Cidaris papil- lata, Leskn; Echinus norvegicus, D. and K.; and Lophohelia prolifera, PAuLas, were found in these dredgings. The ‘ Porcupine’ next put into Killibegs Bay, on the north coast of Co. Donegal, and coaled there for her trip to Rockall. As it was anticipated that this 90 THE DEPTHS OF THE SEA. [CHAP. III. trip would require a clear fortnight, as much coal was stacked on deck as was considered prudent. This cruise was entirely successful. The weather was remarkably fine, and Mr. Gwyn Jeffreys’ party found it possible to work the dredge during seven days at depths exceeding 1,200 fathoms, and on four days at less depths. The greatest depth achieved was 1,476 fathoms (Station 21), and this dredging yielded mollusca, a stalked-eyed crustacean with unusually large eyes, and a fine specimen of Holothuria tremula. The deep dredgings in this trip yielded an abund- ance of novel and most interesting results in every sub-kingdom of the invertebrates. Among the mol- lusca were valves of an imperforate brachiopod, with a septum in the lower valve, which Mr. Jeffreys proposes to name Alretia gnomon, Among the crus- tacea were new species of the Diastylide, and many forms of Isopoda, Amphipoda, and Ostracoda, several of them new to science. Two or three specimens were obtained at a depth of 1,215 fathoms (Station 28) of a very remark- able echinoderm belonging to the genus Powr- talesia, A. AG. All these specimens were appa- rently immature, judging by the condition of the ovaries. I have named this species provisionally Pourtalesia phiale. After careful consideration I have come to the conclusion that it is not the young of a form of which we afterwards took a mature example in the cold area between Feroe and Shetland (Station 64), which will be described here- after. Fine corals were constantly dredged in the more moderate depths, particularly great living masses of Lophohelia prolifera (Fig. 30), with smaller tufts CHAP, LIT. } THE CRUISES OF THE ‘ PORCUPINE’ 91 of Amphihelia ramea, and everywhere the several varieties of Caryophyllia borealis. The foraminifera, as before, were remarkable for their size, and the same types were predominant ; but species were here obtained for the first time of a F1G. 10.—Orbitolites tenuissimus, CARPENTER MSS. Magnified. (No. 28.) peculiarly interesting Orbitolite, a type not hitherto discovered farther north than the Mediterranean, and there attaining a comparatively small size. Orbitolites tenuissimus, CARPENTER MSS. (Fig. 10), is when complete about the size of a sixpence, and as 92 THE DEPTHS OF THE SEA. (CHAP. Il. thin as paper. From its extreme tenuity and the ease with which the rings of chamberlets of which it is composed separate from one another, all our large specimens were more or less injured. All the chamberlets are on the same plane; this spe- cies therefore belongs to the ‘simple type’ of the genus, though the form of the chamberlets corre- sponds, as Dr. Carpenter has pointed out, with those of the superficial layer in the complex type. Another peculiarity which Dr. Carpenter regards as of special importance in its general bearings, is that, instead of commencing with a ‘central’ and ‘ cireumambient’ chamber like the ordinary Orbitolites, this form com- mences with a spine of several turns like that of a young Cornuspira, thus showing the fundamental conformity of this cyclical type to the spiral plan of growth.’ As I have already mentioned, it was the original intention to devote the second cruise to the exploration of an area to the west of the outer Hebrides, between Rockall and the south-western limit of last year’s work in the ‘ Lightning.’ During the first cruise however dredging had been carried down successfully to a depth of nearly 1,500 fathoms; and the result so far realized our anticipations, and confirmed the experience of last year. The conditions (to that ereat depth at all events) were consistent with the life 1 Researches on the Foraminifera. Part I. In the Philosophical Transactions of the Royal Society of London for the year 1855. P. 195 et seq. Introduction to the Study of the Foraminifera. By William D. Carpenter, M.D., F.R.S., F.L.S., F.G.S., &e. Published for the Ray Society, 1862. P. 106 et seg. CHAP. III. ] THE CRUISES OF THE ‘ PORCUPINE, 93 of all the types of marine invertebrata; though undoubtedly in very deep water the number of species procured of the higher groups was greatly reduced, and in many cases the individuals appeared to be dwarfed. From these observations (which thoroughly corroborated those of Dr. Wallich and others, about which there had been some difference of opinion on account of the imperfection of the appliances at the command of the observers), we concluded that prob- ably in no part of the ocean were the conditions so altered by depth as to preclude the existence of animal life,—that life had no bathymetrical limit. Still we could not consider the question thoroughly settled; and when upon consultation with Captain Calver we found him perfectly ready to attempt any depth, and from his previous experience sanguine of success, we determined to apply to the Hydrographer to sanction an attempt to dredge in the deepest sound- ings within our reach, viz. 2,500 fathoms indicated on the chart 250 miles west of Ushant. The deepest reliable soundings do not go much beyond 3,000 fathoms; and we felt that if we could establish the existence of life, and if we could determine the conditions with accuracy down to 2,500 fathoms, the eeneral question would be virtually solved for all depths of the ocean, and any further investigation of its deeper abysses would be mere matter of curiosity and of detail. The Hydrographer cordially acquiesced in this change of plan; and on the 17th of July the ‘Porcupine’ left Belfast under the scientific direction of the writer; Mr. Hunter, F.C.S., Chemical Assistant in Queen’s College, Belfast, taking charge of the examination and analysis of the sea-water. Q4 THE DEPTHS OF THE SEA. [CHAP. III. The weather was very settled. On the Sunday, as we steamed down the Irish Channel there was nearly a dead calm, a slight mist hanging over the water and giving some very beautiful effects of coast scenery. On the evening of Sunday the 18th we anchored for the night off Ballycottin, a pretty little port about fifteen miles from Queenstown, and dropped round to Queenstown on Monday morning, where we anchored off Haulbowline Island at 7 a.m. At Queenstown Mr. P. Herbert Carpenter joined Mr. Hunter in the laboratory, to practise under his direction the gas-analysis, which it had been arranged that he should undertake during the third eruise. Monday the 18th was employed in coaling and pro- curing in Cork some things which were required for the chemical department ; and at 7 P.M. we cast off from the wharf at Haulbowline and proceeded on our voyage. | During Monday night we steamed in a south- westerly direction across the mouth of the Channel. On Tuesday we dredged in 74 and 75 fathoms on the plateau which extends between Cape Clear and Ushant, on a bottom of mud and gravel with dead shells and a few living examples of the generally diffused species of moderate depths. The weather was remarkably fine, the barometer 30°25 in., and the temperature of the air 22°°5 C. On Wednesday, July 21, we continued our south- westerly course, the chart indicating during the earlier part of the day that we were still in the shallow water of the plateau of the Channel. At 4.30 a.m. we dredged gravel and dead shells in 95 fathoms, but towards mid-day the lead gave a much greater depth ; See NORTH ATLANTIC 250 450 “75 1180 SSS ——— Ss ES ee ee ee SSS eS HMMS. “Porcupine” —1869. ——$——} Se as SAN ASN ANS AS NNN A A AS NN A, OS AT NS SS SG Ba SS A SB pe 7° () 20 46 2 7 ¢ 35 = S25 ee. x ry aN cas fing * RY en Se i é Prate IIL.—Second Cruise of H.M.S. “Porcupine” —1869. ORTH ATLANTIC ase he /0t see “ 7 pe my ” Ne 7 ee ees 2 ue % x aso 2 a” i" . fe a0 SO psy ee 4 te © * Le 21 aye ae 8 “ A v té / 2 ; » | amrsron, CHANNEL w 6 * 20 a 2 } > “Ushant ae ay a als? se ¥ EX oo \* » 7 CHAP. II1.] THE CRUISES OF THE ‘ PORCUPINE’ 5) and in the afternoon, rapidly passing over the edge of the plateau, we dredged in 725 fathoms with a bottom of muddy sand (Station 36). This is about the bathymetrical horizon at which we find the vitreous Sponges in the northern area; and although the bottom is here very different, much more sandy with but a slight admixture of globigerina ooze, we dredged a specimen, tolerably perfect though dead, of Aphrocallistes bocagei, WRIGHT, a vitreous sponge lately described by Dr. E. Perceval Wright from a specimen procured by Professor Barboza de Bocage from the Cape-Verde Islands, and one or two small specimens of Holtenia carpenteri, Wy. T. The muddy sand contained a considerable proportion of gravel and dead shells. On Thursday, July 22, the weather was still re- markably fine. The sea was moderate, with a slight swell from the north-west. We sounded in lat. 47° 38" N., long. 12°08 W., in a depth of 2,485 fathoms (Station 87), when the average of the Miller-Casella thermometers gave a minimum temperature of 2°°5 C. As this was about the greatest depth which we had reason to expect in this neighbourhood, we prepared to take a cast of the dredge. This operation, rather a serious one in such deep water, will be described in detail in another chapter. It was perfectly suc- cessful. The dredge-bag which was safely hauled on deck at 1 o'clock on the morning of the 28rd, after an absence of 74 hours and a journey of up- wards of eight statute miles, contained 12 ewt. of very characteristic grey chalk-mud. ‘The dredge appeared to have dipped rather deeply into the 96 THE DEPTHS OF THE SEd. [CHAP. III. soft mud, as it contained amorphous paste with but a small proportion of fresh shells of Globigerina and Orbulina. There was an appreciable quantity of diffused amorphous organic matter, which we were inclined to regard as connected, whether as processes, or ‘mycelium,’ or germs, with the various shelled and shell-less Protozoa, mixed very likely with the apparently universally distributed moner of deep water, Bathybius. On careful sifting, the ooze was found to contain fresh examples of each of the Invertebrate sub-king- doms. When examined at daylight on the morning of the 23rd none of these were actually living, but their soft parts were perfectly fresh, and there was ample evidence of their having been living when they entered the dredge. The most remarkable species were : — Motuusca.—Dentalium, sp. n., of large size. Pecten fenestratus, FKorBes, a Mediterranean species. Dacrydium vitreum, TorELL; Arctic, Norwegian, and Mediterranean. Scrobicularia nitida, Miut.tEr; Norwegian, British, and Mediterranean. Neera obesa, Loven ; Arctic and Norwegian. Crustacea.—Anonyx hilbollii, KROYER (—A. den- ticulatus, BATE), with the secondary appendage of the upper antennze longer and more slender than in shallow-water specimens. Ampelisca equicornis, BRUZELIUS. Munna, sp. n. One or two ANNELIDES and GEPHYREA, which haye not yet been determined, CHAP. 111. ] THE CRUISES OF THE ‘ PORCUPINE? 97 ECHINODERMATA.— Ophiocten sericeum, Forxs ; several well-grown specimens. Echinocucumis typica, SARS. This seems to be a very widely distributed species ; we got it in almost all our deep dredgings, both in the warm and in the cold areas. A remarkable stalked ecrinoid allied to Rhizocrinus, but presenting some very marked differences. Potyzoa.—Salicornaria, sp. n. C@LENTERATA. — Two fragments of a hydroid zoophyte. Protozoa.—Numerous foraminifera belonging to the groups already indicated as specially charac- teristic of these abyssal waters; together with a branching flexible rhizopod, having a chitinous cortex studded with globigerinse, which encloses a sarcodic medulla of olive-green hue. This singular organism, of which fragments had been detected in other dredg- ings, here presented itself in great abundance. One or two small SponGEs, which seem to be referable to a new group. On Friday, July 23, we tried another haul at the same depth; but when the dredge came up at 1.30 P.M. it was found that the rope had fouled and lapped right round the dredge-bag, and that there was nothing in the dredge. The dredge was sent down again at 3 P.M., and was brought up at 11 p.m, with upwards of -2 ewt. of ooze.—We got from this haul a new species of Pleurotoma and one of Dentalium ; Scrobicularia nitida, MULLER; Dacrydium vitreum, ToRELL; Ophiacantha spinulosa, M. and T.; and Ophiocten kriéyeri, LUTKEN ; with a few crustaceans and many foraminifera, H QS THE DEPTHS OF THE SEA. [CHAP. III. In both of these last deep dredgings the dredge brought up a large number of extremely beautiful Polycystina, and some forms apparently intermediate between Polycystina and Sponges, which will be described shortly. ‘These organisms did not seem to be brought from the bottom, but appeared to be sifted into the dredge cn its way up. They were as numerous adhering to the outside of the dredging-bag as within it. During the soundings taken near this locality quite a shower of several beautiful species of the Polycystina and Acanthometrina fell upon the chart- room skylight from the whole length of the sounding- line while it was being hauled in. We were now steaming slowly back towards the coast of Ireland; and on Monday, July 26, we dredged in depths varying from 557 to 584 fathoms (Stations 39-41) in ooze, with a mixture of sand and dead shells. In these dredgings we got one or two very interesting alcyonarian zoophytes, and several ophiurideans, including Ophiothrix fragilis, Amphiura balliit, and Ophiacantha spinulosa. Many of the animals were most brilliantly phosphorescent, and we were afterwards even more struck by this phenomenon in our northern cruise. In some places nearly every- thing brought up seemed to emit light, and the mud itself was perfectly full of luminous specks. The aleyonarians, the brittle-stars, and some annelids were the most brilliant. The Pennatule, the Virgu- laviev, and the Gorgonie shone with a lambent white light, so bright that it showed quite distinctly the hour on a watch ; while the light from Ophiacantha spinulosa was of a brilliant green, coruscating from the centre of the disk, now along one arm, now along CHAP. IIL. | THE CRUISES OF THE * PORCUPINE, ga another, and sometimes vividly illuminating the whole outline of the star-fish. On the 27th we dredged in 862 fathoms (Station 42), the weather being still very fine, and the sea quite smooth. The bottom was ooze, with sand and dead shells. Among the Mollusca procured were a new species of Pleuronectia, Leda abyssicola (Arctic), Leda messinensis (a Sicilian tertiary fossil), Dextalinm gigas (sp. n.), Siphonodentalium (sp. n.), Cerithium metula, Amaura (sp. n.), Columbella haliweti, Cylichna pyramidata (Norwegian and Mediterranean), and many dead shells of Cavolina trispinosa. These latter were very common in all the northern dredg- ings, though we never saw a living specimen cn the surface. During the afternoon we took a series of inter- mediate temperatures, at intervals of 50 fathoms, from the bottom at 562 fathoms to the surface. On the 28th we dredged in 1207 fathoms (Station 43), with a bottom of ooze. A large Fusus of a new species (7 attenuatus, Jeffreys) was brought up alive, with two or three Gephyrea, and an example each of Ophiocten sericeum and Echinocucumis typica. We again dredged on the 29th and 80th, gradually draw- ing in towards the coast of Ireland in 865, 458, 180, and 118 fathoms successively (Stations 44, 45). In 458 fathoms (Station 45) we procured a _ breken example of Lrisinga endecacnemos, previously taken by Mr. Jeffreys off Valentia, and a number of interesting Mollusca; and in 458 and 180 fathoms (Stations 45 and 45a) an extraordinary abundance of animal life, including many very interesting forms— Dentalium abyssorum, Aporrhais serresianus, Solarium H 2 100 THE DEPTHS OF THE SEA. [cHaP. III, Sallaciosum, Fusus fenestratus, with abundance of Caryophyllia borealis, and all the ordinary deep- water forms of the region. The last station, 45a, gave us a most singular as- semblage of Ophiurideans. Ophioglypha lacertosa was in large numbers and of extraordinary size, and associated with it were two most conspicuous species, new to science; one a large species of Ophiothria, coming near O. fragilis, but of much larger size ; the disk in the larger specimens 25 mm. in diameter, and the span from tip to tip of the rays 275 mm. ‘The colours of the disk are very vivid, purple and rose; and all the plates of the disk, and the dorsal plates of the arms, are studded with delicate spines. Notwithstanding its totally different aspect, I had a misgiving that this might yet prove only an extreme variety of O. fragilis. My friend Dr. LitKen, however, protests that it is totally distinct. On such a question I bow to his authority, and dedicate it to him, doubts and all, under the name of Ophiothrix liitkent. 'The second novelty was a fine species of Ophiomusium. About mid-day on Saturday, the 31st of July, we steamed into Queenstown. Having coaled at Haul- bowline on Monday, the 2nd of August, we were moored in the Abercorn Basin, Belfast, after a pleasant return passage up the channel, on the evening of Wednesday, the 4th. As it was necessary that her boilers should be thoroughly cleared out after having been so long at sea, the ‘Porcupine’ did not leave Belfast till Wednesday, the 11th of August; when she pro- ceeded to Stornoway, her final port of departure. CHAP. 111.] THE CRUISES OF THE ‘ PORCUPINE 101 The scientific staff consisted of Dr. Carpenter, Mr. P. Herbert Carpenter (who had gone through his apprenticeship in making analyses under unfavourable circumstances in the former cruise with Mr. Hunter, and was now prepared to undertake this task on his own account), and myself; and our intention was, in accordance with our original programme, to go care- fully over again the region which we had examined in the ‘ Lightning,’ to test with better appliances and more trustworthy instruments the singular distri- bution of temperatures in the ‘warm’ and ‘cold’ areas, to map out as accurately as we could the paths of the warm and cold currents, and to deter- mine the influences of these currents upon the character and distribution of animal life. We left Stornoway on the afternoon of Sunday the 15th of August, and made straight for the scene of our most successful ‘warm area’ dredging of the year before. We were equally successful on this occasion, and procured several good specimens of Holtenia, and a beautiful series of ITyalonema, ranging from 2 mm. in length up to 30 and 40 centimetres, and thus giving all the stages in the development of the wonderful ‘glass rope,’ and proving to demon- stration its relation to the body of the sponge— Dr. J. E. Gray’s so-called Carteria. The most interesting novelty however which re- warded us was a very fine Echinid belonging to the Cidaridz to which I had given the name Porocidaris purpurata (Fig. 11). I believe I am justified in referring this handsome species to the genus Poroci- daris, although in it the special character is absent on which that genus was founded by Desor. Some 102 TH DEPTHS OF THE SE4. [cuar. U1. == Fic. 11.—Porocidaris purpurata, WyviLtte Taomsoy, Natural size. (No. 47.) CHAP, III. | THE CRUISES OF THE ‘ PORCUPINE’ 103 ‘radioles,’ as the fossil spines of Cidarites are usually called, presenting a very marked character, had been found in various formations from the lower oolite upwards. These spines are paddle-shaped, compressed, longitudinally grooved, flattened almost into plates, and strongly serrated on the edges. In the nummu- litie beds of Val-Dominico near Verona such spines were found associated with plates much resembling those of Cidaris, but with the unique peculiarity of a row of holes penetrating the test in the areolar space round the primary tubercle. This character our new Urehin does not possess, but the radioles have the flatness, the longitudinal strize, and the serrated edges of those of Porocidaris. IT do not attach much importance to the perfora- tions in the plates. From Desor’s figures they are not round and defined in outline, but lengthened and somewhat irregular, and. they radiate from the inser- tion of the spine. Our species has a set of depres- sions occupying the position of these perforated grooves Which are undoubtedly for the insertion cf tie muscles moving the large long spines, and as the test is thin these grooves might readily penetrate the plate, or so nearly penetrate it as to be worn into holes by very little drifting or wear. Our recent species and the eocene form have another character in common; the areolar circles are not well defined, and the areolze tend to become confluent. Seattered plates only of this genus have been found fossil, and the ovarial plates were till now unknown. They present a very singular character, which is certainly of generic value. ‘The ovarial 104 THE DEPTHS OF THE SEA. [CHAP, IIL. aperture does not penetrate the plate, but perforates a membrane which fills up a diamond-shaped space, one-half of which is cut out of the outer edge of the ovarial plate in the form of a large triangular notch, while the other half is formed by a separation into a like notch of the two upper interradial plates, in the middle line of the interradial space. The charac- teristic paddle-shaped spines are ranged in several rows round the mouth. The large spines round the equator of the corona are diverse in form, some of them cylindrical, only slightly tapering towards the tip, and others bulging out and thick near the neck and coming somewhat rapidly to a sharp point. ‘The colouring of the animal is very remarkable. The short spines covering the test are of a rich purple, and a purple of even a deeper and richer hue dyes about one-third of the length of the spine, from the head of the spine outwards, ending abruptly in a sharply defined line. The spine beyond this purple portion is of a beautiful pale rose colour. Two mature examples of this fine species were found, and two young ones, one nearly half-grown and the other much smaller. We now moved slowly to the northward towards the Fwroe Bank, and soundings were taken to fix as closely as possible the point of passage from the warm water into the cold: a temperature sounding taken in lat. 59° 37’, long. 7° 40’, gave a depth slightly less than that of the ‘ Holtenia ground, —475 fathoms,— with a slightly higher bottom temperature, 7°4C.; and at Station 50, lat. 59° 54’, long. 7° 52’, with a depth of 335 fathoms, the minimum temperature had risen to 7°9C. A sounding at Station 51, lat. 60° 6’, long. CHAP. III. | THE CRUISES OF THE ‘ PORCUPINE’ 105 8° 14’, gave 440 fathoms, and a bottom temperature of 5°5 C., showing that we were passing into another set of conditions; and at Station 52, lat. 60° 25’, long. 8° 10’, only a few miles further on, with a depth of 384 fathoms, nearly the same as that of Station 20, the thermometers recorded a minimum of —0°8 C., We now altered our course towards the east-south- east, and, after a run of about 25 miles, sounded in 490 fathoms, with a bottom temperature of —1°'1 C. The following six stations, Nos. 54 to 59, were all in the cold area with a temperature below the freezing- point of fresh water. At the last station, No. 59, lat. 60° 21’, long. 5° 41’, at a depth of 580 fathoms, the guarded thermometer recorded the lowest temperature which was met with —1°3 C. While we were passing through the cold area and making these observations, the weather was extremely settled and fine, and under the careful management of Captain Calver all our appli- ances worked admirably. The temperatures were noted in every case by the same pair of Miller-Casella ther- mometers, which were sometimes compared with other instruments and found to give perfectly accurate indi- cations, even after being so frequently subjected to prodigious pressure. The sounding instruments and the dredges never failed, and an ingenious device, for which we are indebted to our Captain, enabled us sometimes to multiply our prizes a hundred-fold. ° ° ° Q A » (| ————————————— sastl he meee | | | | = ee — ¥ = Piate 1V.—Third Cruise of JIMS. “Poreupine”—1869. ORKNEY I? NORTH ATLANTIC 7 eo ~ EAN CHAP. UI. | THE CRUISES OF THE ‘ PORCUPINE? LOW with twelve blue-jacketed Shetlanders sitting like statues, their white oars glittermg in the sun. The Governor looked with the critical eye of a sailor at the two boats,—he still spoke lovingly of the ‘ Maid of Féroe, but I suppose he saw that, as Tennyson says, ‘we were all of us Danes;’ and the question of a trial of strength lapsed by mutual consent ! We were obliged to remain a few days at Thorshavn replenishing in various ways, and while there we were very anxious to have had an opportunity of seeing Myling Head—-a magnificent cliff at the north-western point of Stromoe, which falls perpendicularly, even slightly overhanging its base, froma height of upwards of 2,000 feet into the sea. ‘The tide runs among and round these islands lke a miull-race, and the Governor told us that if we started with the morning flood, and our vessel kept pace with the tide, we might make the circuit of the island, passing under Myling, and returning to Thorshavn in six hours. If we did not carry the tide with us, it became a matter of dif- ficulty only to be achieved at considerable expense both of fuel and time. We found that high water would occur on the fol- lowing Monday, Aug. 23, at 4 o'clock in the morning ; and as the weather was brilliant up to the evening of Sunday—unusually brilhant for those regions—we made ail our arrangements in high hope of a pleasant trip, as we had persuaded our kind host and hostess to accompany us. With the first dawn of Monday morning it was blowing and pouring, and we were obliged to defer our visit to the celebrated headland to some possible future opportunity. The next morning was fine again, and we left 108 THE DEPTHS OF THE SEA. [CHAP. 111. Thorshavn about noon, steaming east by south, so as to cross the deep channel between Fieroe and Shetland. Our first two stations were on the Féroe plateau, at depths a little over a hundred fathoms, but the third sounding, taken in the evening of the 24th at a depth of 317 fathoms, gave a bottom temperature of —0°9 C.; we were therefore once more in the cold current. Having kept the same course under easy steam during the night, we took a sounding next morning, lat. 61° 21’ N., long. 3° 44° W., at a depth of 640 fathoms, with a bottom temperature of — 1°1C. A haul of the dredge brought up rolled pebbles and Fic. 12.—Pourtalesia jefreysi, WYVILLE THomson. Slightly enlarged.! (No. 64.) fine gravel with few animal forms, but among them one of extraordinary interest, a large specimen of a fine species of the genus Powrtalesia, a heart-urchin, one of whose congeners had been discovered by M. de Pourtales in the gulf-stream explorations off the American coast, and a second by Mr. Gwyn Jeffreys near Rockall. The present example (Fig. 12) was much larger than either of those previously dredged, and it appeared to be specifically distinct. 1 T have the pleasure of dedicating this interesting species to our accomplished colleague, J. Gwyn Jeffreys, F.R.S. CHAP. IIT. | THE CRUISES OF THE ‘ PORCUPINE’ 109 The shell is singularly unlike that of any other known living echinoderm. It is about two inches in length, almost cylindrical, ending posteriorly in a blunt rostrum, and the anterior extremity is truncated. The surface of the shell is covered with short spatulate spines, and near the anterior end there is a kind of fringe of long thin cylindrical spines, especi- ally congregated on the upper surface. ‘The mouth is at the bottom of a deep anterior and inferior groove, and the excretory opening is at the bottom of a pit on the dorsal surface, above the terminal rostrum. The arrangement of the ambulacra is most peculiar. The four ovarial openings and the madreporic tubercle are on the dorsal surface, just above the truncated anterior end at the base of which the mouth lies, and the three ambulacral vessels of the ‘trivium’ take a short course from the oral vascular ring, one along the centre of the anterior face, and the other two round its edges to meet in a ring surrounding the ovarial openings. ‘The two vessels of the ‘bivium’ have a very singular course. They run back into the great posterior prolongation of the shell, on the sides of which they form long loops, sending conical water-feet through single pores in long double lines of somewhat irregularly-formed ambulacral plates, which finally converge in a point a considerable distance behind the point of convergence of the three am- bulacra of the bivium. Between these two points of convergence, which are both on the middle line of the back, several plates are intercalated. We have thus the three anterior ambulacra ending in their ocular plates, meeting at one point, where there are likewise four genital plates, and the madreporic 110 THE DEPTHS OF THE SEA. [CHAP, 111, tubercle; and the two posterior ambulacra, with their ocular plates, meeting at another point and forming a kind of secondary apex. The fifth genital plate is obsolete. The specially interesting point is that, while we had so far as we were aware no living representative of this peculiar arrangement of what is called ‘disjunct’ ambulacra, we have long been well acquainted with a fossil family, the Dysasteride, possessing this character. | Many species of the genera Dysaster, AGAssiz, Collyrites, DESMOULINS, Metaporhinus, MicuELIn, and Grasia, MICHELIN, are found from the lower oolite to the white chalk, but there the family had previously been supposed to haye become extinct. The next attempt was one of our very few entirely unsuccessful hauls, the dredge coming up empty. This we attributed to an increase of wind and swell, and consequent drift on the vessel, which seemed to have prevented the dredge from reaching the ground. We devoted the morning to a series of temperature soundings at intervals of 50 fathoms from the surface to the bottom, and this we accomplished in a very satisfactory manner, with results which will be fully discussed hereafter. After a rapid descent for the first 50 fathoms the next 150 fathoms maintained a high and a tolerably equable temperature, and there was then a rapid fall between 200 and 3800 fathoms, the thermometer at the greater depth indi- eating O°C. From 300 fathoms to the bottom the temperature fell little more than a degree. ‘“* Thus the entire mass of water in this channel is nearly equally divided into an upper and lower stratum, the lower being an Arctic stream of nearly 2,000 feet CHAP. III. | THE CRUISES OF THE § PORCUPINE’ TET deep, flowing in a south-westerly direction, beneath an upper stratum of comparatively warm water moving slowly towards the north-east; the lower half of the latter, however, having its temperature considerably modified by intermixture with the stratum over which it lies.’’’ Our next few dredgings were on the Shetland plateau, in depths under 100 fathoms, and over ground already carefully worked by our colleague Mr. Gwyn Jeffreys. We got few novelties, but owing to our very effective dredging appliances we took some of the ‘ Haaf’ rarities, such as Fusus nor- vegicus, CHEMN.; Fusus berniciensis, KING; Pleuro- toma carinatum, BIvoNA; in considerable numbers. The hempen tangles stood us in good stead with the echinoderms. On one occasion the dredge brought up at a single haul, in the bag and on the tangles, cer- tainly not less than 20,000 examples of the pretty little urchin, Hehinus norvegicus, D. and Kk. On the 28th of August we anchored in Lerwick Harbour. We remained at Lerwick several days taking in necessary supplies, looking at the geology and the many remarkable antiquities of the neigh- bourhood, and ransacking the haberdashers’ shops for those delicate fleecy fabrics of wool which imitate in a scarcely grosser material, and with almost equal delicacy of design, the fretted skeletons of Holtenia, Euplectella, and Aphrocallistes. In this earlier part of the cruise nearly all the dredgings had been confined to the cold area, and 1 Dr. Carpenter, in ‘“‘ Preliminary Report on the Scientific Ex plora- tion of the Deep Sea, 1869.” (Proceedings of the Royal Society, vol. xvi. p. 441.) 112 THE DEPTHS OF THE SEA. [CHAP. ITT. ad over that region we had found a great uniformity of conditions. As already mentioned, the average bottom temperature throughout was a little below the freezing- point of fresh water, and it sometimes fell to nearly 2° C. below the zero of the centigrade scale. The bottom was uniformly gravel and clay, the gravel on the Scottish side of the channel consisting chiefly of the débris of the laurentian gneiss and the other metamorphic rocks of the North of Scotland, and the devonian beds of Caithness and Orkney. On the Feroe side of the channel, on the other hand, the pebbles were chiefly basaltic. This difference shows itself very markedly in the colour and composition of the tubes of annelids, and the tests of sundry fora- minifera. The pebbles are all rounded, and the varying size of the pebbles and roughness of the gravel in different places give evidence of a certain amount of movement of material along the bottom. There seems to be but little doubt, from the direction of the series of depressions in the isothermal lines of the region (PI. 7), that there is a direct move- ment of cold water from the Spitzbergen Sea into the North Sea, and that a branch of this cold indraught passes into the Féroe Channel. The fauna of the cold area is certainly characteristic, although many of its most marked species are common to the deep water of the warm area whenever the temperature sinks below 2° or 3° C. Over a considerable district in the Fieroe Channel there is a large quantity of a sponge which is pro- bably identical with Cladorhiza abyssicola, SARs, dredged by G. O. Sars in deep water off the Loffoten Islands. This sponge forms a kind of CHAP. III. ] THE CRUISES OF THE ‘ PORCUPINE’ a bush or shrub, which appears to clothe the bottom in some places over a large area like heather on a moor. There are at least three species. In one the branches are strict and rigid; while in another the arrangement is more lax, side branches coming off from a flexible centrai rachis ike the barbs from the shaft of an ostrich feather. The branches seem in some cases to be from 50 to 80 centimetres in height, and the stems near the base are 2 to 3 centimetres in diameter. The stem and branches consist of a firm central axis, semi-transparent and of a_ peculiar yellowish green colour; composed of a continuous horny substance filled with masses of needle-shaped spicules arranged longitudinally in dense sheaves. This axis is overlaid by a soft bark of sponge sub- stance supported by needle-shaped spicules, and full of the bihamate ‘spicules of the sarcode’ so charac- teristic of the genus Lsperia and its allies. The crust is covered with pores, and rises here and there into papille perforated by large oscula. ‘This sponge appears to belong to a group allied to the Espe- riadee, and perhaps even more closely allied to some of the fossil branching forms whose remains are so abundant in some beds of the cretaceous period. +4 59 4 f o2 5 440 be 5 10:9 60 6 8 14 52 384 | —0°8 dis eae 60 25 8 10 53 29 0n a bX) talises 2, 60 25 i 26 54 360: | —O0°3 11°4 59 56 Als 55 CU? i Paar 60 4 Shel WS, 56 AS Or 7, 11-4 60 2 6. 57 632 | — 0-8 1 era 60 14 blige 58 DAU —=0 6 LO" 6 60 21 Oot 59 580.) — I+ 3 i a) 60 21 5 41 60 167 6° 9 eer 6k 3 5-58 61 114 te 2 Oe 62-1 5 19 62 125 C20 9° 8 61 59 A: 3 63 alg je=-0 <9 9°4 Oley 4 2 144 THE DEPTHS OF THE SEA. [CITAP. 111. SU Aen GEE teres: |" nem ee Position. 64 640} = 1° 1-6 cars Im. 61°25 WN. o At W. 65 O43. 4 Sb “iL List 61-10 pla B 66 267 476 1 i bie OL ts 1 44 67 64 ors i ip et 60 32 0 29 68 75 637% i al ar 60 23 0-33. 69 67 6725 0 60. et 0 136 55 70 66 fap: tt 9 60 4 O 2 gt 103 oe EG 60 17 2-53 72 76 9 4 i Me ais 60 20 & 5 73 84 9-4 (i ee 60 29 3» 6 feel” 2203 cee 1 ey Mae 8 60 39 3425 75 250 bee 5 103 60 45 a 6 76 544") at LG Pak 60 36 3 58 The | -b60 | Sata 1G =o 60 3 4 40 78 290 5*3 11? *2 60 14 4 30 79 76 9°4 iB Ree 59 44 4 44 80 92 926 iba tei 59 49 4 42 81 142 925 bys 8 59 54 ee | teeZ aby Tyee 1t.~2 60 O sete 83 362 a La ey 60 6 5 a 84 155 G25 dad oa: 59 34 6 34 85 190 9-3 it 59 40 6 34 86 AA ele ae £2220 59 48 6 31 87 767 Bi a5 Mi t=! 59 35 9 11 88 705 5° 9 12 6) 59 26 Si 23 89 445 i fees 1g Rie #7 59 38 7 46 90 458 a) a By BIST 59 41 7 34 CHAPTER IV. THE CRUISES OF THE ‘ PORCUPINE’ (continued). From Shetland to Stornoway.—Phosphorescence.—The Hchinothuride. —The Fauna of the ‘Warm Area.’---End of the Cruise of 1869. Arrangements for the Expedition of 1870.--From England to Gibraltar.—Peculiar Conditions of the Mediterranean.— Return to Cowes. Appenpix A.—Extracts from the Minutes of Council of the Royal Society, and other official documents referring to the Cruise of H.M.S-‘ Porcupine’ during the Summer of 1870. Appenptx B.—Particulars of Depth, Temperature, and Position at the various Dredging-stations of H.M.S. ‘Porcupine’ in the Summer of 1870. * * The bracketed numbers to the woodcuts in this chapter refer to the dredging- stations on Plates IV. and V. We left Lerwick on the 3lst of August, and ran south- and westward, passing close to Sumburgh Head; Fair Isle, of evil repute among mariners, lying on the southern horizon like a little grey cloud. The weather was still very fine, and we had a good tossing with scarcely a breath of wind in the famous Roost of Sumburgh. Past Norna’s eyrie on the ‘Fitful Head ;’ past in the falling shadows of the autumn night the rocky Island of Foula, still the haunt of one or two pairs of the great skua gull, Lestris cataractes, a species fast L 146 THE DEPTHS OF THE SEA. [CHAP. IV. hastening to join the dodo and the gair-fowl among the creatures of bygone times. We now steered somewhat to the north of west, and early on the 1st of September sounded in lat. 60°17’, long. 2°53’, at a depth of 103 fathoms, and a bottom temperature of 9°°2 C. We were still in the shallow water, and had not touched the arctic stream. All day we slipped over the edge of the plateau, dredging chiefly well-known Shetland forms, and the tempera- ture falling slightly, reaching in the afternoon at a depth of 203 fathoms, 5"7 C. (Station 74). The next sounding, about ten miles farther north, gave us the stratum of intermixture, a temperature of 5°5 C. at a depth of 250 fathoms. We ran about thirty miles in the night, and early next morning dredged in the frigid water again in lat. 60° 36° N., long. 3°58’ N., at a depth of 344 fathoms, with a bottom temperature of —1°:1 C., the temperature at the surface being 10"1 C. Five-and-twenty miles to the westward, we sounded again at noon of the same day at 560 fathoms, with —1°2C. In these two or three last cold dredgings the character of the bottom was much the same—gravel of the older rocks, and clay. The preponderance of echinoderms and sponges was again remarkable, and the paucity of mollusca, though in this region we took a single specimen of a mollusk which seemed to be greatly out of its latitude. This was a pretty little brachiopod, Platydiaan omioides, Saccut (Morrisia, DAvipson), hitherto found only in the Mediterranean. The size of this specimen greatly exceeded that of Mediterranean examples of the same species a singular circumstance which leads CHAP. IV. ] THE CRUISES OF THE ‘ PORCUPINE’? 147 our friend Mr, Gwyn Jeffreys to the somewhat hazardous presumption that ‘‘its original home is in the boreal, perhaps even in the arctic region.”’ Two very peculiar little sponges were met with here ‘rather frequently sticking to stones. >. 28 dsr HS Alboran Gia Cibralta?, Siratt 3\¢ pak ees / ©... BELGIUM o Parts ga a SQ wd Venice ai ssaWa a <= 2 : Z c S\Pantal re Algter = we Pais ALGIER pr RI —=———_ Pirate V.—Track of Hy . © Porcupine ’—1870. a a ——— Bs ~ A a Wer. al p xd > baa A ~ WISTOL chaw P 5 —goueke™ BELGIUM : © we a _— 7 ft \cS DO Selly no a gto Cwermery cn Pw Jersey Treesrte Venice . ce \ foe J —ppocere \ ORGICA /c CHAP, Iv. | THE CRUISES OF THE ‘PORCUPINE, 18l Geryon tridens, is a fine Norwegian species. With these are associated two forms of a more southern character, Inachus dorsettensis and Hbalia cranchii, which I should not have expected at so great a depth.” The echinoderms were a very northern group. They included Cidaris papillata, Echinus nor- vegicus and BH. microstoma, the young of Brissopsis lyrifera, Astropecten arcticus, Archaster andromeda, and A. parellii, with a small specimen of Ophio- musium lymani, several examples of Ophiacantha spinulosa, and as usual one or two of the universally distributed Lchinocucumis typica. Dr. McIntosh, to whom the annelids were referred, notices as a species supposed to be specially northern, Thelepus coro- natus, Fas.; and Hollenia carpenteri, our familar anchoring sponge, of all sizes and ages and in consider- able numbers, was entangled in the hempen ‘swabs.’ July 9th—The wind still too light for effective work. Dredged in 717 and 358 fathoms, the assem- blage of mollusca having the usual character of being to a great extent common to the recent fauna of the seas of Norway and to the pliocene fauna of Sicily and the Mediterranean. It included on this occasion Terebratella spitzbergensis, an arctic and Japanese form, Pecten vitreus, and P. aratus, Leda pernula, Trochus suturalis, Odostomia nitens, and Pleurotoma hispidulum. Among the echinoderms was a fine specimen of Brisinga endecacnemos, ABSJORNSEN, very markedly different from B. coronata, which was the form commonly met with in the north. The corals were represented by Amphihelia oculata and Desmophyllum crista-galli. Among the annelids were Pista cristata, O. F. Mituuer, and Trophonia glauca, 182 THE DEPTHS OF THE SEA. [CHAP, IV. Matmeren, both of them Arctic species. The 10th was Sunday, and the vessel lay-to, and on the 11th they dredged, still on the slope of the channel plateau, with nearly the same result as before, the fauna maintaining the same character. Mr. Gwyn Jeffreys was now anxious to get a haul or two in the very deep water off the mouth of the Bay of Biscay, which we had explored successfully in 1869. They therefore steamed southwards, going a considerable distance without dredging, as they were afraid of coming in contact with the cable between Brest and North America. When they got to their ground unfortunately bad weather set in, and they were obliged to make for Vigo. On Thurs- day, July 14th, they passed Cape Finisterre, and dredged in 81 fathoms about 9 miles from _ the Spanish coast. Along with a number of familiar forms, some of them with a wide northern exten- sion, they here took on the tangles two specimens, one young and one apparently mature, both con- siderably injured, of the singular Echinidean already mentioned, Calveria fenestrata. This is evidently not a rare form nor is it confined to very deep water ; it is rather remarkable that it should have escaped notice so long. On the 15th, they sounded in from 100 to 200 fathoms, about 40 miles from Vigo, and on the 16th took one or two hauls in Vigo Bay at a depth of 20 fathoms. This locality had already been well-nigh exhausted by Mr. McAndrew in 1849, and only a few additions were made to his list. They left Vigo on the 18th. I quote from Mr. Gwyn Jeffreys :— “« Wednesday, Juiy 20th.—Dredged all day with CHAP. IV. | THE CRUISES OF THE ‘ PORCUPINE’ Ls3 considerable success at depths from 380 to 994. fathoms (Stations 14-16): the wind and sea had now gone down; and we took with the scoop-net a few living specimens of Clio cuspidata. The dredgings in 380 and 469 fathoms yielded among the mollusca Leda lucida (Norwegian and a Sicilian fossil), Avinus eumyarius (also Norwegian), Newra obesa (Spitz- bergen to the West of Ireland), Odostomia, n. sp., O. minuta (Mediterranean), and Cerithiwm, n. sp.; and among the echinoderms were brisinga endecacnemos and Asteronyx lovéni. But the results of the dredg- ing in 994 fathoms were so extraordinary as to excite our utmost astonishment. It being late in the even- ing, the contents of the dredge could not be sifted and examined until daylight the next morning. We then saw a marvellous assemblage of shells, mostly dead, but comprising certain species which we had always considered as exclusively northern, and others which Mr. Jetlreys recognized as Sicilian tertiary fos- sils, while nearly 40 per cent. of the entire number of species were undescribed, and some of them repre- sented new genera. The following is an analysis of the mollusca perfect and fragmentary taken in this one haul :— { | Total | pe Orders. number | Recent. | Fossil. | _Unde- | of Species. | | | scribed. = | ia a Sa! Brachiopoda,..2°< =>. | i — — Wonchilera y= 3s. 50 32 1 wi Solenoconchia . .. . 7 3 as 4 Gasteropoda. . . . Sik Oa, 2 23 48 Heteropoda. . . . 1 ] — — We veropodsjs aso. (3 Lae st lhe — 2 — io2) =r) = bo q | — 184 THE DEPTHS OF THE SEA. [CHAP. IV. The northern species above referred to are 34 in num- ber, and include Dacridium vitreum, Nucula pumila, Leda lucida, L. frigida, Verticordia abyssicola, Neera jugosa, N. obesa, Tectura fulva, Fissurisepta papillosa, Torellia vestita, Pleurotoma turricula, Admete viridula, Cylichna alba, Cylichna ovata, JEFFREYS n. sp., Bulla conulus, 8S. Woop not Drsuayers (Coralline Crag), and Scaphander librarius. Leda lucida, Neera jugosa, Tectura fulva, Fissurisepta papillosa, Torellia vestita, as well as several other known species in this dredging, are also fossil in Sicily. Nearly all these shells, as well as a few small echinoderms, corals, and other organisms, had evidently been transported by some current to the spot where they were found; and they must have formed a thick deposit similar to those of which many tertiary fossiliferous strata are composed. It seemed probable also that the deposit was partly caused by tidal action, because a fragment of IWelam- pus myosotis (a littoral pulmonibranch) was mixed with deep-water and oceanic Pectinibranchiates and Lamellibranchiates. None of the shells were Miocene or of an older period. “This remarkable collection, of which not much more than one-half is known to conchologists, not- withstanding their assiduous labours, teaches us how much remains to be done before we can assume that the record of Marine Zoology is complete. Let us compare the vast expanse of the sea-bed in the North Atlantic with that small fringe of the coast on both sides of it which has yet been partially explored, and consider with reference to the dredging last men- tioned what are the prospeets of our ever becoming acquainted with all the inhabitants of the deep CHAP. IV. | THE CRUISES OF THE ‘ PORCUPINE’ 185 throughout the globe! We believe, however, that a thorough examination of the newer Tertiaries would materially assist us in the inquiry ; and such exami- nation is feasible and comparatively easy. Much good work has been done in this line; but although the researches of Brocchi, Bivona, Cantraine, Phi- lippi, Caleara, Costa, Aradas, Brugnone, Seguenza, and other able paleontologists in the south of Italy have extended over more than half a century, and are still energetically prosecuted, many species of molluscous shells are continually being discovered there, and have never been published. Besides the Mollusea in this dredging from 994 fathoms, Pro- fessor Duncan informs us that there are two new eenera of corals, and Flabellum distinetum, which last he regards as identical with one from North Japan. It coincides with the discovery on the Lusitanian coasts of two Japanese species of a curious genus of Mollusea, Verticordia, both of which are fossil in Sicily and one of them in the Coralline Crag of Suffolk.” In the same dredging there are a number of very singular undescribed sponges, many of them recalling some of the most marked characters of one of the sections of Ventriculates. These will be referred to in a future chapter. On Thursday, the 21st of July, dredging was carried on all day at depths from 600 to 1095 fathoms, lat. 39° 42’ N., long. 9°43’ W., with a bottom tempera- ture at 1095 fathoms of 4°3 C. and at 740 fathoms of 9°4C. The dredging was most successful; many of the new and peculiar mollusca of the last dredging were taken here alive, with several additional forms. 186 THE DEPTHS OF THE SEA. [CHAP, IV. Several undescribed crustaceans were added ;—a new species of the genus Canocyathus among the corals, and a species of an unknown genus allied to Bathy- cyathus. Brisinga endecacnemos and some new ophi- urids were part of the treasures, but the greatest prize was a splendid Pentacrinus about a foot long, of which several specimens came up attached to the tan- oles. This northern Sea-lily, on which my friend Mr. Gwyn Jeffreys has bestowed the name Pentacrinus wyville-thomsoni, will be described hereafter with some other equally interesting members of the same group. Cape Espichel was reached on the 25th. The weather was now, however, so rough that Captain Calver was obliged to take shelter in Setubai Bay. Professor Barboza de Bocage of Lisbon had given Mr. Gwyn Jeffreys a letter of introduction to the coastguard officer at Setubal, who knew the place where the deep-sea shark and the Hyalonema are taken by the fishermen, but the state of the weather prevented his taking advantage of it. Off Cape Espichel in 740 and 718 fathoms, with a temperature of 10°2 C., the mollusca were much the same as those from Station 16, but included Leda pusio, Limopsis pygmea (Sicilian fossils), and Verti- cordia acuticostata. The last-named species is in- teresting in a geological as well as a geographical point of view. It is fossil in the Coralline Crag and the Sicilian Pliocene beds, and it now lives in the Japanese archipelago. Mr. Jeffreys suggests a mode of accounting for the community of so many species to the eastern borders of the Atlantic basin and the Mediterranean, in which several Japanese — brachi- opods and crustaceans are found, and the seas of CHAP. IV. ] THE CRUISES OF THE ‘ PORCUPINE, TSF Northern Asia, by supposing a migration through Fre, 36.—Chondrocladia virgata, Wyvitte THomsox. One-half the natural size, (No. 33, Pl. V.) the Arctic Sea. We must know, however, much 188 THE DEPTHS OF THE SEad. [cHAP. IV. more than we yet do of the extension both in time and space of the fauna of deep water before we can come to any certain conclusion on these questions. Dredging across the entrance of the Strait of Gib- raltar in 477, 651, and 554 fathoms, Stations 31, 32, and 33, with a bottom temperature of 10°38, 10°1, and 10°°0 respectively, many remarkable forms were dredged, including a very elegant sponge, apparently allied to, if not identical with, Oscar Schmidt’s, Caminus vulcani, and some beautiful forms of the Corallio-spongize, which will be noticed in a future chapter. Station No. 81 yielded a sponge form which recalled the branching heather-like Cladorhiza of the cold area off Froe. Chondrocladia virgata (Fig. 36) is a graceful branching organism from twenty to forty centimetres in height. A branching root of a cartilaginous consistence, formed of densely packed sheaves of needle-shaped spicules bound together by a structureless organic cement, attaches the sponge to some foreign body, and supports it in an upright position; and the same structure is continued as a solid axis into the main stem and the branches. The axis is made up of a set of very definite strands like the strands of a rope, arranged spirally, so as to present at first sight a strong resemblance to the whisp of JZyalonema ; but the strands are opaque, and break up under the point of a knife; and under the microscope they are found to consist of minute needle-like spicules closely felted together. The soft sponge substance spreads over the surface of the axis and rises into long curving conical processes, towards the end of which there is a dark greenish oval mass of granular sponge matter, and the outline of the CHAP. IV. | THE CRUISES OF THE ‘ PORCUPINE’ 189 cone is continued beyond this by a number of groups of needle-shaped spicules which surround a narrow oscular opening. All parts of the sponge are loaded with triple-toothed ‘bihamate’ spicules of the sarcode. On the 5th of August the ‘ Porcupine’ steamed into Tangier Bay, after ineffectually trying to dredge in 190 fathoms off Cape Spartel. In Tangier Bay two casts were taken at a depth of 35 fathoms. The fauna was chiefly British, with a few more southern forms. On the 6th of August Mr. Jeffreys went to Gib- raltar, and there yielded up the reins to Dr. Car- penter, going on to Sicily vd Malta, for the purpose of examining the newer tertiary formations in the south of Italy, and the collections of fossil shells at Catania, Messina, Palermo, and Naples, in connec- tion with the results of his cruise. On Monday, the 15th of August, Captain Calver, with Dr. Carpenter, who fortunately retained the services of Mr. Lindahl as assistant, in charge of the science department, steamed out into the middle of the Strait for the purpose of commencing a series of observations on the currents of the Strait of Gibraltar. These experiments, which at the time were not considered very satisfactory, were repeated and ex- tended in the summer of 1871 by Captain Nares, R.N., and Dr. Carpenter, in H.M.S. ‘Shearwater.’ Their curious results have been given in great detail by Dr. Carpenter in the Proceedings of the Royal Society of London, and by Captain Nares in a special report to the Admiralty. As it is my purpose to 190 THE DEPTHS OF THE SEA. [CHAP. IV. confine myself at present almost exclusively to the description of the phenomena of the deep water in the Atlantic so far as these have been worked out, I will not here repeat the narrative of the experiments in the Strait. I will, however, give a brief sketch of Dr. Carpenter’s cruise in the Mediterranean, as the remarkable phenomena connected with the distribu- tion of temperature and of animal life which he observed, illustrate while they contrast with the singularly different conditions which have been already described in the outer ocean. The first sounding in the basin of the Mediter- ranean was taken on the 16th of August, lat. 36° 0’ N., long. 4° 40’ W., at a depth of 586 fathoms, with a bottom of dark grey mud. The surface temperature was 23°6 C., and the bottom temperature 12°8 C., about three degrees higher than at the same depth in the ocean outside. A serial sounding was taken to determine the rate of the diminution of temperature, with the following curious result :— Surface 2 o/s < stubs Ce SERS oe een 1.0 ‘fathonts’.*. Se ee ee 20" 2. OO Se ea Ou | me Ai a « ola lage ok Irate en Tan teen £0 21 kaa e008 4 ie tei Be Lena 7 eae ee is a AUS Ras oe Ah SD 100..." 5; a ee! tn, fe kee 586 4 oe Tae be We nh ekd iteee SORE eae Thus the temperature fell rapidly for the first 30 fathoms, more slowly for the next 20, from 50 to 100 lost only 3° C., and before reaching the depth of a hundred fathoms had attained its minimum tempera- CHAP. Iv. | THE CRUISES OF THE ‘ PORCUPINE’ PON ture, there being no further diminution to the bottom. This serial sounding and all the subsequent tempera- ture observations taken during the Mediterranean cruise showed that the trough of the Mediterranean from the depth of 100 fathoms downwards is filled with a mass of water at almost exactly the same temperature throughout, a temperature a little above or below 12°75 C. The following instances have been cited by Dr. Carpenter from the earlier observations in the Medi- terranean basin, to show the great uniformity of the bottom temperature for all depths :— | Number | Depth Bottom Surface | | of | in | Tempera- | Tempera- | Position. | Station. | Fathoms. ture. ture. 41 730 | 13°°4C,| 23°° 6C.! Lat. 35°57 N. | Long. 4°12’ Ww. POMC Marne 29) ales ey 35 45 3 57 ABP MGS TS 4 938 I 85 4 Pu ee 44 45D PASO 2120 ao AD 20. ral) Os 0) Ae NDOT Oa 2D) -6G 35-36 10” 2 29 30’ 46 ome Pi aenOmemlieee Oe | Seer) 1 56 Ae Ne OLD Al L2E-6 | Ole Ouea) ot 209 30” 1 10, 30% At this last Station (No. 47) a serial sounding was taken, which entirely confirmed the results of the first (No. 40) :— SUM ACC ee Sim ee pt enst rot Ate, AD Oey ROP ROMS ie. Pa Ue Re a eS PD PAU ME toe Aes ome Lo A ce) eee ge ame (ae 0) ae Fgh: Dieie Sed ess ee ese ee SS 40. ;, SP ei pA Ae ce ae a eB a DO ene Ee Ne ye es > soe oe | RO ae ee ge ee eo at os Be $45 1 2o2'6 99 192 THE DEPTHS OF THE SE4. [CHAP. IV. —again a mass of water lying at the bottom, 745 fathoms—not far from a mile—in depth, at the uniform temperature of 12°6C. (54°7 F.) The dredge was sent down at each successive station, but with very poor result; and Dr. Car- penter was driven to the conclusion that the bottom of the Mediterranean at depths beyond a few hundred fathoms is nearly azoic. The conditions are not actually inconsistent with the existence of animal life, for at most of the stations some few living forms were met with, but they are certainly singularly un- favourable. Thus at Station 49, at a depth of 1412 fathoms, and a temperature of 12°:7 C., the following species of mollusea were obtained : Nucula quadrata, n.sp.; V. pumila, ABSJORNSEN ; Leda, n. sp.; Verti- cordia granulata, SEG.; Hela tenella, JEFFREYS ; Trochus gemmulatus, Pu.; Rissoa subsoluta, ARADAS ; Natica affinis, GMELIN; Trophon multilamellosus, Pu.; Nassa prismatica, Br.; Columbella halieti, JEFF.; Buccinium acuticostatum, Pu.; Pleurotoma carinatum, CRriIstoFoRI and Jan; P. torquatum, Pu.; P. decussatum, PH. Near the African coast the fauna was more abun- dant, but the bottom was so rough that it was unsafe to use the dredge, and the tangles were usually sent down alone. Many polyzoa, echinoderms, corals, and sponges were taken in this way, but they were mostly well-known Mediterranean species. After remaining for a few days at Tunis and visiting the ruins of Carthage, dredging was resumed on the 6th of September on the ‘ Adventure’ Bank, so called from its having been discovered by Admiral Smyth when surveying in H.M.S. ‘Adventure.’ Here, at depths CHAP. IV. ] THE. CRUISES OF THE ‘ PORCUPINE’ 198 from 30 to 250 fathoms, animal life was tolerably abundant. With other mollusca the following were found: —Trochus suturalis, Pu. (Sicilian fossil) ; Xenophora crispa, Konte (Sic. fossil); Cylichna striatula, ForBeEs (Sic. fossil); C. ovulata, Broccut (Sic. fossil); Gadinia excentrica, TIBERL; Scalaria Jrondosa, J. SowERBY (Sicilian and Coralline Crag fossil); Pyramidella plicosa, BRONN (Sic. and Cor. Crag fossil); Acteon pusillus, FoRBES (Sic. fossil). The Echinodermata were abundant so far as indi- viduals went, but the number of species was small, and they were nearly all well-known Mediter- ranean forms. Cidaris papillata, LESKE, showing many varieties, but differing in no specific character from the many forms of the same species which range from North Cape to Cape Spartel in the ocean outside. The Mediterranean varieties of this species are certainly Cidaris hystrix, of Lamarck. I feel a degree of uncertainty about the pretty little Cidaris, described by Philippi under the name of C. affinis. Characteristic examples of it, which are abundant on the ‘Adventure’ Bank and along the African coast, look very distinct. They are of a beautiful deep rose red, the spines are banded with red and brownish-yellow, and come to a fine point, while those of C. papillata are usually blunt at the point, and frequently even a little expanded or cupped;. and the portion of the interambu- lacral plates covered with miliary granules is wider, and two defined rows. of body spines nearly of equal size lie up against the bases of the primary spines, over the alveole. These would appear to be cha- racters of specific value, but then again there are O 194 THE DEPTHS OF THE SEA. [CHAP. Iv. a mass of intermediate forms; and although after careful consideration I have described the two species as distinct, I find it a matter of great diffi- ‘culty to draw the line between them. Several specimens of a handsome Astrogonium allied to A. granulare were taken on the ‘ Adventure’ Bank. Professor Duncan reports some interesting corals, and Professor Allman two new species of Aglaophenia; and Dr. Carpenter detected once more the delicate Orbitolites tenuissimus, and the large nautiloid ZLituola, with which he was familiar in the dredgings in the Atlantic. After a short stay at Malta, on September 20th the ‘Porcupine’ steamed out of Valetta Harbour, and steered in a north-easterly direction, towards a point seventy miles distant, at which a depth of 1700 fathoms was marked on the chart. This was reached early the next morning, and the line ran out 1743 fathoms, lat. 836° 31’ 30” N., long. 15° 46’ 30" (No. 60), with a temperature of 13°4C., more than half a degree higher than the temperature of the deepest sounding in the western basin. The tube of the sounding apparatus brought up a sample of yellow clay, so like the bottom at some of the most unpro- ductive spots in the western Mediterranean, that it was not considered advisable to delay the time necessary for even a single cast of the dredge, which at that depth would have occupied nearly a day. Having thus satisfied themselves as far as_ they could by «a few observations that the physical con- ditions of the eastern basin of the Mediterranean were similar to those of the western, they steered for the coast of Sicily. Quietly along the Sicilian coast CHAP. IV.] THE CRUISES OF THE ‘ PORCUPINE’ 195 during the night, in early morning through the narrowest part of the Strait between Messina and Reggio, past Charybdis and the castled rock of Scylla, and so out of the ‘Faro’ into the open sea to the north of Sicily, studded with the Lipari Islands. A temperature sounding taken near Stromboli, lat. 38° 26’ 30" N., long. 15°32’ E., gave a depth of 730 fathoms, and a bottom temperature of 18°1 C., while the temperature of the surface was 22°°5 C. Under the rugged cone of Stromboli the dredgers took another set of temperatures, with the result com- mon to the whole volcanic neighbourhood of Sicily, of a temperature slightly higher than that of the deep water in the western basin of the Mediterranean, a phenomenon of which it would take long and careful observation to determine the cause ; and while doing so they pondered on the cloud of smoke hanging over the peak, so suggestive of the theatre of subterranean change beneath, and admired the industry and enter- prise of those who, rendered contemptuous by the familiarity of ages, carried their vineyards “all over the cone, save on two sides, looking north-west and south-east, over one or other of which there is a con- tinual discharge of dust and ashes.” Their course was now laid straight for Cape de Gat, which they passed on the 27th of September, arriving at Gibraltar on the 28th. At Gibraltar, Dr. Carpenter resumed his observations and experi- ments on the currents of the Strait. These obser- vations were continued until the 2nd of October, when it became necessary for Captain Calver to re- turn homewards. The coast of Portugal was repassed in fine weather, the time at their disposal not allow- 02 196 THE DEPTHS OF THE SEA. [cHAP. Iv. ing any further use of the dredge in the deep water, and after encountering a fresh breeze in the chops of the Channel, on the evening of October the 8th, the ‘ Porcupine’ anchored at Cowes. LILLE DIMON, CHAP. Iv. ] THE CRUISES OF THE ‘PORCUPINE’. LF APPENDIX A. Extracts from the Minutes of Council of the Royal Society, and other Official Documents referring to the Cruise of HMLS. ‘ Porcupine’ during the Summer of 1870 :— March 24, 1870. A Letter was read from Dr. Carpenter, addressed to the President, suggesting that an Exploration of the Deep Sea, such as was carried out during 1868 and 1869 in the regions to the North of the British Islands, should now be extended to the South of Europe and the Mediterranean, and that the Council of the Royal Society should recommend such an undertaking to the favourable consideration of the Admiralty, with a view to obtain the assistance of Her Majesty’s Government as on the previous occasions. Resolved,—That a Committee, consisting of the President and Officers, with the Hydrographer, Mr. Gwyn Jeffreys, Mr. Siemens, Professor Tyndall, and Dr. Carpenter, with power to add to their number, be appointed, to consider the expediency of adopting the proposal of Dr. Carpenter, and the plan to be followed in carrying it out, as well as the instruments and other appliances that would be required, and to report their opinion thereon to the Council; but with power previously to communicate to the Admiralty a draft of such report as they may agree upon, if it shall appear to them expedient to do so in order to save time. April 28, 1870. Read the following Report :— “The Committee appointed on the 24th of March to consider a proposal for a further Exploration of the Deep Sea during the 198 THE DEPTHS OF THE SEA. [cHAP, tv. ensuing summer, as well as the scientific preparations which would be required for a new expedition, beg leave to report as follows :— “The general course proposed to be followed, and the chief objects expected to be attained in a new expedition, are pointed out in the following extract from the letter of Dr. Carpenter, read to the Council on the 24th ult., which was referred to the Committee :— “) bo THE DEPTHS OF THE SEA. [CHAP. IV. APPENDIX B. Particulars of Depths, Temperature, and Position at the various Dredging-stations of H.M.S. ‘ Porcupine, in the Summer of 1870 :— | oft Sah: Peniomne, | reg gee Position. 1 567 — — 48°38’ N.| 10°15’ W. 2 B05 bA°> 8G. +> 16°: 256. | AB eaT LQ 9 =] 690 — — 48 31 10-3 + La, C99 opr 48 32 Sa, 5 100 10> 7 16°8 48 29 9 45 6 308 LOO 1243 48 26 9 44 7 93 LO. 16 L6°> 2 48 18 DLs 8 257 99 L529 48 15 + eB 9 539 org 17“ 8 48 6 9 18 10 81 +9 16°4 2 44 9 23 11 332 10.2 1674 42 32 9 24 12 128 11° 3 L6.* 3 42 20 ae 13 220 11> 0 i ieee | 40 16 9 37 14 469 10°8 18:4 40 6 9 44 15 722 9°38 20°0 40 2 9 49 16 994 4°5 21°0 39 55 9 56 LZ 1095 4°3 19°35 39 42 9 43 18 1065 4°5 18-2 39 29 9 44 19 248 BG) 15 <2 39 27 9 39 20 965 | — — go 0 9 45 21 620 1 410."'2 19% 3 55 19 9 30 22 TA a ok 17 1p? 38 15 9 35 23 S024 "9% 0 19 ge? 4 eisT 20 9 30 24 Be Wek? Woe) kD 36 WS) 9 13 60 1743-) CHAP. 1V.] THE CRUISES OF THE ‘ PORCUPINE’ 203 lof Station. ee eee oe | 1G)s nati OBN 1 (ST4: 1d: 9°. 20°96 37° 117 N. OF 7? W. 26 | 364 | 11°5 22. 36 44 Si. 8 2 | oe LOGE DO BO or Hetoo 28 | 504 A ea Pid lea 36°29 7 6 28a | 286 | — — 36 27 6 54 BQ sy 227 19 DOES: 36 20 6 47 30 386 dla ere 226 36. Lo 6 52 alt ATT OPS Di icch'f aoLoOe a aa 32 651 Oval Wiles 35 41 eo ao HbA hor 26 WO As Bon Oo 6 54 34 414 Gi k DS 35 44 Goo 30 33) 10°9 D3 32, ig) Gs, 6 38 36 128 ae9 23r 8 35) 30 6 26 37 LOO? | i era) Da, GAY Sa) 10) 6x0 38 503 1 eas: 22° 0 Say tie: 5 26 oe 517 dE rs) 71.0 20-09 mall 40 586 13-4 23-20 367 0 4 40 Al 730 13) 24 Daan 6) SDM 4 12 42 790 ie a4 Da 2 35 40 SOO 3 62 [3.74 DRS EO To, 35 24 3 54 44 455 13) “0 Diese 35 42 Sa) Abe > 201 12:4 DAS a0. OU 229 46 493 ies) 0) Zora) 3D 209 1-56 AT 845 Woe) Aten |) SM aes) dee Re) 48 1328 dpe) 230° .0) ote 20 Opal 49 1412 1 ey 22; °.0 36 29 0 3l 50 aa — — 36 14 017E 50a iiby — — 36 18 0 24 th 1415 Da, 24 °0 36 55D 0 52 660 — — 36 38 1 38 52a 590 — — 30F 30 I.-3 De £12 13.20 PAF eae) 36) DS Pee) 54 1508 Lieven) 24-4 37 Al 6 27 55 | 1456 12° <-8 DLO) af mee) Grok 56 390 3-6 Dy 3G ors 3 1 Bye rea 224 | = —- Die 13 10 Pe iecile D6 Gre lee.6 Dak 36 43 13-36 5G 44b es 6 2A G 36 32 14°12 an 4 Dey coo 3G) om 15 46 204 THE DEPTHS OF THE SEA. [CHAP. Iv. Surface Temperature. Depth in Bottom Fathoms. | Temperature. Number of Station. Position. 61 392 13° deCS Q2B- C5) See 26 IN. fe oe 62 730 i3°"0 22° 5 38 38 15 21 63 181 12°4 20-2 ae 5 26 W 64 460 12-4 18°8 3D 58 5 28 65 198 £2 #1 DY fae 35 50 5 57 66 147 = = 35 56 seni 67 188 12.8 22°9 35 49 62t CHAPTER V. DEEP-SEA SOUNDING. The ordinary Sounding-lead for moderate Depths. — Liable to Error when employed in Deep Water. — Early Deep Soundings un- reliable.—Improved Methods of Sounding.—The Cup-lead.— Brooke’s Sounding Instrument.—The ‘ Bull-dog’ ; Fitzgerald’s ; the ‘Hydra.’—Sounding from the ‘ Porcupine.—The Contour of the Bed of the North Atlantic. In all deep-sea investigations it is of course of the first importance to have a means of determining the depth to the last degree of accuracy, and this is not so easy a matter as might be at first supposed. Depth is almost invariably ascertained by some modification of the process of sounding. A weight is attached to the end of a line graduated by attached slips of different coloured buntine (the woollen mate- rial of which flags are made, in which the colours are particularly bright and fast) into fathoms, tens of fathoms, and hundreds of fathoms; or, for deep-sea work, with white buntine at every 50, black leather at every 100, and red buntine at every 1,000 fathoms. The weight is run down as rapidly as possible, and the number of fathoms out when the lead touches the bottom gives a more or less close approximation to the depth. 206 THE DEPTHS OF THE SEA. [CHAP. V. The ordinary deep-sea lead is a prismatic leaden block about two feet in length and 80 to 120 Ibs. in weight, narrowing somewhat towards the upper end, where it is furnished with a stout iron ring. Before heaving, the lead is ‘ armed,’ that is to say the lower end, which is slightly cupped, is covered with a thick coating of soft tallow. If the lead reach the bottom it brings up evidence of its having done so in a sample sticking to the tallow. Usually there is enough to indicate roughly the nature of the ground, and it is on the evidence of samples thus brought up on the ‘arming’ of the lead that our charts note ‘mud,’ ‘shells,’ ‘gravel,’ ‘ooze,’ or ‘sand,’ or a com- bination of these, as the kind of bottom at the particular sounding ; thus we have ,,?s",, mud, shells, and sand at 2,000 fathoms; 2°), ooze and stones at 2,050 fathoms; ,, 22°.., mud, sand, shells, and scoriz at 2,200 fathoms, and so on. When no bottom is found, that is to say, when there is no arrest to the running out of the line and nothing on the ‘arming’ of the lead, the sounding is entered on the chart thus, sap WO bottom at 3,200 fathoms. Such soundings are not to be depended upon in deep water, but they are usually quite reliable for moderate depths, so far as they go. They give us no help in the exploration of the bottom of the sea, but they are of great practical value, and indeed they give all the information which is directly required for the purposes of navigation ; for if there be ‘no bottom’ at 200 fathoms, there is probably no dangerous shoal in the immediate neighbourhood. Soundings are usually taken from the vessel, and while there is some way on. Where great accuracy CHAP. V. | DEEP-SEA SOUNDING. 207 is required, as in coast-surveying, it is necessary to sound from a boat, which can be kept in position by the oars and reference to some fixed objects on shore. This ordinary system of sounding answers perfectly well for comparatively shallow water, but it breaks down for depths much over 1,000 fathoms. The weight is not sufficient to carry the line rapidly and vertically to the bottom; and if a heavier weight be used, ordinary sounding line is unable to draw up its own weight along with that of the lead from great depths, and gives way. No impulse is felt when the lead reaches the bottom, and the line goes on running out, and if any attempt be made to stop it it breaks. In some cases bights of the line seem to be carried along by submarine currents, and in others it is found that the line has been running out by its own weight only, and coiling itself in a tangled mass directly over the lead. All these sources of error vitiate very deep soundings. In many of the older observations made by officers of our own navy and of that of the United States, the depth returned for many points.in the Atlantic we now know to have been greatly exaggerated; thus Lieutenant Walsh, of the U.S. schooner ‘Taney,’ reported a cast with the deep-sea lead at 34,000 feet without bottom ;' Lieutenant Berryman, of the U.S. brig ‘Dolphin,’ attempted unsuccessfully to sound mid- ocean with a line 39,000 feet long; Captain Denham, of H.M.S. ‘ Herald,’ reported bottom in the 1 Maury’s Sailing Directions, 5th edition, p. 165, and 6th edition (1854), p. 213. * Maury, Physical Geography of the Sea. Eleventh edition, p- 309. 208 TUE DEPTHS OF THE SEA. [CHAP. V. South Atlantic at a depth of 46,000 feet;' and Lieutenant Parker, of the U.S. frigate ‘ Congress,’ ran out a line 50,000 feet without reaching the bottom.’ In these cases, however, the chances of error were too numerous; and in the last chart of the North Atlantic, published on the authority of Rear-Admiral Richards in Noy. 1870, no soundings are entered beyond 4,000 fathoms, and very few beyond 3,000. A great improvement in deep-sea sounding, first introduced in the United States navy, was the use of a heavy weight and a fine line. The weight, a 32 or 68 lb. shot, is rapidly run down from a boat ; and when it is supposed to have reached the bottom, which is usually indicated with tolerable certainty by a sudden change in the rate of running out of the line, the line is cut at the surface, and the depth calculated by the length of line left on the reel. As the great problems of physical geography, the strength and direction of currents, and the general conditions of the bottom of the sea began to acquire more general interest, the particles brought up on the ‘arming’ of the lead from great depths were eagerly sought for and scrutinized; it thus became important that a greater quantity should be procured, enough at all events for the purposes of chemical and micro- scopical examination. Many instruments have been contrived from time to time for this purpose, and a vast amount of information has been gained by their use. It has now been shown that dredging on a large scale is possible at all depths, but dredging can only be performed under specially favourable cireum- stances, and requires a vessel specially fitted at con- 1 Loe. cit. 2 Loe. cit. CHAP. V. | DEEP-SEA SOUNDING. 209 siderable expense. We must still, therefore, depend mainly upon some form of sounding apparatus for the gradual accumulation of observations which will give us in time a consistent idea of the nature of the bottom of the sea throughout. S=> ———— So [ Yr Fie. 41.—The ‘ Fitzgerald’ Sounding Machine. FB THE DEPTHS OF THE SEA. [cHAP, V. apparatus is so adjusted, that when the weight is attached and the instru- ment hanging ready for use, as repre- sented in the figure, the rod F main- tains a horizontal position. When the instrument strikes the ground, the tension on the bar F is relieved, the weight draws the rod p off the claw i and slips off, at the same time filling | the scoop. When hauling up, all the ihc instrument falls into a nearly vertical | line, and the scoop comes up full in : the middle, the weight of pb keeping its mouth closed up against its lid. The apparatus used during the cruise of the ‘ Porcupine,” where sounding was carried on to the utmost attainable accuracy and at great depths, was a somewhat elaborate modification of Brooke’s sounding machine which had been previously employed by Captain Shortland in the voyage of H.M.S. ‘ Hydra,’ sound- ing across the Arabian Gulf prepara- tory to laying the Indian Cable. This special modification, which cer- tainly answered remarkably well, ap- pears to have been due entirely to Mr. Gibbs, the blacksmith on board the vessel! We christened it the ' Sounding Voyage of H.M.S. ‘ Hydra,’ Captain P. F. Shortland, 1868. Published by order of the Fig. 42.—The ‘Hydra’ Tords Commiss. of the Admiralty. London : 1869. Sounding Machine : cHaP. v. | DEEP-SEA SOUNDING. 219 ‘Hydra,’ in recognition of its inventor and of the vessel in which it was first used. The axis of the ‘ Hydra’ (Fig. 42) is a strong brass tube, which unscrews into four chambers. ‘The three lowest of these are closed above by conical valves opening upwards, but not fitting absolutely tightly, so as to allow a little water to pass, and the lowest chamber B is closed by a butterfly valve also open- ing upwards. The upper (fourth) chamber A contains a piston, and the piston-rod ¢ 1s continued upwards nto a rod which ends in the ring to which the sounding-line 1s attached. The upper chamber in which the piston works has a large hole on either side about the middle of its length, and a smail hole passes through the piston itself. Projecting from the upper part of the rod there is a notched tooth p, and over the tooth passes an arched steel spring, with a slit which allows the tooth to pass through its centre, and its two ends fastened moveably to the rod. When the spring 1s forcibly pushed back, it allows the tooth with its notch to protrude through the central slit. The weight consists of three or four cylinders of iron F, toothed and notched so as to fit into one another and make one mass. The weight used in the ‘Poreupine’ was from two to three hundredweight, according to the depth. The weight is suspended by an iron wire sling which passes over the notched tooth, the spring having been pressed pack. The weight is amply sufficient to retain the spring in that position. The figure represents the instrument prepared to let eo, the whole weight suspended from the ring at the top of the piston-rod, which is thus fully drawn out 220 THE DEPTHS OF THE SEA. (CHAP. V. of its cylinder. As the instrument runs down the water passes freely through the tube and valves, and pours out by the holes in the wall of the cylinder. When it touches the ground the piston is pulled down by the weight, but its progress is somewhat arrested by the water in the lower part of the cylinder, which can only escape slowly, thus giving the weight time to force the terminal chamber with the butterfly valves into the ground. The weights then rest upon the bottom and relieve the spring which throws the sling off the tooth. The tube comes up free with all the valves closed, and the last chamber filled with the substance of the bottom, and the other chamber with bottom water. In the skilful hands of Captain Calver the ‘ Hydra’ never once failed, and from the great weight used it is admirably suited for accurate soundings in deep water; but it is somewhat complicated, and it brings up very small samples of the bottom. In the case of the cruise of the ‘ Porcupine,’ where the large dredge was sent down at almost every sounding-station, this was of little consequence; but where dredging is im- practicable, and all information as to the condition of the bottom must be got from soundings, some simple adaptation of the ‘ Bull-dog’ scoops or the Fitzgerald apparatus would certainly have a great advantage. During the cruise of the ‘ Poreupine’ in 1869 soundings were taken with the utmost care at ninety stations, and in 1870 at sixty-seven stations, and on every occasion the operation was conducted by Capt. Calver himself, whose great experience on the sur- veying service was in itself a guarantee of the greatest possible accuracy. Captain Calver told me that on CHAP, V.] DEEP-SHEA SOUNDING. 991 every occasion, even at the greatest depths, he felt distinctly the shock of the arrest of the weight upon the bottom communicated to his hand. the dred. accululator ’ the * showing the mode of stowing the rope. ? ’ orcupine tern Derrick of the ‘P The § 1G. 46. Yr CHAP. VI.] DEEP-SEA DREDGING. QAY ewts. an approximation at all events to the strain on the rope. A second derrick, nearly equally strong, was rigged over the stern, and we dredged sometimes from one and sometimes from the other. The stern derrick was, however, principally used for sounding; the letting- go board, &c., being fitted up in connection with it. We had an excellent arrangement for stowing the dredge-rope in the ‘Porcupine; an arrangement which made its manipulation singularly easy, not- withstanding its great weight—about 5,500 lbs. A row of about twenty great iron pins, about two and a half feet in length, projected over one side of the quarter- deck, rising obliquely from the top of the bulwark. Each of these held a coil of from two to three hun- dred fathoms, and the rope was coiled continnously along the whole row (Fig. 46). When the dredge was going down, the rope was taken rapidly by the men from these pins—‘ Aunt Sallies’ we called them, from their ending over the deck in smooth white balls—in succession, beginning with the one nearest the dredging derrick; and in hauling up, a relay of men carried the rope along from the surging drum of the donkey-engine and laid it in coils on the pins in inverse order. Thus, in letting go, the rope passed to the block of the derrick directly from the ‘Aunt Sallies;’ in hauling up, it passed from the block to the surging drum of the donkey-engine, from which it was taken by the men and coiled on the ‘ Aunt Sallies.’ The length of the dredge-rope was 3,000 fathoms, nearly three and a half statute miles. Of this, 2,000 fathoms were ‘hawser-laid,’ of the best Russian 250 THE DEPTHS OF THE SEA. [cHAp. VL. hemp, 25 inches in circumference, with a breaking strain of 21 tons. The 1,000 fathoms next the dredge were ‘ hawser-laid,’ 2 inches in circumference. A Russian hemp rope appears to be the most suit- able. A manilla rope is considerably stronger for a steady pull, but the fibre is more brittle and liable to goat a ‘kink.’ I have never seen a wire-rope used, but I should think it would be liable to the same objection. The ‘Challenger’ is to be supplied with ‘whale-line’ for her great expedition. ‘The frame of one of the dredges which we used in the Bay of Biscay is represented at Figs. 47 and 48. The length of <----3°---> Fic. 47.—The End of the Predge frame. the dredge-frame is 4 ft. 6 in., and it is 6 Inches wide at the throat or narrowest part. The dredge used in the deepest haul was somewhat different. About half of each arm next the eye to which the rope was attached, was of heavy chain. I doubt greatly, how- ever, if this is an advantage. ‘The chain drags along in front of the dredge, and may possibly obstruct the entrance of objects and injure them more than a pair of rigid arms would do. On one side the chain was attached to the arm of the dredge by a stop of five turns of spun-yarn, so that in case of the dredge CHAP. V1.] DELP-SEA DREDGING. 251 becoming entangled or wedged among rocks or stones, a strain less than sufficient to break the dredge rope would break the stop, alter the position of the dredge, and probably enable it to free itself ; n nS) 4 of i i f i CE GCCECEC COCCI Ga ATH a | \\ | \ Fic. 48 —Dredge-frame showing the mode of attachment of the Bag. a. Spunyarn Stoy and in case of its taking in a greater load of mud than the rope could bring up, the stop would like- wise give way and allow the dredge to fall into such a position that a large e part of its contents would slip 252, TUL DEPTHS OF THE SEA. [cHapP. VI. out. The weight of the frame of this dredge, the largest we ever used, was 225 lbs.; it was forged by Messrs. Harland and Wolff of Belfast of the best Jioowmoor iron, ‘The dredge-bag was double—the outer of strong twine netting, the inner of bread- bag. Three sinkers—one of 1 ewt., the other two of 56 lbs. each—were attached to the dredge-rope at 500 fathoms from the dredge. The operation of sounding at a depth of 2,435 fathoms in the Bay of Biscay on the 22nd of July, 1869, has already been described in detail. When the depth had been accurately ascertained, about 4.45 Pm. the dredge was let go, the vessel drift- ing slowly before a moderate breeze (force=4) from the N.W. The 3,000 fathoms of rope were all out at 5.50 pM. The diagram (Fig. 50) will give an idea of the various relative positions of the dredge and the vessel according to the plan of dredging adopted by Captain Calver, which Fie. 49—The End of the WOrked admirably, and which ap- Dredge-frame, showing : > the mode otatachment PATS, In fact, to be the only mode ‘ which would answer for great depths. A represents the position of the vessel when the dredge is let go, and the dotted line a B the line of descent of the dredge, rendered oblique by the ten- sion of the rope. While the dredge is going down the vessel drifts gradually to leeward; and when the whole (say) 3,000 fathoms of rope are out, c, w, CHAP. VI.] DEEP-SEA DREDGING. 253 and D might represent respectively the relative posi- , i il mis iii ital Hi tnd in mt phiweht. Panag Tr ii Minin NHN i \ nm - | vj TTTVGWUTTONITTVENITTITT WAU © ) Fic. 50.—Diagram of the relative position of the Vessel, the Weights, and the Dredge, in dredging in deep water. tions of the vessel, the weight attached 500 fathoms 254 THE DEPTHS OF THE SEA. [cHAP, VI. from the dredge, and the dredge itself. The vessel now steams slowly to windward, occupying successively the positions E, F, G, and u. The weight, to which the water offers but little resistance, sinks from w to w’, and the dredge and bag more slowly from p to B. The vessel is now allowed to drift back before the wind from u towards c. The tension of the motion of the vessel, instead of acting immedi- ately on the dredge, now drags forward the weight w, so that the dredging is carried on from the weight and not directly from the vessel. The dredge is thus quietly pulled along with its lip scraping the bottom in the attitude which it assumes from the centre of weight of its iron frame and arms. If, on the other hand, the weights were hung close to the dredge, and the dredge were dragged directly from the vessel, owing to the great weight and spring of the rope the arms would be continually lifted up and the lip of the dredge pre- vented from scraping. In very deep dredging this operation of steaming up to windward until the dredge-rope is nearly perpendicular, after drifting for half an hour or so to leeward, is usually repeated three or four times. At 8.50 p.m. we began to haul in, and the ‘ Aunt Sallies’ to fill again. The donkey-engine delivered the rope at the rate of rather more than a foot per second, without a single check. A few minutes before 1 A.m. the weights appeared, and a little after one in the morning, eight hours after it was cast over, the dredge was safely hauled on deck, having in the interval accomplished a journey of upwards of eight statute miles. The dredge contained 1} ewt. cHAP. vi. } DERP-SEA DREDGING. 955 of very characteristic pale grey Atlantic ooze. The total weight brought up by the engine was— 27,000:fathoms, 25-inch rope. . . .. . . 4,000/bs. HOOOhathomse,.2-inch rope. . % “s «2 .°. 2,500" ,, 5,500 Ibs. Weight of rope reduced to one-fourth in water = 1,375 lbs. Dredecvamusbaos ees Wa A oe tae het ha WADE Osze,broughtvips, 2 sens rez secs oe Ss lGS*., Wetghitrattacheds 9.0 25 <2) ef sh a 224 ,, 2,042 lbs. Much more experience will yet be necessary before we can assure ourselves that we have devised the dredge of the best form and weight for work in the deep sea. I rather think that the dredges, 150 to 225 lbs., which we have been in the habit of using, are too heavy. In many instances we have had evidence that the dredge, instead of falling gently upon the surface and then gliding along and gather- ing the loose things in its path, has fallen upon its mouth and dug into the tenacious mud, thereby clogging itself, so as to admit but little more. I mean to try the experiment of heavier weights and lighter dredge-frames in the ‘Challenger,’ and [ believe it will be an improvement. In many of our dredgings at all depths we found that, while few objects of interest were brought up within the dredge, many echinoderms, corals, and sponges came to the surface sticking to the outside of the dredge-bag, and even to, the first few fathoms of the dredge-rope. This suggested many expedients, and finally 256 THE DEPTHS OF THE SEd. [cHap. vr. Captain Calver sent down half-a-dozen of the ‘swabs’ used for washing the decks attached to the dredge. The result was marvellous. The tangled hemp brought up everything rough and moveable which came in its way, and swept the bottom as it might have swept the deck. Captain Calver’s invention ini- tiated a new era in deep-sea dredging. After various experiments we came to the conclusion that the best plan was to attach a long iron transverse bar to the bottom of the dredge-bag, and to fasten large bunches of teazed-out hemp to the free ends of the bar (Fig. 51). We now regard the ‘ hempen tangles’ as an essential adjunct to the dredge nearly as important as the dredge itself, and usually much more conspicuous in its results. Sometimes, when the ground is too rough for ordinary dredging, we use the tangles alone. There is some danger, how- ever, in their use. The dredge employed under the most favourable circumstances may be supposed or hoped to pass over the surface of the floor of the sea for a certain distance, picking up the objects in its path which are perfectly free, and small enough to enter the dredge mouth. If they chance to be attached in any way, the dredge rides over them. If they exceed in the least the width of the dredge- opening, at the particular angle at which the dredge may present itself at the moment, they are shoved aside and lost. The Mollusca have by far the best chance of being fully represented in investigations carried on by the dredge alone. ‘Their shells are comparatively small solid bodies mixed with the stones on the bottom, and they enter the dredge along with these. Echino- CHAP, VI.] DEEP-SEA DREDGING. DAW derms, corals, and sponges, on the contrary, are bulky objects, and are frequently partially buried in the TV Fre. 5i.—Dredge with ‘hempen tangles ° mud or more or less firmly attached, so that the dredge generally misses them. With the tangles it S 258 THE DEPTHS OF THE SEA. [cItaP. VI. is the reverse. ‘The smooth heavy shells are rarely brought up, while frequently the tangles loaded with the spiny spheres of Cidaris, great white-bearded Holtenia, glistening coils of Hyalonema, relieved by the crimson stars of Astropecten and Brisinga, pre- sent as remarkable an appearance as can well be imagined. On one occasion, to which I have already referred, [ am sure not fewer than 20,000 examples of Hehinus norvegicus came up on the tangles at one haul. They were warped through and through the hempen fibres, and actually filled the tangles so that we could not get them out, and they hung for days round the bulwarks like nets of pickling onions in a greengrocer’s shop. The use of the tangles, which seem so singularly well adapted to their capture, gives therefore a totally unfair advan- tage to the radiate groups and the sponges, and this must always be taken into account in estimating their proportion in the fauna of a particular area. The tangles certainly make a sad mess of the specimens; and the first feeling is one of woe, as we undertake the almost hopeless task of clipping out with a pair of short nail-scissors the mangled remains of sea-pens, the legs of rare crabs, and the dismembered disks and separated arms of delicate crinoids and ophiurids. We must console ourselves with the comparatively few things which come up entire, sticking to the outer fibres; and with the re- flection that had we not used this somewhat ruthless means of capture the mutilated specimens would have remained unknown to us at the bottom of the sea. ‘The dredge comes up variously freighted according to the locality. Usually, if dexterously managed, CHAP. VI. ] DEEP-SEA DREDGING, 2.59 the bag is about half full. Tf, from a great depth, beyond the reach of currents, where there is only so slow a movement of the mass of water that the finest sediment is not carried away, it contains usually fine caleareous or aluminous mud alone, with the animals forming the fauna of the locality distributed through it. In shallower water we may have sand or gravel, or stones of various sizes mixed with mud and sand. The next step is to examine the contents of the dredge carefully, and to store the objects of search for future use. The dredge is hauled on deck, and there are two ways of emptying it. We may either turn it up and pour out its contents by the mouth, or we may have a contrivance by which the bottom of the bag may be made to unlace. The first plan is the simplest and the one most usually adopted. The second has the advantage of letting the mass out more smoothly and easily, but the lacing introduces rather a damaging complication, as it is apt to loosen or give way. In a regularly organized dredg- ing expedition, a frame is often arranged with a ledge round it to receive the contents of the dredge, but it does very well to capsize it on an old piece of tarpauling. Any objects visible on the surface of the heap are now carefully removed and placed for identification in jars or tubs of sea-water, of which there should be a number standing ready. The heap should not be much disturbed, for the delicate objects contained in it have already been unavoid- ably subjected to a good deal of rough usage, and the less friction among the stones the better. Close to the place where the dredge is emptied si2 260 THE DEPTHS OF THE SBA. [cuar. vr. there ought to be one or two tubs about two feet in diameter and twenty inches deep, and each tub should be provided with a set of sieves so arranged that the lowest sieve fits freely within the bottom of the tub, and the three succeeding sieves fit freely within one another (Fig. 52). Each sieve is pro- vided with a pair of iron handles through which the hand can pass easily, and the handles of the largest sieve are made long, so that the whole nest = 39 ean be lifted without stooping and putting the arms Fic. 52.—Set of Dredging Sieves. into the water. The upper smallest sieve is usually deeper than the others; it is made of a strong open net of brass wire, the meshes a half inch to a side. The second sieve is a good deal finer, the meshes a quarter inch to a side. The third is finer still, and the fourth so close as only to allow the passage of mud or fine sand. The sieves are put into the tub, and the tub filled up to the middle of the top sieve with sea-water. The top sieve is then half filled with the contents of the dredge, and the set of sieves are gently moved up and down in the CHAP. VI.] DEEP-SEA DREDGING. DR II water. It is of great importance not to give any rotatory motion to the sieves in this part of the process, for such is very ruinous to fragile organisms. The sieves should be gently churned up and down, whether singly or together. The result, of course, 1s that the rougher stones and gravel and the larger organisms are washed and retained in the upper sieve. The fine mud or sand passes through the whole of the sieves and subsides into the bottom of the tub, while the three remaining sieves contain, in eraduated series, the objects of intermediate size. ‘The sieves are examined carefully in succession, and the organisms which they contain gently removed with a pair of brass or bone forceps into the jars of sea-water, or placed at once in bottles of weak spirit of wine. The scientific value of a dredging operation de- pends mainly upon two things,—the care with which the objects procured are preserved and labelled for future identification and reference, and the accuracy with which all the circumstances of the dredging, position, depth, nature of ground, bottom tempera- ture, date, &c., are recorded. With regard to the preservation of the animals, I cannot here go into detail. There are many ways of preserving, special to the different invertebrate groups ; and ‘ taxidermy ’ is in itself a complicated art. I will merely men- tion one or two general points. A specimen in almost every group is of infinitely greater scientific value if it be preserved entire with its soft parts. For this purpose the most usual plan is to place it at once in spirit of wine diluted to about proof. Care must be taken not to put too many specimens 262 THE DEPTHS OF THE SEA. (CHAP. VI. together in one jar, or they will very shortly become discoloured; and the jars ought to be looked to care- fully and the spirit tested, and if necessary renewed after they have been set aside for a day or two, as sea animals contain a large quantity of water. In hot weather, and if the specimens be bulky, it is often better to use strong spirit. The ordinary methylated spirit of commerce answers sufficiently well for ordinary purposes, though if a specimen be reserved for minute dissection, I prefer using pure, or even absolute alcohol. “For very delicate transparent objects,—such as salpx, siphonophora, polycystina, &c.,—Goadby’s solution seems to be preferable: but do what we may, a preserved specimen of one of these lovely objects is a mere caput mortuum, a melancholy sug- gestion of its former beauty; good only for the demonstration of anatomical structure. In preserving marine animals dry, as much of the soft parts should be removed as possible, and replaced by tow or cotton, and the object to be dried should be steeped in several changes of fresh water to get rid of the whole of the salt, and then dried very thoroughly and not too quickly. Every specimen, whether dry or in spirit, should be labelled at once, with the number under which this particular dredging is entered in the dredger’s note-book. It is wonderful how soon things get into confusion if this be not rigorously attended to. The small paper tickets with a fancy margin and gummed on the back, which haberdashers use for ticketing their goods, are to be had of all wholesale stationers at nominal prices, and they are very con- CHAP. VI] DEEP-SEA DREDGING. 263 venient. Their great disadvantage is that if the bottles on which they are fixed get wet they are apt to come off. Pencils are sold by seed-merchants for writing on tallies which are to be exposed to rain. Perhaps the safest plan is to mark the number and date with such a pencil on a shred of parchment or parch- ment paper, and put it cto the bottle. This may seem a trifling detail, but so great inconvenience constantly arises from carelessness in this matter, that I feel sure of the sympathy of all who are interested in the scientific aspect of dredging when I insist upon the value of accurate labelling. It is of even greater importance that certain circumstances relating to every individual haul of the dredge should be systematically noted, either in the dredger’s diary, or on a special form prepared for the purpose. ‘The precise position of the station ought to be defined in shore dredging by giving the distance from shore and the bearings of some fixed objects; in ocean dredging by noting accurately the latitude and longitude. In the ‘ Lightning,’ in 1868, we dredged at a station about 100 miles to the north of the Butt of the Lews, and came upon a singular assemblage of interesting animal forms. Next year, in the ‘ Porcupine,’ we were anxious to try again the same spot to procure some additional specimens of a sponge which we were studying. The position had been accurately given in the log of the ‘ Lightning,’ and the first haul at a depth of upwards of half a mile gave us the very same group of forms which we had taken the year before. On our return Captain Calver again dropped the dredge 264 THE DEPTUS OF THE SEA. [CHAP. VI. upon the same spot, with like success. The depth in fathoms should be carefully noted, as a most im- portant element in determining the conditions of life and distribution of species; and the nature of the bottom—whether mud, sand, or gravel; and if the latter, it is well to state the nature and composition of the pebbles, and if possible the source from which they may probably have been derived. Now that we have in the Miller-Casella thermometer a reliable instrument for this purpose, the bottom temperature ought always to be noted. This is important whether in shallow or in deep water. In shallow water it eives a dacum for determining the range of annual variation of temperature which can be endured by certain species; and at great depths it is even more important, as we are now aware that, owing to the movement of masses of water at different tempera- tures in various directions, totally different condi- tions of climate may exist in deep water within a few miles of one another, and the limits of these conditions can only be determined by direct experi- ment. It is important when determining the bottom temperature to note also the temperature of the surface of the sea, the temperature of the air, the direction and force of the wind, and the general atmospheric conditions. If the dredger be purely a zoologist, having no particular interest in special physical problems, it will still be well worth his while to make all the observations indicated and to publish the results. These then pass into the hands of physical geographers, to whom all trust- worthy additions to the myriad of data which are required to arrive at a true generalization of the CHAP. VI. | DEEP-SEA DREDGING. 265 phenomena of the distribution of temperature are most acceptable. At the Birmingham Meeting of the British Asso- ciation in 1889 an important committee was ap- pointed “for researches with the dredge, with a view to the investigation of the marine zoology of Great Britain, the illustration of the geographical distribution of marine animals, end the more accurate determination of the fossils of the plio- cene period: under the superintendence of Mr. Gray, Mr. Forbes, Mr. Goodsir, Mr. Patterson, Mr. Thompson of Belfast, Mr. Ball of Dublin, Dr. George Johnston, Mr. Smith of Jordan Hill, and Mr. A. Strickland.” The appointment of this committee may be regarded as the initiation of the systematic employment of this method of research. Edward Forbes was the ruling spirit, and under the genial influence of his contagious enthusiasm great pro- eress was made during the next decade in the know- ledge of the fauna of the British seas, and many wonderfully pleasant days were spent by the original committee and by many others who, from year to year, were ‘added to their number.’ Every annual report of the British Association contained commu- nications from the English, the Scottish, or the Irish branches of the committee, and in 1850 Edward Forbes submitted its first general report on British marine zoology. This report, as might have been anticipated from the eminent qualifications of the reporter, was of the highest value; and tal:en along with his remarkable memoirs previously published, ‘‘on the distribution of the Mollusca and Radiata of the Aigean Sea,” aud “on the geological relations °66 THE DEPTHS OF THE SEA. [CHAP. VI. of the existing Fauna and Flora of the British Isles,’ may be said to mark an era in the progress of human thought. After enumerating various additions to our know- ledge of the distribution of marine invertebrata within the British area which were still to be de- sired, Forbes concludes his report with the following sentence: ‘And lastly, though I fear the consum- mation, however devoutly wished for, is not likely soon to be effected, a series of dredgings between the Zetland and the Féroe Isles, where the greatest depth is under 700 fathoms, would throw more heght on the natural history of the North Atlantic and on marine zoology generally than any investigation that has yet been undertaken.” To Forbes’s general report succeeded many reports from the different sections into which from year to year the committee divided itself. Among these I may mention particularly the very excellent work done by the Belfast dredging committee, communi- cated to several meetings of the Association by the late Mr. George C. Hyndman; the reports of the Dublin committee by the late Professor Kinahan and Professor E. Perceval Wright; the important lists of the fauna of the East Coast of England re. ported on behalf of the Natural History Society of Northumberland, Durham, and Neweastle-upon-Tyne, and of the Tyne-side Naturalists’ Field Club, by Mr. Henry 'T. Mennell and Mr. G. 8. Brady; and lastly the invaluable reports on the marine fauna of the Hebrides and Shetland, compiled at an extraordinary expense of labour, discomfort, and privation—doubt- less with an immediate guerdon of infinite enjoyment cap. vi.] _- DEEP-SEA DREDGING. 267 —through many years, by Mr. Gwyn Jeffreys, Mr. Barlee, the Rev. A. Merle Norman, and Mr. Edward Waller, and communicated to the Transactions of the Association from 1863 to 1868. The dredging com- mittees of the British Association, combining the pursuit of knowledge with the recreation of their summer holidays, may be said to have worked out the fauna of the British area down to the 100-fathom line, for the dredger is now rarely rewarded by a conspicuous novelty, and must be contented that the ereater number of his additions to the British list are confined to the more obscure groups. Meanwhile some members of the dredging com- mittee and their friends who had time and means at their disposal pushed their operations farther a-field, and did good service on foreign shores. In 1850, Mr. MacAndrew published many valuable notes on the lusitanian and mediterranean faunze; and in 1856, at the request of the biological section of the British Association, he submitted to the Chel- tenham meeting a general “report on the marine testaceous mollusca of the North-east Atlantic and neighbouring seas, and the physical conditions affect- ing their development.” The field of these arduous labours extended from the Canary Islands to the North Cape, over about 43 degrees of latitude, and many species are recorded by him as having been dredged at depths between 160 and 200 fathoms off the coast of Norway. Subsequently, Mr. Gwyn Jeffreys went over some of the same ground, and made many additions to the lists of his predecessors. Nor were our neighbours idle. In Scandinavia a brilliant triumvirate— Levén of Stockholm, Steen-. 9258 TOE DEPTHS OF THE SEA. [CHAP. VI. strup of Copenhagen, and Michael Sars of Chris- tiania—were making perpetual advances in the knowledge of marine zoology. Milne-Edwards was illustrating the fauna of the coast of Irance, and Philippi, Grube, Oscar Schmidt, and others were continuing in the Mediterranean and the Adriatic the work so well begun by Donati, Olivi, Risso, Delle Chiage, Poli, and Cantraine; while Deshayes and Lacaze Duthiers illustrated the fauna of the coast of Algeria. So much progress had already been made at home and abroad, that in the year 1854 Edward Forbes considered that the time had arrived for giving to the public, at all events a pre- liminary sketch of the fauna of the European seas —-a work which he commenced, but did not live to finish. I need scarcely say that these operations of the British Association dredging committees were carried on generally under the idea that at the 100-fathom line, by which amateur work was practically limited, they approached the zero of animal life—a notion which was destined to be gradually undermined and finally completely overthrown. From time to time, however, there were not wanting men of great skill and experience to maintain, with Sir James Clark Ross, that ‘from however great a depth we may be enabled to bring up the mud and stones of the bed of the ocean, we shall find them teeming with animal life.’ From the very general prevalence of the negative view there was little to stimulate to the investigation of the bottom at great depths, and data gathered very slowly. I have already referred (p. 18 eé¢ infra) tothe CHAP. VI.] DEEP-SEA DREDGING. 2969 observations of Sir John Ross in 1818, of Sir James Ross in 1840, and of Mr. Harry Goodsir in 1845. In the year 1844 Professor Lovén con- tributed a paper, ‘‘on the bathymetrical distribu- tion of submarine life on the northern shores of Seandinavia,” to the British Association. He says, “With us the region of deep-sea corals is character- ized in the south by Oculina ramea and Terebratula, and in the north by Astrophyton, Cidaris, Spatangus purpureus of an immense size, all living; besides Gor- gonie and the gigantic Alcyonium arboreum, which continues as far down as any fisherman’s line can be sunk. As to the point where animal life ceases, it must be somewhere, but with us it is unknown.”’* In 1863 the same naturalist, referring to the result of the Swedish Spitzbergen expedition of 1861, when mollusca, crustacea, and hydrozoa were brought up from a depth of 1,400 fathoms, expresses the remarkable opinion, which later investigations appear generally to support, that at ereat depths, wherever the bottom is suitable, “a fauna of the same general character extends from pole to pole through all degrees of latitude, some of the species of the fauna being very widely distributed.” ° In 1846 Keferstein mentions having seen in Stock- holm a whole collection of invertebrate animals— erustacea, phascolosoma, annelids, spatangus, myrio- trochus, sponges, bryozoa, rhizopeda, &e.—taken at a depth of 1,400 fathoms during O. Torell’s Spitz- 1 Report of the Fourteenth Meeting of the British Association, held at York in September 1844. (Transactions of the Sections, p. 50.) 2 Forh. ved de Skand. Naturforskeres Mode i Stockholm, 1863, p 384. 270 THE DEPTHS OF THE SEd. (CHAP. VI. bergen expedition in the ‘Maclean nets,’ and in the same year O. Torell alludes to one of the crus- taceans from that depth being of a bright colour.’ In 1846 Captain Spratt, R.N., dredged at a depth of 310 fathoms forty miles east of Malta a number of mollusca which: have been subsequently examined by Mr. Gwyn Jeffreys and found to be identical with species dredged at considerable depths in the north- ern seas during the ‘ Porcupine’ expedition. The list includes Leda pellucida, Puttrpr1; Leda acu- minata, JEFFREYS; Dentalium agile, Sars; Hela tenella, JEFFREYS; Eulima stenostoma, JEFFREYS; Trophon barvicensis, JOHNSTON ; Pleurotona cart- natum, Bivona; and Philine quadrata, 8. V. Woop. Captain Spratt observes that he ‘ believed animal life to exist much lower, although the general character of the Mgean is to limit it to 3800 fathoms.” * In 1850 Michael Sars, in an account of a zoolo- gical excursion in Finland and Loffoten, expressed his conviction that there is a full development of animal life at considerable depths off the Norwegian coast. He enumerated nineteen species taken by himself at depths beyond 300 fathoms, and pointed out that two of these were the largest species known of their respective genera.’ 1 Nachrichten der Konigl. Gesellsch. der Wissensch. za Gottingen. Marz 1846. 2 On the Influence of Temperature upon the Distribution of the Fauna in the A®*gean Sea. Report of the Eighteenth Meeting of the British Association, 1848. 3 Beretning om en i Sommeren, 1849, foretagen zoologisk Reise i Lofoten og Finmarken, Christiania, 1850. CHAP. V1. ] DEEP-SEA DREDGING. bo 71 I have referred likewise (p. 26) to Professor Fleeming Jenkin’s notes on the living animals attached to the Mediterranean cable at a depth of 1,200 fathoms, and to the results of Dr. Wallich’s special investigations on board H.MLS. ‘ Bull-dog.’ In a general review of the progress of knowledge as to the conditions of life at great depths, these investi- gations deserve special notice, as, even if they must still be regarded as somewhat unsatisfactory, they distinctly mark a stage in advance. Although, from the imperfection of the means at his disposal, Dr. Wallich could not bring home evidence sufficient absolutely to satisfy others, he was convinced in his own mind from what he saw, that living beings high in the scale of organization might exist at any depth in the ocean; he expounded clearly and forcibly the train of reasoning which led him to this belief, and subsequent events have amply justified his con- clusion. The space at my disposal will not allow me to quote and discuss Dr. Wallich’s arguments, in some of which I thoroughly concur, while from others I am compelled to dissent. The facts were most important, and their significance increases now that they are fully confirmed and illustrated by ope- rations on a large scale. In lat. 59° 27’ N., long. 96° 41’ W., a depth of 1,260 fathoms having been previously ascertained, “a new kind of deep-sea dredge was lowered ; but in consequence of its partial failure, a second apparatus (namely, the conical cup) was em- ployed, fifty fathoms of line in excess of the recorded depth being paid out in order to ensure the unchecked descent and impact of the instrument at the bottom. The dredge had already brought up a small quantity 272 THE DEPTHS OF THE SEA. [cHaP. VI. sf unusually fine globigerina deposit and some small stones. The second instrument came up quite full of the deposit ; but it was neither so free from amorphous matter, nor did it contain any of the small stones. Adhering, however, to the last fifty fathoms of line, which had rested on the ground for several moments, were thirteen ophiocome, varying in diameter across the arms from two to five inches.” The misfortune of these star-fishes was that they did not go into the dredge; had they done so, they would at once have achieved immortality. Mow, of course, we have no doubt that they came from the bottom, but their irregular mode of appearance left, in the condition of knowledge and prejudice at the time, a loophole for scepticism. In three soundings, including that in which the star-fishes were obtained, at 1,260, 1,918, and 1,268 fathoms respectively, ‘“‘ minute cylindrical tubes ac- curred, varying from one-eighth to half an inch in length, and from one-fiftieth to one-twentieth of an inch in diameter. These were built up almost ex- clusively of very small globigerina shells, and still more minute calcareous débris cemented together.” . . “The shells forming the outer layer of the tubes were colourless, and freed of all sareodic matter; but the internal surface of the tubular cylinder was lined with a delicate yet distinct layer of reddish chitine.” Dr. Wallich is satisfied that these tubes contained some species of annelid. ‘In a sounding taken in lat. 63° 31’ N., long. 13° 45’ W.., in 682 fathoms, a portion of a serpala-tube five- twelfths of an inch in length, and about threc- sixteenths of an inch in diameter, belonging to a CHAP, VI. ] DEEP-SEA DREDGING. 273 known species, came up in such a condition as to leave no room for doubt that it had been broken off the rock or stone to which it was adherent by the sounding-machine, and that the animal was living; whilst a smaller Serpuia and a cluster of apparently living polyzoa were adherent to its ex- ternal surface. A minute Spirorbis also occurred in this sounding. Lastly, from a depth of 445 fathoms, within a short distance of the south coast of Iceland, a couple of living amphipod crustaceans were ob- tained, and a filamentous annelid about three-quarters of an inch in length.” Basing his opinion principally upon these facts, Dr. Wallich, in conclusion, submits several propositions, the two most important of which may be said to anticipate the more remarkable results of our subsequent work. As the others are merely founded upon what I conceive to be a mistaken determination of the animal species captured, I need not now quote them.’ “1. The conditions prevailing at great depths, although differing materially from those which pre- vail at the surface of the ocean, are not incompatible with the maintenance of animal life. * * % * * * * ‘““5. The discovery of even a single species, living normally at great depths, warrants the inference that the deep sea has its own special fauna, and that it has always had it in ages past; and hence that many fossiliferous strata heretofore regarded as having been ' And see Professor Sars’ “ Bemcerkningen over det dyriske Livs Udbredning i Havets Dybder, med scerligt Hensyn til et af. Dr. Wallich 1 London mylig udkommet Skrift, ‘The North Atlantic Sea- bed?” (Vid.-Selsk. Forhandlinger for 1864.) Ab 274 THE DEPTHS OF THE SEA. [CHAP. VI. deposited in comparatively shallow water, have been deposited at great depths.’’’ In 1864, Professor Sars made a great addition to his list of species from depths of from 200 to 300 fathoms off the coast of Norway. He remarks :— “'The species of animals named are not certainly very numerous (92), yet when we consider that most of them were taken accidentally, attached to the lines of the fishermen, and that only in a few instances the dredge was used at these great depths, it will be seen that there is a very interesting field here for the Naturalist furnished with the proper instruments.” In 1868 Professor Sars made a still further addi- tion to the deep-sea fauna of the Norwegian Seas ; an addition so important, that he remarks ‘that it is so great as to give a tolerably complete idea of the general fauna of these coasts.” ‘This increase of knowledge, Professor Sars states, is almost entirely due to the indefatigable labours of his son, G. O. Sars, an Inspector of Fisheries under the Swedish Government, who took advantage of the opportuni- ties given by his occupation to dredge down to 450 fathoms on some parts of the coast, and among the Loffoten Islands. Sars likewise acknowledges many contributions from his old fellow-lahbourers, Danielssen and Koren. The number of species from depths be- tween 250 and 450 fathoms on the coast of Norway now reaches 427, thus distributed :— Species. Rbizopoda 9 [5 os 5. "= oaks ee eee ( Poritota ca 9S. Sei — 73 Protozoa . 1 North Atlantic Sea bed, p. 154, CHAP, v1. DEEP-SEA DREDGING. 275 : Species. iy drozoaiy. me ; ae 2 | White. Fusus muricatus it a : ae l nee pia at | ibraltar. Pleurotoma nanum 1 : secalinum . : 1 Murex tetrapterus ... . #: 2 Chenopus pes-pelecani . 1 Bucermuny Py fs. 1 Mitraebenea .... ; 1 Bright orange » oo” = ag Suamopa XC 1 colour, banded, | | small, striated Ringicula auriculata . ee og 2 Marginella secalina . . . . 3 + * clandestina . . | Several. Several. | Cyprea pulex . . . aro 2 | Cidaris histrix . 3 Zoophytes . . : : DCE See eee NG CHAPTER VET DEEP-SEA TEMPERATURES. Ocean Currents and their general Effects on Climate.-—Deiermination of Surface Temperatures. ---Deep-sea Thermometers,—The ordinary Self-registering Thermometer on Six’s_ principle-—The Miller- Casella modification.—The Temperature Observations taken during the Three Cruises of H.M.S. ‘ Porcupine’ in the year 1869, Appenpix A.—Surface Temperatures observed on board H.M.S, ‘Porcupine’ during the Summers of 1869 and 1870. Appenpix b.—Temperature of the Sea at different Depths near the Eastern Margin of the North Atlantic Basin, as ascertained by Serial and by bottom Soundings. Appenpix C.—Comparative Rates of Reduction of Temperature with Increase of Depth at Three Stations in different Latitudes, all of them on the Eastern Margin of the Atlantic Basin. Appenpix D.—Temperature of the Sea at different Depths in the Warm and Cold Areas lying between the North of Scotland, the Shetland Islands, and the Firoe Islands ; as ascertained by Serial and Bottom Soundings, Appenpix E.—Intermediate Buttom Temperatures showing the Inter- mixture of Warm and Cold Currents on the Borders of the Warm and Cold Areas, Ir the surface of this world of ours were one uniform shell of dry land, other circumstances of its central heat, its relation in position to the sun, and to its investing atmospheric envelope, remaining the same, some zones would present certain pecu- CHAP. VI).] DEEP-SEA TEMPERATURES, 985 liarities in temperature, owing to the mixture of hot and cold currents of air; but in the main, iso- thermal lines, that is to say, lines drawn through places having the same mean temperature, would coincide with parallels of latitude. eal 5 i (a: 5) That is to say, the temperature remaining the same, the pressure forced up No. 57 to 12°75 C., and left its index there. 1 On Deep Sea Thermometers, by Captain J. E. Davis, R.N. Nature, vol. iii. p. 124. Abridged from a Paper read before the Meteorolo- gical Society, April 19th, 1871. 296 THE DEPTHS OF THE SEA. [CHAP. VII. This experiment at once proved the advantage of the encased bulb. It was repeated with other ther- mometers with the same pressure and for the same period of time, and it was found that while the mean difference of the encased bulbs was only 0°95, that of the ordinary deep-sea thermometers was, as in No. 57, 7°25. It follows, also, from these experiments, that very nearly all the difference or error is due to pres- sure on the full bulb, and that by encasing that bulb we have a nearly perfect instrument. The next series of experiments was made to esta- blish a scale by which observations by the ordinary instruments might be approximately corrected for pressure. The following table gives the errors of six thermometers at different pressures. The ‘standard’ is an encased Miller-Casella, the last a yvegistering minimum thermometer by Casella enclosed in a hermeticaliy sealed glass tube on Sir William Thomson’s plan. Pressure | | in | Standard. No. 54. No. 56: “| Novey6) |= Wo: 73: Thomson. Fathoms. | | | | 250 | 0-4. GC. O8BiC. | eC OP eal 0 ee a. ae, OOO? A WL 7 i | eae ae 0:05 Jao |) OF 7. 2°2 2°2 Nee peas Dio 0:0 1,000 }-0°8 2°9 vee | Dak ey | 0-2 1,250 | 0-9 3°5 ae 3:5 4°] 0-05 1,500 | 0-8 4°3 £73 a AS Oe 3} 1750-095 | 4-6.) 4-9 4°7 5° 7 0-2 2,000 | 1:1 5:4 625.0 th Be BiB nak = ars RO5O |, 124 G<25 | 670 6-0 6-8 0-4 2,900 | 1°2 (Gee: Ore 6°5 ae QO: 2 | The mean difference for each 250 fathoms in each thermometer is as follows :— CHAP. VII. } DEEP-SEA TEMPERATURES. 297 Thermometer. Difference. Standard . + 0-12C B4 + 0-72 Dore OST Or: + 0°65 (i sav Me + 0°76 Thomson . + 0°03 During these experiments the water in the cylin- der was of course maintained as far as possible at the same—or at a known temperature; a certain amount of calorific effect must, however, be pro- duced by the sudden compression of the water, and the next series of experiments was performed in order to determine the amount of that effect. Three of Phillips’s encased maximum thermometers (Sir William Thomson’s design), being entirely protected from any effect from compression, were employed for this purpose, with the following result :— Pressure, 6,817 lbs. = 2,500 fathoms. Thermometer. Difference. SPY Oe oe ae ae + 0° 05 C. ORG AOS WE is te, cee hy, + 0:22 9.645 . Le Od So that this source of error is absolutely trifling. The true error of the Miller-Casella thermometer, as deduced from these observations, is— For 250 fathoms 0°:079 C. For 2,500 fathoms 0°79 C. 298 "THE DEPTHS OF THE SEA. [omar VIL This, therefore, may be regarded as a perfect instru- ment for all ordinary purposes. A number of the instruments which had been previously tested in the press were sent out in the ‘Porcupine’ on her summer cruise in 1869, and on her return the results of Captain Calver’s observa- tions at different depths in the ocean were carefully compared with the effects of equivalent pressures ap- plied to the thermometers in Mr. Casella’s ‘ Bramah’s press. The result in the ocean, contrary to that in the hydraulic press, proves that the elasticity is not regular or in a ratio to the pressure, but that after continuing regular up to a pressure of 1,000 fathoms, it decreases in a compound ratio to a pressure of 2.000 fathoms, when its elasticity nearly ceases. The following table gives an abstract of the behaviour of Casella’s ordinary Hydrographic Office thermometers in the ocean and in the press :— | ERROR, PER 250 FATHOMS. Pressure. —_—— | Press. Ocean. Press. Ocean. Fathoms. | 250 0726 CL) 0° 738 C. | | O26 Gal nO aceon 500 1-548 1+ 564 0° 774 0: 782 | 750 DNS 2° 223 0: 708 0: 741 ' = 1,000 2°474 3D O15 0: 674 i Uae AS = 3 | 1,250 3° 255 3-499 0-651 | 0-698 | 1,500 4-107 3.5 921 0 684. ~ 4 Oras 1,750 4° 555 4°056 | 0-650 0-579 2,000 5-354 | 4-284 0+ 669 0-536 2,250 6: 021 = 0+ 669 pl 2,500 | 6:°817 — 0 682 a | Tor taking bottom temperatures at great depths two or more of the Miller-Casella thermometers are CHAP. VII. | DEEP-SEA TEMPERATURES. 299 lashed to the sounding-line at a little distance from one another, a few feet above the attaching ring of a ‘detaching’ sounding instrument. The lead is run down rapidly, and, after the weight has been disengaged by contact with the ground, an interval of five or ten minutes is allowed to elapse before hauling in. The shorter of these periods seems to be quite sufficient to insure the instrument acquiring the true temperature. In taking serial temperature soundings—that is to say, in determining the tem- perature at certain intervals of depth in deep water —the thermometers are attached above an ordinary deep-sea lead, the required quantity of line for each observation of the series run out, and the ther- mometers and lead are hove in each time. This is a very tedious process; one serial sounding in the Bay of Biscay, where the depth was 850 fathoms and the temperature was taken at every fifty fathoms, occupied a whole day. | IT ought to mention that in taking the bottom temperature with the Six’s thermometer the instru- ment simply indicates the lowest temperature to which it has been subjected; so that if the bottom water were warmer than any other stratum through which the thermometer had passed, the observation would be erroneous. This is only to be tested by serial soundings, but in every locality where the temperature was observed during the ‘ Porcupine’ expeditions the temperature gradually sank, some- times very steadily, sometimes irregularly, from the surface to the bottom, the bottom water having been constantly the coldest. It is probable that under certain conditions in the Polar seas, where the sur- 300 THE DEPTHS OF THE SEA. [CHAP. VII. face is sometimes subjected to intense cold, warmer water may be found below, until the balance is restored by convection. This I believe, however, to be entirely exceptional; and it may certainly be taken as the rule for all latitudes that if we dis- regard the film which is affected by diurnal altera- tions, the temperature sinks from the surface to the bottom. The first important series of deep-water tempera- ture observations was made during the Arctic voyage under Sir John Ross in the year 1818. On Sept. the Ist, lat. 73° 37’ N., long. 77° 25’ W., the temperature at the surface being 1°3 C., the registering thermo- meter gave at eighty fathoms 0°C., and at 250 fathoms —1"4 C. On the 6th of September, lat. 72° 23’ N., long. 73° 07’ W., the first serial sounding on record was taken, the thermometer having been let down to 500, 600, 700, 800, and 1,000 fathoms in succession, the thermometer showing each time a lower temperature and indicating at the greatest depth named a temperature of —3°6 C. On the 19th of September, in lat. 66° 50’ N., long. 60° 30’ W., another serial sounding was taken, the tempera- ture being registered at 100 fathoms —0°9 C., at 200 —1°:7 C., at 400 —2°-2 C., and at 660 fathoms —3'6 C. On the 4th of October, lat. 61° 41’ N., long. 62° 16’ W., Sir John Ross sounded, but found no ground in 950 fathoms; at the same time the self-registering thermometer was sent down, and the temperature of the sea at that depth was found to be 2° C., while at the surface it was 4° C., and the air at 2°°"7 C. I am informed by General Sir Edward Sabine, who accompanied Sir John Ross’s expedition, CHAP. Vil. | DEEP-SEA TEMPERATURES. 301 that these observations were made with registering thermometers guarded somewhat in the same way as those which we employed in the ‘ Porcupine.’ There is almost sufficient internal evidence that the mode of protecting these thermometers must have been satisfactory, for the temperatures at the greatest depths are such as might have been expected from Miller-Casella thermometers. Unguarded instru- ments would certainly have given higher indica- tions. The last of the observations quoted, a considerable way up Davis’ Strait, is of great interest. The tem- perature of the surface of the sea was nearly a degree and a half Centigrade above that of the air, and the temperature of the water was altogether unusually high. It is now well known that at certain seasons of the year a very marked extension of the Gulfstream passes into the mouth of the Strait. The isotherms for September and July are shown on the chart from data kindly procured for me by Mr. Keith Johnston. Sir Edward Sabine, in an extract from his pri- vate Journal of Sir John Ross’s voyage quoted by Dr. Carpenter,' gives a lower temperature than any hitherto recorded. He says: ‘“‘ Having sounded on September 19th, 1818, in 750 fathoms, the regis- tering thermometer was sent down to 680 fathoms, and on coming up the index of greatest cold was at 25°75 Fahrenheit (—8°5 C.), never having known it lower than 28° (—2°2.C.) in former instances, even at a depth of 1,000 fathoms; and at other times 1 Dr, Carpenter’s Preliminary Report on Deep-Sea Dredgings. Pro- ceedings of the Royal Society of London, vol. xvil. p. 186, 302 THE DEPTHS OF THE SEA. [CHAP. VII. when close to the bottom, I was very careful in examining the thermometer, but could discover no other reason for it than the actual coldness of the water.” Notwithstanding these observations and _ several others telling in the same direction,—such as those of Lieutenant Lee of the U.S. Coast Survey, who in August 1847 found a temperature of 2°-7 C. below the Gulf-stream, at the depth of 1,000 fathoms, in, lat.» 35° 26° N:, and: lone, 73712) W 22] ander lieutenant Dayman, who found the temperature at 1,000 fathoms, in lat. 51° N. and long. 40° W. to be 0°4C., the surface temperature being 12°5 C., the impression seems to have prevailed among physicists and physical geographers that salt water followed the same law as fresh water, attaining its ereatest density at a temperature of 4°C. The necessary result of this condition, were it to exist, is thus stated by Sir John Herschel: “In very deep water all over the globe a uniform temperature of 39° Fahrenheit (4°C.) is found to prevail; while above the level where that temperature is first reached, the ocean may be considered as divided into three great regions or zones—an equatorial and two polar. In the former of these warmer, and in the latter colder water is found on the surface. The lines of demarkation are of course the two isotherms of 389° mean annual temperature.’ Dr. Wallich gives an excellent réswmé of this curious fallacy. He says: ‘‘ But whilst the temperature of the atmo- sphere beyond the line of perpetual congelation goes on gradually increasing, that of the water below the isothermal lmne remains constant to the bottom. CHAP, VII. | DEEP-SEA TEMPERATURES, 305 Were it not for the operation of the law on which the latter phenomenon depends, the entire ocean would long since have become solidified, and both sea and land rendered unfit for the habitation of living organisms. Unlike other bodies which ex- pand and become lighter with every rise in tempera- ture, water attains its maximum density, not under the lowest degree of cold, but at 39°5 Fahrenheit ; and consequently so soon as the superficial layer of sea is cooled down to this degree, it descends, and allows a fresh portion to ascend and be in turn cooled. This process is continued until the whole upper stratum is reduced in temperature to 39°°5, when, instead of contracting further, it begins to expand and get lighter than the water beneath, floats on it, becomes further cooled down, and at 28°5 is converted into ice... . Thus under the operation of an apparently exceptional law, the equilibrium of the oceanic circulation is maintained ; for whilst at the equator the mean temperature of the surface layer of water, which is 82°, gradually decreases, until at a depth of 1,200 fathoms it be- comes stationary at 39°°5, and retains that tempera- ture to the bottom, within the Polar regions and extending to lat. 56° 25’ in either hemisphere, the temperature increases from the surface downwards to the isothermal line, beyond which it remains uniform as in the former case. Hence in lat. 56° 25’ the temperature is uniform the whole way from the surface to the bottom; and as has been found by observation about lat. 70°, the isothermal line occurs at 750 fathoms below the surface.” ! 1 Dr. Wallich : North Atlantic Sea-bed, p. 99. 304 THE DEPTHS OF THE SLA. [cHAP. VII. There can be no doubt that this view, which of late years has received almost universal acceptance, is entirely erroneous. It has been shown by M. Despretz,' as the result of a series of carefully con- ducted experiments which have since been frequently repeated and verified, that sea-water, as a saline solution, contracts and increases steadily in density down to its freezing-point, which is, when kept perfectly still, about —3°67C. (25°4F.), and when agitated — 2°55 C. The temperature observations of Sir James Clarke Ross during his Antarctic voyage in 1840-41, seemed to give support to the theory of a constant temperature of 4°5 C. for deep water, but these obser- vations have as evidently been made with unguarded instruments, as those of Sir John Ross in 1818 with instruments defended from pressure; and although I believe they must be taken as proving that in high southern latitudes the surface temperature is sometimes lower than the temperature of the water at a considerable depth beneath, still the amount of correction for pressure is uncertain, depending upon the construction of the thermometers used, and in any case it must reduce the difference considerably. A large number of thermometers of the ordinary Hydrographic Office pattern were sent out with us, as I have already mentioned, in the ‘ Lightning,’ and these were of course the instruments used by Staf/Commander May for his temperature obser- vations. ‘There was an opportunity of testing these thermometers, however, on the return of the vessel, * Recherches sur le Maximum de Densité des Dissolutions aqueuses. Loe, cit. CHAP. VII.] DEEP-SEA TEMPERATURES. 305 so that we are tolerably certain by actual experi- ment of the amount of their error. In speaking of the ‘ Lightning’ temperatures, | mean, therefore, the actual temperatures taken by the ordinary ther- mometers, corrected approximately to the standard of the Miller-Casella thermometers, afterwards used in the * Porcupine.’ Leaving Stornoway in the ‘ Lightning,’ on the 11th of August, 1868, and directing our course towards the F&roe banks, we sounded in 500 fathoms about 6O miles to the north-west of the Butt of the Lews, and took a hottom temperature of 9°-4 Cent. with the ordinary Six’s thermometer-—— the only form of the instrument in use at the time. This, when corrected for pressure, gives about 7°8C. We were surprised to find the temperature so high, and we were at the time inclined to think that the observation, which was taken in a breeze of wind, was scarcely to be depended upon. Subsequent observations, however, in the same locality, con- firmed its accuracy. On the Féroe Banks, at a depth under 100 fathoms, the bottom temperature averaged 9°C., while that of the surface was about 12° C.; temperature indications on this bank were, however, of little value, as the water is no doubt affected to some extent through its entire depth by direct solar radiation. The next observation was in lat. 60° 45’ N. and long. 4° 49’: W., at a depth of 510 fathoms, with a bottom temperature of —0°5C., about 140 miles nearly directly north of Cape Wrath. Then followed a series of sound- ings, Nos. 7, 8, 10, and 11 of the chart (Plate I.), taken while traversing the northern portion of the X 306 THE DEPTHS OF THE SEA. [cCHAP, VIL. channel between Scotland and the Fiwéroe plateau ; and giving, respectively, the temperatures of —1°1, — 1:2, —0°7,and —0°5C. No. 9, with a depth of 170 fathoms and a temperature of 5° C., is excep- tional; it is apparently the top of a circumscribed ridge or bank. We dredged at this station and got large numbers of the rare and beautiful Terebratula cranium ; but when we tried for the same spot in the following year in the ‘ Porcupine,’ we could not find it. On the 6th of September we sounded and took temperatures in lat. 59° 36 N., long. 7° 20’ W., in 530 fathoms, when the mean of three thermometers, which only differed from one another by about 3 of a degree, gave a bottom temperature of 6°4 C. A temperature sounding, at the moderate depth of 189 fathoms, was taken on the morning of the 7th September in lat... 59°-5° Ni; Jong, 7° 295 °W) and gave a bottom temperature of 9°6 C. The three soundings, Nos. 13, 14, and 17, at the depths 650, 570, and 620 fathoms, extending into the North Atlantic as far westward as long. 12° 36’ W., gave a bottom temperature of 5°8, 6°4, and 6°6 C., respectively. ‘The general result of these observations we could not but regard as very remarkable. The region which we had somewhat imperfectly examined in- cluded, in the first place, the channel about a couple of hundred miles in width, with an extreme depth of rather under 600 fathoms, extending between the northern boundary-line of the British plateau and the shoal which culminates in the Feroe Islands and their extensive banks; and secondly, a small portion of the North Atlantic extending westwards CHAP. VII. | DEEP-SEA TEMPERATURES. 307 and northwards of the western entrance of the channel. We found that in these two areas, freely communi- cating with one another and in immediate proximity, two totally different conditions of climate existed at all depths below the immediate surface, where they differed but slightly. In the Fieroe channel, at a depth of 500 fathoms, the bottom temperature aver- aged —1°0 C., while at a like depth in the Atlantic the minimum index stood at + 6° C., a difference of 7 degrees Centigrade, nearly 13 degrees Fahrenheit. The conclusion at which we speedily arrived as the only feasible explanation of these phenomena was that an arctic stream of frigid water crept from the north-eastward into the Froe channel lying in the deeper part of the trough, owing to its higher specific gravity ; while a body of water warmed even above the normal temperature of the latitude, and therefore coming from some southern source, was passing northwards across its western entrance and occupying the whole depth of that comparatively shallow portion of the Atlantic from the surface to the bottom. Several important facts of very general applica- tion in Physical Geography had been placed beyond doubt by these observations. It had been shown that in nature, as in the experiments of M. Despretz, sea-water does not share in the peculiarities of fresh water, which, as has been long known, attains its maximum density at 4° C.; but, like most other liquids, increases in density to its freezing-point : and it had also been shown that, owing to the movement of great bodies of water at different temperatures in different directions, we may have in close proxt- ee 308 THE DEPTHS OF THE SEA. (cHar. vu, mity two ocean areas with totally different bottom climates—a fact which, taken along with the dis- covery of abundant animal life at all depths, has most important bearings upon the distribution of marine life, and upon the interpretation of palzeonto- logical data. The conditions during the ‘ Lightning’ cruise were so unfavourable to careful observation, that we deter- mined to take the earliest opportunity of going over this region again, and determining the limits of these warm and cold areas, and investigating their con- ditions more in detail. Accordingly, in the follow- ing year, when we had H.M.S. ‘ Porcupine’ at our disposal, Dr. Carpenter and I once more left Storno- way on the 15th of August, 1869. On this occasion we had everything in our favour; the weather was beautiful, the vessel suitable, and we were provided with Miller-Casella thermometers on whose accuracy we could depend. Ne SU a eed OM aes ord 200, 7-5 ADOE— e: A RE co re ee ae ea aoe) 300 Meer eae We cc eee ees 20) 20) 384 (Bottom) . 0°8 We thus ascertained that the minimum tempera- ture was at the bottom; and this we have found to be universally the case over the whole of the area which we have examined, whatever the bottom temperature might be. And we also ascertained that the decrease in heat from the surface downwards was by no means uniform, but that while after passing the surface layer it was tolerably regular for the first 200 fathoms, there was an extraordinary fall amounting to upwards of 7°C. from 200 to 300 fathoms, at which latter depth the minimum is nearly gained. The next few observations, Stations 53 to 59, were all within the limits of the cold area, the bottom tem- perature at depths ranging from 360 to 630 fathoms, nowhere reaching the freezing-point of fresh water ; and at one point, Station 59, lat. 60° 21’ N., long. 5°41’ W., at a depth of 550 fathoms, the mide Pear. ing so low as —1°3C. On Saturday the 21st we took a sounding in 187 fathoms, on the edge of the Fréroe 310 THE DEPTHS OF THE SEA. [CHAP. VII. plateau, and about twenty miles north of the pre- vious station, with a temperature of 6°9C., and so found that we had passed the limits of the cold basin. Our first two soundings after leaving Thorshayn (Stations 61 and. 62) were in shallow water on the Feéroe Bank, 114 and 125 fathoms, with a tempera- ture of 7°2 and 7°0 C. respectively; but the next Station, No. 638, after a run of eighty miles, gave 317 fathoms and 0°9 C., showing that we were once more in the cold region. From that point, passing in a south-easterly direction across the channel towards the northern point of Shetland, we traversed the cold area in its most characteristic form, finding at Station 64, lat. 61° 21’ N., long. 3 44’ W., a depth of 640 fathoms, with a bottom temperature of —1°2C. Here we took another serial sounding, and its results corresponded generally with those of No. 52. The surface temperature was lower, and the temperature down to 200 fathoms some- what lower; at 350 fathoms it was a little higher :-— SHUPEACG: wk gc ka’! n> coe ee eet. ee ee 50 fathoms fee KOO 5 of cee Wide Oi (ee DSO pp aeie —.5 72%, ipa eee Cen 200°”, att sac B te has Lehi: eee oul 250 L ee ee ee ee es B00 | as bo ee! ie Wiha ne * ae 0:2 350 sa, 0:3 400 ,, CB A UE ey mee ee eee £50. % y Sie, «bey ame Ore Ore.6 500. +4; ys ae dees at he ec ae Te tk ae eM eo OS GOO. “5. ik a Ca Ae ee a te ) 640 x as te ta ees CHAP, VII. ] DEEP-SEA TEMPERATURES. Sil At this point, therefore, the ice-cold water of the Arctic current filling up the bottom of the trough is nearly 2,000 feet deep, while the temperate water above has nearly an equal depth. The lower half of the latter, however, has its temperature considerably reduced by intermixture and diffusion. Tig. 55 represents diagrammatically the general result of temperature observations in the cold area. ‘The depth at the next Station, No. 65, was 354 fathoms, showing that the channel had begun to shoal towards Shetland; the temperature was, however, still low, almost exactly 0° C. The next: Station,-No. :66, eighteen miles further on towards the Shetland banks, gave a depth of 267 fathoms, with a bottom temperature of 7°°6 C., the temperature at the surface being 11°3C. We had therefore got beyond the edge of the trough filled by the cold stream, and passed into lesser depths occupied from the surface to the bottom by the warm scuthern stratum. The next series of soundings, Nos. 67 to 75, are either in shallow water round Shetland, or in water on the shelving edge of the plateau, not deep enough to reach the frigid stream. It is of some interest that the two soundings, Nos. 68 and 69, in 75 and 67 fathoms respectively, to the east of Shetland, show a bottom temperature of 6°6 C., while a serial sounding in the warm area at the western entrance of the Féroe Channel gives for the same depth a temperature of about 8°8C. This circumstance, along with others to be mentioned hereafter, would seem to show that a considerable indraught of cold water spreads over the bottom of the shallow north sea. At Stations 76 to 86, which are along the southern Fie.55.—Serial sounding, Station 64 Fia. 56.—Serial sounding, Station 87 CHAP, VII. | DEEP-SEA TEMPERATURES, a13 border of the cold area, temperature soundings were taken mainly with a view to define its southern limit, and they are sometimes on one side and sometimes on the other. The general result is indicated on Plate IV. by the southern border of the shaded space. Nos. 87 to 90 are once more in the warm area, the water reaching a depth of upwards of 700 fathoms, but maintaining, after the first 300 fathoms, a tempera- ture of from 6 to 7° C. above that of corresponding depths in the cold area. At Station 87, lat.59°35' N., long. 9°11’ W., with a depth of 767 fathoms, a serial sounding was taken, which contrasts remarkably with the series at Station 64. The general result of this sounding is represented diagrammatically by Fig 56. ‘The temperature was taken at every 100 fathoms after the first 200. GRC CIE vas! So bs bay Fe, eee A ee FOREUCMOMISRsp eto es ae es cokes 9-30) HO Oper ea tea vie ac DA) eS Bred 15), ees By ae me (Ms si “ad . don Be Se ke ane ORES PO Omh > Rar erage ws Xd Ae cea Cre AQQ 2S. ae Tin far ees sea 8: Couns Deeks sh hs es Meet ee a Pe (538) GOOg 3: Le ot Pri iron) eee ee ieee 767 Tage ate (i mE Ss Datel! It will be seen by reference to the chart that two nearly parallel series of soundings were taken, ex- tending from the shallow water on the Scottish side to the edge of the Fieroe Bank close to the western opening of the Froe Channel, and that one of these chains, including Stations 52, 53, 54, and 56, are in the cold area, while the other chain of Stations, 48, ee THE DEPTHS OF THE SEA. (CHAP. VII. 47, 90, 49, 50, and 51, are in the warm area. There is no great difference in depth between the two series of soundings; and there is no indication of a ridge separating them. The only possible explanation of these two so widely different submarine climates, existing apparently under the same circumstances and in close proximity to one another, is that the Arctic indraught which passes into the deeper part of the Feroe Channel is banked in at its entrance, by the warm southern stream slowly passing north- wards. There is a slight but very constant depres- sion of the isothermal lines of surface temperature in the shallow water along the west coast of Britain. This, I believe, indicates that a portion of the cold Froe stream makes its escape, and, still banked in close to the land by the warm water, gradually makes its way southwards, so mixed and diluted as only to be perceptible by its slight effect on the lines of mean temperature. Diagrams 55 and 56 illustrate the dis- tribution of temperature in the cold and warm areas respectively ; and in Fig. 57, the results of the serial soundines Nos. 52, 64, and 87, are reduced to curves. From these diagrams, taken together, it will be seen that in the first 50 fathoms there is a rapid fall of nearly 3° C. Station No. 64 is a good deal farther north than the other two, and the surface tempera- ture is lower, so that the fall, which is nearly to the same amount, starts from a lower point. The surface temperature is doubtless due to the direct heat of the sun, and the first rapid fall is due to the rapid decrease of this direct effect. From 50 to 200 fathoms the temperature in all three cases falls but little, re- maining considerably above the normal temperature cemineee™ 767 leet Sasa ceag 384 = F 640 constructed from serial soundings in the ‘ warm-’ and ‘ cold-areas’ in the channel between Scotland and Fééroe. —Curves 1c. 57 316 THE DEPTHS OF THE SEa. [cmap. vil. of the ocean for the parallel of latitude. At a depth of 200 fathoms, however, the divergence be- tween the curves of the warm and cold areas is most remarkable. The curve of the warm area, No. 87, shows a fall of scarcely half a degree at 500 fathoms, and less than one degree more at 767 fathoms at the bottom. Between 200 and 590 fathoms the cold area curves run down from 8° C. to 0°C., leaving only one degree more of gradual descent for the next 300 fathoms. The temperature of the ‘hump’ on the curves of the ‘cold area’ between 50 and 200 fathoms corresponds so nearly with that of the long gradual sinking of the curve of the warm area from the surface nearly to the bottom, that it seems natural to trace it to the same source. We there- fore conclude that a shallow layer of Gulf-stream water drifting slowly northwards overlies in the cold area an indraught of cold water represented by the sudden and great depression of the curves, while in the warm area this cold indraught is absent, the Gulf-stream water reaching to the bottom. Tracing the ‘warm area’ southwards from the mouth of the Froe Channel along the coast of Scot- land, we find that the area between Féroe, the Lews, and Rockall, is a kind of plateau with a depth of from 700 to 800 fathoms; and we may be certain from analogy, although this region has not yet been actu- ally examined, with a bottom temperature not lower than 4°5 C. Commencing opposite Rockall, and ex- tending between the great shoal which culminates in the Rockall fishing banks and the singular isolated rock, and the west coast of Ireland, there is a wide trough deepening gradually southwards, and at length CHAP. VII. ] DEEP-SEA TEMPERATURES. 317 continuous with the general basin of the North Atlantic. The temperature of this ocean valley was investi- gvated with great care during the first and second cruises of the ‘ Porcupine’ in 1569, and the results were so very uniform throughout the area that it will be needless to describe in detail the slight differences in different localities. These differences, in fact, only affected the surface layer of the water, and depended merely upon differences of latitude. The temperatures in deep water may be said to have been practically the same everywhere. ‘The first chain of soundings, taken by Captain Calver during the first cruise under the scientific direction of Mr. Gwyn Jeffreys, was between Lough Swilly and Rockall. The greatest depth, 1,380 fathoms, is in the middle of the channel, and a sounding at that depth, lat. 56° 24’ N., long. 11° 49’ W., gave a bottom temperature of 2°8 C. A depth of 630 fathoms, No. 23, a little to the south of Kockall, gave a temperature of 6°4 C., almost exactly the same as the temperature of a lke depth in the warm area off the entrance of the Féroe Channel; anda temperature at 500 fathoms, one of a series taken at Station 21 with a bottom temperature at 1,476 fathoms of 2°7 C., was 85 C., rather less than a degree higher than the temperature at a correspond- ing depth at Station 87. At Station 21 the tempera- ture was taken at every 250 fathoms. Seece Meats ee ane N St ud eee a Bs FO 250 fathoms 9-0 DOOR: ema lar aaron rt a Sew (Meee Rey ee CE ses) OE 318 THE DEPTHS OF THE SEA. [cHAP. VIT 1,000 fathoms . 5 ph 1,250 —;, 3-3 PATO 5 9-7 We have here on a large scale, as Dr. Carpenter has pointed out, conditions very analogous to those which exist in comparatively shallow water, and on a small scale in the cold area in the Firoe Channel. There is a surface layer of about 50 fathoms, super- heated in August by direct solar radiation, and, as we see by the variations of surface isothermals, varying greatly with the seasons of the year. Next, we have a band extending here to a depth of nearly 800 fathoms, in which the thermometer sinks slowly through a range of about 5°C. ‘Then a zone of intermixture of about 200 fathoms, where the temperature falls rapidly, and finally a mass of cold water from a depth of 1,000 fathoms to the bottom, through which, what- ever be its depth, the thermometer falls almost im- perceptibly, the water never reaching the dead cold of the Arctic undercurrent in the Féroe Channel, and the lowest temperature being universally at the bottom (Fig. 58). The area investigated during the second cruise of the ‘ Porcupine’ at the mouth of the Bay of Biscay, about a couple of hundred miles west of Ushant, may be regarded as simply a continuation southwards of the tract between Scotland and Ireland and the Rockall ridge. As, however, the depths were greater than any attained on any former occasion—were so great, indeed, as probably to represent the average depth of the great ocean basins—it may be well to deseribe the methods of observation and the econdi- tions of temperature somewhat in detail. BYNOY PUL PULTJOOR UaaM eq [eUURYD df} Ul SSUIPUNOS W070 PUB [CLIaS UOJ payOUtTJSUOD SBAINI— "Sg TLEY9OY PUB PULTPOIS 79 | {9 9} ul IT ZOE } : f OLv1 Shr! O9E1 c9zi 320 THE DEPTHS OF THE SEA. [cuap, vit. The sounding at Station No. 387, at a depth of 2,435 fathoms, has already been fully described as an example of the most recent method of determining extreme depths with accuracy. Two Miller-Casella thermometers, numbered 100 and 103 respectively, were. lashed to the sounding-line in their copper cases, one a little above the other, about a fathom and a fathom and a half above the ‘Hydra’ sounding- machine. These two instruments had been prepared and tested with extreme care, and had been employed throughout the first cruise; their freezing-points had been again verified at Belfast in case the enormous pressure to which they had been subjected might have affected the glass, and we had absolute confidence in their indications. ‘The indices were set before the instruments were let down at the temperature of the surface, 21°°1C., and 21°15 C, They were allowed to remain at the bottom for ten minutes, and on their return to the surface in upwards of two hours and a half, they were unanimous in recording a minimum of 1°65 C., the slight differences between the two instruments, which gave the almost inappreciable error for one of them of 0°05C. at 21°C., being imperceptible at the lower temperature. It had a strange interest to see these two little instruments, upon whose construction so much skilled labour and consideration had been lavished, con- signed to their long and hazardous journey; and their return eagerly watched for by a knot of thoughtful men, standing, note-book in hand, ready to register this first message, which should throw so much light upon the physical conditions of a hitherto unknown world. CHAP. VII] DEEP-SEA TEMPERATURES. ek A series of temperature- soundings, at depths in- creasing progressively by 250 fathoms, was taken to a depth of 2,090 fathoms, on the 24th of July, lat. 47° 39’ N., long. 11° 33’ W. Suriace- . « 17- 08C. 250 fathoms. 10° 28 less than Surface C25 © HOMES - 8:8 Bc 250 a POMss 0 oi leas 5°17 : BOO Sika aseaBEnG bOGO a=. =e fe 750 os aa eye Pape ae 17. * fb; 00R a= maa Qhets Te Ore oe 9 i 1 25a arse ceo Bi5Oe fC: ar 6 | = 1,500 ae ae eas) 2 090SCE.. 2°4 re 1,750 - 0-2 The same two Miller-Casella thermometers were employed as in the previous observation. Another serial sounding was taken a few days late. in water 862 fathoms deep, somewhat nearer the coast of Ireland. In this case the temperature was taken at intervals of 10 fathoms from the surface to a depth of 50 fathoms, and thence at intervals of 50 fathoms to the bottom. This was done to deter- mine exactly the rate of diminution of temperature, and the exact position of the most marked irregu- larities. Surface 7°: 22 C. 10 fathoms. 16° 72 less than surfaceli.. 0.1 02°35: CG: Oe Es, mere: 22 less than 10 fathoms . 1°95 BOMon female 33 es 20ers ea en) As tas: = 12-44 Pe SOmSe eee ya) st Reema suena late 8 whee AOR cies . 0: 64 NOs 2.210: 6 ‘ 502. Bec ae Lates. ete: 5 x OG ieee reg Naa | PAO caer ele 3 F 150) 6 ae Oma JOOS ss ga O7: 11 « DOOR ta. soe Ole 300 9°8 250, wlgisiive.o Fic. 59.—Diagram representing the Fic. 60.—Diagram representing the relation between depth and tem- relation between depth and tem- perature off Rockall. perature in the Atlantic basin. between temperature and depth,—the serial soundings reduced to curves. JST., and IV. 1600 1700 1800 1900 2000 2100 2200 2300 2400 Fathoms ~ 1600 1700 1800 1900 2000 2100 2200 2300 2400 Fathoms . ’ ‘ } r Prate VI... Diagram of the ‘Porcupine’ soundings m i IN) a an vd i rit li SR the Atlantic and in the Faroe Channel, showing the relation be Ke The numbers refer to the stations on the Charts, Plates II, 7 tet | | | | | | | | | i | HL | oe Fy et Pay = PL EN Ber en ae es -= bind temperature and gk ee serial ac reduced to curves. and IV, ey Rats gue Me ALP eS May a 4 bam fi ** ¥y wih 7 ai 7) te, ry 1) y yh ' CHAP. VI1.] DEEP-SEA TEMPERATURES. pep) 350 fathoms 9°°5 C. Jlessthan 300 fathoms . 0° 3C. 400? ache SO TF Wee 2 Os3 rs 8° 7 eye? rue fen BOUL” 8° 55 ae (eee AO = 15 550, 8-0 hee ue (1) aoe . 0°55 600, 7:4 oe eee res 650, 6-83 ce RE PSDiC6 BOD yop Mage, a Pent | ray 7 sac) see SS 4 Re eiey: (UL eae 595 EN i eae ae | 862 (Bottom) 4°3 WS 5 Younes . 1°25 The general result of these two series of soundings is very important. The high temperature reduced by 7°5 C. in the first series at 250 fathoms is undoubtedly due to superheating by direct solar radiation. This is shown still more clearly in the second series, where nearly 4° C. are seen to be lost between the surface and 30 fathoms, and somewhat above 2° C. more between 30 and 100 fathoms. From 100 to 500 fathoms the temperature is still high and tolerably uniform, and it falls rapidly between 500 and 1,000 fathoms. A reference to the second series shows that this rapid fall is between 650 and 850 fathoms, in which inter- val there is a loss of more than 38°C. This second stage of elevated temperature from 250 to 700 fathoms, which is represented graphically by the singular ‘hump’ on the temperature curves in Fig. 61 and Plate VI. would seem to be caused by the north-easterly reflux under peculiar conditions, which will be referred to in next chapter, of the great equatorial current. From 1,000 fathoms down- wards, the loss of temperature goes on uniformly at the rate of about 0°3 C. for every 250 fathoms. The most singular feature in this decrease of tem- ¥ 2 “aise oTjURITY oY} Ul sBurpunos ainqesod urs} W10z40q PUL [BIAS WO poyoniysu0d saAIng— "19 ‘O1T CHAP. VII. | ' DEEP-SHA TEMPERATURES. 325 perature for the last mile and three-quarters is its absolute uniformity, which appears to be incon- sistent with the idea of anything like a current in the ordinary sense, and rather to point to a slow and general indraught of cold water, falling in chiefly by gravitation from the coldest and deepest sources available, to supply the place of the warm water constantly moving to the northward. In 1870, My. Gwyn Jeffreys took his first tem- perature observations at the mouth of the Channel, and found them to correspond very closely with those of the previous year; on the 9th of July the bottom temperature at 358 fathoms, Station 6 PL V., was 10°0C., against 9°°8 C., at about the same depth in a serial sounding in 1869, in the immediate neighbourhood. The next few soundings, Stations 10 to 18, are in comparatively shallow water, off the coast of Portugal, while the next four Stations, a little north of Lisbon, may serve as an example of the temperatures to a considerable depth in that latitude. Station 14, 469 fathoms, with a surface temperature of 18°3 C., has a bottom temperature of 10°7 C.; Station 15, at 722 fathoms, a temperature of 9°7C.; Station 16, at 994 fathoms, 4°4C.; and Station 17, at 1,095 fathoms, 4°3C. This result is very similar to that which we met with in 1869 off Ushant. With certain differences, which seem to de- pend mainly upon the differences of latitude, we have the same phenomena—a thin surface-layer, superheated by the direct rays of the sun; a layer of warm water through which the temperature descends very slowly down to 800 fathoms; a zone of intermixture and rapid descent of the thermometer of nearly 200 326 THE DEPTHS OF THE SEA. (CHAP. VII. fathoms in thickness ; and finally the deep cold layer into which these soundings do not penetrate very far, through which the temperature sinks almost imper- ceptibly from 4°C. The difference between these soundings and those of the year before at the mouth of the Bay of Biscay is that the temperatures at all depths are somewhat higher. I refrain for the present from going into any detail with regard to the distribution of temperature in the Mediterranean, further than to give a mere outline of the remarkable conditions which were observed there by Dr. Carpenter. Dr. Carpenter’s observations were principally con- fined to the western basin of the Mediterranean, and during the months of August and September the surface temperature averaged between 23°C. and 26°C. On two occasions only the surface tempera- ture fell considerably lower, and the fall was attri- buted in both cases to the influence of the colder surface current passing from the Atlantic through the Straits of Gibraltar. The following table of the series taken at Station 53 gives about the average rate of fall of temperature for the first 100 fathoms :— Surface . 25°-0:.C. 5 fathoms . 24°5 jb aoa 21-6 30 ps: eee eit on eae 16+ 4 30, Rea eee es 1b <5 ae 14-1 ee 13°6 LOO mas: 13* 0 and Dr. Carpenter made the remarkable observa- tion that ‘whatever the temperature was at 100 100 rom the tempera erature, from t be es Saee uae eo August 1870, ese cay Gare teeoe Cape Finisterre an eae yations taken be ture observa 328. THE DEPTHS OF THE SEA. [cmar, VI. fathoms, that was the temperature of the whole mass of water beneath, down to the greatest depth explored.’ The temperature at 100 fathoms varies very little from 13°C. (555° Fahrenheit), and the Mediterranean attains in many places a depth of up- wards of 1,500 fathoms, so that here we have the strange phenomenon of an underlying mass of water, 1,400 fathoms deep, of a uniform moderate tempera- ture; a state of things singularly different from that which obtains at like depths in the Atlantic. Dr. Carpenter’s ingenious speculations as to the cause of this difference will be considered later. VAA¥ CHURCH IN SUDERO. CHAP, VII.] DEEP-SEA TEMPERATURES. 3 APPENDIX A. Surface Temperatures observed on board H.M.S. ‘ Porcupine’ during the Summers of 1869 and 1870. I. TEMPERATURES OBSERVED IN 1869. | Date and Position, May 28th Skelligs May 29th | May 30th | 2 E 4 5 R | Date and Position. | Z g a 5 # = zs es m | ES ze eB | BS gS | ee IS) | iS | Deg. Deg. || Deg Deg Cent. Cent. | } | Cent Cent 9) 4| 10-0 1-9-4. || May 30th... -3), 4 4. F100. or4 AT TOE atOs2 a6 | LOB | LO8 6 | 8 | 122 | il 8 | 108 5-05 11-1 10 | 10:0 | 10°5 || In Valentia . . | Noon.| 15°0 | 12°7 Off the Great : | FOr aD | 122 Noon.| 9°4 | 10°8 | 4 | 195 | 11-4 2 119 | seco we Sata late An V6?) Te) 8 6 | 11:4 | 10;21510'0) 7) Ll 8 i Midn.| 9°4 | 11-1 10. | 16 P10 || May Sist. . ..| 2 94 | 108 |Midn.| 10°0 | 10°5 | AppalLO:O= | ile age) | Go ee eked 4 72 | 8, ders. |p Lb | GAR TLEG. sali LO) a ies. | Lit Sl TPL 10:8 Tat. 51°52’ N.-) | Oe ee Were tie Ww. yj oem | 289 Lhe In Dingle Bay . | Noon.) 13°9 | 11°6 | De | ESO | Tt le 2eula Ochiai es Oe ie, Apel hiya 4 WM Ge a| bo een Ig eal 10°5 | | 38 D2 2k eG 8 | 100 | 105 | |, 10 | 116 11°6 10 | 116 | |Midn.| 11°9 | 11°9 Midn. | 11°1 | June Ist | 2 | Ot awe 94) TCG ! | 4 | 122.) 122 330 THE DEPTHS OF THE SEAd. [CHAP, VIL Date and Position. | | June 5th . cave flbel | 2 2s | | 3 Be | u 1 esis 25 Date and Position. Bie || 24 2% = ES = 5 5) oR is) Ais Deg. Deg | Cent. Cent. | Junelst. . . 6 12 EES) 8 130 11°9 || LO. | P33) .ES Lat.” 61° 22 N..) ne : Long. 12° 26’ W. § Noon. 14°4 | 119 | | 2 (brat) Te | 4 12:2 11°6 6 Ie | 19 g | 122 | 11°9 10 | 11°9 L222) |Midn.| 11°6 | 11:9 || June 2nd. PWV) |) ALTERS). 4 111 11°9 || 6 1105 | 119 |] 8 16 | 10 | 122 | 19-2 Lat. 52° 8’ N. )| De | Long. 12°50’ W. | Noon.| 15°0 | 12°2 2 14°4 | 12°2 | | A Bb Oe 19-3 | 6 | 139 | 12:2 |] 8 a as 10 TO cS] Midn.| 111 | 11°9 || June 3rd. . . 2 | Tis ee 4 | 108 | 116 || 6°) eo 8 | 1271116 | : = 10 | 150 | 11°9 || at. 52° 26°N.-)) Ae i en | | Long. 11°41’ W. t Noon, 13°3 | 116 2, 14°7 11°9 4 13°0 I pB2. 6 11°6 12-2 8 Picw 11°8 VOR eis 11°6 |Midn.| 10°8 | 11°6 Sune ns i i) Tae ea ee 4 | eG 6 LAL 11°6 8 | 10°8 11°6 } 10 | 105 | 116 | Lat. 52°14’N. ) een a | Long. 11°45 W. J pact 105 | 111 | | | June 6th . June 4th . In Galway Dock In Galway Dock | June 7th . In Galway Dock | | | | | June.8th.. ~ , | eM eecly oe te) a | a Fin | Deg. Deg. | Cent, Cent 2 133) GG 4 13°3 11°6 6 1258 eg 8 | 128 | 122 10) abeeye Tle Midn.| 11°9 | 11:9 2 TES | 11E9 As 8) PUGG ey IEG 6 ELS 7s ee: S| TQ ane 10 Ds, Wee Noon.! 16°71 | 13:3 2 155 150 4 | 13°9 6 [bid 8 133 ee C0) 13°3 Midn. 13°9 DN S23. 4 12:7 6 8 10 | 14-4 Noon.) 12°2 QF yi nee 4 19°4 6 19°4 8 | 10 13°9 Midn. 13°3 2 13°3 4 12°7 6 8 | 1O} | gG=t Noon. | 18°3 a | 4 iby (er 6 72 8 15:0 10) | 139 Midn.| 12°2 2 ale A CHAP. VII. | DEEP-SEA TEMPERATURES. Date and Position. June 8th. In Galway Dock | June 9th . | In Galway Dock June 10th Lat. | June 11th | Lat. 53° 22'N, | Long 13° 23’ W. 53° 16’ N. ) | Long. 11° 52’ W. § | E 53 3% Date and Position. E 2 : Ba o> | Be Bo lobe | GE) 125: || 6 ar | 122 : Se LO 1233 Noon.| 1277 | 12°5. | | 10 In1 | 199 ISS eran | Midn.| 1171 | 122 "A. 19:2 || 199) || Sune 14th i elebeten| ah c2 Gy Ue | a7 AA Ae ee, Se NO acs. |) 6, | lile4 119 LOD AO) 1253) 1 8-11-98 |) 12:5 Midn.| 10:0 | 12°3 || TO | iste ||) 122 2100) | 12-2. it late 53-43. N..) || : 4 | 100 | 122 || Long. 13°48’ W. {Noon rene) Nery 6, | Eli 125 | DN ee | ee Sores, | 1275). || A ise: | 122 LO. 12:5) 12°5-.\| Ge 4 Pes ae Seats laronce 8 +) Da. | es Noon 150 | 12°23 1 | 10 jae one ba Ua Dison lel Oey, |Midn.| 11-1 | 11°4 A aaa 2-7 | June 15th 2 | 10°8 | 11-1 332 THE DEPTHS OF THE SEd. [orap. VIL. : =. s ou | £E Date and Position. E a4 | Date and Position. iS 4 ae ‘ Boo a 5° | 8a a =) Fins Deg. Deg. |i ae ae Deg I ae | Cent. Cent. Lat. 64° 10'N Cent. Cent une l5th . . Ay iS" | 1556 at. 5 ON. Piel Omir 6 | 111 | 116 || Long. 10°59’ w. 5 | Noom.| 125 | 12 fe 8 | tae re | 2 | 199 | 19-2 10 | 192 | 116 | id 2 ee Let Boe IN)" 2 | oe erg eee 6. | 127") 10s Tae Sa Wey | en) Eee 8 | 11:9 | 118 2 | 136 | 116 10: | asl ee 4 | 130 | 116 Midn.| 11-4 | 11-4 6 | 13°9 | 118 || Junel9th . . 2 | dk |) ae 8 | 108 | 118 A | ik | rt 10 | 108 | 116 | | 26°72 | Ste) ee Midn.| 105 | 1171 | be 8. Pasa: Vee 2 | 10 | 139 | 11°8 June l6th . . Ze GOOF Oy sateen Diss Se 10°2 | 11-4 || At Killibegs. . | Noon.| 13°9 | 11°9 6. ey aes [2 eS) ya | 8 | 12:0 | 11°5 | 4 | 12-9 | 12-9 : 2 iets CO mes pw sam ft Be 6) SG ee tee oa) ON. aa Pes Sioa WUT So fa 2479 Long. 12°14’ W. Noon. | 15:0) 46S | 10 a ar ea | 32° [2s | 419 Midn.| 10°5 | 12:2 | 4 133° |g dame 20th” =, 0 Oe ee | 06. 1a) LG LO SRE Da ae 8.) 162° ae | Gx | a -SP Re VO | RAL), aa 8 ).18 74) 123 | Midn.| 11-4 | 11°4 10 | 23°0. | 2r9 June 17th | 2 | 116 | 11°6 || At Killibegs. . | Noon.| 13°9 | 122 [a A IG alee 2 | 150 | 122 fo 2G "LG! abs 4 | 144 | 1 8 | 136 | 116 6 | 144 | 1 ee e 10. | 125 (26 8 | 122 | 1 ‘Lat. 54°97’ N. : at, ; LO OL ee | Long. 11°43’ W. Noon.) 13°9 11°8 Midn.| 10°8 | I 2 | 133) 119 | June 2ist. . il se 3 (| | Ar) ABS | See AO) Sea 6 | 122 | 11:9 6 ass" at | 8 | 122 | 116.| 8 | 122°} 1 10-9). 2859) LRG 10 | 13:0 | 1 Midn.! 12°2 | 11°6 || At Killibegs. . | Noon.| 15°0 | 1 June lSth . . O54) FAG? | ATG DI wsleaeseo ated 4 | 116 | 12:0 A) TAR i 6 18") 19-0 6 Sao ite B |) FRB: | 19-1 8. “|. Lega 1 rm bo bt mnmMmwwhyNwNwWwNWW dw wt Se 0 bd Cr bd Or bd w} wb} 9 WS Or Crt ht CHAP. V11.] DEEP-SEA TEMPERATURES. 333 = £s Bf §2 |o88 Date and Position. See oe Date and Position. 5 a8 ae E5) om | GB Ene | | Deg Deg | Cent Cent. | June 2lst_ . . | Midn.! 10°5 | 122 | June 25th June 22nd... 2 alt, Tes peated aig Gaels 116 8 1AEG Ie) 10 13°3 | 12:2 || June 26th At Killibegs . Noon leis: "12:94 2, 13°9 a | 4 | 133 | 122 | 6 Pe? 17) 8 In Donegal Bay TOE Spee Fale | aay || Mian) aia 11°9 June 23rd 2 Oss ao 4 Wale 12°2 6 | 12-4 | 19-9 | 8 TED De | 10 | 155 | 125 || June 27th At Killibegs . Noon.| 16°6 | 12°5 | 2 159) 117055 4 Nace I) W227 6 16°6 1bai32 8 | 133 | 13:0 | At Killibegs. 10 13°6 ore Midnite al27 30 | diume 24th: 5: 2 12S {aes | Ae els =o) ssn || 6 14:4 1345) 8 | aeai | 13:3 10 | 166 | 135 | June 28th At Killibegs. Noons)-£7°5 | 13:5 | 2 sleia-7) 391 -| 4 Ie S7/ Nai || Go 2 sets 20 || 8 | 161 |} 141 || Lat. 54°54’N, ) 10 | 147 | 15:0 || Long. 10° 59’ W. { Mien.) l427) 2) 115-3 | June Both 2. Ora AA! | Aaah te Tait 6 13°9 13°6 | 8 | 18°3 14°4 10 200 13°9 | At Bundoran Noon.! 20°5 |-16°6 June 29th 2 23:9 | 16°6 +3 ae || a5 sre sf) ence an =| Be °o reed Deg. | Deg Cent Cent 4 TSZO% 50: 6 16°1 13°9 | 8 15-0 141 10 ae) 55) Midn.| 14:4 15)45) 2 as 15°8 Ay | 1359 1ai20) 6 139 Ui} 8 133} 13°6 10 | 18-0 | 14-4 | Noon. 19:1 139 2 222, ate 4 19°4 161 6 16°6 115)43) 8 a5) 1LSi95) IO yh 87 Lay} |Midn.| 12°5 | 15-0 oh Wailea 14°4 4 11°4 14:4 6 17 39 to) 13°6 13°9 10 15)5) 14°4 Noon.| 16°6 14:4 2 20°0 15-0 4 eg 14°4 6 ene 133 8 iis Ils 10F 33> \is-3 Midn.| 13°3 | 13:3 Vy || IS 7 1333} 4 Der 129 6 Bee ieey) 8 S35} 130 10 13°9 | S733 Noon.| 14:7 | 13:3 | 2 | 147 | 13:3 4 13°9 1333 6 30 13°9 i. 8) 513-6.) eiaep Fe, LO) Pe LSPs} | Midn. | 12°9 13°6 | Piii| M9 ore 4 | 122 133 THE DEPTHS OF THE SEA. 334 | s | Be | BS | Date and Position. iS ga 22 5 | 8a B&B Bis D g. Deg. Cent. | Cent. June 29th 6 | 1s6° ss 8 14:4 | 133 10 166 | 13°9 ‘| Lat. 55° 11'N. ) Long. 11° 31' W. § Noon.| 16°6 | 144 2 161 4 a1570 + 15°5 | 144 6 155 | 144 8 | 150 | 14°4 10 | 136 | 13°9 Midn.| 13°3 | 13°9 June 30th Da) Ae Oo 1a + 13°3 | 14:0 6 | 166 | 139 8 18°0 | 13°9 + A 10 | 1671 | 14°4 at. 55° 44'N, ; ; Long. 12°53’ W. | Noon.| 164 | 14°4 2 17-7 | 145 rT Vi Uy fay fo i 6 15°8 | 15:0 8 15:0 | 15:0 10 144 | 15°3 Midn,| 13°6 | 14°4 July Ist . By Ta +t 13°3 | 13°9 6 155 | 14:4 8 16°3 | 14°4 10 bese |S 7/ Noon. 17:2 | 148 2 17-2) GsS 4 166 | 15°0 6 15:0 | 14°4 8 144 | 14°4 10 141 | 141 Midn,| 141 | 141 July 2nd. 2 | 141 | 13:9 4 141 | 140 6 15°0 | 141 8 | 155 | 141 | 10 | 15:5 | 14:4 Lat. 56° 9'N. Q| Sie At as 3 Long. 14° 10° W. ! N@es CN 2 | 17-4 | 147 | July 5th . Date and Position. Hour, July 2nd . 4 6 8 10 July 4th. . . 2 10 Long. 12° 49’ W. [> 4 | 3 8 10 2 + | 6 8 0) Lat. 56°41'N | Long. 12° 56’ W. | Midn. |. ouly Sree = 2 (CHAP. VII. | | | Lat. 56°47’ N. | Noon. | Midn. Temperature of Air Temperature of Sea-Surface. CHAP. VII. | DEEP-SEA TEMPERATURES. Boul Dat d Positi g EE £3 Dat d Positi 5 EE EE ate an OS1t1ION. = BS a3 ate an Os1tlon, x BS Es & Eien H As \| | | Deg Deg | Deg. Deg. | | Cent Cent. Cent. Cent. | July 6th . 2 | 12:2 | 139 || In Lough Swilly | Noon.) 15°8 | 13:3 AP No 1S9) | OF 16d: 133 61s 438 4 | 155 | 130 S | iso p41.) 6. (163), 133 . i 10 | 141 | 139 Sw |skS:Onielas at. 56°22’ N, } LOY 1229) 3 Long. 11°37’ W. 5 | Noon. mS Midn.| 11-6 | 12°7 2 | 15:0 July 10th .. Be LEG) | 1356 4 es, | 4a Ae 12-98 36 6 | 139 | 144 | 6 | 141 | 130 8 | 133 | 144 8 | 16 | 13-4 10> |) 12:05 |Mis9 10) |) 161) 13-4 | Midn.| 11:1 | 13:3 | In Lough Foyle | Noon.| 17-7 | 14:4 July 7th *- 21s Wisse 2 | 17) 15-0 | A TAN g:3: il An ES |. 17 6s ps7 || 13:3 I 16: 1 16a 4) 144 8, | 147, 13:8 } 8 | 144.) 139 > 10 150.) 134 pat 13:9) 33 at. 55°55’ N. )| idn.| 14-4 | 13°9 ones tor in Was| cc) 80: 183" ll suty Tighe <0 |- 2 |, 1e-ov Meee [P25 6150) (139 4 | 13:9 | 144 4. | 15:0) | 13:6. | 6) | 147-1139 6 |:150, | 13°9 8 | 163 | 13:9 Ha fet a0 a Fs) pra | 10 | 166 | 13°6 10 | 144 | 13°3 t Moville, | ; ’ | Midn.| 14.4 | 133 | Lough Foyle Noon.| 189 | 14:4 duly 8th, . -. 2 | 144 | 13:9 | 12 Die te2OeD el Mes 4 | 144 | 136 4 -| 211 | 15-0 6 5155") 13-9. | 6 | 189 | 14-4 8 | 155 | 139 8 | 18:0 | 14:4 10 | 15:0 | 13°9 | 10 | 15:8 | 13°9 Lat. 56° 6 N. ; : |Midn.| 15°8 | 14°4 Long. 9° 36° W. Fee Oe a letaiy ody =<. 4° > Of Nibecl ast 9 Ae Wile:6- | AS | 130") 127 Ae 150/136 | Ge sols eu FoeG* 5s 3 5139). | eSBs aba. | ar fo eBrate 3 /l1a6- 4 10 | 161 | 105 10 | 133 | 13:9 || Off Belfast | : : Midn. 127 ssk2:7 Lough . ; } Noon.) 155 | 111 July 9th... 2 | 12°2 | 189 || Her) | Gels ind AN AQ | 1277" | | 4 |.139 | 144 6 | | 6 | 144 | 144 Soa T4133" | |. Bae) Maa Say 10 | 155 | 133 | | 10 | 12°7 | 122 [CILAP, VII. | 336 THE DEPTHS OF THE SEA. 2 ae 2 5 aS | = H | #4 | #3 | 4 ie Date and Position. | 2 ay Be Date and Position. Ss | zo = Sige ar ee tee | a | aie) BR Deg. Deg. Deg. Cent Cent. Cent July 12th |Midn.) 12°2 | 116 | July 16th 4 161 July 13th ls oa tO. 133 -| 6 16°1 are a a ee | SR yar 1. 86 12:2) fol3i3 | ho Wee | 28 13°3 | 13°6 | Midn,| 14°7 10 | 13°3 | 141 || July 17th 2 | 197 At Belfast Noon.| 15°5 | 15:5 4 | 122 2 A Al pee 6 16°4 - 16:6.) Wve2 |) 8 Wien 6 ieeTin alate || 10 19°4 § | 155 | 17-2 || At Belfast Noon.| 26°1 10s} 122) 166>)) 2 18°9 Midn.| 11°6 | 166 | 4 15°3 July 14th 2 | 133 | 166 6 2) aay 4 13°3 | 16°6 8 15°0 6 141 | 163 10 15°0 8 155853) 656 Midn.} 16°6 bea a iE: G6 “July 18th 2 1671 At Belfast Noon.) 17°8 | 16°6 4 15°5 | 2 18°3 | 16°6 6 LE" + 17°8 8 15'5 6 10 16°9 [te al | Off Tuskar L.H. | Noon.) 16°6 boda Kora ! ee A alo | Midn.| 16°1 | 16°6 || 4 | 19°4 July 15th 2) 15 16s 6 | 17-9 +f T5:0° 16:6 8 19°4 6 3) 166.9) toa 10 18°0 8 | 183 | 164 | Midn.| 17°7 10 | 205 | 17-7 | July 19th 2 | 161 At Belfast Noon. 21:4 | 41\ 455 | Q | 21-1 | 6 | 163 4 | 81-17 | Shao 6 | 205 | 17-2 | 10 | 216 ee ee Vere At Haulbowline Noon.! 22°8 10 | 194 | 17-2 2 | 20°0 Midn.| 17°7 | 17:2 }} ] 4 July 16th Mee mele S| | 6 | 200 4 | 166 | 172 | PB ae 6 | 175 | 172 | | 10 | 166 8 | 189 | 172 Midn. 16°6 10 |-22% | 17°7 | July 20th 2.1; 169 At Belfast Noon. | 22°5 | 18°9 Jj | 4 | 166 2 172 | 18:9 6 176 | Temperature of Sea-Surface. 2 2g 2 2g on =a 28 Bie ee hes eee eee Date and Position. iS ae 2 Date and Position. 3 Bes 2% s oN 5 5m i= Eis al Sr) Deg Deg: || Deg. | Deg. Cent Cent. | Cent. | Cent. July 20th . . Sajo20or | Ss. fduby ard eB). Se Ta icles 1O9P | 2rd | 18:95 || 6 | 189 | 183 Lat. 50° 28’ N. ) | =i ey Se iyo E83 Long. 9° 37’ W. { Noon he | 10 | 17-2 | 183 2 =| 208. | 519° «|| | Midn.|} 16°6 | 183 4 | 200 | 194 || July 24th Wee eh7-2e | 183 6 | 20:0 | 189 Peeeen TROL Wess 8 | 186} 183. | [nn Uae Os Wiveen te: ||| Perse les 6) 180 |Midn.| 17°2 | 18:0 LOM US One ae:3 uly 2igter. Sa Qe) Lee Lee thats 4740! Ne = . 4 4 | 172 | 169 || Long. 11°34’ wi | aioe: Greet Doe DO WO AT S:S Saal ler elie 4.) 189e) 183 Owe | USO ne |e le7-5e| Gael ese | rey Lat. 48° 51' N. NBSP Mets | SELON N19850 Long. 11° swf te ee | 10 | 183 | 183 bee Dias QOS | a7] | Midn.| 17°7 | 18°3 Pieces Stasi gee Sully Doth 2). sae Oba 7-oue lesO Peri oulelorse lL 721) eA geVale?On | 18s Pe ree eo herOn i tyag a cc y ene glee bola Play Sl Mee oe alle Beata ETI |Midm.|) 1727 | 1720 | LOS (tS), Vela July 22nd [ee OF ol IG OMe) Wate 49eq 1 ON, ete ie are : | 4 | 17% | 17-7 || Long. 19°29" Ww. ¢ | Noom-| 18°9 | 1i7 e SGr ale au eral on SO Me liege SBA ES OM 18:0 CR aMiay hot a Wel PSL Oia eter Dpn| lene GLAS Sy 177 lat; 47°38 N.) |: eee ahs 8 1g. | ie3 Long, 12° 11' W. {Noon eae bam 10 | 183 | 17-7 2 | 194 | 183 Midn.| 189 | 17°5 4 | 200 | 183 || July 26th Qe WUe se 17-2 Gaal 1ecoMsh (es Aoi) Gag iy 2 Sa Lone 1S al 6 LZ ee LE Peto: sini 18:3. | Sater 735 | Midn.| 17-2 | 18:0 || Ore 1S. W777 lyre eae | Soa les) 1870) || ats 7497 0.N.n?' | ; oie J eigen iss, || Mearttisss way oon | 188) |e? Gakelieme| Lay el Ler UT ‘ Sea G-4ac'-18:0: || 4. | 16:90 | Van 10 | 19-1. | 18°0 -|| G |) 16-Seieir a Lat, (47°39 Nae . 8. \, LGa lay Long. 11°52’ W. { ae 20°0 | 18:0 10 | 161 | 17-7 2 | 200 | 18°3 Midn.|} 15°8 | 17°7 CHAP. VII. |] DEEP-SEA TEMPERATURES. 398 THE DEPTHS OF THE SEA. [CHAP. VII. | 2 Slee Date and Position. | as Date and Position. e ae ae | = a's oa #6 | 88 | | | & a see | [ares Deg. | Deg. || Deg. | Deg } jaly-aveh 5 ore soe I Tat, 51° 5’ N Cent. | Cent JULY 24 a Lore : at. ae pak : | ‘ 4 | 150 | 17-2 || Tees Noon. | 17°7 Pea | es ae Tet Wig) ame Na by | | 8 | 146 | 175 | | 4 |175 | 161 | . | 10 | 189 | 17°5 6 | 172 | 166 | Lat. 49°10’ N. } Bese ech 8 | 166 | 166 Tine 19°45" Wey | COE ae a | 10 | 166 | 155 2 ate areal Midn.| 16°6 | 15°8 AS ASO Nay ol duly olshe ws 2 | 163 | 155 6 (As8 4 ey | 4 | 155 | 155 88) Je cies 6. | 153 | 147 LO Sea eet 8 172 | iy Midn.| 15°8 | 17°7 Near Cork Har- } 10 | 189 | 125 July 28th 2s ers eles ear Cork Har- } | niles, : 1: 4 | 150 |166 || bour . .« .§|Noom| 166 jue | 6 | 155 | 169 | ge) | 8 | 186 | 166 || 4 | 183 | 161 be PLO tee" | ese 6 | 161 | 15°8 Lat. 49°59’ N.) | ; Nil 8 | 144 | 14-4 Long. 12° 22' Ww. } Noon. AM ee 10 | 12-7 | 11°6 2 |19°7 1.169: | Midn.} 12°7 | 1171 4 | 183 | 1771 || August Ist 2 | 122 6 | 166 | 169 | 4 | 122 8 | 155 | 169 6 | 13-9 | 0, WSS) Sb 8 | 166 | | Midn.| 1671 | 166 || eet) ran | Ley July 29th... 2 16:1 | 17°2 || At Queenstown. | Noon.| 19°71 | 14°7 AS) ar 2 .| 189 | 153 6 | 158 | 169 4 | 189 | 158 8 | 164 | 169 i ac 10 | 166 | 166 8 1359" il alee Lat. 50°24’ N. | | 710) 19389] 1570 Noon, 272) | 63 Long. 11° 42’ W. Midn.| 12°5 | 14°7 2 | 1671 | 163 || August 2nd. . 2 | 122 | 144 4 Lia) Lore 4 11°9 | 15:0 Celi | 166 6 | 12:7 | 155 8 16°3 | 172 8 15:0 | 15°3 10 V6c || 16:6 10, | ae Midn.| 16°71 | 17-2 || At Queenstown. | Noon.} 15°5 July 30th . . me (We Hor MRS a Bas .x || August 8th . 2) 139 150 end pio | Oo) 144 es | 4 | 139 | 15-0 eagerly 10320) ol 6 | fe Al eee |) eet | 8 | 15-0 |. 150 6 166 | 15°8 1 10 155 | 15°3 Sie lores | At Belfast | Noon.| 17-2 | 15°8 10: 133 | 15:0-_|| | 2 | 20:8 | 161 Midn.| 11-1 | 139 AS NGO. | las August 5th . . a fe a i | 6 Wl39e ela 4 10°55 | 144 8 144 | 158 6 12°7 | 146 10 136 | 15°8 8 15°3 | 14°7 | AW Ene eis |) ALG) |) aay: 10 | 183 | 15°0 || August 9th . 2 | 133 | 155 At Belfast = . |Noon.| 16:9 | 15°5 4 | 133 | 155 2 | 174 | 6 | 133 | 153 4 | 17-7 | 164 | S|. 13:3 us /6 12S | Sb. || ie LO 144 | 155 8 | | At Belfast | Noon: 5:0) =) 165 LOS Tie, |. 15:0«. || PEO TG 0 Voss Midn.| 10°0 | 15°0 || 4 | 166 | 15°5 August 6th .. Te LOp | La 6 | 144 | 15°8 4 | 100 | 14-4 || 8 | 114 | 155 Go| 125. | 141. 4 10 | 10°5- | 15:0 8 | 166 | 14-4 || ‘Midn. 100 | 14-4 | | 340 THE DEPTHS OF THE SEA. [CItAP. Vil. Shiant Islands, ) N.N. W. 6 miles § |~ 2 Date and Position. | 5 ae isa) ao | Pete Deg. Cent August 10th. 2, Ca | t 10°5 Ge) i 8 | 114 1 LO 39 At Belfast Noon.| 15°5 2 | 15°0 4 | 147 6. slau 8 | 11:9 10 | 116 | Midn.) 11°6 August llth. . 2 | 10°5 AS. La 6 12:2 8: 4 133 10 | 144 In Belfast Lough | Noon.) 14°4 eee Bt Bs} 4 | 15:0 1 6 eae (ees 12°2 {DO's ae Midn.| 12°0 : August 12th. . 2 | 122 4 lige! 6 11°4 8 13°3 10 17°2 Coll — Island, aA North, 3 miles Noon.)18% 2 | 15°3 + 144 6 12°7 8 12°2 10 ey | Midn.| 12°0 August 13th. Heh pag es et le Ae | 1 Pa ot i" 20 12°5 | 10 14°7 i w «>, ow 2 2 23 2p Date and Position. 2” 0 |e aes Ea Be | ar eal ace ans z ae Deg Deg. | Deg Cent. 5 Cent Cent 139 | August 13th. yim ie 2a fa 1 8 14°7 | + 12°7 | 12:2 14-4 | 6 | 133 | 116 14-4 || 8 12:09 ek | 10" |) 2s 15:0 || Midn. 111 | 122 | August 14th. 2 | $P6. | 1270 4 | 11-4 | 114 6 | 114 | 122 15°0 8 | 13387) 1250 14-4 LO; 18-7 13°99 | At Stornoway Noon.| 15°5 | 12°2 139° | D2) VG | 125 13'3 A) 15:0 toa 13°6 6 | 147 139 I 8 lots 12°2 | 10 | 133 | 125 14:4 || Midn.| 12°7 | 12°2 12:2 | August 15th. 2M ove ele 13°0 4 13°3. | 12°2 12°2 6 13°3. | 12:2 | 12°2 8 -|.13°9 | 122 eae, F 10 | 139 | 122 11°7 | At Stornoway Noon.| 14°4 | 12°2 12°2 2 1578 | 12° lily 4 161 | 13 12°0 6 15°5: | 12°5 19°5 | 8 | 133 | 125 12°7 | 10 | 12°7 | 127 125 || Midn.} 13°0 | 12°2 7 | August 16th. Q | 19°7 | 12:2 133 || AN LRT el Bee 12°2 6 13:3) 12:2 12°2 8 133 | 12:2 12°0 10 136 | 12:2 12:2 ||, Lat. 59° 21’ N. = : 122 Long. 6° 58 W. Noon.! 13°3 12°0 11°6 2 1370) 1 1252 11°6 | 13°3 | 12:2 12°0 6 | 13:3 | 192 12°0 8 12°7 | 12°2 116 10 | 12°5 | 12°2 116 | a Midn.| 12°2 | 12°2 August 17th. 2 1s ES) Kas He LSC CHAP. VII] DEEP-SEA TEMPERATURES. 341 Date and Position. 2 5a SR | Date and Position. 2 BS Ea a ES aS || a aS) aS D ce) i) on a Biss = Bs Deg Deg. || Deg Deg Aueust 17th 4 12 1-9 Lat. 60° 35’ N. ) Baer = 6 199 | 11°9 1 Long. 6° 41’ W. § Noon.| 13°3 | 11°4 8- | 12°2 | Be oe Sa A * No) 10 13:9 | 12:2 || 4 Ze eG | Lat. 59° 36" N. re : 6 | 94 | 11-4 | Long. 7°12 W. §| Noon.) 18°99 | 122 8 | 94 | 10°5 2 W3ié | Lg 10 97 | 10:0 4 14:1 Wales) || Midn., 10:0 9°4 6 13:0 | 11°9 || August 21st . 2 10:0 9°4 8 12°5 | 114 | 4 9°4 9-4 LO ieee) tele 9 6 | 100 | 9-4 Midn.| 12°2 | 11:1 || 8 10:0 | 10°0 August 18th. BE) WO RON 7 FihS36 977 AY | OO.) Wet. | OR ‘Sandor im) sus ‘ 6 | 12°7 | 111 || Féroelslands § Mision Gs oh 8 | 13:9 | 114°] 2 | 14.8 | 10 13#(03, 6 |) IOS} 4 4 itz oul Lat. 60° 25’ N. 6s | 6 -|1il4e) oa Long. ge 9 W. ( Noon. | 13°6 114 8 105 O°] 2 RA |) abet 10 10°8 94 A 125) | 10-8 Midn.| 10°5 9-4 6 | 12:2 | 11:1 | August 22nd 211055 91 8 U2 2 tel 4 10°8 9-4 10 2) al] ALLL 6 leat gall Iii hay |) Sy aL 8 116 9°4 | August 19th. QW WD hy eh TO. Wl 9-4 4 | 12:2 | 11:1 || At Thorshavn Noon. | 144 94 6 Aare | lial! 2 13°3 9°7 8 ee | A | 4 12:2 | 10:0 | N) 10 13°3 | 114 | 6 13°3 97 | Lat. 60°13’ N. 2 | see ; S| 10% 94 | Long. 6° 41’ W. § Noon.| 12°7 | 11 | 10) =) L070 9°4 2 Sse gle: Midn.} 10:0 9-4 4 | 13°9 August 23rd 2 9°4 9°4 6 Ie |) allreat 4 8 Dee) hel 6 10°8 9°4 10 Wr) LSI Se LO 94 Midn.| 1272) |. 10°5 10 12°7 9:7 August 20th. 2 + 12°2 | 10°5 || At Thorshavn Noon. | 12°7 9°7 4 | 120 | 100 Dee Lark 9°4 6 122 | 10°8 4 | 12°7 9-4 8 12 || 105 6 12°2 9°4 10 12" +) L038 8 116 91 342 THE DEPTHS OF THE SEA. Hour. | Date and Position. = August 23rd August 24th. 10 About 10 miles | East of Haalso § August 25th. | Lat. 61° 36’ N. Long. 3° 45’ W. 2 4 6 8 10 Midn. August 26th. . |. 2 Lat. 61°14 N. ) | Long. 1° 58’ W. § August 27th. . be Noon. Noon. of Air. Temperature Date and Position. August 27th. | Lat. 60° 26’ N. Long. 0° 15’ E. August 28th. At Lerwick . August 29th. At Lerwick . August 30th. At Lerwick . Hour. | 10 | Midn. (CHAP. VII. 2 2g oa 22 & Bes | Deg. Deg Cent Cent. | 111 | 11°4 VEG 116 DT aah US Sei eae 12°2 | 11°9 AOL eS i Le Nat a 3 2 10500 ee 9°4 Se 10°5 11°6 12°2 11°6 LS; iS 10°0 ASML. LOO) el: 9:4) Tel LOD ye! Tiki te: Syma allel Sieaaelelel 75 1 Te2 lala: Tor? ey 77, | Lows 7 | ale | Oi: 9°7 Tg tl 94 ita ies bi 9°4 1121! 94 | 111 9°1 TW Hed. a ll LOSS 89 | 10°8 So tee br 8:3 | 10°8 LOS) ee Att! TAIL 116 eet VO Ne ce LOD i eS Wek iD be CHAP. VII. ] DEEP-SEA TEMPERATURES. 343 | | | ! . | | | 2 28 | ys Es Pa face ane ene ue he eat | Date and Position. 5 Pie Siva) Date and Position. | Saal | ea a ae | Ve eee ge ao || len a BQ || | i= ei sl | | — — — ae 7 = | are = evra rae | Deg | Deg. | Deg Deg | Cent. | Cent. | Cent Cent | | August 30th. . 10 | 72 | 111. | September 3rd. | 10 | 13:0 | 11°6 | 66 |. 111 % Lat. 60° 3 N. Qian | August 31st... 2 GQ |-10°5) i Long 5.107 W.. <4 4s ene 0:5 9 | 125 | 11°6 65 100N fick 4 | 192% | 11°6 Se Ose, iatacd Gy) tas) 10m ideG | 108 easel! At Lerwick . . | Noon. 122 | 111 | Eat) 127 | 116 Oise | el Midn.) 127 | 122 4 | 111 | 11:1 || September 4th . eo) 120) | 122 6 | 105 | 111 4 | 133 | 199 ace sy fe Dc Pe fa 6 | 139 | 12:5 |_ 10° | 10°8 | 10°8 8 | 139 | 195 | Midn.| 10°5 | 11:1 10 | 14:4 | 192 September Ist. etal Aen) Siete Maas nO meen ec )nieae een ; Nae Tha GaN liens s 6s a5 Ws bone lee Go} Ué-| iee 2 is sm la Se tabicG. |, Linge) 4 | 130 | 12-2 boll kit | 114 aR ee jee Tats 60° 277 Na) here. 6 [oe Se alee allele Eero (oe) ek EEG fro" W220 letiee 2 > el ele Midn.} 12°5 | 12:0 4 | 133 | 11:4 | September 5th . 2 Beez E20 Ge) | lle Gra ets) Ae) POs el is Se eiiean setae 6 | 12°7 | 11°6 LOp | Tees) te «| Seo 7 a ties Midn.} 11-1 | 116 || LOM else S *Q . KQ° 2a’ September 2nd . 2) 108) || 10:8 ! a oe 38 ay ‘Noon 144 | 199 én iret | 10382) 2 | 136 | 116 8 | 111 | 103 | 4 | 19:0 | 11°6 10° | 11-1 | 10:3. |] I Gre! ties lace Lat. 60° 29° N. Reed |e cried rales Long. 4° 38! W. EE a ee, 10 | 108 | 11-4 2 Tbe WaKOn ee oh Midn. 11°1 | 11-4 4 | 116 | 105 | September 6th .. |° 2 | 111 | 11°4 Gol WleG aa A TSN hs tele Seiciteie ie | 6 | 19% | 11°6 10 | 116 | 11:4 ellis: | take Midn.| 11:1 | 11°6 | 10 | 127 | 12-0 September 3rd . Peels Grilet eluate Oysu. IN). | ae Peli | tit hones? 4 we. (| Nom | 1Ae | 122 Geritit b1i-6 | | 2 | 130 | Bite ke | fee do | 12 eran eo 344 THE DEPTHS OF THE SEA. [CHAP. VII. Date and Position. How. Temperature of Air. Temperature -Surface. of Sea Date and Position. Hour. | September 6th . September 7th . Lat. 59° 41’ N. ) | Long. 7° 32! -W. 4 September 8th . at. 59 7° wN.) | Long. 6° 35' W. § September 9th . At Stornoway September 10th fosl| ome femme) Jameel — wmwmwo ao HTS 12°7 | September llth {| 2 | In Loch Sheil- ) ee bo bo bo WW Wb bo ~T-T “I Go ~T “I-17 September 10th — 6 _ At Stornoway . | Noon.) 10 _ At Stornoway . | Noon, September 12th 2 At Stornoway . | Noon. 10 |. | Midn. | | September 13th 2 a 6 8 10 dag . of Air. Temperature pe ee | 1% Noon. Temperature of Sea-Surface top be to bb rw ly boty “ | OR NOES SS hos i NO oS fs fs fits fi ~ ~ bd bd bh or or bd & — a bo bo to bo bo bo b 12°0 CHAP. VI. | DEEP-SEA TEMPERATURES. 2 28 2 | 2¢ Date and Position. e , 54 5 a ! Date and Position z 5 4 | és R mH | ge | es | i LReree ih ale © on || D | om = Sissy || = | ice 3h core va Deg Deg. |} | mee Eee Cent Cent. |} Cent Cent September 13th 8 | 13:0 | 12°2 | Abreast of Mull | Noon.| 12°77 | 13°0 | 10 122; 290 2 ial |) lake Midn. | 12°2 Ion | 4 14°4 ere September 14th 2 | ALE 2 i Gee) LS Olle 4 12°2 12 8 13°0 13°3 6 12°5 12° 2 | 10 1G9725) 13°0 8 | ig2) | dara) Midn.| 12:0 | 13:0 TOE) WEG) eters Il. Surrace TEMPERATURES OBSERVED DURING THE SUMMER.OF 1870. Date and Position. July 6th . Off Scilly Islands | July 7th . | Lat. 48° 49° N. \ "Long. 9° 35° W. § E aS 5 BS H | BE | BB q | #8 ) 83 S oe on Date and Position. e on aa A Eee iI Exe Deg Deg Deg. Deg Cent, Cent Cent. Cent 2 ise) pales July 7th . 6 19°4 | 16°4 4 ACA ety 8 IAQ AUP 6 13:9") L2:5 10 169 | 164 8 A Mee Midn.| 16°6 | 16°4 10s | 53.) 1369) Suly Sth. RRR Wat Sec yal Sy Noon.| 18°6 | 18°3 Pa GAM Gel 2 19°7 | 174 6 NGO lest 4 19°4 18°3 8 19°1 16°2 6 189 | 18°3 10 20°38 | 1671 8 WN Ayer Lat. 48°31 N. ; = 10 | 166 | 17-2 |) Long. 10° 6’ wi} Neon ee el = Midn.| 1671 | 17:2 2 90:0 || 17°5 2 G36) 4 LG:6 4 USe6e || 17e5 4 166 | 16°6 6 19s |) VES 6 NGRGen| L656 8 Ure ae My 8 169" 121639 10 16:9 | 17°2 NOM etary) |) 1674 |Midn.| 16°6 | 16:9 QO 5 5 °C Megniaea tags | uy 9h Pamala: v) 194 | 16°4 6 1G) ShGEG 4 TSROE je? 8 16a | 1656 346 THE DEPTHS OF THE SEA. [CHAP. VII. | Date and Position. e aS | 2% Date and Position. iS | a 2% niet ED " 5 = Sn eA As a Bs | Deg. Deg. || Deg. Deg Cent. Cent. | Cent. Cent. July 9th. . ") 10. | 175-| 166 July 12th .. 6) 4) 179 4480 | Lat. 48° 26’ N. 2 | aie eta, fea 8 | 166 | 18°0 | Long. 9° 43’ W. 5 | Noon.) 17°5' | 166 | 10 | 166 | 17-2 2) 164 | 166 | Midn.| 16°6 | 17-7 4 |172 | 166 | Julyi3th . . | 2 | 172°) 17-7 6 | 164 | 166 L447 25 8 | 164 | 161 6. .| Bee mie | 10 | 166 166 8 | 186 | 175 | Midn | 16:1 | 16°4 tet ae | 10 S29) \ Sie July 20th =. ~. 2 | 161 | 166 || Lat. 44°59’ N. | 5.1] oe | 4 | 16-4 | 16-4 || Long. 9°33’ W. {|N0B-| 19°7 | 18 6 | 166 | 1674 | 2 | 211 | 189 Bol Tess | ale 4 | 225 | 18°9 mn 10 | 173 | 166 6. 4 211 9) da 1 ree eto De ee ee ee ee | Sl 175.185 Long. 9° 49’ W. \ Noon. | 16°1 16 6 | 10 175 18:0 bee | ee tie osal “Midn.| 17-2 | 18°0 | 4 | 194 | 169 || July 14th SO Ar WAS) | 6 | 196 | 166 | 4 |17-2 | 17-2 | 8 | 162 “166 | 6. |.169 ) 164 epi bom Ps Na 8: 11830) 1641 | Midn.| 1671 | 1671 10 | 186 | 15°5 July llth .. | 2 | 169 | 166 |} Cape Pees) fA eera |e E. N.N. Noon.| 186 | 158 6 | 164 | 161 | 10 miles . J Se (A637 atoelat 2 | 186 | 15: tie 10 | 186 | 16°6- | 4 | 191 | 15: | Lat. 48° 8’ N. )| : . 6 175. 5 Long. 9° 18° W. {| Noom-| 18°6 | 169 | | g | 166 | 15: 2 | 1Se)\) ae) 10 | 166 | 15° \ ee VO SPS) Midn.| 166 16° Ve en ae 2 Uy Ss), oe 1 a 2 | 166 | 161 8 166 | 166 4 | 166 | 166 10 | 17:2 | 172 | 6 | 175 | 164 Midn.| 17:2 | 17°7 8 18°3 | 16:9 July 12th . tr Alan i By i is Be 10] 18:9 are A CATA) REO diate 42° a 6 | 17-4 | 180 || Long. 9°13’ w. (+ Noon-| 20°0 | 16 Solver al Ge | 2 | 933 | 175 10 | 186 | 18°0 4-1 S13 ato Lat. 46° 26’ N. a as ace 6 | 19°0 | 189 Long. 9° 31’ W. {Noon ate | 8 | 179 | 18-9 ee | 04. | 180 1024) 2 ps | 4 | 17-7 | 18°0 | Midn. 189 | 193 CHAP. VII. } DEEP-SEA TEMPERATURES. ) | Date and Position. 2 a oe | Date and Position. S aN SA = aS | —) ai] Deg. Deg Cent. | Cent. uly6th. = ys) | 207) toe 190} July doth 2 | hh FAS Sintey=2) | Tea" | A 6 | 183 | 179 | feeg 8 | 2071 | 19°4 | 8 LON, | 22252) Oia : | lo At Vigo . . . | Noon.) 23°6 ie ato || | Midn. | | ieee 2, | 9-6) (Oe i July 20th iin |) — 2s) 4 | 23:4 | 18°0 || 4 6 OisGiey deve2 Gn} 8 184 | 16:1 | 8 | 10 Wieth) \neli ORG 10 | Midn.| 17-2 | 16°9 |) Lat. 40° 0 N. din July Lith =. . pa ia Ura | 1671 || Long. 9° 49° W. ci Praia Aga) lGrs. a 2 6 | 177 | 166 | 4 8 | 19°7 | 164 || 6 NO We2222/e Gall 8 At Vigo. . . | Noon.| 32:2 | 16°4 | 10 22669 Go" | Midn. AL |) 95:8" |-A5:8- duly Zieh. . 3 Lk 2 Ine 6 29°5 | 16°4 4 | 8 | 20°8-| 164 6 l= 102" | 26:0") 165 | 8 | ; | Midn.| 18°6 | 16°2 | 10 | July 18th | 2 | 183 | 164 || Lat. 39°39' N. )in | A | 17-7 V Tong.9 360Won he 6 LS FOP OHS ey 2 8 19°4 | 166 || +t | 10- | 18°9 | | 6 | Lat, 41°55’ N. ) : 8 | Long. 9° 30’ W. $| Noon.| 19°1 | 16°2 | 10 | 2 | ig6 (es. | ‘“Midn. 42 08-9) P1634 duly. 22nd\ ~. 2 6 189 | 16:4 || 4 8 ishss |) UG; 6 | 10° | 18°3 |.16:6 | 8 | Midn.| 17°7 | 16°4 | 40 | laly WOthes sss |. 2. | b7-7. | 46-9" |. The Farilhoes, } | 7 [ee zs SoA er Fa 2) S.S.E. 5 miles § | ee 6 | 19:4 | 169 ie Sim) 20:81 317.5 4 | LeetOS ie Q0rL. | 17-7 [uae Lat. 40° 16’ N. }| rm - lg Long. 9° 33' W. Wocne aU ants 1) ei THE DEPTHS OF THE SEA. [CHAP. VIL. 348 eee he Date and Position. | e | as } ee : Deg. Deg | Cent. Cent July 22nd Midn.| 1971 | 18°0 July 23rd 2h TBO? |) EBS: 4 19°3 | 19°4 6 20°5 183 tsi eee ese Us ara) 947 | 22-0 At Lisbon | Noon.| 29:5 | 21-1 2 23°6 19°71 4 21°6 20°0 6 | 230 | 21°6 8 205) 122073 10 19°5 19°1 Midn.| 2071 19°5 July 24th ) 2 | TO SG 4 19°4 | 20°5 6 20°1 21°6 8 20°8 | 20°8 10 Des eA ral | At Lisbon Noon.} 24:1 | 19:4 2h Qa 20°5 4 277: 20°1 (oy y | DB lea 8 90°5 Q21°4. | 10 | 20:0 | 20°0 | Midn.| 19°4 | 19°7 i July 25th 2 19°1 20°0 4 19°0 20°0 6 90°3 19°1 8 20°4 19°4 10 20°8 19°1 Lat. 38° 10’ N. E Long. 9° 29’ W. Noon.} 21°8 | 194 2 91-1 | 19°4 4 | 20°83 | 19-4 6 | 21°6 19°4 8 | 20°0 180 eo) 186 evi |Midn.| 18°0 | 17°7 July 26th Wea ie igs | ie ge 4 | 18°3 ers 6 | 191 | 1971 8 | 19°4 19°] 10 20°3 19:3 | Date and Position. S 2 oN x ES aS Deg. Deg. Teh Se’ ON | Cent. Ceut aun saa aa Noon} 200 | 189 vy 20°0 19°1 4 20°0 19°1 6 20°0 19°4 8 | 19:4 19°1 10 | 20:0 19°1 Midn.} 20-0 19°0 | July 27th 2 | 194 | 1971 4 19°4 191 6 19°4 19°1 8 20°0 | 19°0 * 10 218: | 20:0 Hitewete ALOueINE F Long. 9° 12 W. | Noon. | 21-1 | 20°3 2 23°3) || 2075 4 DA aa 20°6 6 20°0 QOr7. 8 | 20°0 | 20°5 10 19:4" 206 Midn.} 19°5 |} 20°8 July 28th 2 | 19:4 | 203 4 | 19°4-| 20°5 6 19'1 20:0 8 PATE f DUST. 10 AG | Al Lat. 36° 55° N. PIES ie? | Tong. 8° 44" W. Noon.) 218 | 21°3 2 21°6 216 4 | 216 22:0 6 20°5 20°5 8 18°99 | 20°0 ake) 18°9 19°4 | Midn.| 18°6 | 19°1 July 29th ">. a Seay 4 18°3 | 19°7 6 PAV 21°6 B22 a ee ; 10 23°0 DO: pene’ sé a Noon.| 23°3 |. 22°5 2 Dat Wee 4 24'°8 Para | } | | CHAP. VI1. | DEEP-SEA TEMPERATURES. 349 Date and Position Hour. Temperature of Air erature D of Sea-Surface. Tem Date and Position. Hour. 2 = = ~~ 5 SH Sine! aed ey. a =e) e Temperature of Sea-Surface. July 29th July 30th Lat. 36°27 N. ) Long 6° 39’ W. § July 31st. At Cadiz . August Ist At Cadiz . | August 2nd . | Midun. | 8 | 10 | Midn. 2 8 | 10 he 28 i LO Midn. fone hae x2 | 6 Midn. 20°5 3 20°5 20°5 22'4 23°3 bo bo bo bO BO bo bo tO = = BS hor OS? > Or 0 — . No} SS bo bo He bore SKMOwWwarWSScHeNMaans b 24° 23 bO bO bO bo bO bo bo bo bo bo bo bo Dow Re KR bo © ) bo kb NS) bo b . . . . . tok . . . . . 4 ODWWeNHeEH HK OUAMNOARWaASs bo SNe eR Co Ww w | Long. 7° August 2nd . Lat. 36°18 N. } Long. 6° 45’ W. § August 3rd Tat. 35° 397 N. ) 4’ Ww. | August 4th Raty Soe Ne.) Long. 6° 24’ W. § October Ist Ine eStrait of) Gibraltar . . | 10 | Midn. ) 8 10 Noon.| 25 2 4 6 8 10 Midn. | NOR et DS be ne (oe) bo bo I el el bo bo bo bo wwe Ss bo bo bw bo bo ~~) WWHNNE EWE H GS SCHWONNODWOANRFD D®D wWwWtonorwnwonr DNMMNMNNWWKLE ~ CAE S us SOR NNN E SD Mr~IwATW bw Wwe Ore-t =) ee SO bo eo y Ww eH Ww HB bo Le bo Ne sO m~rS4 929 bo bo bo bo PIN bo bo bw bo Oe) bo bo bok tw tb bo BS wew w bo bo bo dO Ge | | 350 THE DEPTHS OF THE SEA. [CHAP. VII. | ° oo o oo OP ey ip || Midn.| 18'3 | 17°7 4 | 211 | 211- || October 7th... | - @ | 168") 166 6 | 205 | 206 |) Sa PPE TBS 8 | 20°0 | 19°8 |] | 6 | 167 | 166 LO’ * 4206 71-20'3. || | 8 | 166 | 17°2 Midn.| 20°5 | 20°5 eae) LD. elses October 4th... 2 | 20° | 2171 || Lat; 48°51’ N. -) N Tb 40) | 4 | 206 | 2171 || Long. 5°54 W. 4 |NO0B) ro | Tr 6 | @11 | 21:1 Ree bes We dey Ang 8 | 21°6 | 21°5 A | 177.1136 10.) geeo *)'SI-0 6 | 15°3 | 13°6 Lat. 40°57° N. )| Hh aiee hist 8 | 147 | 141 tempo Bau. 4 Cos ee | ote 10 | 153 | 14°4 |} 2 | 23°9 | 21: Midn.| 1671 | 15°5 4 | 222 | 21:0 | October 8th 2 | ABS | USS FB 52070) |. 206 4 | 15:07] 158 | 8 | 20°3 | 20-4 6 | 156 | 16°0 | | 10 | 189 | 19-4 8 | 161 | 161 | Midn.| 19°3 | 1974 10 | 166 | 16°4 CHAP. VII.) DEEP-SEA TEMPERATURES. oon | 2 2g 2 2s fa S45 es =| | Ss Date and Positi 8 ae) 22 Date and Positi é ge! | om ate al Osltion. a] Bg Bg ate an OS1TIOL. sn] ao ee 5 Bm 5 5 i=) B o =) i) ol Deg. Deg. | Deg. | Deg Cent Cent. Cent. | Cent. St. Alban’s Hd., | October 8th. . G 15°04) 15°8 English Chan- > Noon.| 18°6 | 16°2 | BS) | 47 i ls: TCLs ce ent NOM els b eve lias [oe 2h}, 19eo 160} || At Gowes: °° | Midna) lord); 25: er TGS), | | | 392 THE DEPTHS OF THE SEA. APPENDIX B. [CHAP. VII. Temperature of the Sea at different Depths near the Eastern Margin of the North Atlantic Basin, as ascertained by Serial and by Bottom Soundings. SERIAL SOUNDINGS. Borrom SouNDINGs. Tempe- Tempe- Tempe- Tempe- Tempe- Tempe- Tempe-| Sta- Surface | Bottom Depth. rature.| rature.| rature | rature.| rature.| rature. rature.| tion. |Depth.| Tempe- | Tempe- Ser. 23.|Ser. 42.|Ser. 22. Ser. 19.|Ser. 20 Ser. 21. Ser. 38.| No. rature. rature, Deg. | Deg. | Deg. | Deg. | Deg. | Deg. | Deg. Deg. Deg. Fms. | Cent. | Cent. | Cent. | Cent. | Cent. | Gent. | Cent. Fms Cent. Cent. 1420.) 17-0 | PSB. 126 1330 1 Sass aly 50 wae 11°8 27 54 usyal 9-0 | 34 | 275| 18-9 9°8 6 90 122, 10-0 35 96 17-4 10°7 100 91 | 10°6 8 106 12:3 10°6 24 109 14°3 8-0 150 10°5 if 159 11°8 10-2 14 173 118 9°7 , | 18 183 11°8 96 200 8°9 | 10:2 | | 13 208 12:0 9-7 250 al(o et 9-1 8:9 91 9:0 | 10:2 4 251 12:0 9°7 300 87 9-7 26 345 14:1 8:1 350 9°5 1 370 13°2 9-4 400 86 9:1 | 15 422 11:2 8-3 450 8:6 45 458 15°9 8-9 500 | 7:7 8:5 81 81 83 8°6 8°8 40 517 17-4 8-7 550 ae 8-0 39 557 172 ebay 600 6:9 75 41 584 17°4 8-0 630 6°83 650 6°8 23h 664 14:1 5:3 700 6-4 12 670. |. 11°2 5°9 3 (2p) 125 61 | 36 725 Ua 6°6 750 | 5:8 5:5 ay SOI le eLIRL D2 800 DD | 2 808 12:3 Hp 16 816 11°6 4-1 862 4°3 | 44 865 16:2 4-1 1000 | cca ll, CONE SCs) ot aimeo sO 35 || 43 | 1207 16°5 371 | | |} 28 | 1215) 14-2 2°8 | | 17 1230 11:8 3°2 1250 {sage 32 3:1 || 29 1264 13°8 27 1300 | | $2 1320 13°3 3°0 1360 3°0 30 1880 13°3 2°8 1400 1443 2°7 1476 3 27 1500 ee lee | | 1750 2°6 || 2090 2-4 || | || 87 | 2485 | 186 2:5 CHAP. VII.] DEEP-SEA TEMPERATURES. 353 APPENDIX C, Comparative Rates of Reduction of Temperature with Increase of Depth at Three Stations in different Latitudes, all of them on the Kastern Margin of the Atlantic Basin. STATION 42. Staion 23. STATION 87, Lat. 49° 19’. | Lat. 56° 13’. | Lat. 59° 35’, Depth. | | pede Ta- | Difference Pema Difference. peers Difference. Fathoms. Surface. yO OF 14°° OC; 11 2G; 6° 4C. 4° 9C. 22° 9'C: 100 10°6 ony ; 8°5 0:4 0°2 0°3 200 10°2 | hey) 8°2 0°5 0°2 On? 300 LS ea ie Bg Sra ORIG OS al 0°3 400 9°1 eer foes) hs Osa | TSFON | 0°5 500 S71 Neat 7acaG yack 0°6 (0) 0 LD 600 1 °8 6°9 6°1 Wey, 750 5°8 og 767 5 2 | t THE DEPTHS OF THE SEA, APPENDIX D. [CHAP, VIT. Temperature of the Sea at different Depths in the Warm and Cold Areas lying between the North of Scotland, the Shetland Islands, and the Faeroe Islands; as ascertained by Serial and by Bottom Soundings. N.B.—The Roman numerals indicate the ‘ Lightning’ Temperature Soundings, WaRM AREA. Series 87. Sta- tion. Depth. Tempe- No. Deg. Fms. | Cent. 0 11:4 59 8-9 73 80 109 8°5 71 81 150 8°3 |. 84 85 200 8-2 74 300 8-1 59 | 46 400 | 7-8 | | 89 90 49 500 | 7-2 | XII. 47 XV 609 671 XVII XIV 700 88 767 D-2 Depth. Surface Tempe- rature. Deg. | Cent. na es) 11°8 11°6 11°8 12°3 1271 11:4 ee Nee we a mH be 11°9 a erme Omg corrected for pressure. | Bottom|| Tempe- rature. sts Aan COM HOD eK } (| CoLtp AREA. Series 64. Ser. 52. | Tempe- Tem e- Depth. tine ature. . Deg. Deg. . || Ems. Cent Cent. I 0 9°8 111 | 50 fa 91 | 100 | 72 | 85 } | 150 6:2 8-0 200 4-2 75 | 250 1°2 3°5 300 0:2 —07 | | 350 | —0°3 384 —0°8 | 400 | —0O°6 | 459 —0°8 , 500 —11 i 559 —11 | 600 | —1-2 | 640 | —1-4 Sta- tion. No. oO =) Surface! Bottom Depth. Tempe-,| Tempe- rature,| rature. Deg Deg. Fms. Cent. | Cent 66 | 11:9 73 67 | 11-9 6°5 75, | 14 6°6 114 | 10:2 72 125 9°7 7:0 167 | 97| 68 L707 |b: 317 9-4 | —1°0 345 | 11-1 | —12 344 | 10-2 | —1°3 363 11°4 | —0°3 445 | 12:0 | —1°1 480 | 11-4 | —07 49) 11-2 | —1:1 | 500 | 105 | —0°7 540 | 10-8 | —0-7 550 | 11:6 | --1°3 560 | 10:5 | —1°3 580 | 11°5 | —1°3 605 | 11-4 | —-138 632 | 11:1 | —08 CHAP. VIL. | DEEP-SEA TEMPERATURES. APPENDIX IE. 395 Intermediate Bottom Temperatures, showing the Intermixture of Warm and Cold Currents on the Borders of the Warm and Cold Areas. Station. No. Depth. Fathoms. 76 76 84 | Surface Tempera- ture. Deg. Cent. 11°3 11:2 11°5 11°6 11°4 114 | Bottom Tempera- || ture. Deg. Cent. 9°3 9°3 9°3 9°2 8'7 76 || Station. No. 15 Depth. Fathoms. 250 290 440 Surface Bottom Tempera- | Tempera- ture. ture. Deg. Deg. Cent. Cent. 10°8 55 11:2 5:3 11°3 51 118 3°0 10°9 56 CHAPTER VIII. THE GULE-STREAM. The Range of the ‘ Porcupine’ Temperature Observations.—Low Temperatures universal at great Depths.—The Difficulty of in- vestigating Ocean Currents.-—The Doctrine of a general Oceanic Circulation advocated by Captain Maury and by Dr. Carpenter.— Opinion expressed by Sir John Herschel.—The Origin and Exten- sion of the Gulf-stream.—The Views of Captain Maury; of Pro- fessor Buff; of Dr. Carpenter.—The Gulf-stream off the Coast of North America.—Professor Bache’s ‘ Sections. —The Gulfstream traced by the Surface Temperatures of the North Atlantic.— Mr. Findlay’s Views.—Dr. Petermann’s Temperature Charts.—Sources of the underlying Cold Water.—The Arctic Return Currents.— Antarctic Indraught.—Vertical Distribution of Temperature in the North Atlantic Basin. Att the temperature investigations carried on in H.M.S.S. ‘Lightning’ and ‘ Porcupine’ during the years 1868-69 and 1870, with the exception of a series of observations already referred to taken in the Mediterranean under Dr. Carpenter’s direction in the summer of 1870, were included within an area nearly 2,000 English miles in length by 250 in width, extending from a little beyond the Feroe Islands, lat. 62° 30’ N., to the Strait of Gibraltar, lat. 36° N. The greater part of this belt may be described as CHAP. VIII. } THE GULF-STREANM. oy the eastern border of the North Atlantic fringing Western Europe. A small but very interesting por- tion of it forms the channel between the Froe Islands and the North of Scotland, one of the chan- nels of communication between the North Atlantic and the North Sea; and a few soundings in shallow water to the east of Shetland are in the shallow North Sea basin. It is evident, therefore, that the greater part if not the whole of this belt must par- ticipate In the general scheme of distribution of temperature in the North Atlantic, and must owe any peculiarities which its thermal conditions may present to some very general cause. All our temperature observations, except the few taken in the ‘ Lightning’ in 1868, were made with thermometers protected from pressure on Professor Miller’s plan, and the thermometers were individually tested by Captain Davis at pressures rising to about three tons to the square inch before they were fur- nished to the vessel; they were also more than once reduced to the freezing-point during the voyage to ascertain that the glass had been in no way distorted. The results may therefore be received with absolute reliance within the limits of error of observation, which were reduced to a minimum by the care of Captain Calver. A large number of scattered observations, most . of which have unfortunately been made with instru- ments which cannot thoroughly be depended upon for accuracy of detail,—the error, however, being probably in the direction of excess of heat,—esta- blished the singular fact that although the tempera- ture of the surface of the sea in equatorial regions 358 THE DEPTHS OF THE SEA. [CHAP. VIII. may reach 30° C., at the greatest depths both in the Atlantic and in the Pacific the temperature is not higher than from 2° to 4° C., sometimes falling at great depths to 0° C. I quote from Mr. Prestwich’s able presidential address to the Geological Society for the year 1871, a table of the most important of these earlier observations in the Atlantic and the F ii Paciie -— TEMPERATURES OF THE ATLANTIC. | Temperature. Depth Latitude. Longitude. in Observer and Date. Faths. Surface. Bottom. 499- 0’ N. | 34°40 W..| 780.) 16°7°C.) (6:6°C.|)" Chevalier. - 1637 29 0 34 50 | 1400 | 24°4 61 “s o> pe alive 7 2) 20 40 505 | 26°6 22, benz) Sse lee A 25 26 6 1006 | 27°0 32 Tessa. tote sy Bi} 23 14 1200 | 25°0 4°] a . 2 -L841 25 10 7 59K, 886 | 19°6 30 2 ye 164k 29 33 Osos 1051 | 19°1 2°0 a Selo 32 20 43 50 1074 | 21°6 9-4 Meng .2 2. 832 38 12 54 80 W. 333 | 16°8 30 Tessan . . 1841 TEMPERATURES OF THE PACIFIC. Temperature, Depth | , | Latitude. Longitude. in Observer and Date. Faths. | surface. | Bottom. 51°34’ N. | 161°41’ E. OB, jetales GC: ObUC. | eLessan mes lose 28 52 173 9 600 | 25°5 50 Beechey 7 be Lae LS) 2d 174 10 710 | 24°7 48 “3 S836 4 32 134 24 W.| 2045 | 27°2 17 The ‘Bonite’ 1837 Equator. | 179 34 1000 | 30°0 2°5 Kotzebue . 1824 91148. | 196 1 916 | 27:2 2°2, |" Wenz t=. se tisos | 32 57 | 176 42 BE. | 782 | 1674 54 Matton eal lsSi! | 43 47 |: 380). "OW, | 1066 | 13°0 2°3 Tessan . . 1841 | ' Address delivered at the Anniversary Meeting of the Geological Society of London on the 17th of February, 1871, by Joseph Prest- wich, F.R.S. Pp. 36, 37. CHAP. VIII. ] THE GULF-STREAM. 859 To these may be added the observations of Lieu- tenant 8S. P. Lee, of the United States Coast Survey, who, in August 1847, recorded a temperature of 2°77 C. below the Gulf-stream at a depth of 1,000 fathoms, lat. 35° 26° N., long. 73° 12’ W.; and of Lieutenant Dayman, who found the temperature at 1,000 fathoms in lat. 51° N. and long. 40° W. to be — 0°4 C., the surface temperature being 12°5 C. These results are fully borne out by the recent determinations of Captain Shortland, R.N., who observed a temperature of 2°°5 C. in deep water in the Arabian Sea between Aden and Bombay,’ by those of Commander Chimmo, R.N., and Lieutenant Johnson, R.N., who found at various points in the Atlantic a temperature of about 3°9C. at 1,000 fathoms, and a slow decrease from that point to 2,270 fathoms, where the temperature registered by unprotected thermometers was 6°6 C., reduced by the necessary correction for pressure to about 16 C.,’ and finally by the temperature determinations of the ‘Porcupine’ expeditions, carefully conducted with protected instruments, but not carried nearer the tropics than the latitude of the Strait of Gibraltar ; and they appear to go far to establish a nearly uni- ‘form temperature for abyssal depths, not far from the freezing-point of fresh water. As it was evident that the low temperature for deep water in tropical regions could not be acquired 1 Sounding Voyage of H.M.S. ‘ Hydra,’ Captain P. F. Shortland. London: 1869. ? Soundings and Temperatures in the Gulf-stream. By Commander W. Chimmo, R.N. (Proceedings of the Royal Geographical Society, vol. xiii.) 360 THE DEPTHS OF THE SEA. [cHAP. VIII. by contact with the surface of the crust of the earth, the inevitable conclusion seems to have been early arrived at that, if such temperatures existed, they must be due to a general oceanic circulation,— to surface currents of warm water passing towards the poles, and compensating counter-currents of cold water from the poles towards the equator. Hum- boldt states that he showed, in 1812, “that the low temperature of the tropical seas at great depths could only be owing to currents from the poles to the equator.”’? D’Aubuisson, in 1819, also attributed the low temperature of the sea at great depths at or near the equator to the flow of currents from the poles.’ But although the fact of the existence of currents lowering the temperature of deep water in equa- torial regions was admitted by various authorities in physical geography, little hght was thrown upon the causes of this circulation. Latterly, the whole subject became obscured by the very general adop- tion of the doctrine already referred to of a perma- nent temperature of 4° C. all over the world beyond a certain depth; and it was not until the publi- cation of Captain Maury’s fascinating book on the ‘Physical Geography of the Sea’ had given an extra- ordinary stimulus to the study of this department of science, that the question was again raised. It was natural from its geographical position, and from the much greater opportunity which it offered for the acewnulation of the almost infinite number 1 Fragments de Géol. et de Climatol. Asiat., 1831. 2 Traité de Géognosie.—Quoted in the Anniversary Address to the Geological Society of London, 1871. CHAP. VI111.] THE GULF-STREAM. 861 of data required for the consideration of such sub- jects, that the basin of the North Atlantic should be selected for investigation, more particularly as peculiarities of climate seemed there to be limited in space, and well defined and even extreme in character. It seems at first somewhat singular that there should be any room for question as to the causes, the sources, and the directions of the ocean currents which traverse the ocean in our immediate neigh- bourhood, and exercise a most important influence on our economy and well-being. ‘The investigation is, however, one of singular difficulty. Some currents are palpable enough, going at a rate and with a force which make it easy to detect them, and even com- paratively easy to gauge their volume and define their path; but it seems that the great movements of the water of the ocean, those which produce the most important results in the transfer of tempera- ture and the modification of climate, are not of this character. These move so slowly that their surface movement is constantly masked by the drift of vari- able winds, and they thus produce no sensible effect upon navigation. The path and limits of such bodies of moving water can only be determined by the use of the thermometer. The equalizing of the temperature of bodies of water in contact with one another and differently heated, by conduction, diffusion, and mixture, is however so slow, that we usually have but little difficulty in distinguishing currents from different sources. Up to the present time little had been done in determining the depth and mass of currents by the 362 THE DEPTHS OF THE SEA. [CHAP. VIII. thermometer, and under-currents were practically unknown; but the limits of surface currents had been traced with considerable precision by observa- tions of the temperature of the surface of the sea, even when the movement was so slow as not to be otherwise perceptible. ‘The amount of heat received directly from the sun may be taken approximately to depend upon latitude only, and this heat is in addition to the heat of the surface water derived from other sources, whatever these may be. Observa- tions of surface temperature accordingly give us the heat derived directly from the sun in the region, and the heat derived from the same source during the passage of the water to the region, in addition to the original heat of the water ; if, therefore, the water of any region be derived from—that is to say, form part of—a movement of water from a polar source, and if the surface water of another area on the same parallel of latitude form part of an equatorial current, although in that particular latitude they receive in both cases the same amount of heat from the sun, there will be a marked difference in their tempera- ture. To take an extreme case; the mean tem- perature of the sea in the month of July off the Hebrides, in lat. 58° N., in the path of the Gulf- stream, is 13° C.; while in the same latitude off the coast of Labrador, in the course of the Labrador current, it is 4°°5 C. The distribution of surface temperature in the North Atlantic is certainly very exceptional. A glance at the chart Pl. VII., representing the general distribution of heat for the. month of July, shows that the isothermal lines for that month, instead of ATE VIL.—Physical Chart of the North Atlantic ; showing the depth, and the general distribution of temperat Jor the month of July. HLUoON LP ULy oF 7 2h Meus, 3 9 a By by 2 9 JMO aS Cc showing the depth, and the general distribution of temperatur PLATE VII. —Physical Chart of the North Allantie ; Jor the month of July. CHAP. VIII. ] THK GULF-STREAM. 363 tending in the least to coincide with the parallels of latitude, run up into a series of long loops, some of them continued into the Arctic Sea. The temperature of the bordering land is not affected to any perceptible degree by direct radia- tion from the sea; but it is greatly affected by the temperature of the prevailing winds. Setting aside the still more important point of the equalization of summer and winter temperature, the mean annual temperature of Bergen, lat. 60° 24° N., subject to the ameliorating influence of the prevailing south- west wind blowing over the temperate water of the North Atlantic, is 6°7 C.; while that of Tobolsk, lat. 58° 13’ N., is — 2°4-C; But the temperature of the North Atlantic and its bordering lands is not only raised above that of places on the same parallel of latitude having a ‘continental’ climate, but it is greatly higher than that of places apparently similarly circumstanced to itself in the southern hemisphere. Thus the mean annual temperature of the Féroe Islands, lat. 62° 2'N., is 7°1C., nearly equal to that of the Falkland Islands, lat. 52° 8., which is 8°2 C.; and the temperature of Dublin, lat. 53° 21’ N., is 9°°6 C., while that of Port Famine, lat. 53° 8’ S., is 5°3 C. Again, the high temperature of the North Atlantic is not equally distributed, but is very marked in its determination to the north-east coast. Thus the mean annual temperature of Halifax (Nova Scotia), lat. 44° 39’ N., iNvoee Oreewhilestiate ot Dublins lat; 53° 21" N., is 96 C.; and the temperature of Boston (Mass.), lata 4a, 2 Nees exactly the same as: that: of Dublin. 864 THE DEPTHS OF THE SEA. [CHAP. V1I1. This remarkable diversion of the isothermal lines from their normal direction is admittedly caused by ocean currents affecting the temperature of the surface while conveying the warm tropical water towards the polar regions, whence there is a con- stant counterflow of cold water beneath to supply its place. We thus arrive at the well-known result that the temperature of the sea bathing the north-eastern shores of the North Atlantic is raised greatly above its normal point by currents involving an_ inter- change of tropical and polar water; and that the lands bordering on the North Atlantic participate in this amelioration of climate by the heat imparted by the water to their prevailing winds, This phenomenon is not confined to the North Atlantic, although from its peculiar configuration and relation to the land that ocean presents the most marked example. A corresponding series of loops, not so well defined, passes southwards along. the east coast of South America, and a very marked series occupies the north-eastern angle of the Pacific off the Aleutian Islands and the coast of California. Two principal views have been held as to the causes of the currents in the North Atlantic. One of these, which appears to have been first advanced in a definite form by Captain Maury, and which has received some vague support from Professor Buff, is that the great currents and counter-currents of warm and cold water are due to a circulation in the watery shell of the globe, comparable to the circulation of the atmosphere,—that is to say, caused by tropical heat and evaporation, and arctic cold. CHAP. VIII. } THE GULF-STREAM. 365 It is not easy to understand Captain Maury’s view, He traces all ocean currents to differences in specific gravity. He says: “If we except the tides, and the partial currents of the sea, such as those that may be created by the wind, we may lay it down as a rule that all the currents of the ocean owe their origin to the differences of specific gravity between sea-water at one place and sea-water at another; for wherever there is such a difference, whether it be owing to dif- ference of temperature or to difference of saltness, &e., it is a difference that disturbs equilibrium, and currents are the consequence.”! These differences in specific gravity he attributes to two principal causes ; differences in temperature, and excess of salts produced by evaporation. Captain Maury explains his views as to the first of these causes by an illustra- tion. * Let us now suppose that all the water within the tropics to the depth of one hundred fathoms sud- denly becomes oil. The aqueous equilibrium of the planet would thereby be disturbed, and a general system of currents and counter-currents would be immediately commenced, the oil in an unbroken sheet on the surface running towards the poles, and the water as an under-current towards the equator. The oil is supposed, as it reaches the polar basin, to be re- converted into water, and the water to become oil as it crosses Cancer and Capricorn, rising to the surface in intertropical regions, and returning as before.” “Now, do not the cold water of the north, and the warm water of the gulf made-specifically lighter by tropical heat, and which we see actually presenting * The Physical Geography of the Sea, and its Meteorology. By M. T. Maury, LL.D. 366 THE DEPTHS OF THE SEA. [CHAP. VIIl. such a system of counter-currents, hold at least, in some degree, the relation of the supposed water and oil,’”? «There can be no doubt that Maury concludes that the waters in intertropical regions are expanded by heat, and those in polar regions are contracted by cold, and that this tends to produce a surface-current from the equator te the poles, and an under-current from the poles to the equator.’’’ With regard to increased specific gravity produced by excess of salt, Captain Maury says,— ‘The brine of the ocean is the ley of the earth. From it the sea derives dynamical power, and its cur- rents their main strength.’ ‘One of the purposes which in the grand design it was probably intended to accomplish by leaving the sea salt and not fresh, was to impart to its waters the forces and powers necessary to make their circulation complete.’’* ‘In the present state of our knowledge concerning this wonderful phenomenon (for the Gulf-stream is one of the most marvellous things in the ocean), we can do little more than conjecture. But we have the causes in operation, which we may safely assume are among those concerned in producing the Gulf- stream. One of these is the increased saltness of its water after the trade-winds have been supplied with vapour from it, be it much or little; and the other is the diminished quantum of salt which the 1 Captain Maury, op. cit. 2 On Ocean Currents. Part III. On the Physical Cause of Ocean Currents. By James Croll, of the Geological Survey of Scotland. (Philosophical Magazine, October 1870.) * Captain Maury, op. cit. + Tbid. CHAP. VIII. | THE GULF-STREAM. 367 Baltic and the northern seas contain.”’! ‘* Now, here we have on one side the Caribbean Sea and Gulf of Mexico with their waters of brine; on the other, the great Polar Basin, the Baltic, and the North Sea, the two latter with waters that are but little more than brackish. In one set of these sea-basins the water is heavy, in the other it is light. Between them the ocean intervenes; but water is bound to seek and to maintain its level; and here, therefore, we unmask one of the agents concerned in causing the Gulf-stream.”’ ” As Mr. James Croll has very clearly pointed out, Captain Maury’s two causes tend to neutralize each other. ** Now it is perfectly obvious that if difference in saltness is to co-operate with difference in tempera- ture in the production of ocean currents, the saltest waters, and consequently the densest, must be in the polar regions; and the waters least salt, and consequently lightest, must be in equatorial and in- tertropical regions. Were the saltest water at the equator and the freshest at the poles, it would tend to neutralize the effect due to heat, and, instead of producing a current, would simply tend to prevent the existence of the currents which otherwise would result from difference of temperature.” “ According to both theories it is the differences of density be- tween the equatorial and polar waters that gives rise to currents; but according to the one theory, the equatorial waters are lighter than the polar, whilst according to the other theory they are heavier than the polar. Either the one theory or the other may Captain Maury, op. cit. 2 Tid: 368 THE DEPTHS OF THE SEA. [ciap. VIL. be true, or neither; but it is logically impossible that both of these can, for the simple reason that the waters of the equator cannot at the same time be both lighter and heavier than the water at the poles.” “So long as the two causes continue in action, no current can arise unless the energy of the one cause should happen to exceed that of the other, and even then a current will only exist to the extent by which the strength of the one exceeds that of the other.’’} It seems scarcely necessary to enter further into detail in reference to Captain Maury’s theory of ocean currents, which is really chiefly remarkable for its ambiguity, and for the pleasant popular style in which it is advocated; since my friend and col- league Dr. Carpenter has latterly brought into great prominence what appears to be a modification of the same view, put in a more definite form. Professor Buff, in his excellent little volume on the Physics of the Earth, speaking of the layer of cold water derived from the Arctic seas which underlies the tropical ocean, and its method of transport, says : «The following well-known experiment clearly illus- trates the manner of the movement. A glass vessel is to be filled with water with which some powder has been mixed, and is then to be heated at bottom. You will soon see, from the motion of the particles of powder, that currents are set up in opposite direc- tions through the water. Warm water rises from the bottom, up through the middle of the vessel, and spreads over the surface; while the colder, and there- fore heavier liquid, falls down at the sides of the * James Croll, op. cit. CHAP. VIII.] THE GULF-STREAM. 369 glass. Currents like these must arise in all water- basins, and even in the oceans if different parts of their surface are unequally heated.’ This is of course a common class-experiment illus- trating convection. It is evidently impossible that movements of ocean water can be produced in this way, for it is well known that everywhere, except under certain exceptional circumstances in the polar basin, the temperature of the sea decreases from the surface to a minimum at the bottom, and tropical heat is applied at the surface only. It is singular that this irrelevant illustration should have been introduced by Professor Buff; for his account of the origin and extension of the Gulf-stream, which may be taken as the type and exponent of ocean currents, is quite consistent with the commonly received opinions. On working up the temperature results of the ‘Porcupine’ expedition of 1869, Dr. Carpenter satis- fied himself that the mass of comparatively warm water, 800 fathoms deep, which we had established as existing, and probably moving in a north-easterly direction, along the west coasts of Britain and the Lusitanian peninsula, could not be an extension of the Gulf-stream, but must be due to a general circu- lation of the waters of the ocean comparable with the circulation of the atmosphere. ‘The influence of the Gulf-stream proper (meaning 1 Familiar Letters on the Physics of the Earth ; treating of the chief Movements of the Land, the Water, and the Air, and the Forces that give rise to them. By Henry Buff, Professor of Physics in the University of Giessen. Edited by A. W. Hofmann, Ph.D., F.R.S. London: 1851. BB 370 THE DEPTHS OF THE SEA. [CHAP. VIII. by this the body of superheated water which issues through the ‘narrows’ from the Gulf of Mexico), if it reaches this locality at all— which is very doubtful —could only affect the most superficial stratum ; and the same may be said of the surface-drift caused by the prevalence of south-westerly winds, to which some have attributed the phenomena usually ac- counted for by the extension of the Gulf-stream to these regions. And the presence of the body of water which lies between 100 and 600 fathoms depth, and the range of whose temperature is from 48° (8°85 C.) to 42° (5°5 C.), can scarcely be accounted for on any other hypothesis than that of a great general movement of equatorial water towards the polar area, of which movement the Gulf-stream con- stitutes a peculiar case, modified by local conditions. In like manner the arctic stream which underlies the warm superficial strata in our cold area, con- stitutes a peculiar case, modified by the local condi- tions, to be presently explained, of a great general movement of polar water towards the equatorial area, Which depresses the temperature of the deepest parts of the great oceanic basins nearly to the freezing-point.”’ } At first Dr. Carpenter appears to have regarded this oceanic circulation as a case of simple convection. «lo what, then, is the north-east movement of the warm upper stratum of the North Atlantic attri- butable? I have attempted to show that it is part of a general interchange between polar and equa. torial waters, which is quite independent of any such 1 A Lecture delivered at the Royal Institution, abstracted with the Author’s signature in Nature, vol, 1. p. 488 (March 10th, 1870). CHAP. VIIT. ] THE GULF-STREAM. 37 lt local accidents as those which produce the Gulf- stream proper, and which gives movement to a much larger and deeper body of water than the latter can affect. The evidence of such an interchange is two- fold—that of physical theory, and that of actual observation. Such a movement must take place, as was long since pointed out by Professor Buff, when- ever an extended body of water is heated at one part and cooled at another ; it is made use of in the warm- ing of buildings by the hot-water apparatus, and it was admirably displayed at the Royal Institution a few months since in the following experiment kindly prepared for me by Dr. Odling.”’ Dr. Carpenter then repeats Professor Buff’s convection experiment, the heat being applied by a steam jet introduced vertically at one end of a narrow glass trough while a block of ice was wedged into the other end. “Thus a circulation was shown to be maintained in the trough by the application of heat at one of its extremities and of cold at the other, the heated water flowing along the surface from the warm to the cold end, and the cooled water flowing along the bottom from the cold to the warm end; just as it has been maintained that equatorial water streams on the surface towards the poles, and that polar water returns along the bottom towards the equator, if the movement be not interfered with by interposed obstacles, or prevented by antagonistic currents arising from local peculiarities.’ ! That such a movement cannot take place on this hypothesis has been already shown; and Dr. Car- * The Gulf-stream. A letter from Dr. Carpenter to the Editor of Nature, dated Gibraltar, August 11th, 1870. (Mature, vol. ii. p. 334.) BB2 3/2 THE DEPTHS OF THE SEA. [CHAP. VIII. penter in a lecture to the Royal Geographical Society, in an illustration drawn from two supposed basins, one under equatorial conditions and the other under polar, connected by a strait,’ says: “The effect of surface-heat upon the water of the tropical basin will be for the most part limited to its uppermost stratum, and may here be practically disregarded. But the effect of surface-cold upon the water of the polar basin will be to reduce the temperature of its whole mass below the freezing-point of fresh water, the surface stratum sinking as it is cooled, by virtue of its diminished bulk and increased density, and being replaced by water not yet cooled to the same degree. The warmer water will not come up from below, but will be drawn into the basin from the surface of the surrounding area; and since what is thus drawn away must be supplied from a yet greater distance, the continual cooling of the surface stratum in the polar basin will cause a ‘set’ of water towards it to be propagated backwards through the whole inter- vening ocean in connection with it, until it reaches the tropical area.’ And further on in the same address: “‘It is seen that the application of cold at the surface is precisely equivalent as a moving power to that application of heat at the bottom by which the circulation of water is sustained in every heating apparatus that makes use of it.’ No doubt the application of cold to the surface of a mass of water previously at the same temperature throughout, would ? On the Gibraltar Current, the Gulf-stream, and the general Oceanic Circulation. By Dr. W. B. Carpenter, F.R.S. Reprinted from the Proceedings of the Royal Geographical Society of London, 1870, CHAP. VIII. THE GULF-STREAM. 373 have the same effect as the application of heat to the bottom, and in either case we should have an instance of simple convection, the warmer under- water rising through a colder upper layer; but that is not what we have in the polar sea; for the temperature of the arctic sea gradually sinks from a few fathoms beneath the surface to a minimum temperature, and consequent maximum density, at the bottom. Therefore in this case the application of cold at the surface is not equivalent to the appli- cation of heat to the bottom in a hot-water heating apparatus, and Dr. Carpenter has shown that he is aware of this by requiring the backward propagation of a sunface-current. That a certain effect in increase of specific gravity must be produced by the cooling of the surface film of the arctic ocean there seems to be little doubt; but the area of maximum effect is very limited, and during the long arctic winter the greater part of that area is protected by a thick layer of ice, one of the worst possible conductors. It certainly appears to me that this cause is totally inadequate to induce a powerful current of great depth, six thousand miles long and several thousand miles in width, the effect which Dr. Car- penter attributes to it. During the summer of 1870, and afterwards in 1871, Dr. Carpenter made a series of observations on the current in the Strait of Gibraltar. The existence of an under-current out of the Mediterranean was considered to be established by these observations, and the conclusions arrived at as to its cause did not differ materially from those already very generally 274 THE DEPTHS OF THE SEA. (CHAP. VILL accepted. Dr. Carpenter believes, however, that the conditions in the Strait of Gibraltar and in the Baltic Sound aptly illustrate the general circulation in the ocean, and confirm his views. I quote from the general summary of Dr. Car- penter’s address to the Geographical Society :— «‘The application of the foregoing principles to the particular cases discussed in the paper is as follows :— | «‘ VITI.—A vertical circulation is maintained in the Strait of Gibraltar by the excess of evaporation in the Mediterranean over the amount of fresh water returned into its basin, which at the same time lowers its level and increases its density; so that the surface inflow of salt water which restores its level (exceeding by the weight of salt contained in it the weight of fresh water which has passed off by evaporation) disturbs the equilibrium and _ pro- duces a deep outflow, which in its turn lowers the level. The same may be assumed to be the case in the Strait of Babelmandeb. «« TX.—A vertical circulation is maintained in the Baltic Sound by an excess in the influx of fresh water into the Baltic; which at the same time raises its level and diminishes its density, so as to produce a surface outflow, leaving the Baltic column the lighter of the two, so that a deep inflow must take place to restore the equilibrium. The same may be assumed to be the case in the Bosphorus and Dardanelles. « X.—A vertical circulation must, on the same principles, be maintained between polar and equa- torial waters by the difference of their temperatures : CHAP. VIL. ] THE GULF-STREAM. 375 the level of the polar water being reduced, and its density increased by the surface-cold to which it is subjected, whilst a downward motion is also imparted to each stratum successively exposed to it; and the level of equatorial water being raised and its density diminished by the surface-heat to which it is exposed. (The first of these agencies is by far the more effec- tive, since it extends to the whole depth of the water, whilst the second only affects, in any considerable degree, the superficial stratum.) Thus a movement will be imparted to the upper stratum of oceanic water from the equator towards the poles, whilst a movement will be imparted to the deeper stratum from the poles towards the equator.” It seems to me that the doctrine here propounded by my distinguished colleague, if I understand it aright, is open to the objection to which I have already referred in connection with the speculations of Captain Maury. If the currents flow in the direction and with the permanence accepted by Dr. Carpenter in the Strait of Gibraltar and in the Baltic Sound, if their flow and its direction be due to the causes to which Dr. Carpenter attributes them, and if there be any analogy whatever between the conditions of equi- librium of these inland seas and that of the outer ocean,—none of which propositions appear to me at all satisfactorily proved,—I should think that the vast equatorial region, the path of the trade-winds and the belt of vertical solar radiation, must, so far as eva- poration is concerned, resemble, or rather greatly exaggerate, the conditions of the Mediterranean. The consequent accumulation of salt,—through the whole 376 THE DEPTHS OF THE SEA. ~ [cHAP. VII. depth of course, the brine sinking downwards,—must sreatly outweigh (I give this as what Petermann would call a gratuitous speculation) the slight ex- pansion caused by the heating of the surface layer. The more restricted arctic basin on the other hand, as was long ago pointed out by Capt. Maury, partici- pates to a certain extent in the characteristics of the Baltic; and I am greatly mistaken if the low specific gravity of the polar sea, the result of the condensation and precipitation of vapour evaporated from the intertropical area, do not fully counter- balance the contraction of the superficial film by arctic cold. The North Atlantic ocean bears a proportion in depth to the mass of the earth considerably less than that of the paper covering an eighteen- inch globe to that of the globe it covers, while the film heated by direct solar radiation may be represented by its surface coating of varnish, and is not actually thicker than the height of St. Paul’s. Physicists seem to find a difficulty in giving us the amount of palpable effect in pro- ducing currents in this shell of water, six thousand miles in length by three thousand in width and two miles in thickness, which may be due to causes such as those relied upon by Dr. Carpenter, acting under the peculiar circumstances and to the amount in which we find them in nature; and probably we are not yet in a position to give them sufficient data to enable them todoso. Mr. Croll, a good authority in such matters, has attempted to make some calcu- tions, and comes to the conclusion that none of them are sufficient to overcome the friction of water and to CHAP, VII1.] THE GULF-STREAM. ol7 produce any current whatever;! but in this view he does not certainly receive universal support. I am myself inclined to believe that in a great body of salt water at different temperatures, with unequal amounts of evaporation, under varying barometric pressures, and subject to the drift of variable winds, currents of all kinds, great and small, variable and more or less permanent, must be set up;* but the probable result appears to be reduced to a minimum when we find that causes, themselves of doubtful efficiency, actually antagonize one another; and that we are obliged to trust for the final effect to the amount by which the least feeble of these exceeds the others in strength. Speaking in the total ab- sence of all reliable data, it is my general impres- sion that, if we were to set aside all other agencies, and to trust for an oceanic circulation to those con- ditions only which are relied upon by Dr. Carpenter, if there were any general circulation at all, which seems very problematical, the odds are rather in favour of a warm under-current travelling north- wards by virtue of its excess of salt, balanced by a surface return-current of fresher though colder arctic water. With regard, then, to this question of a general circulation caused by difference in specific gravity, for the present I cordially endorse the opinion ex- pressed by the late Sir John Herschel in a cautious 1 James Croll, op. cit. 2 On the Distribution of Temperatures in the North Atlantic. An Address delivered to the Meteorological Society of Scotland at the General Meeting of the Society July 5th, 1871, by Professor Wyville Thomson. 378 THE DEPTHS OF THE SEA. [CHAP. VIII. and excellent letter addressed to Dr. Carpenter—-a letter which there is no impropriety in my quoting in full as it is already in print, and which has a special interest as being probably one of the last written by Sir John Herschel on scientific subjects :— *< CottIncwoon, April 9th, 1871. “My DEAR Str,—Many thanks for your paper on the Gib- raltar current and the Gulf-stream. Assuredly, after well con- sidering all you say, as well as the common sense of the matter, and the experience of our hot-water circulation pipes in our greenhouses, &c., there is no refusing to admit that an oceanic circulation of some sort must arise from mere heat, cold, and evaporation, as vere cause, and you have brought forward with singular emphasis the more powerful action of the polar cold, or rather the more intense action, as its maximum effect is limited to a much smaller area than that of the maximum of equatorial heat. “The action of the trade and counter-trade winds, in like manner, cannot be ignored; and henceforward the question of ocean currents will have to be studied under a twofold point of view. The wind-currents, however, are of easier investigation : all the causes lie on the surface; none of the agencies escape our notice; the configuration of coasts, which mainly determines their direction, is patent to sight. It is otherwise with the other class of movements. They take place in the depths of the ocean ; and their movements and directions and channels of concentra- tion are limited to the configuration of the sea-bottom, which has to be studied over its entire surface by the very imperfect method of sounding. “Tam glad you succeeded in getting specimens of Mediter- ranean water near the place of the presumed salt spring of Smyth and Wollaston, making it clear that the whole affair must have arisen from some accidental substitution of one bottle for another, or from evaporation. I never put any hearty faith in it. CHAP, VIII. ] THE GULF-STREAM. 379 “So, after all, there is an under-current setting outwards in the Straits of Gibraltar. “ Repeating my thanks for this interesting memoir, believe me, dear Sir, “Yours very truly, “J... W. HERSCHEL. “Dr. W. B. Carpenter.” + The second view, supported by Dr. Petermann of Gotha, and by most of the leading authorities in physical geography in Germany and Northern Europe, and strongly urged by the late Sir John Herschel in his ‘Outlines of Physical Geography’ published in the year 1846, attributes nearly the whole of the sensible phenomena of heat-distribution in the North Atlantic to the Gulf-stream, and to the arctic return-currents which are induced by the removal of tropical water towards the polar regions by the Gulf-stream. If we for a moment admit that to the Gulf-stream is due almost exclusively the singular advantage in climate which the eastern borders of the North Atlantic possess over the western, the origin of this great current, its extent and direction, and the nature and amount of its influence, become questions of surpassing interest. Before considering these, however, it will be well to define what is here meant by the term ‘Gulf- stream,’ for even on this point there has been a good deal of misconception. I mean by the Gulf-stream that mass of heated water which pours from the Strait of Florida across the North Atlantic, and likewise a wider but less definite warm current, evidently forming part of the same great movement of water, which curves north- 1 Nature, vol. iv. p. 71. 380 THE DEPTHS OF THE SEA. [CHAP. VIII. wards to the eastward of the West Indian Islands. I am myself inclined, without hesitation, to regard this stream as simply the reflux of the equatorial current, added to no doubt during its north-easterly course, by the surface-drift of the anti-trades which follows in the main the same direction. The scope and limit of the Gulf-stream will be better understood if we inquire in the first place into its origin and cause. As is well known,—in two bands, one to the north and the other to the south of the equator,—the north-east and south-east trade- winds, reduced to meridional directions by the east- ward frictional impulse of the earth’s rotation, drive before them a magnificent surface current of hot water 4,000 miles long by 450 miles broad at an average rate of thirty miles a day. Off the coast of Africa near its starting-point to the south of the Islands of St. Thomas and Anna Bon, this ‘ Equa- torial Current’ has a speed of forty miles in the twenty-four hours, and a temperature of 23° C. Increasing quickly in bulk, and spreading out more and more on both sides of the equator, it flows rapidly due west towards the coast of South America. At the eastern point of South America, Cape St. toque, the equatorial current splits into two, and one portion trends southwards to deflect the isotherms of 21°, 15°5, 10°, and 4°°5 C. into loops upon our maps, thus carrying a scrap of comfort to the Falkland Islands and Cape Hoorn; while the northern portion follows the north-east coast of South America, gaining continually in temperature under the influence of the tropical sun. Its speed has now increased to sixty- eight miles in twenty-four hours, and by the union CHAP. VIII. | THE GULF-STREAM. 381 with it of the waters of the river Amazon, it rises to one hundred miles (6°5 feet in a second), but it soon falls off again when it gets into the Caribbean sea. Flowing slowly through the whole length of this sea, it reaches the Gulf of Mexico through the Strait of Yucatan, when a part of it sweeps immediately round Cuba; but the main stream “having made the circuit of the Gulf of Mexico, passes through the Strait of Florida; thence it issues as the ‘ Gulf-stream’ in a majestic current upwards of thirty miles broad, two thousand two hundred feet deep, with an average velocity of four miles an hour, and a temperature of 86° Fahr. (30° C).”1 The hot water pours from the strait with a decided though slight north-easterly impulse on account of its great initial velocity. Mr. Croll calculates the Gulf-stream as equal to a stream of water fifty miles broad and a thousand feet deep flowing at a rate of four miles an hour; consequently conveying 5,575,680,000,000 cubic feet of water per hour, or 133,816,320,000,000 cubic feet per day. This mass of water has a mean temperature of 18° C. as it passes out of the gulf, and on its northern journey it is cooled down to 45, thus losing heat to the amount of 13°5C. The total quantity of heat therefore trans- ferred from the equatorial regions per day amounts to something like 154,,959,300,000,000,000,000 foot- pounds.” This is nearly equal to the whole of the heat ! Physical Geography. From the ‘Encyclopedia Britannica.’ By Sir John F. W. Herschel, Bart., K.H.P. Edinburgh, 1861, p. 49. * On Ocean Currents. By James Croll, of the Geological Survey of Scutland. Part I. Ocean Currents in relation to the Distribution of Heat over the Globe (Philosophical Magazine. February 1870.) 382 THE DEPTHS OF THE SEA. [cHAP. VIII. received from the sun by the Arctic regions, and, reduced by a half to avoid all possibility of exaggera- tion, it is still equal to one-fifth of the whole amount received from the sun by the entire area of the North Atlantic. The Gulf-stream, as it issues from the Strait of Florida and expands into the ocean on its north- ward course, is probably the most glorious natural phenomenon on the face of the earth. The water is of a clear crystalline transparency and an intense blue, and long after it has passed into the open sea it keeps itself apart, easily distinguished by its warmth, its colour, and its clearness; and with its edges so sharply defined that a ship may have her stem in the clear blue stream while her stern is still in the common water of the ocean. «The dynamics of the Gulf-stream have of late, in the work of Lieutenant Maury already mentioned, been made the subject of much (we cannot but think misplaced) wonder, as if there could be any possible ground for doubting that it owes its origin entirely to the trade-winds.’’! Setting aside the wider ques- tion of the possibility of a general oceanic circulation arising from heat, cold, and evaporation, I believe that Captain Maury and Dr. Carpenter are the only authorities who of late years have disputed this source of the current which we see, and can gauge and measure as it passes out of the Strait of Florida ; for it is scarcely necessary to refer to the earlier speculations that it is caused by the Mississippi river, or that it flows downwards by gravitation from a ‘head’ of water produced by the trade-winds in the Caribbean sea. * Herschel, op. cit. p. 51. CHAP. V1II.] THE GULF-STREAM. 383 Captain Maury writes! that “the dynamical force that calls forth the Gulf-stream is to be found in the difference as to specific gravity of intertropical and polar waters.” ‘The dynamical forces which are expressed by the Gulf-stream may with as much pro- priety be said to reside in those northern waters as in the West India seas: for on one side we have the Caribbean sea and Gulf of Mexico with their waters of brine; on the other the great polar basin, the Baltic, and the North Sea, the two latter with waters which are little more than brackish. In one set of these sea-basins the water is heavy; in the other it is light. Between them the ocean intervenes; but water is bound to seek and to maintain its level; and here, therefore, we unmask one of those agents concerned in causing the Gulf-stream. What is the power of this agent ? Is it greater than that of other agents ? and how much? We cannot say how much; we only know it is one of the chief agents concerned. More- over, speculate as we may as to all the agencies con- cerned in collecting these waters, that have supplied the trade-winds with vapour, into the Caribbean Sea, and then in driving them across the Atlantic, we are forced to conclude that the salt which the trade-wind vapour leaves behind it in the tropics has to be con- veyed away from the trade-wind region, to be mixed up again in due proportion with the other water of the sea—the Baltic Sea and the Arctic Ocean included —and that these are some of the waters, at least, which we see running off through the Gulf-stream. To convey them away is doubtless one of the offices which in the economy of the ocean has been assigned 1 Maury’s Physical Geography of the Sea, op. cit. 384 THE DEPTHS OF THE SEA. (CHAP, VIII. to it. But as for the seat of the forces which put and keep the Gulf-stream in motion, theorists may place them exclusively on one side of the ocean with as much philosophical propriety as on the other. Its waters find their way into the North Sea and Arctic Ocean by virtue of their specific gravity, while water thence, to take their place, is, by virtue of its specific gravity and by counter-currents, carried back into the gulf. The dynamical force which causes the Gulf-stream may therefore be said to reside both in the polar and in the intertropical waters of the Atlantic.” According to this view, the tropical water finds its way on account of its greater weight towards the poles, while the polar water, owing to its less weight, moves southwards to replace it. ‘The general result would be of course a system of warm under- and cold surface-currents, and these we do not find. I merely quote the passage as a curious illustration of the adage that on most questions a good deal can be said on both sides. We have already considered the doctrine of a general oceanic circulation, which has been so strongly ad- vocated of late by Dr. Carpenter, and I have merely to advert in this place to the bearing which that doctrine has upon our views as to the origin of the Gulf-stream ; its bearings on the extension and dis- tribution of the current will be discussed hereafter. As already stated, Dr. Carpenter attributes all the ereat movements of ocean water to a general con- vective circulation, and of this general circulation he regards the Gulf-stream as a peculiarly modi- fied case. In the passage already quoted (p. 370) of CHAP. VIII. | THE GULF-STREAM. 885 his address to the Royal Institution, Dr. Carpenter states, that “the Gulf-stream constitutes a peculiar case, modified by local conditions,” of “a great general movement of equatorial water towards the polar area.” I confess I feel myself compelled to take a totally different view. It seems to me that the Gulf-stream is the one natural physical pheno- menon on the surface of the earth whose origin and principal cause, the drift of the trade-winds, can be most clearly and easily traced. The further progress and extension of the Gulf- stream through the North Atlantic in relation to influence upon climate has been, however, a fruitful source of controversy. ‘The first part of its course, after leaving the strait, is sufficiently evident, for its water long remains conspicuously different in colour and temperature from that of the ocean, and a current having a marked effect on naviga- tion is long perceptible in the peculiar Gulf-stream water. ‘‘ Narrow at first, it flows round the penin- sula of Florida, and, with a speed of about 70 or 80 miles, follows the coast at first in a due north, afterwards in a north-east direction. At the lati- tude of Washington it leaves the North American coast altogether, keeping its north-eastward course ; and to the south of the St. George’s and New- foundland Banks it spreads its waters more and more over the Atlantic Ocean, as far as the Acores. At these islands a part of it turns southwards again towards the African coast. The Gulf-stream has, so long as its waters are kept together along the American coast, a temperature of 26°6 C.; but, even under north latitude 36°, Sabine found that cc 386 THE DEPTHS OF THE SEA. [CHAP. VIIL. 23°3 C. at the beginning of December, while the sea-water beyond the stream showed only 16°9 C. Under north latitude 40—41° the water is, accord- ing to Humboldt, at 225 C. within, and 17°5 C. without the stream.” ! The Gulf-stream off the coast of North America has been most carefully examined by the officers of the United States Coast Survey, at first under the superintendence of Professor Bache, and latterly under the direction of the present able head of the bureau, Professor Pierce. In 1860 Professor Bache published an account of the general result.2 Four- teen sections through the Gulf-stream had been care- fully surveyed at intervals of about 100 miles along the coast—the first almost within the Gulf of Mexico, from Fortingas to Havana, and the last off Cape Cod, lat. 41° N., where the stream loses all parallel- ism with the American coast and trends to the east- ward. These sections fully illustrate the leading phenomena during this earlier part of its course of this wonderful current, which Professor Bache well characterizes as “‘ the great hydrographic feature of the United States.” Opposite Fortingas, passing along the Cuban coast, the stream is unbroken and the current feeble; the temperature at the surface is about 26°7C. Issuing from the Strait of Bemini the current is turned nearly directly northwards by the form of the land ; 1 Professor Buff, op. cit. p. 199. 2 Lecture on the Gulf-stream, prepared at the request of the American Association for the Advancement of Science, by A. D. Bache, Superintendent U.S. Coast Survey. From the American Journal of Science and Arts, vol. xxx. November 1860. CHAP. VIII. | THE GULF-STREAM. 387 ‘a little to the north of the strait, the rate is from three to five miles an hour. The depth is only 325 fathoms, and the bottom, which in the Strait of Florida was a simple slope and counter-slope, is now corrugated. The surface temperature is about 26°5C., while the bottom temperature is 4°°5; so that in the moderate depth of 325 fathoms the equa- torial current above and the polar counter-current beneath have room to pass one another, the current from the north being evidently tempered consider- ably by mixture. North of Mosquito inlet the stream trends to the eastward of north, and off St. Augustine it has a decided set to the eastward Between St. Augustine and Cape Hatteras the set of the stream and the trend of the coast differ but little, making 5° of easting in 5° of northing. At Hatteras it curves to the northward, and then runs easterly. In the latitude of Cape Charles it turns quite to the eastward, having a velocity of from a mile to a mile and a half in the hour. A brief account of one of the sections will best explain the general phenomena of the stream off the coast of America. I will take the section following a line at right angles to the coast off Sandy Hook. From the shore out, for a distance of about 250 miles, the surface temperature gradually rises from 21° to 24° C.; at 10 fathoms it rises from 19° to 22° C.; and at 20 fathoms it maintains, with a few irregu- larities, a temperature of 19°C. throughout the whole space; while at 100, 200, 300, and 400 fathoms it maintains in like manner the respective temperatures of 8°8, 5°°7, 4°5, and 2°5C. ‘This space is therefore occupied by cold water, and observation has sufli- cc2 388 THE DEPTHS OF THE SEA. [cHAP. VIII. ciently proved that the low temperature is due to a branch of the Labrador current creeping down alone the coast in a direction opposite to that of the Gulfstream. In the Strait of Florida this cold stream divides—one portion of it passing under the hot Gulf-stream water into the Gulf of Mexico, while the remainder courses round the western end of Cuba. 240 miles from the shore the whole mass of water takes a sudden rise of about 10°C. within 25 miles, a rise affecting nearly equally the water at all depths, and thus producing the singular pheno- menon of two masses of water in contact—one passing slowly southwards, and the other more rapidly northwards, at widely different temperatures at the same levels. This abutting of the side of the cold current against that of the Gulf-stream is so abrupt that it has been aptly called by Lieutenant George M. Bache the ‘ Cold wall.’ Passing the cold wall we reach the Gulf-stream, presenting all its special characters of colour and transparency and of temperature. In the section which we have chosen as an example, upwards of three hundred miles in length, the surface temperature is about 26°5 C., but the heat is not uniform across the stream, for we find that throughout its entire length, as far south as the Cape Canaveral section, the stream is broken up into longitudinal alternating bands of warmer and cooler water. Off Sandy Hook, beyond the cold wall, the stream rises to a maximum of 27°8C., and this warm band extends for about 60 miles. The temperature then falls to a minimum of 26°5C., which it retains for about 30 miles, when a second maximum of 27°4 succeeds, which includes CHAP. VIII. ] THE GULF-STREAM. 389 the axis of the Gulf-stream, and is about 170 miles wide. This is followed by a second minimum of 25°°5 C., and this by a third maximum, when the bands become indistinct. It is singular that the minimum bands correspond with valley-like depres- sions in the bottom, which follow in succession the outline of the coast and lodge desp southward exten- sions of the polar indraught. The last section of the Gulf-stream surveyed by the American Hydrographers extends in a south- easterly direction from Cape Cod, lat. 41° N., and traces the Gulf-stream, still broken up by its bands of unequal temperature, spreading directly eastward across the Atlantic; its velocity has, however, now become inconsiderable, and its limits are best traced by the thermometer. The course of the Gulf-stream beyond this point has given rise to much discussion. I again quote Professor Buff for what may be regarded as the view most generally received among Physical Geo- eraphers :— «A ereat part of the warm water is carried partly by its own motion, but chiefly by the prevailing west and north-west winds, towards the coasts of Hurope _and even beyond Spitzbergen and Nova Zembla; and thus a part of the heat of the south reaches far into the Arctic Ocean. Hence, on the north coast of the old Continent, we always find driftwood from the southern regions, and on this side the Arctic Ocean remains free from ice during a great part of the year, even as far up as 80° north latitude; while on the opposite coast (of Greenland) the ice is not quite thawed even in summer.” The two forces invoked 390 THE DEPTHS OF THE SEA. [CHAP. VIII. by Professor Buff to perform the work are thus the vis a tergo of the trade-wind drift, and the direct driving power of the anti-trades, producing what has been called the anti-trade drift. This is quite — in accordance with the views here advocated. The proportion in which these two forces act, it is un- doubtedly impossible in the present state of our knowledge to determine. My. A. G. Findlay, a high authority on all hydro- graphic matters, read a paper on the Gulf-stream before the Royal Geographical Society, reported in the 18th volume of the Proceedings of the Society. Mr. Findlay, while admitting that the temperature of north-eastern Europe is abnormally ameliorated by a surface-current of the warm water of the Atlantic which reaches it, contends that the Gulf-stream proper, that is to say the water injected, as it were, into the Atlantic through the Strait of Florida by the impulse of the trade-winds, becomes entirely thinned out, dissipated, and lost, opposite the Newfoundland banks about lat. 45° N. The warm water of the southern portion of the North Atlantic basin is still carried northwards; but Mr. Findlay attributes this movement solely to the anti-trades—the south-west winds—which by their prevalence keep up a balance of progress in a north-easterly direction in the surface layer of the water. Dr. Carpenter entertains a very strong opinion that the dispersion of the Gulf-stream may be affirmed to be complete in about lat. 45° N. and long. 35° W. Dr. Carpenter admits the accuracy of the projection of the isotherms on the maps of Berghaus, Dové Petermann, and Keith Johnston, and he admits like- CHAP. VIII] THE GULF-STREAM. 391 wise the conclusion that the abnormal mildness of the climate on the north-western coast of Europe is due to a movement of equatorial water in a north-easterly direction. ‘What I question is the correctness of the doctrine that the north-east flow is an extension or prolongation of the Gulf-stream, still driven on by the vis a tergo of the trade-winds-—a doctrine which (greatly to my surprise) has been adopted and defended by my colleague Professor Wyville Thom- son. But while these authorities attribute the whole or nearly the whole of this flow to the true Gulf- stream, I regard a large part, if not the whole, of that which takes place along our own western coast, and passes north and north-east between Iceland and Norway towards Spitzbergen, as quite independent of that agency; so that it would continue if the North and South American continents were so com- pletely disunited that the equatorial currents would be driven straight onwards by the trade-winds into the Pacific Ocean, instead of being embayed in the Gulf of Mexico and driven out in a north-east direc- tion through the ‘narrows’ off Cape Florida.’’? Dr. Carpenter does not mean by this to endorse Mr. Findlay’s opinion that the movement beyond the 45th parallel of latitude is due solely to the drift of the anti-trades; he says, ‘On the view I advocate, the north-easterly flow is regarded as due to the vis a fronte originating in the action of cold upon the water of the polar area, whereby its level is always tending to depression.”? The amelioration of the climate of north-western Europe is thus * Dr. Carpenter : Proceedings of the Royal Geographical Society for 1870, op. cit. 2 Ops cit: 392 THE DEPTHS OF THE SEA. [cHAP. VIII. caused by a ‘modified case’ of the general oceanic circulation, and neither by the Gulf-stream nor by the anti-trade drift. Although there are, up to the present time, very few trustworthy observations of deep-sea tempera- tures, the surface temperature of the North Atlantic has been investigated with considerable care. The general character of the isothermal lines with their singular loop-like northern deflections, has long been familiar through the temperature charts of the geographers already quoted, and of late years a pro- digious amount of data have been accumulated both abroad and by our own Admiralty and Meteoro- logical Department. In 1870, Dr. Petermann, of Gotha, published? an extremely valuable series of temperature charts, embodying the results of the reduction of upwards of 100,000 observations, derived chiefly from the following sources :— 1. From the wind and current charts of Lieu- tenant Maury, embodying about 30,000 distinct temperature observations. 2. From 50,000 observations made by Dutch sea- captains, and published by the Government of the Netherlands. 3. From the journal of the Cunard steamers be- tween Liverpool and New York, and of the steamers of the Montreal Company between Glasgow and Belleisle. 4, From the data collected by the secretary of the * Der Golf-Strom und Standpunkt der thermometrischen Kenntniss des Nord-Atlantischen Oceans und Landgebietes im Jahre 1870. Justus Perthe’s ‘Geographische Mittheilungen,’ Band 16. Gotha, 1870. CHAP. VIII. | THE GUILF-STREAM. 393 Scottish Meteorological Society, Mr. Buchan, with regard to the temperature of the sea on the coasts of Scotland. 5. From the publications of the Norwegian Insti- tute on sea-temperatures between Norway, Scotland, and Iceland. 6. From the data furnished by the Danish Rear- Admiral Irminger on sea-temperature between Den- mark and the Danish settlements in Greenland. 7. From the observations made by Earl Dufferin on board his yacht ‘Foam’ between Scotland, Ice- land, Spitzbergen, and Norway. And finally, from the recent observations collected by the English, Swedish, German, and Russian ex- peditions to the arctic regions and towards the North Pole. Dr. Petermann has devoted the special attention of a great part of his life to the distribution of heat on the surface of the ocean, and the accuracy and con- scientiousness of his work in every detail are beyond the shadow of-a doubt. Plate VII. is in the main copied from his charts, with a few modifications and additions derived from additional data. The remark- able diversion of the isothermal lines from their normal course is undoubtedly caused by surface ocean- currents conveying warm tropical water towards the polar regions. This is no matter of speculation, for the current is in many places perceptible through its effect on navigation, and the path of the warm water may be traced by dipping the thermometer into it and noting its temperature. In the North Atlantie every curve of equal tem- perature, whether for the summer, for the winter, for 394 THE DEPTHS OF THE SEA. (CHAP. VII1. a single month, or for the whole year, instantly declares itself as one of a system of curves which are referred to the Strait of Florida as a source of heat, and the flow of warm water may be traced in a continuous stream, indicated when its movement can no longer be observed by its form,—fanning out from the neighbourhood of the Strait across the Atlantic, skirting the coasts of France, Britain, and Scandinavia, rounding the North Cape and passing the White Sea and the Sea of Kari, bathing the western shores of Novaja Semla and Spitzbergen, and finally coursing round the coast of Siberia, a trace of it still remaining to find its way through the narrow and shallow Behring’s Strait into the North Pacific (see Plate VIT.). Now, it seems to me that if we had only these curves upon the chart, deduced from an almost in- finite number of observations which are themselves merely laboriously multiplied corroborations of many previous ones, without having any clue to their rationale, we should be compelled to admit that whatever might be the amount and distribution of heat derived from a general oceanic circulation,— whether produced by the prevailing winds of the region, by convection, by unequal barometric pres- sure, by tropical heat, or by arctic cold,—the Gulf- stream, the majestic stream of warm water whose course is indicated by the deflections of the isother- mal lines, is sufficiently powerful to mask all the rest, and, broadly speaking, to produce of itself all the abnormal thermal phenomena. The deep-sea temperatures taken in the ‘ Porcu- pine’ have an important bearing upon this question, CHAP. VITI.] THE GULF-STREAM. 395 since they give us the depth and volume of the mass of water which is heated above its normal tempera- ture, and which we must regard as the softener of the winds blowing on the coasts of Europe. Refer- ring to Fig. 60, in the Bay of Biscay, after passing through a shallow band superheated by direct radia- tion, a zone of warm water extends to the depth of 800 fathoms, succeeded by cold water to a depth of nearly two miles. In the Rockall channel (Fig. 59) the warm layer has nearly the same thickness, and the cold underlying water is 500 fathoms deep. Off the Butt of the Lews (Fig. 56) the bottom tem- perature is 5°2 C. at 767 fathoms, so that there the warm layer evidently reaches to the bottom. In the Féroe channel (Fig. 55) the warm water forms a surface layer, and the cold water underlies it, commencing at a depth of 200 fathoms,—567 fathoms above the level of the bottom of the warm water off the Butt of the Lews. The cold water abuts against the warm—there is no barrier between them. Part of the warm water flows over the cold indraught, and forms the upper layer in the Féroe channel. What prevents the cold water from slipping, by virtue of its greater weight, under the warm water off the Butt of the Lews? It is quite evident that there must be some force at work keeping the warm water in that particular position, or, if it be moving, compelling it to follow that particular course. The comparatively high tem- perature from 100 fathoms to 900 fathoms I have always attributed to the northern accumulation of the water of the Gulf-stream. The amount of heat derived directly from the sun by the water as it 396 THE DEPTHS OF THE SEA. (CHAP, VIII. passes through any particular region, must be re- garded, as I have already said, as depending almost entirely upon latitude. Taking this into account, the surface temperatures in what we were in the habit of calling the ‘warm area’ coincided precisely with Petermann’s curves indicating the northward path of the Gulf-stream. I extract the following from a letter dated 28rd September, 1872, from Professor H. Mohn, director of the Norwegian Meteorological Institute at Christiania, to Mr. Buchan, the excellent secretary of the Scottish Meteorological Society :—“I have this summer got some deep-sea temperatures which may be of general interest for our climate. In the Throndhjems-fjord I found 16°°5 C. on the surface, and from 50 fathoms to the bottom (200 fathoms) a very uniform tempera- ture of 6°5 C. in one place, and 6 C. in another place further in. In the Sceguefjord I found 16° C. on the surface, and 6°5 C. constantly from 10 to 700 fathoms. Between Iceland and Froe, Lieu- tenant Miiller, commander of the Bergen and Iceland steamer, has found this summer 8° C. at the bottom in 300 fathoms. This proves that the Gulf-stream water fills the whole of the channel, contrary to what is the case in the Féroe-Shetland channel, where there is ice-cold water in a depth of 3800 fathoms.” ‘The facts here mentioned are very important, and entirely confirm our results; but my chief object in giving the quotation is to show the unhesitating way in which the explanation which attributes the high temperature of the sea on the Scandinavian coast to the Gulf-stream is adopted by those best qualified to form an opinion. CHAP. VIII. | THE GULF-STREAM. 397 The North Atlantic and Arctic seas form together a cul de sac closed to the northward, for there is practically no passage for a body of water through Behring’s Strait. While, therefore, a large portion of the water, finding no free outlet towards the north-east, turns southward at the Acores, the re- mainder, instead of thinning off, has rather a ten- dency to accumulate against the coasts bounding the northern portions of the trough. We accordingly find that it has a depth off the west coast of Iceland of at least 4,800 feet, with an unknown lateral extension. Dr. Carpenter, discussing this opinion, says: ‘ It is to me physically inconceivable that this surface film of lighter (because warmer) water should collect itself together again—even supposing it still to retain any excess of temperature—and should burrow downwards into the ‘trough,’ dis- placing colder and heavier water, to a depth much greater than that which it possesses at the point of its greatest ‘glory’—its passage through the Florida Narrows. The upholders of this hypothesis have to explain how such a re-collection and dipping-down of the Gulf-stream water is to be accounted for on physical principles.”’ I believe that as a rule, experimental imitations on a small scale are of little use in the illustration of natural phenomena; a very simple experiment will, however, show that such a process is possible. If we put a tablespoonful of cochineal into a can of hot water, so as to give it a red tint, and then run it through a piece of india- rubber tube with a considerable impulse along the surface of a quantity of cold water in a bath, we see * Dr. Carpenter’s Address to Geographical Society, op. cit. 398 THE DEPTHS OF THE SEA. (CHAP. VIIL, the red stream widening out and becoming paler over the general surface of the water till it reaches the opposite edge, and very shortly the rapidly heightening colour of a band along the opposite wall indicates an accumulation of the coloured water where its current is arrested. If we now dip the hand into the water of the centre of the bath, a warm bracelet merely encircles the wrist; while at the end of the bath opposite the warm influx, the hot water, though considerably mixed, envelopes the whole hand. The North Atlantic forms a basin closed to the northward. Into the corner of this basin, as into a bath,—with a north-easterly direction given to it by its initial velocity, as if the supply pipe of the bath were turned so as to give the hot water a definite impulse,—this enormous flood is poured, day and night, winter and summer. When the basin is full —and not till then—overcoming its northern impulse, the surplus water turns southwards in a southern eddy, so that there is a certain tendency for the hot water to accumulate in the northern basin, to ‘bank down’! along the north-eastern coasts. It is scarcely necessary to say that for every unit of water which enters the basin of the North Atlantic, and which is not evaporated, an equivalent must return. As cold water can gravitate into the deeper parts of the ocean from all directions, it is only under peculiar circumstances that any move- ment having the character of a current is induced ; ‘Ocean Currents. An Address delivered to the Royal United Service Institution June 15th, 1871. By J. K. Laughton, M.A., Naval Instructor at the Royal Naval College. (From the Journal of the Institution, vol. xv.) CHAP. VIL. ] THE GULF-STREAM. 399 these circumstances occur, however, in the confined and contracted communication between the North Atlantic and the Arctic Sea. Between Cape Fare- well and North Cape there are only two channels. of any considerable depth, the one very narrow along the east coast of Iceland, and the other along the east coast of Greenland. The shallow part of the sea is entirely occupied, at all events. during summer, by the warm water of the Gulf- stream, except at one point, where a rapid current of cold water, very restricted and very shallow, sweeps round the south of Spitzbergen and then. dips under the Gulf-stream water at the northern. entrance of the German Ocean. This cold flow, at first a current, finally a mere indraught, affects greatly the temperature of the German Ocean; but it is entirely lost, for the slight. current which is again produced by the great con- traction at the Strait of Dover, has a summer tem- perature of 7°5C. The path of the cold indraught from Spitzbergen may be readily traced on the map by the depressions in the surface isothermal lines, and in dredging by the abundance of gigantic amphi- podous and isopodous crustaceans, and other well- known Arctic animal forms. From its low initial velocity the Arctic return current, or indraught, must doubtless tend slightly in a westerly direction, and the higher specific gravity of the cold water may probably even more power- fully lead it into the deepest channels; or possibly the two causes may combine, and in the course of ages the currents may hollow out deep south- westerly grooves. At all events, the main Arctic 400 THE DEPTHS OF THE SEA. (CHAP, VIII. return currents are very visible on the chart taking this direction, indicated by marked deflections of the isothermal lines. The most marked is the Labrador current, which passes down inside the Gulf-stream along the coasts of Carolina and New Jersey, meeting it in the strange abrupt ‘cold wall,’ dipping under it as it issues from the Gulf, coming to the surface again on the other side, and a portion of it actually passing, under the Gulf- stream, as a cold counter-current into the Gulf of Mexico. Fifty or sixty miles out from the west coast of Scotland, I believe the Gulf-stream forms another, though a very mitigated, ‘cold wall.’ In 1868, after our first investigation of the very remarkable cold indraught into the channel between Shetland and Froe, I stated my belief that the current was entirely banked up in the Féroe Channel by the Gulf-stream passing its gorge. Since that time I have been led to suspect that a part of the Arctic water oozes down the Scottish coast, much mixed, and sufficiently shallow to be affected throughout by solar radiation. About sixty or seventy miles from shore the isother- mal lines have a slight but uniform deflection. Within that line types characteristic of the Scandi- navian fauna are numerous in shallow water, and in the course of many years’ use of the towing net I have never met with any of the Gulf-stream pteropods, or of the lovely Polycystina and Acantho- metrina which absolutely swarm beyond that limit. The difference in mean temperature between the east and west coasts of Scotland, amounting to about 1°C., is also somewhat less than might be CHAP. VIII. ] THE GULF-STREAM. 40] expected if the Gulf-stream came close to the western shore. While the communication between the North Atlantic, and the Arctic Sea—itself a second cul de sac—is thus restricted, limiting the interchange of warm and cold water in the normal direction of the flow of the Gulf-stream, and causing the diversion of a large part of the stream to the southwards, the communication with the Antarctic basin is as open as the day ;—a continuous and wide valley upwards of 2,000 fathoms in depth stretching northwards along the western coasts of Africa and Europe. That the southern water wells up into this valley there could be little doubt from the form of the ground; hut here again we have curious corroborative evidence on the map in the remarkable reversal of the curves of the isotherms. The temperature of the bot- tom water at 1,230 fathoms off Rockall is 3°22 C., exactly the same as that of water at the same depth in the serial sounding, lat. 47°38’ N., long. 12° 08’ W. in the Bay of Biscay, which affords a strong presumption that the water in both cases is derived from the same source; and the bottom water off Rockall is warmer than the bottom water in the Bay of Biscay (2"5 C.), while a cordon of temperature soundings drawn from the north-west of Scotland to a point on the Iceland shallow gives no temperature lower than 6°5 C. This makes it very improbable that the low temperature of the Bay of Biscay is due to any considerable por- tion of the Spitzbergen current passing down the west coast of Scotland; and as the cold current to the east of Iceland passes southwards considerably to the westward, as indicated on the map by the successive DD 402 THE DEPTHS OF THE SEA. [cHAP, VII. depressions in the surface isotherms, the balance of probability seems to be in favour of the view that the conditions of temperature and the slow movement of this vast mass of moderately cold water, nearly two statute miles in depth, are to be referred to an Antarctic rather than to an Arctic origin. The North Atlantic Ocean seems to consist first of a great sheet of warm water, the general northerly reflux of the equatorial current. Of this the greater part passes through the Strait of Florida, and its north-easterly flow is aided and maintained by the anti-trades, the whole being generally called the Gulf-stream. This layer is of varying depths, ap- parently from the observations of Captain Chimmo and others, thinning to a hundred fathoms or so in the mid-Atlantic, but attaining a depth of 700 to 800 fathoms off the west coasts of Ireland and Spain. Secondly of a ‘stratum. of intermixture’ which ex- tends to about 200 fathoms in the Bay of Biscay, through which the temperature falls rather rapidly ; and thirdly, of an underlying mass of cold water, in the Bay of Biscay 1,500 fathoms deep, derived as an indraught falling in by gravitation from the deepest available source, whether Arctic or Antarctic. It seems at first sight a _ startling suggestion, that the cold water filling deep ocean valleys in the northern hemisphere may be partly derived from the southern; but this difficulty, I believe, arises from the idea that there is a kind of diaphragm at the equator between the northern and southern ocean basins, one of the many misconceptions which follow in the train of a notion of a convective circulation in the sea similar to that in the atmosphere. There is CHAP. VIII. ] THE GULF-STREAM. 408 undoubtedly a gradual elevation of an intertropical belt of the underlying cold water, which is being raised by the subsiding of still colder water into its bed to supply the place of the water removed by the equatorial current and by excessive evaporation; but such a movement must be widely and irregularly diffused and excessively slow, not in any sense com- parable with the diaphragm produced in the atmo- sphere by the rushing upwards of the north-east and south-east trade-winds in the zone of calms. Perhaps one of the most conclusive proofs of the extreme slowness of the movement of the deep indraught is the nature of the bottom. Over a great part of the floor of the Atlantic a deposit is being formed of microscopic shells. These with their living inha- bitants differ little in specific weight from the water itself, and form a creamy flocculent layer, which must be at once removed wherever there is a perceptible movement. In water of moderate depth, in the course of any of the currents, this deposit is entirely absent, and is replaced by coarser or finer gravel. It is only on the surface of the sea that a line is drawn between the two hemispheres by the equatorial current, whose effect in shedding a vast intertropical drift of water on either side as it breaks against the eastern shores of equatorial land may be seen at a glance on the most elementary physical chart. The Gulf-stream loses an enormous amount of heat in its northern tour. Ata point 200 miles west of Ushant, where observations at the greatest depths were made on board the ‘ Porcupine,’ a section of the water of the Atlantic shows three surfaces at which interchange of temperature is taking place. DD 2 404 THE DEPTHS OF THE SEA. [CHAP. VII1. First, the surface of the sea—that is to say, the upper surface of the Gulf-stream layer—is losing heat rapidly by radiation, by contact with a layer of air which is in constant motion and being per- petually cooled by convection, and by the con- version of water into vapour.’ As this cooling of the Gulf-stream layer takes place principally at the surface, the temperature of the mass is kept pretty uniform by convection. Secondly, the band of con- tact of the lower surface of the Gulf-stream water with the upper surface of the cold indraught. Here the interchange of temperature must be very slow, though that it does take place is shown by the slight depression of the surface isotherms over the principal paths of the indraught. But there is a good deal of intermixture extending through a con- siderable layer. The cold water being beneath, convection in the ordinary sense cannot occur, and interchange of temperature must depend mainly upon conduction and diffusion, causes which in the case of masses of water must be almost secular in their action, and probably to a much greater extent upon mixture produced by local currents and by the tides. The third surface is that of contact be- tween the cold indraught and the bottom of the sea. The temperature of the crust of the earth has been variously calculated at from 4° to 11° C., but it must be completely cooled down by anything like a movement and constant renewal of cold water. * On Deep-sea Climates. The Substance of a Lecture delivered to the Natural Science Class in Qteen’s College, Belfast, at the close of the Summer Session 1870, by Professor Wyville Thomson. (Nature, July 28th, 1870.) CMAP. VIII. | THE GULF-STREAM. 405 All we can say, therefore, is that contact with the bottom can never be a source of depression of tem- perature. Asa general result the Gulf-stream water is nearly uniform in temperature throughout the greater part of its depth; there is a marked zone of intermixture at the junction between the warm water and the cold, and the water of the cold indraught is regularly stratified by gravitation ; so that in deep water the contour lines of the sea-bottom are, speaking generally, lines of equal temperature. Keeping in view the enormous in- fluence which ocean currents exercise in the dis- tribution of climates at the present time, I think it is scarcely going too far to suppose that such currents—movements communicated to the water by constant winds—existed at all geological periods as the great means, I had almost said the sole means, of producing a general oceanic circulation, and thus distributing heat in the ocean. They must have existed, in fact, wherever equatorial land inter- rupted the path of the drift of the trade-winds. Wherever a warm current was deflected to north or south from the equatorial belt a polar indraught crept in beneath to supply its place; and the ocean consequently consisted, as in the Atlantic and doubtless in the Pacific at the present day, of an upper warm stratum, and a lower layer of cold water becoming gradually colder with increasing depth. I fear, then, that in opposition to the views of my distinguished colleague, I must repeat that I have seen as yet no reason to modify the opinion which I have consistently held from the first, that 406 THE DEPTHS OF THE SEA. (CHAP. VIII. the remarkable conditions of climate on the coasts of Northern Europe are due in a broad sense solely to the Gulf-stream. That is to say, that although movements, some of them possibly of considerable importance, must be produced by differences of spe- cific gravity, yet the influence of the great current which we call the Gulf-stream, the reflux of the great equatorial current, is so paramount as to reduce all other causes to utter insignificance. THE GIANT AND THE HAG. CHAPTER IX. THE DEEP-SEA FAUNA. The Protozoa of the Deep-sea.—Bathybius.—‘ Coceoliths,’ and ‘ Cocco- spheres.’—The Foraminifera of the Warm and Cold Areas.— Deep- sea Sponges. —The Hexactinellidee. —Rossella.— Hyalonema,— Deep-sea Corals.—The Stalked Crinoids.—Pentacrinus.—Rhiz0- crinus. — Bathycrinus. — The Star-fishes of the Deep-sea.—The general Distribution and Relations of Deep-sea Urchins.—The Crustacea, the Mollusca, and the Fishes of the ‘ Porcupine’ Expe- ditions. Tur time has not yet arrived for giving anything like a detailed account of the deep-sea fauna; even if it were possible to do so in a popular sketch of the general results of a wide investigation. I must therefore confine myself at present to a brief outline of the distribution of the forms of animal life which were met with in the belt partially examined during the ‘Porcupine’ dredgings, a belt which carries the British zoological area about a hundred miles further out to seaward along the northern and western coasts of the British Isles, and into depths extending from 200 fathoms, the previous limit of accurate know- ledge, to 800 and 1,000 fathoms, and in one or two instances to the extreme depth of upwards of 2,000 fathoms. 408 THE DEPTHS OF THE SEA. [cHAP. 1X. The remarkable general result that even to these great depths the fauna is varied and rich in all the marine invertebrate groups, has inundated us with new material which in several of the larger depart- ments it will take years of the labour of specialists to work up. While referring very briefly to those orders which it has been found impossible as yet to overtake, I will enter a little more fully into the history of certain restricted groups which more par- ticularly illustrate the conditions of the abyssal region, and the relations of its special fauna to the faunze of other zoological provinces, or to those of earlier times. And very prominent among these special groups we find the first and simplest of the in- vertebrate sub-kingdoms, the Protozoa, represented by three of its classes,—the monera, the rhizopoda, and the sponges. The monera have been lately defined as a distinct class by Professor Ernst Haeckel,' for a vast assem- blage of almost formless beings, apparently abso- lutely devoid of internal structure, and consisting simply of living and moving expansions of jelly-like protoplasm; and although the special character on which Haeckel separates them from the remainder of the protozoa,—that they are propagated by no form of sexual reproduction, but simply by spontaneous division,—-may probably prove deceptive as our know- ledge increases, still their number, their general resemblance to one another, presenting obviously different and recognizable kinds although with very indefinable characters, and the important part which * Biologische Studien. Von Dr. Ernst Haeckel, Professor an der Universitit Jena. Leipzig, 1870. CHAP. IX. | THE DEEP-SEA FAUNA. 409 they play in the economy of nature, would seem to entitle them to a systematic position of more than ordinal value. ‘The German naturalists of the new school, in their enthusiastic adoption of the Dar- winian theory of evolution, naturally welcome in these ‘moners’ the essential attribute of the ‘ Ur- schleim,’ an infinite capacity for improvement in every conceivable direction ; and to more prosaic physiologists they are of the deepest interest, as presenting the essential phenomena of life, nutri- tion and irritability, existing apparently simply as the properties of a homogeneous chemical compound, and independent of organization. The monera pass into the rhizopoda, which give a slight indication of advance, in the definite form of the graceful calcareous shell-hke structures which most of them secrete, and the two groups may be taken together. The dredging at 2,485 fathoms at the mouth of the Bay of Biscay gave a very fair idea of the con- dition of the bottom of the sea over an enormous area, as we know from many observations which have now been made, with the various sounding instruments contrived to bring up a sample of the bottom. On that occasion the dredge brought up about 13 cwt. of caleareous mud. There could be little doubt, from the appearance of the contents of the dredge, that the heavy dredge-frame had gone down with a plunge, and partly buried itself in the soft, yielding bottom. The throat of the dredge thus became partly choked, and the free entrance of the organisms on the sea-floor had been thus prevented. ‘The matter contained in the dredge con- 410 THE DEPTHS OF THE SEA. [CHAP, LX. sisted mainly of a compact ‘mortar,’ of a bluish colour, passing into a thin—evidently superficial— layer, much softer and more creamy in consistence, and of a yellowish colour. Under the microscope the surface-layer was found to consist chiefly of entire shells of Globigerina bulloides (Fig. 2, p. 22), large and small, and fragments of such shells mixed with a quantity of amorphous calcareous matter in fine particles, a little fine sand, and many spicules, portions of spicules, and shells of Radiolaria, a few spicules of sponges, and a few frustules of diatoms. Below the surface-layer the sediment becomes gradually more compact, and a slight grey colour, due probably to the decomposing organic matter, becomes more pronounced, while perfect shells of elobigerina almost entirely disappear, fragments be- come smaller, and calcareous mud, structureless and in a fine state of division, is in greatly preponderating proportion. One can have no doubt, on examining this sediment, that it is formed in the main by the accumulation and disintegration of the shells of globigerina—the shells fresh, whole, and living in the surface-layer of the deposit, and in the lower layers dead, and gradually crumbling down by the decomposition of their organic cement, and by the pressure of the layers above—an animal formation in fact being formed very much in the same way as in the accumulation of vegetable matter in a peat bog, by life and growth above, and death, retarded de- composition, and compression beneath. In this dredging, as in most others in the bed of the Atlantic, there was evidence of a considerable quantity of soft gelatinous organic matter, enough CHAP, IX. ] THE DEEP-SEA FAUNA. AL to give a slight viscosity to the mud of the surface layer. If the mud be shaken with weak spirit of wine, fine flakes separate like coagulated mucus ; and if a little of the mud in which this viscid con- dition is most marked be placed in a drop of sea- water under the microscope, we can usually see, after a time, an irregular network of matter resem- bling white of egg, distinguishable by its maintaining its outline and not mixing with the water. This network may be seen gradually altering in form, and entangled granules and foreign bodies change their relative positions. The gelatinous matter is therefore capable of a certain amount of movement, and there can be no doubt that it manifests the phenomena of a very simple form of life. To this organism, if a being can be so called which shows no trace of differentiation of organs, consist- ing apparently of an amorphous sheet of a protein compound, irritable to a low degree and capable of assimilating food, Professor Huxley has given the name of Bathybius haeckelii (Fig. 63). If this have a claim to be recognized as a distinct living entity, ex- hibiting its mature and final form, it must be referred to the simplest division of the shell-less rhizopoda, or if we adopt the class proposed by Professor Haeckel, to the monera. ‘The circumstance which gives its special interest to Bathybius is its enormous extent : whether it be continuous in one vast sheet, or broken up into circumscribed individual particles, it appears to extend over a large part of the bed of the ocean ; and as no living thing, however slowly it may live, is ever perfectly at rest, but is continually acting and reacting with its surroundings, the bottom of the 412 THE DEPTHS OF THE SEA. [CHAP. IX. a! sea becomes like the surface of the sea and of the land,—a theatre of change, performing its part in maintaining the ‘ balance of organic nature.’ Fic. 63,—‘‘ Eine grossere Cytode von Bathybius mit eingebetteten Coccolithen. Das Proto- plasma, welches viele Discolithen und Cyatholithen enthalt, bildet ein Netzwerk mit breiten Strangen.’ (x. 700,)1 1 Biologische Studien. Von Dr, Ernst Haeckel, Professor an der Universitat Jena. Leipzig, 1870. CHAP. IX.] THE DEEP-SEA FAUNA. 413 Entangled and borne along in the viscid streams of Bathybius, we so constantly find a multitude of minute calcareous bodies of a peculiar shape, that the two were for long supposed to have some mutual relation to one another. These small bodies, which have been carefully studied by Huxley,’ Sorby,? Haeckel,®? Carter,! Giimbel,’ and others, are in shape somewhat like oval shirt-studs. There is first a little oval disk about 0-01 mm. in length, with an oblong rudely facetted elevation in the centre, and round that, in fresh specimens, what seems to be a kind of frill of organic matter, then a short neck, and lastly a second smaller flat disk, like the disk at the back of a stud. To these bodies, which are met with in all stages of development, Professor Huxley has given the name of ‘ coccoliths.” Some- times they are found aggregated on the surface of small transparent membranous balls, and these which seemed at first to have something to do with the production of the ‘ coccoliths’ Dr. Wallich has called ‘coccospheres’ (Fig. 64). Professor Ernst Haeckel has lately described a very elegant organ- ism belonging to the radiolaria and apparently allied to Thalassicolla,—Myxobrachia rhopalum,—and at the ends of some curious diverging appendages of this creature he has detected accumulations of bodies closely resembling, if not identical with, the coccoliths and coccospheres of the sea-bottom. These 1 Quarterly Journal of Microscopical Science, 1868, p. 203. 2 Proceedings of the Sheffield Literary and Philosophical Society, October 1860. 2" Op. cit. 4 Ann. and Mag. Nat. Hist. 1871, p. 184. 5 Jahrbuch Miinch. 1870, p. 753. > 414 THE DEPTHS OF THE SEA. (CHAP. Ix. bodies seem to have been taken in to the Myzo- brachia as food, the hard parts accumulating in cavities in the animal’s body after all the available nourishment had been absorbed. It is undoubted that a large number of the organisms whose skele- tons are mixed with the ooze of the bottom of the sea live on the surface, the delicate silicious or eal- careous shields or spines falling gradually through Fic. 64.—‘ Coccosphere.’ (x. 1000.) the water and finally reaching the bottom, what- ever be the depth. I think that now the balance of opinion is in favour of the view that the coccoliths are joints of a minute unicellular alga living on the sea-surface and sinking down and mixing with the sarcode of Bathybius, very probably taken into it with a purpose, for the sake of the vegetable matter they may contain, and which may afford food for the animal jelly. What the coccospheres are, and CHAP, IX. | THE DEEP-SEA FAUNA. 415 what relation, if any, they have to the coccoliths, we do not know. Living upon and among this Bathybius, we find a multitude of other protozoa,—foraminifera and other rhizopods, radiolarians, and sponges; and we as yet know very little of the life-history of these groups. There can be no doubt that when their development has been fully traced many of them will be found to be di- or poly-morphic, and that when we are acquainted with their mode of multi- plication we shall meet with many cases of pleo- morphism and wide differences between the organs and products involved in propagation and in repro- duction. I feel by no means satisfied that Bathybius . is the permanent form of any distinct living being. It has seemed to me that different samples have been different in appearance and consistence; and although there is nothing at all improbable in the abundance of a very simple shell-less ‘moner’ at the bottom of the sea, I think it not impossible that a great deal of the ‘bathybius,’ that is to say the diffused formless protoplasm which we find at great depths, may be a kind of mycelium—a formless condition connected either with the growth and multiplication or with the decay—of many different things. Many foraminifera of different groups inhabit the deep water, lying upon or mixed in the upper layer of the globigerina ooze, or fixed to some foreign body, such as a sponge, coral, or stone; and all of these are remarkable for their large size. In the ‘warm area,’ and wherever the bottom is covered with ooze, calcareous forms predominate, and large sandy cristellarians, with their sand-grains hound together 416 THE DEPTHS OF THE SEA. (CHAP. Ix. by calcareous cement, so that the sand-grains show out, dark and conspicuous, scattered on the surface of the white shell. Miliolines are abundant, and the specimens of Cornuspira and Biloculina are greatly larger than anything which has been hitherto met with in temperate regions, recalling the tropical forms which abound among the Pacific Islands. Jn the cold area, and in the paths of cold currents, foraminifera with sandy tests are more numerous ; some of those of the genera Astrorhiza, Lituola, and Botellina are gigantic—large examples 30 mm. long by 8 mm. in diameter. The few hauls of the dredge which we have already _ had in deep water have been enough to teach us that our knowledge of sponges is in its infancy,—that those which we have collected from shallow water along our shores, and even those few which have been brought up from deep water on fishing lines, and have surprised us by the beauty of their forms and the delicacy of their lustre, are the mere margin and remnant of a wonderfully diversified sponge-fauna which appears to extend in endless variety over the whole of the bottom of the sea. I cannot attempt here more than a mere outline of the general cha- racter of the additions which have been made to our knowledge of this group. The sponges of the ‘ Por- cupine’ Expedition are now in the hands of Mr. Henry Carter, F.R.S., for description; and an ex- cellent sketch of the sponge-fauna of the deep Atlan- tic, bringing information on certain groups up to a late date, has been published by the best authority we have on sponges, Professor Oscar Schmidt of Gratz. CHAP. VII.] THE DEEP-SEA FAUNA, V7 As I have already said, the most remarkable new forms are referable to the group which seems to be, in a sense special to deep water, the Hexactinellide. I have already (p. 70) briefly described one of the most abundant and singular forms belonging to this order, Holtenia carpenteri; and all the others, though running through most remarkable variations in form and general appearance, agree with Holtenia in essential structure. In the Hexactinellide all the spicules, so far as we know, are formed on the hex- radiate plan; that is to say, there is a primary axis, which may be long or short, and at one point four secondary rays cross this central shaft at right angles. Very often one-half of the central shaft is absent or is represented by a slight rounded boss, and in that case we have a spicule with a cross-shaped head, a very favourite form in the manufacture, defence, and ornament of the surface layer of these sponges; and often the secondary rays are undeveloped: but if that be so,—as in the long fibres of the whisp of Hyalonema,—in young spicules and in others which are slightly abnormal, four little elevations near the middle of the spicule, which contain four secondary branches of the central canal, maintain the permanence of the type. In many of the Hexac- tinellide the spicules are all distinct, and combined, as in Holtenia, by a small quantity of nearly trans- parent sarcode; but in others, as in ‘ Venus’s flower- basket,’ and the nearly equally beautiful genera Iphiteon, Aphrocallistes, and Farrea, the spicules run together and make a continuous silicious net- work. When this is the case the sponge may be boiled in nitric acid, and all the organic matter and EE 418 THE DEPTHS OF THE SEA. [CHAP. VII. other impurities thus removed, when the skeleton comes out a lovely lacy structure of the clearest glass. The six-rayed form of the spicules gives the network which is the result of their fusion great flexibility of design, with a characteristic tendency, however, to square meshes. On the 380th of August, 1870, Mr. Gwyn Jeffreys dredged in 651 fathoms in the Atlantic off the mouth of the Strait of Gibraltar an exquisite sponge, resembling Holtenia in its general appearance, but differing from it in the singular and beautiful cha- racter of having a delicate outer veil about a centi- metre from the surface of the sponge, formed by the interlacing of the four secondary rays of large five- rayed spicules, which send their long shafts from that point vertically into the sponge body (Fig. 65). The surface of the sponge is formed of a network of large five-radiate spicules, arranged very much as in Jol- tenia; but the spicules of the sarcode—the small spicules which are imbedded in the living sponge-jelly —are of a totally different form. A single large ‘osculum’ opens, as in Holtenia, at the top of the sponge, but instead of forming a cup uniformly lined with a netted membrane, the oscular cavity divides at the bottom into a number of branching passages as in Pheronema anne, described by Dr. Leidy. I was inclined at first to place this species in the genus Pheronema, but Dr. Leidy’s descrip- tion and figure are by no means satisfactory, and may refer to some other form of the Holtenia group. The spicules of the ‘beard’ are more rigid and thicker than those of Holtenia, and scattered among them are some very large four-barbed grappling hooks. CHAP. Vu. | THE DEEP-SEA FAUNA. 419 x . aN \\ S NS me ot NS i AY iN i vine IN Wie Yai) oan Fic. 65.—Rossella velata, Wyv1LLe THomson. Natural size. (No. 32, 1870.) 420 THE DEPTHS OF THE SEA. [cHAP. VII. Off the Butt of the Lews, in water of 450 to 500 fathoms, we met on two occasions with full-grown specimens of a species of the remarkable genus Hyalonema (Fig. 66), with the coils in the larger examples upwards of 40 centimetres in length. Hyalonema is certainly a very striking object; and although our specimens belong apparently to the same species, HZ. lusitanicum, which has already been recorded by Professor Barboza du Bocage from the coast of Portugal, it is one of the most interesting additions made to the British fauna during our cruise. A bundle of from 200 to 300 threads of trans- parent silica, glistening with a silky lustre, like the most brilliant spun-glass,—each thread from 30 to 40 centimetres long, in the middle the thickness of a knitting needle, and gradually tapering towards either end to a fine point; the whole bundle coiled lke a strand of rope into a lengthened spiral, the threads of the middle and upper portions remaining compactly coiled by a permanent twist of the individual threads ; the lower part of the coil, which, when the sponge is living, is imbedded in the mud, frayed out so that the glassy threads stand separate from one another, like the bristles of a glittering brush; the upper portion of the coil close and compact, imbedded perpen- dicularly in a conical or cylindrical sponge; and usually part of the upper portion of the silicious coil, and part of the sponge-substance, covered with a brownish leathery coating, whose surface is studded with the polyps of an aleyonarian zoophyte : —such is the general effect of a complete specimen of Hyalonema. Fic. 66.—Hyalonema lusitanicum, Bargoza pv Bocacr. Half the natural size. (No. 90, 1869.) 422 THE DEPTHS OF THE SEA. [CHAP. VIL. The genus was first known in Europe by specimens brought from Japan by the celebrated naturalist and traveller, Von Siebold; and Japanese examples of Hyalonema sieboldi, GRAY, may now be found more or less perfect in most of the European museums. When the first specimen of Hyalonema was brought home, the other vitreous sponges which approach it so closely in all essential points of structure were unknown, and the history of opinion as to its rela- tions is curious. The being consisted of three very distinct parts : first, and greatly the most remarkable, the coil of silicious needles; then the sponge, and for long it was supposed that this was the base of the struc- ture,—from which the glossy brush projected, spread- ing out above it in the water; and thirdly, the apparently constant encrusting zoophyte. This complicated association suggested many pos- sibilities. Was Hyalonema a natural production at all? Was it complete? Were all the three parts essentially connected together ? And if not, were all the three independent, or did two of three parts belong to the same thing? and if so, which two ? Hyalonema was first described and named in 1835 by Dr. John Edward Gray, who has since, in one or two notices in the ‘Annals of Natural History’ and elsewhere, vigorously defended the essential part of his original position. Dr. Gray associated the silicious whisp with the zoophyte, and regarded the sponge as a separate organism. He looked upon the silicious coil as the representa- tive of the horny axis of the sea-fans (Gorgonic). and the leather-like coat he regarded as its fleshy CHAP. VII] THE DEEP-SEA FAUNA. 423 rind. He supposed that between this zoophyte and the sponge at its base, there subsisted a relation of guest and host, the zoophyte being constantly asso- ciated with the sponge; and in accordance with this view he proposed for the reception of the zoophyte a new group of alcyonarians under the name of ‘Spongicolee,’ as distinguished from the ‘Sabulicole’ (Pennatule) and the ‘ Rupicole’ (Gorgonie). Dr. Gray’s view seemed in many respects a natural one, and it was adopted in the main by Dr. Brandt of St. Petersburg, who in 1859 published a long memoir, describing a number of specimens brought from Japan to Russia. Dr. Brandt referred what he believed to be a zoophyte consisting of the coil and the crust, to a special group of sclerobasic zoanth- carians with a silicious axis. One consideration militated strongly against this hypothesis of Dr. Gray and Professor Brandt. No known zoophyte had a purely silicious axis; and such an axis made up of loose separate spicules seemed strangely inconsistent with the harmony of the class. On the other hand, silicious spicules of all forms and sizes were conceivable in sponges ; and in 1857 Professor Milne-Edwards, on the authority of Valenciennes, who was thoroughly versed in the structure of the Gorgoniv, combined the sponge with the silicious rope, and degraded the zoophyte to the rank of an encrusting parasite. Anything very strange coming from Japan is to be regarded with some distrust. The Japanese are wonderfully ingenious, and one favourite aim of their misdirected industry is the fabrication of im- possible monsters by the curious combination of the 424 THE DEPTHS OF THE SEA. (CHAP. VII. parts of different animals. It was therefore quite possible that the whole thing might be an imposi- tion: that some beautiful spicules separated from an unknown organism had been twisted into a whisp by the Japanese, and then manipulated so as to have their fibres naturally bound together by the sponges and zoophytes which are doubtless rapidly developed in the Mongolian rock-pools. Ehrenberg, when he examined Hyalonema, took this view. He at once recognized the silicious strands as the spicules of a sponge quite independent of the zoophyte with which they were encrusted; but he suggested that these might have been artificially combined into the spiral coil and placed under artificial circumstances | favourable to the growth of a sponge of a different species round their base. The condition in which many specimens reach Europe is certainly calculated to throw some doubt on their genuineness. It seems that the bundles of spicules made up in various ways, are largely sold as ornaments in China and Japan. The coils of spicules are often stuck upright with their upper ends in circular holes in stones. Mr. Huxley exhibited a few years ago at the Linnean Society a beautiful specimen of this kind now in the British Museum:—-a stone has been bored, probably by a colony of boring molluscs, and a whole colony of Hyalonemas, old and young, are apparently growing out of the burrows, the larger individuals more than a foot in length, and the young ones down to an inch or so, like tiny camel’s- hair pencils. All these are encrusted by the usual zoophyte, which also extends here and there over the stone (glued on probably), but there is no trace CHAP. VII. | THE DEEP-SEA FAUNA. 425 of the sponge. Such an association is undoubtedly artificial. Dr. Bowerbank, another great sponge authority, takes yet another view. He maintains “that the silicious axis, its envelopment, and the basal sponge are all parts of the same animal.” The polyps he regards as ‘ oscula,’ forming with the coil a ‘columnar cloacal system.’ Professor Max Schultze, of Bonn, examined with great care several perfect and imperfect specimens of Hyalonema in the Museum of Leyden, and in 1860 published an elaborate description of its structure. According to Schultze, the conical sponge is the body-mass of Hyalonema, a sponge allied in every respect to Luplectella; and the siliceous coil is an appendage of the sponge formed of modified spicules. The zoophyte is of course a distinct animal altogether, and its only connection with the sponge is one of ‘commensalism.’ It ‘chums’ with the sponge for some purpose of its own,—certainly getting support from the coil, probably sharmg the oxygen and organic matters carried in by the ciliary system of the sponge passages. This style of association is very common. We have another example of the same thing in Palythoa axinelle, SCHMIDT, a con- stant ‘commensal’ with Axinella cinnamomea and A. verrucosa, two Adriatic sponges. In 1864 Professor Barboza du Bocage, director of the Museum of Natural History in Lisbon, com- municated to the Zoological Society of London the unexpected news that a species of Hyalonema had been discovered off the coast of Portugal ; and in 1865 he published, in the Proceedings of the same Society, 426 THE DEPTHS OF THE SE4. [cmAP. VII. an additional note on the habitat of Hyalonema lusi- tanicum. It appears that the fishermen of Setubal frequently bring up on their lines, from a consider- able depth, coils of silicious threads closely resem- bling those of the Japanese species, which they even surpass in size, sometimes attaining a length of about 50 centimetres. The fishermen seem to be very familiar with them. They call them ‘ sea-whips,’ but with the characteristic superstition of their class they regard all these extraneous matters as ‘ unlucky,’ and usually tear them in pieces and throw them into the water. Judging from some specimens in the British Museum, and from Senhor du Bocage’s figure, the ‘glass-rope’ of the Portuguese form is not so thick as that of H. sieboldi. There is also some slight difference in the sculpture of the long needles, but the structure of the sponge and the very characteristic forms of the small spicules are identical in the two. I doubt if there be more than varietal distinctions between the two forms; and if that be so, it adds another to the list of species common to our seas and the seas of Japan. Perhaps the most singular circumstance connected with this discussion was that all this time we had been looking at the sponge upside down, and that it had never occurred to anyone to reverse it. We had probably taken this notion from the specimens stuck in stones, brought from Japan, and the sponge cer- tainly looked very like the base of the edifice. When- ever the sponges were dredged on the coasts of Europe and compared with allied things, it became evident that the whisp was an organ of support passing out of the lower part of the sponge, and that the flat, CHAP. Vil] THE DEEP-SEA FAUNA. 427 or slightly-cupped disk, with a papilla in the centre receiving the upper end of the coil, with large oscular openings, and a fringe of delicate radiating spicules round the edge, was the top of the sponge, spreading out probably level with the surface of the ooze. In essential structure Hyalonema very closely re- embles Holtenia, and the more characteristic forms of the Hexactinellidse. The surface of the sponge is supported by a square network, formed by the sym- metrical arrangement of the four secondary rays of five-rayed spicules, and the sarcode which binds these branches together is full of minute feathered five- rayed spicules, which project from the branches like a delicate fringe. The oscula are chiefly on the upper disk, and lead into a number of irregular passages which traverse the body of the sponge in all direc- tions. When we trace its development, the coil loses its mystery. On one of the Holteniev from the Butt of the Lews, there was a little accumulation of greenish granular matter among the fibres. On placing this under the microscope it turned out to be a number of very young sponges, scarcely out of their germ state. They were all at first sight very much alike, minute pear-shaped bodies, with a long delicate pencil of silky spicules taking the place of the pear-stalk. On closer examination, however, these littie germs proved to belong to different species, each showing unmistakeably the characteristic forms of its special spicules. Most of them were the young of Tisiphonia, but among them were several Loltenia, and one or two were at once referred to Hyalonema. In two or three hauis in the same locality we got them in every subsequent stage—beautiful little A428 THE DEPTHS OF THE SEA. [CHAP. VII. pear-shaped things, a centimetre long, with a single osculum at the top, and the whisp lke a small brush. At this stage the Palythoa is usually absent, but when the body of the sponge has attained 15 mm. or so in length very generally a little pink tubercle may be detected at the point of junction between the sponge body and the coil, the germ of the first polyp. Hyalonema lusitanicum, BARBOZA DU BocaGE, the species met with in the British seas and along the coast of western Europe, appears to be local, but very abundant at the stations where it occurs. IT am still in doubt whether we are to regard it as identical with the Japanese species, H. sieboldi, GRAY. During Mr. Gwyn Jeffreys’ cruise in 1870, two specimens of a wonderful sponge belonging also to the Hexactinellidee were dredged in 374 fathoms in rocky ground off Cape St. Vincent. The larger of these forms a complete vase or a very elegant form, nearly ninety centimetres in diameter at the top and about sixty in height (Fig. 67). The sponge came up folded together, and had much the appearance of a piece of coarse, greyish-coloured blanket. Its minute structure is, however, very beautiful. It consists, like Holtenia, of two netted layers, an outer and an inner, formed by the symmetrical interlacing of the four cross branches of five-rayed spicules; and, as in Holtenia and Rossella, the sarcode is full of extremely minute five and six-rayed spicules, which, however, have a thoroughly distinct character of their own, with here and there a very beautiful rosette-like spicule, another singular modification of cuap. Vil] THE DEEP-SEA FAUNA. 429 the hexradiate type characteristic of this group. Between the two netted surfaces the sponge sub- stance is formed of loose curving meshes of loosely aggregated bundles of long simple fibres, sparsely mixed with spicules of other forms. This sponge seems to live fixed to a stone. There are no anchoring spicules, and the bottom of the vase, Fic. 67.—Askonema setubalense, Kent. One-eighth the natural size. (No. 25, 1870.) which in our two specimens is a good deal con- tracted and has a square shape something like an old Irish ‘mether,’ has apparently been torn from some attachment. This fine species was named Askonema setubalense, and very briefly described from a specimen in the Lisbon Museum by Mr. Saville Kent, in a paper in which he noticed some 430 THE DEPTHS OF THE SEA. [CHAP. VII. of the sponges dredged from Mr. Marshall Hall’s yacht." Sponges belonging to other groups from the deep water were nearly equally interesting. JI have already alluded, p. 185, to the handsome branching sponges belonging to the Esperadiw, which abound off the coasts of Scotland and Portugal. Near the mouth of the Strait of Gibraltar a number of species were taken in considerable quantity, belonging to a eroup which were at first confused with the Hexac- tinellidee, on account of their frequently forming a similar and equally beautiful continuous network of silica, so as to assume the same resemblance tv deli- cate lace when boiled in nitric acid. ‘The Corallio- spongiv differ, however, from the Hexactinellide in one very fundamental character. While in the latter the spicule is hexradiate, in the former it consists of a shaft with three diverging rays at one end. These frequently spread in one plane, and they often _re-divide, and frequently the spaces between them are filled up with a secondary expanse of silica, variously frilled and netted on the edge, so as to give the spicule the appearance of an ornamental flat-headed tack. These three-rayed stars or disks, in combination, sup- port the outer membrane of sponges of this order ; and spicules of the same type, fused together accord- ing to various plans, form the sponge skeleton. This group of sponges are as yet imperfectly known. ‘They seem to pass into such forms as Geodia and Tethya; and the typical example with which we are most familiar is the genus Dacty- localyx, represented by the cup-shaped pumice-like 1 Monthly Microscopic Journal, November 1, 1870. CHAP. VII.] THE DEEP-SEA FAUNA. 451 masses which are thrown ashore from time to time on the West Indian Islands. Professor P. Martin Duncan has already published an account of the stony corals (the Madreporaria) of the cruise of the ‘ Porcupine’ in 1869, and he has now in hand those procured off the coast of Portugal in 1870, some of which are of even greater interest from their close resemblance to certain cretaceous forms. ‘T'welve species of stony corals were dredged in 1869. Caryophyllia borealis, FLEMING (Fig. 4, p. 27), is very abundant at moderate depths, particularly along the west coast of Ireland, where many varieties are found. The greatest depth at which this species was dredged is 705 fathoms. Jt is found fossil in the miocene and pliocene beds of Sicily. Ceratocyathus ornatus, SEGUENZA.—Of this pretty coral only a single specimen was taken in 705 fathoms, off the Butt of the Lews. It had not pre- viously been known as a recent species, and was described by Seguenza from the Sicilian miocene tertiaries. Flabellum laciniatum, Epwarps and HaimMrE, was frequent in water from 100 to 400 fathoms, from Froe to Cape Clear. _From the extreme thinness of the outer crust, this coral is excessively brittle; and although many hundreds came up in the dredge, scarcely half-a-dozen examples were entire. Another fine species of the same genus, Flabelium distinctum (Fig. 68), was dredged on several occasions off the Portuguese coast in 1570. The special interest attaching to this species, is that it appears to be identical with a form living in the seas of Japan. 432 THE DEPTHS OF THE SEA. (CHAP. VII. Lophohelia prolifera, Patuas (Fig. 30, p. 169). —Many varieties; abundant at depths from 150 to 500 fathoms all along the west coasts of Scot- land and Ireland, at temperatures varying from 0° to 10° C. In some places,—as, for example, at Station 54, between Scotland and Féroe, and Station 15, between the west coast of Ireland and the Porcupine Bank,—there seem to be regular banks of it, the dredge coming up loaded with fragments, living and dead. Five allied species of the genus Amphihelia oc- curred more sparingly. Fic. 68.—Flabellum distinctum Twice the natural size. (No. 28, 1870.) Allopora oculina, EHRENBERG, a very beautiful form, of which a few specimens were procured in the ‘cold area,’ at depths a little over 300 fathoms. Thecopsammia socialis, POURTALES (Fig. 69), a form closely allied to Balanophyllia, and resembiing some crag species. It had been previously dredged by Count Pourtales in the Gulf of Florida. TZheco- psammia is tolerably common in deep water in the ‘cold area,’ growing in patches, five or six examples sometimes coming up on one stone. CHAP. IX.] THE DEEP-SEA FAUNA. 483 I have already adverted to the danger we run in estimating the relative proportions in which any special groups may enter into the sum of the abyssal fauna, by the proportion in which they are recovered by any single method of capture. From their con- siderable size, the length and rigidity of their st ‘ag gling rays, and their habit of clinging to fixed ob- jects, the Echinodermata are not very readily taken Fic. 69.—Thecopsammia socialis, PouRTALES. Once and a half the natural size. (No. 57 1869.) by the dredge, but they fall an easy prey to the ‘hempen tangles.’ It is possible that this cireum- stance may to a certain extent exaggerate their apparent abundance at great depths, but we have direct evidence in the actual numbers which are brought up, that in some places they must be won- FF A34 THE DEPTHS OF THE SEA. [CHAP. IX. derfully numerous; and we frequently dredge sponges and corals actually covered with them in the atti- tudes in which they lived, nestling among their fibres and in the angles of their branches. I have counted seventy-three examples of Amphiura abyssicola, small and large, sticking to one Jloltenia. Both on account of their beauty and extreme rarity, and of the important part they have borne in the fauna of some of the past periods of the earth’s history, the first order of the Echinoderms, the Crinoidea, has always had a special interest to naturalists; and, on the watch as we were for missing links which might connect the present with the past, we eagerly welcomed any indication of their presence. Crinoids were very abundant in the seas of the Silurian period; deep beds of carboniferous limestone are often formed by the accumulation of little else than their skeletons, the stem joints and cups cemented together by limy sediment; and dozens of the perfect crowns of the elegant lily- encrinite are often scattered over the surface of slabs of the muschelkalk. But during the lapse of ages the whole order seems to have been worsted in the ‘struggle for life.’ They become scarce in the newer mezozoic beds, still scarcer in the tertiaries, and up to within the last few years only two living stalked crinoids were known in the seas of the present period, and these appeared to be confined to deep water in the seas of the Antilles, whence fishermen from time to time bring up muti- lated specimens on their lines. Their existence has been known for more than a century; but although many eyes have been watching for them, until very CHAP. IX.]| THE DEEP-SEA FAUNA. 435 lately not more than. twenty specimens had reached Europe, and of these only two showed all the joints and plates of the skeleton, and the soft parts were lost in all. These two species belong to the genus Pentacrinus, which is well represented in the beds of the lias and oolite, and sparingly in the white chalk; and are named respectively Pentacrinus asteria, L., and P. milleri, OERSTED. Fig. 70 represents the first of these. This species has been known in Europe since the year 1755, when a specimen was brought to Paris from the island of Martinique, and described by Guettard in the Memoirs of the Royal Academy of Sciences. For the next hundred years an example turned up now and then from the Antilles. Ellis described one, now in the Hunterian Museum in Glasgow University, in the Philosophical Transactions for 1761. One or two found their way into the museums of Copenhagen, Bristol, and Paris; two into the British Museum; and one fortunately fell into the hands of the late Professor Johannes Miiller of Berlin, who published an elaborate account of it in the Transactions of the Royal Berlin Academy for 18438. Within the last few years, Mr. Damon of Weymouth, a well-known collector of natural his- tory objects, has procured several very good speci- mens, which are now lodged in the museums of Moscow, Melbourne, Liverpool, and London. Pentacrinus asteria may be taken as the type of its order; I will therefore describe it briefly. The animal consists of two well-marked portions, a stem and a head. The stem, which is often from 40 to 60 centimetres in length, consists of a series of FF2 One-fourth the natural size. , LINNEZUS asleria 70.—Pentacrinus Fie CHAP. IX.] THE DEEP-SEA FAUNA. 2155) Ff flattened calcareous joints; it may be snapped over at the point of junction between any two of these joints, and by slipping the point of a pen-knife into the next suture a single joint may be removed entire. The joint has a hole in the centre, through which one might pass a fine needle. This hole forms part of a canal filled during life with a gelatinous nutri- ent matter which runs through the whole length of the stem, branches in a complicated way through the plates of the cup, and finally passes through the axis of each of the joints of the arms; and of the ultimate pinnules which fringe them. On the upper and lower surfaces of the stem-joint there is a very graceful and characteristic figure of five radiating oval leaf-like spaces, each space surrounded by a border of minute alternate ridges and grooves. The ridges of the upper surface of a joint fit into the grooves of the lower surface of the joint above it; so that, though from being made up of man joints the stem admits of a certain amount of motion, that motion is very limited. As the border of each star-like figure exactly fits the border of the star above and below, the five leaflets within the border are likewise placed directly one above the other. Within these leaflets the limy matter which makes up the great bulk of the joint is more loosely arranged than it is outside, and five oval bands of strong fibres pass in the inter- spaces right through the joints, from joint to joint, from one end of the stem to the other. These fibrous bands give the column great strength. It is by no means easily broken even when dead and dry. They also, by their elasticity, admit a certain 438 THE DEPTHS OF THE SEA. [CHAP. IX. amount of passive motion. ‘There are no muscles between the joints of the stem, so that the animal does not appear to be able to move its stalk at will. It is probably only gently waved by the tides and currents, and by the movements of its own arms. In Pentacrinus asteria about every seventeenth joint of the lower mature part of the stem, is a little deeper or thicker than the others, and bears a whorl of five long tendrils or cirri. The stem is, even near the base, slightly pentagonal in section, and it becomes more markedly so towards the head. The cirri start from shallow grooves between the projecting angles of the pentagon, so that they are ranged in five straight rows up and down the stem. The cirri are made up of about thirty-six to thirty- seven short joints; they start straight out from the stem rigid and stiff, but at the end they usually curve downwards, and the last joint is sharp and clawlike. These tendrils have no true muscles: they have, however, some power of contracting round resisting objects which they touch, and there are often star-fishes and other sea animals entangled among them. The specimen figured has thus be- come the temporary abode of a very elegant species of Asteroporpa. Near the head the cirri become shorter and smaller, and their whorls closer. The reason of this is that the stem grows immediately below the head, and the cirrus-bearing joints are formed in this position, the intermediate joints being produced afterwards below and above each cirrated joint,— which they gradually separate from the one on either side of it, till the number of seventeen or eighteen CHAP. IX.] THE DEEP-SEA FAUNA. 439 intermediate joints is complete. At the top of the stem five little calcareous lumps like buttons stand out from the projecting ridges, and upon these and upon the upper part of the stem the cup which holds the viscera of the animal is placed. These buttons are of but little moment in this form, but they represent joints which are often developed into large, highly-ornamented plates in the various tribes of its fossil ancestors. They are called the ‘basal’ plates of the cup. Next, in an upper tier, alternating with the last, we have a row of five oblong plates opposite the grooves of the stem, and all cemented into a ring. These plates are separate when the animal is young; they are called the ‘first radial’ plates. They are the first of long chains of joints which are continued to the ends of the arms. Imme- diately above these plates, and resting upon them, there is a second row of plates nearly of the same size and shape, only they remain separate from one another, never uniting into a ring. These are the ‘second radials,’ and immediately upon these rest a third series of five, very like the plates of the other two rows, only their upper surfaces rise into a cross ridge in the centre, and they have the two sides bevelled off like the eaves of a gable, to admit of two joints being seated upon each of them instead of one. This last ring of joints are the ‘radial axillaries,’ and above these we have the first bifureation of the arms. These three rings of radial joints form the true cup. In the modern species they are very small, but in many fossils they acquire a large size, and enclose, frequently with the aid of various rows of intermediate or 440 THE DEPTHS OF THE SEA. [CHAP. IX. inter-radial plates and a row of basals, a large body-cavity. The two upper joints of each ray are separated from those of the ray next it by a prolongation downwards of the plated skin which covers the upper surface or ‘disk’ of the body. Seated upon the bevelled sides of each radial-axil- lary joint, there is a series of five joints, the last of the five bevelled again like the radial axillaries for the insertion of two joints. These five joints form the first series of ‘ brachials,’ and from the base of this series the arms become free. The first of the brachial joints, that is to say, the joint immediately above the radial axillary, is, as it were, split in two by a peculiar kind of joint, called, by Miiller, a ‘syzygy.’ All the ordinary joints of the arms are provided with muscles producing various motions, and binding the joints firmly together. The syzygies are not so provided, and the arms are consequently easily snapped across where these occur. This is a beautiful provision for the safety of an animal which has so wide and complicated a crown of appendages. If one of the arms get entangled, or fall into the jaws or claws of an enemy, by a jerk. the star-fish can at once get rid of the embarrassed arm; and as all this group have a wonderful power of reproducing lost parts, the arm is soon restored. When the animal is dying, it generally breaks off its arms at these syzygies; so that almost all the specimens which have been brought to Europe have arrived with the arms separate from the body. About six arm-joints or so above the first on either branch there is a second brachial accessory and CHAP. IX. ] THE DEEP-SEA FAUNA. 44] another bifurcation, and seven or eight joints farther on another, and so on, but more irregularly the farther from the centre, till each of the five primary rays has divided into from twenty to thirty ultimate branches, producing a rich crown of more than a hundred arms. ‘The upper surface of each arm-joint is deeply grooved, the lower arched; and from one side of each, alternately on either side of the arm, there springs a series of flattened ossicles. These form the ultimate branchlets, or ‘ pinnules,’ which fringe the arms as the barbs fringe the shaft of a feather. Unfortunately, most of the examples of Pentacrinus asteria hitherto procured have had the soft parts destroyed and the disk more or less injured. One specimen, however, in my possession is quite perfect. ‘The body is covered above by a membrane closely tesselated with irregularly-formed flat plates; this membrane, after covering the disk, dips into the spaces between the series of radial joints, and with the joints of the cup completes the body-wall. The mouth is a rounded opening of considerable size in the centre of the disk, and opens into a stomach passing into a short curved intestine which ends in a long excretory tube,—the so-called ‘proboscis’ of the fossil erinoids,—which rises from the surface of the disk near the mouth. From the mouth five deep grooves, bordered on either side by small square plates, run out to the edge of the disk, and are con- tinuous with the grooves on the upper surface of the arms and pinnules, while in the angles between them five thickened masses of the mailing of the disk surround the mouth like valves. These were at first supposed to answer the purpose of teeth. The 442 THE DEPTHS OF THE SEA. [CHAP. IX, crinoids, however, are not predatory animals. Their nutrition is effected in a very gentle manner. The grooves of the pinnules and arms are richly ciliated. The crinoid expands its arms like the petals of a full- blown flower, and a current of sea-water bearing organic matter in solution and suspension is carried by the cilia along the brachial and radial grooves to the mouth. In the stomach and intestine the water is exhausted of assimilable matter, and the length and direction of the excretory proboscis pre- vent the exhausted water from returning at once into the ciliated passages. The other West Indian Pentacrinus—P. Milleri— seems to be more common off the Danish Islands than P. asteria. The animal is more delicate in form. The stem attains nearly the same height, but is more slender. The rings of cirri occur about every twelfth joint, and at each whorl two stem- joints are modified. The upper joint bears the facet for the insertion of the cirrus, and the second is grooved to receive its thick basal portion, which bends downwards for a little way closely adpressed to the stem, before becoming free. The syzygy is between the two modified joints, and in all the com- plete specimens which I have seen the stem is broken through at one of these stem syzygies, and the ter- minal stem-joint is worn and absorbed, showing that the animal must have been for long free from any attachment to the ground. On the 21st of July, 1870, Mr. Gwyn Jeffreys, dredging from the ‘ Porcupine’ at a depth of 1,095 fathoms, lat. 39° 42’ N., long. 9° 43’ W., with a bottom temperature of 4°°3 C. and a bottom of soft 1870.) 1 Nutural siz2. (No RE YS JEFFE 1.—Pentacrinus wyville-thomsoni i Fie 444 THE DEPTHS OF THE SEA. [CHAP. IX, mud, took about twenty specimens of a handsome Pentacrinus involved in the ‘hempen tangles ;’ and this splendid addition to the fauna of the European seas my friend has done me the honour ta associate with my name. Pentacrinus wyville-thomsoni, JEYFREYS (Fig. 71), is intermediate in some of its characters between P. asteria and P. milleri; it approaches the latter species, however, the more nearly. In a mature specimen the stem is about 120 mm. in length, and consists of five or six internodes. The whorls of cirri towards the lower part of the stem are 40 mm. apart, and the in- ternodes contain from thirty to thirty-five joints. The cirri are rather short and stand straight out from the nodal joint, or curve sharply downwards, as in P. asteria. The nodal joint is single, and the syzygy separates it from the joint immediately beneath it, which does not differ materially from the ordinary internodal stem-joint. All the stems of mature examples of this species end uniformly in a nodal joint, sarrounded with its whorl of cirri, which curve downwards into a kind of grappling root. ‘The lower surface of the terminal joint is in all smoothed and rounded, evidently by absorption, showing that the animal had for long been free. This character I have remarked as occurring in some specimens of P. miillerit. I have no doubt that it is constant in the present species, and that the animal lives loosely rooted in the soft mud, and can change its place at pleasure by swimming with its pinnated arms; that it is in fact intermediate in this respect between the free genus Antedon and the permanently fixed crinoids. CHAP. IX.] THE DEEP-SEA FAUNA. 445 A young specimen of P. wyville-thomsoni gives the mode in which this freedom is acquired. The total length of this specimen is 95 mm., of which the head occupies 35 mm. The stem is broken off in the middle of the eighth internode from the head. The lowest complete internode consists of 14 joints, the next of 18, the next of 20, and the next of 26 joints. There are 8 joints in the cirri of the lowest whorl, 10 in those of the second, 12 in those of the third, and 14 in those of the fourth. ‘This is the reverse of the condition in adult specimens, in all of which the numbers of joints in the internodes, and of joints in the cirri, decrease regularly from below upwards. The broken internode in the young example, and the three internodes above it, are atrophied and un- developed, and suddenly at the third node from the head the stem increases in thickness, and looks as if it were fully nourished. There can be no doubt that in early life the crinoid is attached, and that it becomes disengaged by the withering of the lower part of the stem. The structure of the cup is the same as in P. asteria and P. miilleri. The basals appear in the form of shield-like projections crowning the salient angles of the stem. Alternating with these we have well-developed first radials, forming a closed ring and articulating to free second radials by muscular joints. The second radials are united by a syzygy to the radial axillaries, which as usual give off each two first brachials from their bevelled sides. , tensi. ffo lo izocrinus .—Rhi » ‘4 Fia. i 452 THE DEPTHS OF THE SEA. [cmap.’ 1x. men which was procured, it was 90 mm. in length. The joints are dice-box shaped, as in Rhizocrinus, long and delicate towards the lower part of the stem, 3°0 mm. in length by 0°5 in width in the centre of the joint, the ends expanding to a width of 10mm. As in &hizocrinus, the joints of the stem diminish in length towards the head, and additions are made in the form of calcareous laminz beneath the coalesced joints which form the base of the cup. The first radials are five in number. They are closely apposed, but they do not seem to be fused as in Rhizocrinus, since the sutures show quite dis- tinctly. The centre of each of these first radials rises into a sharp keel, while the sides are slightly de- pressed towards the suture, which gives the calyx a fluted appearance, like a folded filter-paper. The second radials are long, and free from one another, joining the radial axillaries by a straight syzygial union. They are most peculiar in form. A strong plate-like keel runs down the centre of the outer surfaces, and the joint is deeply excavated on either side, rising again slightly towards the edges. ‘The radial axillary shows a continuation of the same keel through its lower half, and midway up the joint the keel bifureates, leaving a very characteristic diamond- shaped space in the centre, towards the top of the joint; two facets are thus formed for the insertion of two first radials; the number of arms is therefore ten. ‘The arms are perfectly simple, and in our single specimen consist of twelve joints each. There is no trace of pinnules, and the arms resemble in character the pinnules of Rhizocrinus. The first brachial is united to the second by a syzygial joint, but after tf A Fig. 73.—Bathycrinus gracilis, W¥VILLE THomson. Twice the natural size. (No. 37, 1869.) AD4 THE DEPTHS OF THE SEA. [CHAP. IX. that the syzygies are not repeated, so that there is only one of these peculiar junctions in each arm. The arm-grooves are bordered by circular fenes- trated plates, as in Rhizocrinus. Certain marked resemblances.in the structure of the stem, in the structure of the base of the cup, and in the form and arrangement of the ultimate parts of the arms, evidently associate DBathycrinus with Rhizocrinus, but the differences are very wide. Five free keeled and sculptured first radials replace the uniform smooth ring formed by these plates in Rhizocrinus. The radial axillaries give off each two arms, thus recurring to the more usual arrange- ment in the order, and the alternate syzygies on the arms, which form so remarkable a character in Rhizoerinus, are absent. Only one nearly complete specimen and a de- tached stem of this very remarkable species were met with, and they were both brought up from the very greatest depth which has as yet been reached with the dredge, 2,485 fathoms, at the mouth of the Bay of Biscay, 200 miles south of Cape Clear. It would seem, in our present state of knowledge, that the stalked crinoids are members of the deep- sea fauna. A second specimen of another very remarkable form, Holopus rangi, D’ORBIGNY, has lately been procured from deep water off Barbadoes, and that species, with those already noted, makes up the tale of living forms belonging to the order which are known at the present time. It is unwise to prophesy; but when we consider that the first few scrapes of the dredge at great depths have added two remarkable new species to the living CHAP. IX. |] THE DEEP-SEA FAUNA. WD . representatives of this group, until now supposed to be on the verge of extinction, and that all the known species are from depths beyond the limit of ordinary dredging, we are led to anticipate that crinoids may probably form rather an important element in the abyssal fauna. de. Beer ore) RAR ENS = Cint Lh Acded i ® OS S iy té a Fie. 74.—Archaster bifrons, WYVILLE THomson. Oralaspect. Three-fourths the natural size (No. 57, 1869.) The general distribution of the deep-sea Asteridea has already been referred to. Perhaps the most obvious peculiarity which they present is the great preponderance of the genera Astrogonium, Archaster, Astropecten, and their allies. Genera belonging to other groups do not apparently become less 456 THE DEPTHS OF THE SEA. [CHAP, 1X. numerous, for species of Asteracanthion, Cribrella, Asteriscus, and Ophidiaster are as abundant as they are at lesser depths; but as we go down new species with tesselated mailing on the disk and massive marginal plates seem to be perpetually added. In our own seas some few very characteristic forms, such as Astrogonium phrygianum and Archaster andromeda and parellii, are on the verge of the deep water, and are now and then taken at the outer limit of shore dredging, or on fishing-lines; while in the deep water all along the north and west of Scot- land Astrogonium granulare, Archaster tenuispinus, and Saas a bade oe Cristellaria cultrata, Mont. oo AEE | ee = rotulata, LaM. . . ent ee SE pe — a crepidula, F. and M. = Se a ee | Lagena sulcata, W. and J. oy Nala —}|/—-{/-}]—-]- | a globosa, Monracu , ; —;/—-/;/—|]|-}- _ Polymorphina lactea, W. and J. i Ras kat an Ps is communis, D’ORBIGNY. —}—}]—]{- - “ compressa, D’ORBIGNY. pa > A Ue eee eo orbignit, Eur. .f—-f—of—-f-}|—-| Globigerina bulloides, D’ORBIGNY. . —{|=—/—]— | — 4 Planorbulina lobatula, W. and ned : ee aa —. | Pulvinulina micheliana, D’ORBIGNY . se en | Spdtroplecta biformis, P. and J. . . —}|/—-}]—-]-] - Verneuilina triquetra, Von M.. . —|- | — | — 4 =f polystropha, Reuss... — |= | = c= = | 1 Wonders of eo 6th A ase: 1348. Vol. i. p. 305, 2 Saturday Review. cHaP. X.] CONTINUITY OF THE CHALK. A479 And the following table, showing the number of foraminifera common to the Atlantic mud and various geological formations in England :— Common to the following Formations. | | Total is —= = = : peer aus | aus | | | Rheetic | arate ‘nq | London alte Upper Lower | and Paw Catia: UNS 3 clay. Chalk. | Jurassic. | Jurassic. | Upper nian. | niferous. | Trias. | | ve sot, Se | |- a ; Vie | | . 11 Bo | 28>) 29 Ciel es ti He hc 1 l | | | — = i The morphology of the foraminifera has been studied with great care, and the differences between closely allied so-called species are so slight that it is possible that in many cases they should only be regarded as varieties; but this careful criticism and appreciation of minute differences renders it all the more likely that the determinations are correct, and that animal forms which are substantially identical have persisted in the depths of the sea during a con- siderable lapse of geological time. In the late deep-sea dredgings by M. de Pourtales off the American coast, and by H.M. ships ‘ Light- ning’ and ‘ Porcupine,’ and Mr. Marshall Hall’s yacht ‘Norna’ off the west coast of Europe, no animal forms have been discovered belonging to any of the higher groups, so far as we are as yet aware, speci- fically identical with chalk fossils; and I do not think that we have any right to expect that such will be found. Toa depth of 5,000 feet or so a large portion of the North Atlantic is at present heated very con- siderably above its normal temperature, while the Arctic and Antarctic indraught depresses the bottom 480 THE DEPTHS OF THE SEA. [CHAP, xX. temperature in deep water to a like extreme degree. These abnormal temperatures are dependent upon the present distribution of sea and land; and I have already shown that we have evidence of many oscillations, in modern times geologically speaking, which must have produced totally different condi- tions of temperature over the same area. Accepting, as I believe we are now bound to do in some form, the gradual alteration of species through natural causes, we must be prepared to expect a total absence of forms identical with those found in the old chalk, belonging to groups in which there is sufficient structural differentiation to require or to admit of marked variation under altering circumstances. The utmost which can be expected is the persistence of some of the old generic types, and such a resemblance between the two faune as to justify the opinion that, making due allowance for emigration, immigration, and extermination, the later fauna bears to the earler the relation of descent with extreme modi- fication. I have already mentioned that one of the most remarkable differences between the recent Atlantic chalk-mud and the ancient white chalk is the total absence in the latter of free silica. It would seem, from the analysis of chalk, that silicious organisms were entirely wanting in the ancient cretaceous seas. In the chalk mud, on the other hand, silica is found in abundance, in most specimens to the amount of from 30 to 40 per cent. ») De > 22») > Dy D aD e DDS> yD p) a hash Viena vaaewares iy f aaah Aa ate MO i Ayan an Aa: A ane NMA ere on My Ae | ahe aN \ WAAAA aN Nani ean ms we An: a ee Paanatinln “Dat a fast are WN is S lay Gieme BARAK , A A at Ay RHANAA nana. a se name, ARRAS gat >= 2 >>» D> Die Sy DST Dy is> ’ Ss DI pana ane Y AARA War, Nag! , bee NS: "e \ | aera AAEP 2 ay AA aA BEA A 4 ote y aha SE any Nay ti PUAN EMA at yt eae RK Aan A Annan A aN RiAYE. 2 -2>».>)> - > 2. 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