ahr: 2 me Coe ae Srna ae a es one Sie ae ean Bacay Sg a8. ae SaaS Ba Rees, re wats See SOeraees = ms = i r - “ * = : | x . x . z ? ; 7 | . . i : = | , | | i | ® : 4 Set ies > MS ates nig 3 “ : ze d ‘ S = : } 3 - 2 2 SP SS zs . > =r om F 7 3 ) : | ne KI AA A : A i ae x pee Aah *, Ae y aoe ae Ne wei NAA’ ony Ny : hy, i x Some nt ee ne vrrph bis Ow ae sAacee nat” “9 i es oP eh THE DEPTHS OF THE SEA. + THE DEPTHS OF THE SEA. AN ACCOUNT OF THE GENERAL RESULTS OF THE DREDGING CRUISES OF H.MSS. ‘PORCUPINE’ AND ‘LIGHTNING DURING THE SUMMERS OF 1868, 1869, AND 1870, UNDER THE SCIENTIFIC DIRECTION OF Dh. CARPENTER, F.R.S., J. GWYN JEFFREYS, F.R.S., AND DR. WYVILLE THOMSON, F.R.S. C. WYVILLE THOMSON, LL.D., D.Sc., F.R.SS. L. &E., F.LS., F.G.S., Erc. Regius Professor of Natural History in the University of Edinburgh, And Director of the Civilian Scientific Staf of the ‘Challenger’ Exploring Expedition. WITH NUMEROUS ILLUSTRATIONS AND MAPS. SECOND EDITION. Tondo: MACMILLAN AND CO. 1874. [ The Right oF Translation and Reproduction is reserved. | =, , ae 6 we tr ~~ oO a _ ‘<< iP © Yi ——— Ww ier = —— i : ra Be: ¥ a ‘A @ ¥y die Pa . 7
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ey iO Ree
“a -_ a)? ae a? eS x :
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LONDON:
R. CLAY, SONS, AND TAYLOR, PRINTERS,
BREAD STREET HILL.
e
4
7 :
: : ;
7 a . fi
TO
MEAD A Mi niks tO 15> iN
This Volume is dedieated,
GRATEFUL REMEMBRANCE OF THE PLEASANT TIMES
SPENT BY HIMSELF AND HIS COMRADES
AT THE
GOVERNOR’S HOUSE IN THORSHAVN,
THE AUTHOR.
PREFACE.
Ar 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.
Sat 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 guoad 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.
I 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
PREFACE. 1X
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 eeneral
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 Gulf-stream.
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 ac-
complish, 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 ease 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
45
KEE
si
Allman, FES.,
PREFACE.
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
to
May and the officers of the
thanks Staff-Commander
‘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, FE.R.S., and Mr.
Gwyn Jeffreys, E.R.S.,
have cordiaily assisted me in
who
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 Kol-
liker, Dr. Carter, (F. Rist we
Professor Martin Duncan, I.R.S.,
PREFACE. xi
and Dy. M‘Intosh, for information courteously
supplied. ve
The whole of the illustrations in the book—with
the exception of the vignettes of F&éroe scenery for
which I 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-
grapher 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.
X1i 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.
EpINBURGH,
December 2nd, 1872.
Iz
Ly
Skaapen ROr
Hod =
> BB ~
eee’
LIBRARYi=
CONT Bans:
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 wpon 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... . ... ... ... 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
Féroe Islands.—Singular Temperature Results in the Froe Channel.—
Life abundant at all Depths.—Brisinga coronata.—Holtenia carpentert.
—General Results of the Expedition ... ... ... -- ... Page 49
Apprenpix 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.
ASV?
X1V CONTENTS.
—Change of Arrangements.—Second Cruise ; to the Bay of Biscay.—
Dredging successful at 2,435 fathoms.—Third Cruise ; in the Channel
between Froe 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 ves’ ane ROGGE res
Aprrnpix B,—Particulars of Depth, Temperature, and Position at the
various Dredging Stations of H.M.S. ‘ Porcupine, in the Summer of
USGOS Mee at ee eal Gite! be. Mae aa Muh ees oe tees, Sone ae eae ma
CHAPTER IV.
. Z _ ‘ - ’ .
THE CRUISES OF THE ‘PORCUPINE’ (continued).
From Shetland to Stornoway.—Phosphorescence.—The Echinothuride,.—
The-Fauna of the ‘Warm Area.’—End of the Cruise of 1869.—Arrange-
ments for the Expedition of 1870.—From England to Gibraltar.
Peculiar Conditions of the Mediterranean.—Return to Cowes. Page 145
Apprnpix A.—Extracts from the Minutes of Council of the Royal Society,
and other official Documents referring to the Cruise of H.M.S. ‘ Porcu-
pine,’ during the Summer of 1870... ... ... ... ... «. Page 197
ApprenpIx B.—Particulars of Depth, Temperature, and Position at the
various Dredging Stations of H.M.S. ‘ Porcupine, in the Summer of
STON she se Sots leah eee tak, Weeel maeel) cohen) (dno ® eee acer) eae
CHAPTER Y.
DEEP-SEA SOUNDING.
The ordinary Sounding-iead for moderate Depths.—Liable to Error when
employed in Deep Water.—Early Deep Soundings unreliable.—Inproved
Methods of Sounding.—The Cup-lead.—Brooke’s Sounding Instrument.—
The ‘ Bull-dog ;’ Fitzgerald’s ; the ‘ Hydra.’—Sounding from the ‘ Porcu-
pine. —The Contour of the Bed of the North Atlantic ... Page 205
CHAPTER VI.
DEEP-SEA DREDGING.
The Naturalist’s Dredge.—O. F. Muller.—Ball’s Dredge.—Dredging at
The Dredge-rope.-_ Dredging in Deep Water.—The
‘Hempen tangtes.—Dredging on board the ‘ Porcupine. — The Sieves.—
moderate Depths.
CONTENTS. XV
The Dredger’s Note-book.—The Dredging Committee of the British
~ Association.— Dredging on the Coast of Britain.—Dredging abroad.—
History of the Progress of Knowledge of the Abvssal Fauna. Page 236
=
AppEnDIx A.—One of the Dredging Papers issued by the British Associa-
tion Committee, filled up by Mr. MacAndrew.... ... .... Page 281
CHAPTER VII.
DEEP-SEA TEMPERATURES.
Ocean Currents and their general Effects on Climate.—Determination of
Surface Temperatures.—Deep-sea Thermometers.—The ordinary Self-
registering Thermometer on Six’s principle-—The Miller-Casella modifi-
cation. —The Temperature Observations taken during the Three Cruises
of H.M.S. ‘ Porcupine’ in the year 1869, ete. cee roca ers Ueege. 284
AppENDIx A.—Surface Temperatures observed on board H.M.S. ‘ Porcupine’
during the Summers of 1869 and 1870 ... ... ... ... ..- Page 329
AvpenDIx B,—Teimperature of the Sea at different Depths near the Eastern
Margin of the North Atlantic Basin, as ascertained by Serial and by
Bottom Soundings... ... : 22s as “ave « Ge sae
Appenpix C.—Comparative Rates oF edncuion of Temperature w a
Increase of Depth at Three Stations in different Latitudes, all of them
on the Eastern Margin of the Atlantic Basm ... ... ... Page 353
AppENDIx 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 Fieroe Islands ; as ascertained by Serial and by Bottom Sound-
ings. Sid iszd,, Soe | evo e
APPENDIX E. Bete mediate Bottom Menem cnr: show ing the Intermixture
of Warm and Cold Currents on the Borders of the Warm and Cold
PATCAS Tones cree. Gree. hcl ie en hee a ges OO
CHAPTER VIII.
THE GULF-STREAM.
The Range of the ‘ Porcupine’ Temperature Observations.— Low Tempera-
tures universal at great Depths.—The Difficulty of investigating 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 Extension of the Gulf-stream.—The Views of
Captain Maury; of Professor Buff; of Dr. Carpenter.— The Gulf-stream
off the Coast of North America.—Professor Bache’s ‘ Sections. —The
Gulf-stream traced by the Surface Temperatures of the North Atlantic.—
(Mr. Findlay’s Views.—Dr. Petermann’s Temperature Charts.—Sources of
XV1 OONTENTS.
the underlying Cold Water.—The Arctic Return Currents.— Antarctic
Indraught.— Vertical Distribution of Temperature in the North Atlantic
BASU 5! Se ace ks” GE Sh CR Gio Ser Oe oc
»
CHAPTER IX.
THE DEEP-SEA FAUNA.
The Protozoa of the Deep Sea.—Bathybius.—‘ Coccoliths, 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.— Rhizocrinus.— Bathy-
crinus.—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’ Expeditions .. ... ... ... .... Page 407
CHAPTER X.
THE CONTINUITY OF THE CHALK.
Points of Resemblance between the Atlantic Ooze and the White Chatk.—
Differences between them.—Composition of Chalk.—The Doctrine of the
Continuity of the Chalk.—Objections.—Arguments in favour of the
View from Physical Geology and Geography.—Former Distribution of
Sea and Land. — Paleontological Evidence. — Chalk-flints. — Modern
Sponges and Ventriculites—Corals.—Kchinoderms.—Mollusca.— Opinions
of Professor Huxley and Mr. Prestwich.—The Composition of Sea-water.
—Presence of Organic Matter.—Analysis of the contained Gases.—Differ-
ences of Specific Gravity—Conclusion ...... ... ... ... Page 467
AppEenDIx A.—Summary of the Results of the Examination of Samples of
Sea-water taken at the Surface and at various Depths. By William Lant
Carpenter, B.A., B.Sc. Pet ies Mra! 7/1/27" 15 |0)2
APPENDIX B. Fels of the imeleces a Bight Samples of Sea-water
collected during the Third Cruise of the ‘ Porcupine.’ By Dr. Frank-
lands ERS. © Sac ns is noes ane genoa
APPENDIX C.—Notes on Spccmene of te Bottom enlleoted during the First
Cruise of the ‘ Porcupine’ in 1869. By David Forbes, F.R.S. Page 514
AppENnpDIx D.—Note on the Carbonic Acid contained in Sea-water. By
John Young Buchanan, M.A., Chemist to the ‘ Challenger’ Expedition.
Page 518
BINGE a ee TT TMOG es PD ae
FIG,
18.
iG}
LIST OF ILLUSTRATIONS.
WOODCUTS.
ASTEROPHYTON LINCKII, Miiller and Troschel. A young speci-
men slightly enlarged (No. 75) ... A, Grae eee
GLOBIGERINA BULLOIDES, D’Orbigny. Highly magnified ..
ORBULINA UNIVERSA, D’Orbigny. Highly magnified
CARYOPHYLLIA BOREALIS, Sages Twice the natural size.
(No. 45) Pgs eon sete pa
BRISINGA CORONATA, G. 0. Sn ‘Wael size. (No. 7)...
HOLTENIA CARPENTERI (sp.n.). Half the natural size. (No. 12)
’ TISIPHONIA AGARICIFORMIS (sp. n.). Natural size. (No. 12) ...
GONOPLAX RHOMBOIDES, Fabricius. Young. Twice the natural
size. (No. 3) ae aeelniane 3P5. gh VRE Ae:
GERYON TRIDENS, pobes Young. Twice the natural size.
(No. 7) Serato bar Sooo Ree Eee
ORBITOLITES TENUISSIMUS, Gampenter ‘Mss. Magnified. (No.
De ee mance. Oe Oey LR. 7 oe ee ee
PoROCIDARIS PURPURATA (sp. n.). Natural size. (No. 47)
PoOURTALESIA JEFFREYSI (sp. n.). Slightly enlarged. (No. 64)
STYLOCORDYLA BOREALIS, Lovén (sp.). Natural size. (No. 64)
SoLASTER FURCIFER, Von Duben and Koren. Natural size.
(No. 55) Reg gee oat Cee ean as
KOoRETHRASTER HISPIDUS WO fee pecs aspect. Twice the
natural size. (No. 57) hig Priel Se tah eM ae
HYMENASTER PELLUCIDUS *) Ventral aspect. Natural
size. (No. 59) itt, ft are ie eran
ARCHASTER BIFRONS (sp. ae Dotal aspect. Three-fourths of
the natural size. (No. 57)
Evsirvus cuspipatus, Kroyer. (No. 55) aie ;
CAPRELLA SpPrINosissimA, Norman. Twice the Sr tineale size.
(No;.59)) ZL. oe:
XVI LIST OF ILLUSTRATIONS.
Aiea wasuTa, Norman. Slightly enlarged. (No.55) ... -.-
ARCTURUS BAFFINI, Sabine. About the natural size. (No.
Nympnon apyssorum, Norman. Slightly enlarged. (No. 56)
THECOPHORA SEMISUBERITES, Oscar Schmidt. ‘Twice the natural
BIZGbemENOf (0) pleat © coe) Win. wee. ann nd aeecoe Aeon ease mmee
THECOPHORA IBLA (sp. n.). Twice the natural size. (No. 76)
ARCHASTER VEXILLIFER (sp. n.). One-third the natural size.
(ING. 7G) G22 08-2 3d Disks © sochecke: Bn eee
Mouoasren FULGENS os n.). One-third the natural size. (No.
CALVERIA HYSTRIX (3 sp. n. oh Two-thirds the natural size. (No.
86) See out 4¢ : * : mod
CALVERIA HYSTRIX Gn n. he Taner ganic of a Eten of the
test showing the structure of the ambvlacral and interambu-
lneral areas-..5 ..0 siaitiege RE
CALVERIA FENESTRATA ee nO Gee of the Fe Wied pedi-
cellarize sit sek) set, casee: ese
LOPHOHELIA PROLIFERA, Pallas ( el Three-fourths the natural
size. < CNO#26)" «as. Veh sane, eee foe ere os er
ALLOPORA OCULINA, Bhrenber awh) wien cad ue A eO ee
OPHIOMUSIUM LYMANI (sp. n.). Dorsal anes Natural size.
(No. 45)
OpuromusIUM LYMANI ae Bie Oral ones)
Dorynenus tHomsonir, Norman. Once and a half tie neice
size ; everywhere in deep water i gai Badin see
AMATHIA CARPENTERI, Norman. Once and a half the natural
size; (Nig CAi) ease gals jeses Wigs) Thue’) (cola
CHRONDROCLADIA VIRGATA al n.). One-half the natural size.
CNio:, 33;0P Ih. Vwi 2c Oe ee ee
Pre" CuP-LWAD.” | cc * oct abe ete eee ek ee a
Brooke’s Drer-SEA Sounpina APPARATUS ... ... ...
Tue ‘ Buuu-Dog’ Sounpinc MAcHINE ee TR Eat. oss
THE ‘FITZGERALD’ SOUNDING MACHINE. ... ... 1... «ss. cos
SERRE byaD RAC S ONIDIENG: UA CELUI: ne enone a
SONTAG Sti] Sans OUINID ING. IVIPACENTNIE) 7) eel enna me oT ae
OTHO ces Muuurr’s Drepes. a.p. 1750
SB ATT Se DREDGE eee ae sie gna. SO kgaae nance ealet aree
Tue SrerRN Derrick oF THE ‘PORCUPINE,’ SHOWING THE
‘ ACCUMULATOR, THE DREDGE, AND THE MODE OF STOWING
MVEDE) TINROPE tote. cars. icc. se “uses go? sk ee
Toe END oF THE Damnen. FRAME ere het occ
PAGE
127
128
129
147
148
150
153
156
248
250
FIG. -
58.
59.
60.
61.
62.
LIST OF ILLUSTRATIONS.
3 Foo aaa SHOWING THE Mopk or ATTACHMENT OF THE
Bae BF SPAS ae
Tor END OF THE Damone FRAME, SHOWING THE Mone OF
ATTACHMENT OF THE BaG 5 : ee
DIAGRAM OF THE RELATIVE POSITION OF THE WHE THE
WEIGHTS, AND THE DREDGE, IN DREDGING IN Deep WATER
DREDGE wiTH ‘HEMPEN TANGLES’ ... ..
Set or Drepa@iIne SIEVES ... .. re 4 he ates
Tur MILLER-CASELLA Monsreanpete OF © Se Ss ae REGISTER-
ING THERMOMETER ... ..- aE ee ME TE Le et ee
Copper CASE FOR PROTECTING THE MiLurr-CAsELLA THER-
MOMETER
SERIAL SouNDING, Station 64
SERIAL Souwonees Station 87 A st ae ; E
CURVES CONSTRUCTED FROM SERIAL SGenineei IN THE a W: ARMW’-
AND ‘ CoLp-AREAS’ IN THE CHANNEL BETWEEN SCOTLAND
AND F ROE sae ee in RS
CURVES CONSTRUCTED FROM SERIAL AND MEGaion Souwomas IN
THE CHANNEL BETWEEN SCOTLAND AND ROCKALL
DIAGRAM REPRESENTING THE RELATION BETWEEN DEPTH AND
TEMPERATURE OFF RocKALL S33 a heen
DIAGRAM REPRESENTING THE RELATION BETWEEN Depen AND
TEMPERATURE IN THE ATLANTIC BASIN ... .... ... see
CURVES CONSTRUCTED FROM SERIAL AND Bortom Mie amaatie
SOUNDINGS IN THE ATLANTIC BASIN ... tee Eat
DIAGRAM REPRESENTING THE RELATION BETWEEN Desi AND
TEMPERATURE, FROM THE ‘l'EMPERATURE. OBSERVATiONS
TAKEN BETWEEN CAPE FINISTERRE AND CaPE St. VINCENT,
AueusT 1870 s.. oe SURE Et Ne ete enMeaccey tare
“EINE GROSSERE CYTODE VON Baers MIT EINGEBETTETEN
Cocconmrermny Ge 100) 4s. > ac Son Shah iad Fe tee
‘ CoccosPHERE’ (x. 1000) Se Eset aee
RossELLA VELATA (sp. n.). Natural size. (No. 32, 1870)
HYALONEMA LUSITANICUM, Barboza du Bocage. Half the natural
sizes, NCNOS 90; 1869) 22) Sa ee .
5 ar
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~
as
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Le =
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a a ee! = i a Pa
So =») ; ; aie =<. 7°: | s
THE
DEPTHS OF THE SEA.
THE DEPTHS OF THE SEA.
CalyAr Eisner:
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.—Bear-
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 like certainty about
its depths, whether in their physical or their biological
relations. The popular notion was, that after arriving
at a certain depth the conditions became so peculiar,
so entirely different from those of any portion of the
earth to which we have access, as to preclude any
other idea than that of a waste of utter darkness,
subjected to such stupendous pressure as to make life
of any kind impossible, and to throw insuperable diffi-
"aie 2 B
2 THE DEPTHS OF THE SEA. [cHar. 1.
<<
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 question 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-
cnar, 1] INTRODUCTION. 3
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
profession, we had placed at our disposal by the
Admiralty 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 24 tons, looked frayed out and worn, as if it
could not have been trusted to stand this extraordinary
ordeal much longer.
4 THE DEPTHS OF THE SEA. | CHAP. I.
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 in time. 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.
cUAP. I. ] INTRODUCTION. 5
During about eighteen months he studied with the
utmost care the conditions of the Aegean and its
dredging operations at depths varying from 1 to 1380
fathoms. In 18438 he communicated to the Cork
meeting of the British Association an elaborate report
on the Mollusca and Radiata of the digean 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.’ 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 Avgean 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.8., G.S., Professor of Botany at King’s
College, London ; Palontologist 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.RS8. 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
eut 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.
5 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 Myr. Wallace,’ and to the genius of Pro-
1 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, commencing
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—stiil infinitely shorter than
eternity—variation may have produced the entire
result.
1 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.
2 Fir 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. 1.
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 circumstances, and is
dangerous to the life of the individual. 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,
carried on for ages in the same direction, must even-
tually 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
difficult to form any idea of ten, fifty, or a hundred
millions of years; or of the relation which such
periods bear to changes taking place in the organic
world.
CHAP. 1.] INTRODUCTION. Teal
We must remember, however, that the.rocks of
the Silurian system, overlaid by ten miles’ thickness
of sediment é¢ntombing 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
their 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. I»
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.
CIEAP. 1.] INTRODUCTION. 13
e
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.
Hastern Fauna. WESTERN Fauna.
Cidaris annulata, GRay. Cidaris thouarsii, Vat.
Diadema antillarum, Put. Diadema mexicanum, A, Ac.
Echinocidaris punctulata, Desmu. LE chinocidaris stellata, Ac.
Echinometra michelini, Des. Echinometra van brunti, A. AG.
o viridis, A, AG. rupicola, A. Aa.
Lytechinus variegatus, A. AG. Lytechinus semituberculatus,
A. Ag.
Tripneustes ventricosus, AG. Tripneustes depressus, A. AG.
Stolonoclypus ravenellii, A. AG. Stolonoclypus rotundus, A. Ac.
Mellita testudinata, Ku. Mellita longifissa, Micn.
* Edward Forbes, Report on Aigean Invertebrata, op. cit. p. 173.
14 THE DEPTHS OF THE SEA. [CHAP. I.
Eastern Fauna. WESTERN Fauna.
Mellita hecapora, A. AG. Mellita pacifica, Vmr.
Encope michelini, AG. Encope grandis, Ac.
- emarginata, AG. » micropora, AG.
Rhyncholampas caribbearum, Rhynchclampas pacificus, A. Aa.
A, Aa.
Brissus columbaris, Aa. Brissus obesus, VER.
Meoma ventricosa, LUTK. Meoma grandis, GRAY.
Plagionotus pectoralis, Ac. Plagionotus nobilis, A. Ac.
Agassizia excentrica, A. AG. Agassizia scrobiculata, V Au.
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 Fauneze on both sides of
the Isthmus a standard by which to measure the
CHAP. 1. ] INTRODUCTION. 15)
changes which these species have undergone since the
raising of the Isthmus of Panama and the isolation
of the two Faune ?’’?
Edward Forbes distinguished round all seaboards
four very marked zones of depth, each characterised
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, Polysiphona, 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,
Talitrus, and Balanus among Crustacea, and Lit-
torina, Patella, 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 Buccinum, .
Fusus, Ostrea, and Pecten ; and among echinoderms
in the European seas we find Antedon sarsi and
celticus, 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. 1.] INTRODUCTION. 177
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
particular assemblage 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
* 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 dis-
cussed in a future chapter. It will suffice at present
to mention in order the few data which gradually pre-
pared the minds of naturalists to distrust the hypo-
thesis 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 employed on board in sounding and in trying
the current, and the temperature of the water. It
being perfectly calm and smooth, I had an excellent
opportunity of detecting these important objects.
Soundings 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 37 N., long. 77° 25’ W., on the lst-of Sept: aor:
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. T. | INTRODUCTION. L9
Carpenter with some more ample particulars of this
Fic. 1.—Asterophyton linckii, MULLER and 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.
1 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.)
©
~~
20 THE DEPTHS OF THE SEA. [CHAP. I.
73° 37’ 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 Lam-
bricus tubicola.’ So far my written journal; but I
ean 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 litile above the mud that
fragments of its arms, which had been broken off in
the ascent of the line, were picked up from amongst
the mud.”
Sir James Clark Ross, R.N., dredging in 270
fathoms, lat. 73° 3’ S., long. 176° 6 #., reports
“ OCorallines, 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 bafjini,
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. I. | INTRODUCTION. it
we shall find them teeming with animal life; the
extreme 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,—mollusca, crustacea,
asterida, spatangi, corallines, &c.”’* 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 in a quill. These trophies
from any depth over 1,000 fathoms were eagerly sought
for by naturalists and submitted to a 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 kK. Godwin-Austen. P. 51.
a2 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, DOrpIGNy. 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. Dey
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,’
Fic. 3.—Orbulina universa, 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,
1864. P. 299.
2 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.
Dek THE DEPTHS OF THE SEA. (CHAP: ies
‘‘ How can animal life be conceived to exist under
such conditions of light, temperature, pressure, and
aération as must obtain at these vast depths? To this
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 light 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 Glo-
bigerine live at these depths, the balance of proba-
bilities seems to me to incline in that direction.”
In 1860 Dr. Wallich accompanied Captain Sir
Leopold McChntock 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 erey ‘Globigerina ooze,
while others were volcanic 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 awell-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. MiuiEer, or
Ophiacantha spinulosa; Mittier and 'TROSCHEL.
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.,
E.LS., F.G.8S., &. Published with the sanction of the Lords Com-
missioners of the Admiralty. London, 1862.
26
a0
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 was then 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. Oi
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
gives 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, Eschara, Salicornaria,
Ascidia, Lima, and Serpula. Y 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, 1861.1! 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-
the cable from the depth of 1,100 fathoms. The list
includes Murex lamellosus, CRISTOFORI and JAN, and
Craspedotus limbatus, PHILipp1, two univalve shells
alhed 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 Thalassiotrochus telegraphieus,
A. Mitne-Epwarbs.
! Observations sur l’Existence de divers Mollusques et Zoophytes a
de trés grandes profondeurs dans la Mer Méditerranée: Annales des
Sciences Naturelles ; quatrieme 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 Caryophyllia 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 to 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. ‘The 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. [CHAP. I.
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 six-
teen at depths beyond 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 abundant: 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
1 Preliminary Report, by Dr. William 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, 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.R.S.
(Proceedings of the Royal Society of London, 1870.)
CHAP. I.] INTRODUCTION. 31
the question of 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 anywhere 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 development 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 ight 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, anda vast
portion 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 all
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. We are
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 34; 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
vould 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 incommoded by it. We sometimes
find when we get up in the morning, by arise 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. I. | INTRODUCTION. 33-
tion to move our bodies in the denser medium. We
are 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 c@lolepis, 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 it 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. T.
feebly, and the spines and pedicellariz: 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. A brass piston or plunger was fitted
accurately into a cylindrical hole in the wall of a brass
water-tight chamber. The chamber was completely
filled with water, and a clasping index on the plunger
marked to what extent the plunger had been driven
into the water contained in the chamber by the
extreme pressure. The required indication is no
doubt given, but such an instrument is at the same
time an extremely delicate thermoscope, and until
lately there has been no perfect means of correcting
for temperature. A more important application of
the pressure-gauge is to check the accuracy of deep
soundings. Probably the best arrangement which
has been proposed for the purpose is a long capil-
lary glass tube, calibrated and graduated to milli-
metres, open at one end, and provided with a moveable
index to show to what amount the air contained in
the tube has been compressed by the entrance of the
water. The principal objection to this device is the
1 Notes on Deep Sea Dredging, by Edward Perceval Wright, M.D.,
F.L.S., Professor of Zoology, Trinity College, Dublin. (Annals and
Magazine of Natural History, December 1868.)
CHAP. I.] INTRODUCTION. Bi)
great difficulty in arranging an index which will
measure with accuracy the extremely small space into
which even a long column of air is compressed when
the pressure becomes very great. It can scarcely be
made available beyond 1,000 fathoms (200 atmo-
spheres).
We have in Sir John Herschel’s ‘ Physical Geo-
graphy,’ and in Dr. Wallich’s ‘ Atlantic Sea-bed,’’
where it is given in the fullest detail, the doctrine of
the distribution of deep-sea temperature as it seems
to have been almost universally adopted up to the
time of the cruise of the ‘Lightning.’ It was gene-
rally understood that while the surface temperature,
which depended upon direct solar radiation, the
direction of currents, the temperature of winds, and
other temporary causes, might vary to any amount ;
at a certain depth the temperature was permanent at
4° C., the temperature of the greatest density of fresh
water. It is singular that this belief should have met
with so general acceptance, for so early as the year
1833 M. Depretz*® determined that the temperature
of the maximum density of sea-water, which contracts
steadily till just above its freezing-point, is — 3°67 C. ;
and even before that time observations of sea-tem-
peratures at great depths, which were certainly trust-
worthy within a few degrees, had indicated several
degrees below the freezing-point of fresh water.
The question of the distribution of heat in the sea,
' Physical Geography ; from the “ Encyclopedia Britannica.” By
Sir John F. W. Herschel, Bart. K.H. &. &¢., p.45. Edinburgh, 1861.
* Atlantic Sea-bed, p. 98.
3 Recherches sur le Maximum de Densité des Dissolutions aqueuses.
(Annales de Chimie, tome Ixx. 1833, p. 54.)
D 2
36 THE DEPTHS OF THE SEA. [crAP. 1.
which is one of the greatest interest in connection
with the distribution of marine animals, will be fully
discussed in a future chapter. The broad conclusions
to which we have been led by late investigations are,
that instead of there being a permanent deep layer of
water at 4° C. the average temperature of the bottom
of the deep sea in temperate and tropical regions is
about 0° C., the freezing-point of fresh water; and that
there is a general surface movement of warm water,
produced probably by a combination of various causes,
from the equatorial regions towards the poles, and a
slow under-current, or rather indraught, of cold water
from the poles towards the equator. From cases
which are recorded, chiefly by the early American
sounding expeditions, of the sounding-line having been
run out into long loops in soundings where, from the
nature of the sea-bed, the bottom water appeared to
be still, it would seem that there are also in some
places intermediate currents; but with reference to
their limits and distribution we have as yet no data.
That a cold flow from the polar seas passes over the
bottom seems to be proved by the fact that in all
parts of the world wherever deep temperature sound-
ings have been taken, from the arctic circle to the
equator, the temperature sinks with increasing depth,
and is lower at the bottom than the normal tempera-
ture of the crust of the earth; an evidence that a
constantly renewed supply of cold water is cooling
down the surface of the crust, which, being a bad con-
ductor, does not transmit heat with sufficient rapidity
to affect perceptibly the temperature of the cold in-
draught. It is probable that in winter, in those parts
of the arctic sea which are not directly influenced by
CHAP. 1. ] INTRODUCTION. SH
the northern extension of the gulf stream, the whole
column of water from the surface to the bottom is
reduced to the lowest temperature which it will bear
without freezing, and is thus an ample source of the
coldest water of the highest specific gravity.
The proof that the flow of the cold indraught is
almost secular in its slowness, is that over a large
portion of the ocean where the low bottom tempera-
ture is known to prevail, the sea-bed is covered with
a light fleecy deposit of microscopic organisms of
great delicacy, into which the sounding-lead has in
some instances sunk several feet, and which must
inevitably be drifted away by a current of appreciable
velocity. In all places where any perceptible current
exists, the bottom consists of sand or mud or gravel
and rolled pebbles. In some cases also, sounding in
the deep water of the mid-Atlantic, the line, after
running out greatly in excess of the depth, has been
found to have coiled itself in a tangled mass right
over the lead—a proof of almost absolute stillness.
In some places, owing to the conformation of the
neighbouring land or of the sea-bottom, warm and
cold currents are circumscribed and localized, and this
sometimes gives us the singular phenomenon of a
patch or stripe of warm and a patch of cold sea meet-
ing in an invisible but very definite line. There is
a curious instance of this in the ‘cold wall’ which
defines the western border of the gulf stream along
the coast of Massachusetts, and another scarcely less
marked which we discovered during the trial cruise
of the ‘ Lightning’ has been fully described by Dr.
Carpenter in his report of that cruise, and will be
referred to hereafter.
38 THE DEPTHS OF THE SEA. [CHAP. I.
In moderate depths sometimes the whole mass of
water from the surface to the bottom is abnormally
warm, owing to the movement in a certain direction
of a great body of warm water, as in the ‘ warm area’
to the north-west of the Hebrides; and sometimes
the whole body of water is abnormally cold, as in the
‘cold area’ between Scotland and Froe, and in the
northern part of the German Ocean. In deep water,
however, after the first few hundred fathoms, the
thermometer usually sinks gradually and very slowly
till it reaches its minimum at the bottom, a little
above or below the zero of the centigrade scale.
The temperature of the sea apparently never sinks
at any depth below —3°'5 C., a degree of cold which,
singularly enough, is not inconsistent with abundant
and vigorous animal life, so that in the ocean, except
perhaps within the eternal ice-barrier of the antarctic
pole, life seems nowhere to be limited by cold. But
although certain sea-animals—many of them, such as
the siphonophora, the salpze, and the ctenophorous
medusee, of the most delicate and complicated organiza-
tion—are tolerant of such severe cold, it would appear
to be temperature almost entirely which regulates the
distribution of species. The nature of the ground
can have little to say to it, for on every line of coast
of any extent almost every condition and every kind
of sediment is usually represented. From their inha-
biting a medium which differs but little in weight
from the substance of their bodies, and from the great
majority of them producing free-moving larvee or fry
in vast numbers which are floated along from place
to place by currents, marine animals would seem to
have every possible chance of extending their area,
CHAP. T. | INTRODUCTION. 39
and yet the geographical distribution of most of the
shallow-water species is well defined, and frequently
somewhat restricted. Unfortunately we know as yet
very little about the general distribution of marine
animals. Except along the coasts of Britain and
Scandinavia, a part of the North American coast, and
a part of the Mediterranean, we know absolutely
nothing beyond the shore zone, or at all events beyond
10 or 15 fathoms. What little we do know is con-
fined almost entirely to the mollusca, and is due, not
so much to scientific research as to the commercial
value which the acquisitive zeal of conchologists has
placed upon rare shells. It may be supposed, how-
ever, that the same laws which regulate the distri-
bution of littoral and sub-littoral mollusca, affect in
hke manner that of shallow-water annulosa, echino-
derms, and coelenterates ; indeed, from the scattered
cbservations which have been made on the distribu-
tion of these latter groups, it seems certain that such
is the case.
Woodward' regarded the marine mollusca as oceupy-
ing eighteen well-defined ‘provinces,’ fulfilling more
or less completely the condition of having at least one-
half of the species peculiar to the province. Edward
Forbes defined twenty-five such ‘regions ;’ but it must
be remembered that in both cases at least three-fourths
of the number of areas defined were based upon the
most imperfect knowledge of the larger and more con-
spicuous shore shells only. It has been constantly
observed in the few cases confined entirely to the
shores of the North Atlantic and the Mediterranean,
1 A Manual of the Mollusca. By S. P. Woodward. London, 1851.
P, 354,
40 THE DEPTHS OF THE SEA. [CHAP. I.
in which dredging has been attempted at any consider-
able depth, say 30 or 40 fathoms, that the number of
species common to the province dredged and to the
province to the north of it, is greatly increased by
the investigation being carried into a deeper zone.’
Thus in the lusitanian province Mr. McAndrew
dredged off the coast of Galicia and Asturias, 212
species, 50 per cent. of which were common to the
coast of Norway; and off the south of Spain 335
species were obtained, of which 28 per cent. were
common to Norway (boreal province), and 51 per
cent. to Britain (chiefly celtic province). The shells
common to the two or three provinces were chiefly
those dredged from considerable depths. The littoral
forms had amuch more distinct aspect. The mollusca
of the ‘Porcupine’ expedition have not yet been
thoroughly worked out. ‘They are in the hands of
Mr. Gwyn Jeffreys, and his preliminary reports give a
most interesting forecast of what we may expect when
his labour is completed. He announces something
like 250 new species. Some of the more interesting
of these, and the general phenomena of their distri-
bution, will be referred to in a future chapter.
The echinoderms of the expedition are more limited
in number, and have already been examined by the
writer with some care. The general distribution of
the Echinodermata is not so well known as that of the
Mollusca. There are many littoral and sub-littoral
species. Many of these are local, but many have a
wide geographical distribution, usually along what
Edward Forbes calls a ‘homoiozoic belt,’ a belt of
nearly similar circumstances of climate extending
' Woodward, loc. cit. p, 362.
CHAP. 1.] INTRODUCTION. 4]
through many degrees of longitude. but few of latitude.
Asaclass, however, they prefer a depth rather beyond
20 fathoms,’ beyond the reach of very violent climatic
vicissitudes. They are conspicuous things, showing
usually sufficiently bold specific characters, and thus
they are less liable to confusion than most other groups.
They involve in their history and economy several of
the principal questions discussed in this volume ; while
giving, therefore, such a brief sketch as the space at
my disposal and the amount of my present informa-
tion may permit, of the additions which have been
made during our dredging cruises to the knowledge
of the other invertebrate classes, I will use the echi-
noderms and the protozoa principally for the purpose
of general illustration.
Littoral and shallow-water species of animals must
be much more liable to have their migrations inter-
rupted by ‘natural barriers,’ such as deep water
through which they cannot pass, or currents of
warmer or of colder water; they must likewise be
much more affected by local circumstances, such as
extreme differences between summer and winter tem-
perature ; so that they might be expected to be more
circumscribed and local in their distribution than the
denizens of greater depths—and they certainly are so.
The conditions of the bottom in the zone from 20 to
50 fathoms are much more equable than near the
surface. Direct solar radiation in temperate regions
affects this zone very slightly, so that it probably
1 Distribution of Marine Life. By Professor Edward Forbes, F.R.S.,
President of the Geological Society. (From the Physical Atlas of
Natural Phenomena, by Alexander Keith Johnston, F.R.G.S., &c.
(Edinburgh, 1854.)
42, THE DEPTHS OF THE SEA. [cHAP. I.
maintains nearly the same conditions of temperature
through many degrees of latitude; and when as it
passes southwards it does become gradually affected
by increasing warmth, it may be supposed merely to
sink a few fathoms deeper, carrying its conditions and
its fauna along with it. For example, animal forms
which abound in the celtic province at 25 fathoms
with a mean temperature of 10° C. may be expected
in greatest number in perhaps 40 or 50 fathoms,
with the same temperature, in the lusitanian province.
Such a zone may thus be continuous for a great dis-
tance, while the surface climate has been altering
greatly, and the migrations of littoral forms have
been again and again interrupted. But the deeper
zone also sometimes meets with a ‘ natural barrier,’
as at the line of junction between the warm and cold
areas already mentioned; which causes a curious
sifting out of those species which are intolerant of a
change of temperature. ‘hus the fauna of the tem-
perate northward flow of water off the west coast of
Scotland is materially different from that of the cold
indraught along the east coast.
If there be this overlapping bétween the lusitanian
and celtic provinces, the same relation may be antici-
pated between our own and the boreal province; and
it is well known that this is the case, for the great
majority of the mollusca which have been dredged by
McAndrew, Barlee, and especially by Gwyn Jeffreys,
from depths below 50 fathoms, are identical with those
found in shallower water on the Scandinavian coast.
Our recent work, while it has brought out more fully
the overlapping, has gone much farther towards the
indication of a general law.
CHAP. I.] INTRODUCTION. 43
It seems probable that the distribution of marine
animals is determined by the extremes of temperature
rather than by the means. The mean winter tempera-
ture of the surface and of moderate depths off the
north coast of Norway is about 2° C., and the extreme
about 0° C.; and on the coast of Greenland the mean
sinks to—1°C., and the extreme to —3° C.
The temperature of the trough between Scotland
and Feroe at the depth of 500 fathoms is from 0° to
—1°C., and we find in that trough, along with many
undescribed forms which are special to very deep
water, every one of the echinoderms hitherto found
on the coast of Scandinavia and Greenland, with the
single exception, I believe, of Ophioglypha stiwitzii, a
shallow-water Greenland form among the ophiurids,
and of one or two holothurids which have as yet
evaded us.
The temperature of the telegraphic plateau at 1,000
to 2,000 fathoms is apparently usually from 3° to 2°C.,
and at 2,500 fathoms in the Bay of Biscay it is 2° C.
From 800 to 2,000 fathoms all along the west coasts
of Scotland, Ireland, and France, we have dredged
Scandinavian echinoderms in abundance, and from
the deep water as far south as the coast of Portugal
I have received examples of some of the best marked
northern forms, such as Hehinus elegans, D. and K. ;
Toxopneustes drobachiensis, O. F. MULLER; Brissopsis
lyrifera, ForBES; Tripylus fragilis, D. and K.; the
magnificent Brisinga coronata, G. O. Sars (Fig. 7),
and B. endecacnemos, ABSJORNSEN ; Pteraster mili-
taris, M. and T.; Ophiacantha spinulosa, M. and 7. ;
Ophiocten sericewn, Forses ; Ophioglypha sarsii,
LirK.; Lava Siw 8 ee a8 Several.
Turritella terebra. . . . . Few. | 6 Small.
3 tricostalis . . . . i
Cerithum vulgatum, var... a 1
As reticulatum . . . | Er Several.
. - at | ee 2 White.
HesuSs;muricatUS -. . 2. ./| 1
l § This species at
2 ‘ eee | Gibraltar.
Pleurotoma nanum . .. .| I
+3 secalinum : 1
Murex tetrapterus . . . . | oe 2
Chenopus pes-pelecani . . . 1
BUeCINUMI 3 6) te | 1
Mitra ebenea. . 2... . | Se 1
| Bright orange
“ = SL Serisoey <7 1 | colour, banded,
| small, striated.
Ringicula auriculata. . . . Ee | 2
Marginella secalina . . . . | 3 | 4
As clandestina . . ./| Several. Several.
Cypreapulem sts s,s Ae | 2
Cimanisshystrix.9/5 GH. | 3 |
PASO ste rear tor is
.
FDOPUYOES) fos ss pe os ‘
CHAPTER, VIL
DEEP-SEA TEMPERATURES.
Ocean Currents and their general Effects on Climate.— Determination
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.
AppEnpDIx A,—Surface Temperatures observed on board H.M.S.
‘Porcupine’ during the Summers of 1869 and 1870.
Appgenpix 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.
APPENDIX 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.
AppEeNDIxX 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 Féroe Islands; as ascertained by
Serial and Bottom Soundings.
Appenpix E.—Intermediate Bottom 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 samc, some zones would present certain pecu-
CHAP. VIT.] DEEP-SEA TEMPERATURES. 285
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. A glance at any
isothermal chart, whether for the whole year, for
summer, for winter, or for a single month, will show
that this is far from being the case. The lines of
equal temperature deviate everywhere, and often
most widely, from their normal parallelism with the
parallels of latitude and with each other. A glance
at the same chart will also show, that while there
is an attempt, as it were, on the part of the iso-
thermal lines to maintain their normal direction
through the centre of great continents, the most
marked curves, indicating the widest extensions of
uniform conditions of temperature, are where there
is a wide stretch of open sea extending through
many degrees of latitude, and consequently includ-
ing very different climatal conditions.
The lands bordering upon the ocean partake in
this general diffusion of heat and amelioration of
climate, and hence we have the difference between
continental and insular climates—the former giving
extremes of summer heat and winter cold, and the
latter a much more uniform temperature, somewhat
below the normal temperature within the tropics,
and usually greatly above it beyond their limits.
The islands of Ireland and Great Britain and the
west coast of the Scandinavian peninsula are in-
volved in the most extreme system of abnormal
curves which we have in any of the ocean basins;
and to this peculiarity in the distribution of tem-
286 THE DEPTHS OF THE SEA. [cHAP. VII.
perature in the North Atlantic we are indebted for
the singular mildness of our winter climate. The
chart Pl. VII., the general result reduced from many
hundreds of thousands of individual observations,
gives the distribution of the lines of equal mean
temperature for the surface of the North Atlantic
for the month of July; and it will be seen that
the isotherms, instead of passing directly across the
ocean, form a series of loops widening and flatten-
ing northwards, all participating in certain secondary
deflections which give them a scalloped appearance,
but all of them primarily referred to some common
cause of the distribution of heat, having its origin
somewhere in the region of the Straits of Florida.
These peculiarities in the distribution of tempera-
ture on the surface of the sea may usually be very
immediately traced to the movement of bodies of
water to and from regions where the water is exposed
to different climatal conditions ;—to warm or cold
ocean currents, Which make themselves manifest like-
wise by their transporting power, their effect in
speeding or retarding vessels, or diverting them from
their courses. Frequently, however, the current,
although possibly involving the movement of a vast
mass of water, and exerting a powerful influence
upon climate, is so slow as to be imperceptible; its
steady onward progress being continually masked
by local or variable currents, or by the drift of the
prevailing winds.
The Gulf-stream, the vast ‘warm river’ of the
North Atlantic, which produces the most remark-
able and valuable deviations of the isothermal lines
which we meet with in any part of the world, is in
cHaAP. V1. ] DEEP-SEA TEMPERATURES. DONT
this way imperceptible by any direct effect upon
navigation beyond the 45th parallel of north latitude,
a peculiarity which has produced and still produces
ereat misconceptions as to its real character.
The mode of determining the surface temperature
of the ocean is sufficiently simple. A bucket is
let down from the deck of the vessel, dashed about
for a little in the water to equalize the temperature,
and filled from a depth of a foot or so below the sur-
face. ‘The temperature of the water in the bucket is
then taken by an ordinary thermometer, whose error
is known. A common thermometer of the Kew
Observatory pattern graduated to Fahrenheit degrees
can be read with a little practice to a quarter of a
degree, and a good-sized centigrade thermometer to
a tenth. Observations of surface-temperature are
usually made every two hours, the temperature of
the air being taken with each observation, and the
latitude and longitude noted at noon, or more fre-
quently by dead reckoning if required.
Every observation of the surface-temperature of
the sea taken accurately and accompanied by an
equally exact note of the date, the geographical
position, and the temperature of the air, is of value.
The surface observations taken from H.M.S. ‘ Por-
cupine’ during her dredging cruise, in the summer
of 1869, are given in Appendix A.
The surface-temperature of the North Atlantic has
been the subject of almost an infinite number of such
observations, more or less accurate. Dr. Petermann,
in a valuable paper on the northern extension of
the Gulf-stream, reduces the means of more than a
hundred thousand of these, and deduces the scheme
288 THE DEPTHS OF THE SEA. [CHAP. VII.
of curves which has been used with some slight
modification in the construction of this chart.
Until very recently little or nothing has been
_ known with any certainty about the temperature of
the sea at depths below the surface. This is, however,
afield of inquiry of very great importance in Physical
Geography, as an accurate determination of the tem-
perature at different depths is certainly the_best,
frequently the only available means of determining
the depth, width, direction, and generally the path of
the warm ocean currents, which are the chief agents
in the diffusion of equatorial heat; and more espe-
cially of those deeper indraughts of frigid water
which return to supply their place and to com-
plete the general cycle of oceanic circulation. The
main cause of this want of accurate knowledge of
deep-sea temperatures is undoubtedly the defective-
ness of the instruments which have been hitherto
employed.
The thermometer which has been almost universally
used for this purpose is the ordinary self-registering
thermometer on Six’s construction, enclosed in a
strong copper case, with valves or apertures below
and above to allow a free current of water to pass
through the case and over the surface of the
instrument. Six’s registermg thermometer (Fig. 53)
consists of a glass tube bent in the form of a V,
one limb terminating in a large cylindrical bulb,
entirely filled with a mixture of creosote and water.
The bend of the tube contains a column of mercury,
and the other limb ends in a small bulb partially
filled with creosote and water, but with a large
space empty, or rather containing the vapour of the
CHAP. VIL.] DEEP-SEA TEMPERATURES. 289
liquid and slightly compressed air.
250)| 0-4.) O° SC.) 1° 0C | 0-7C)) 0-8 C tO
500 | 0:4 fi 7 1°5 1-4 1:7 | 0=65 4
aes) %o. | 99 2-2 2°3 2:5 | s0=0an
1,000 0-8 2:9 2-9 a 9-7. Oe
1,250 | 0-9 S50 ego padres ye Wem feo
1,500 | 0-8 4-3 A> 3 8 Aza 4°3 | 0°38
1,750 | 0-95 | 4-6 4-9 | 497. 9) 527m SG
}2000:)1s1) |) 5-4 | 5:5 | 5:38 1) 6-4 ie
2 250 1) len 6-2 6-0 6-0 | 6°8 | Oe8
12,500 | 1-2 Too | 6% 6-5 | 726 | Org
The mean difference for each 250 fathoms in each
thermometer is as follows :—
CHAP. VIT.] HEP-SEA TEMPERATURES. 297
Thermometer. Difference.
Standard . = 1 C.
54 , 479
56 . + 0°67
(hae + (0) °65
(Bie j + 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 fron. compression, were employed for
this purpose, with the following result :—
Pressure, 6,817 lbs. = 2,500 fathoms.
Thermometer. | Difference.
5 Se 7 + 0°05 C
Orde Se es es +0 92
9,645 . + 0°11
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. [CHAP. VII.
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. A s: | 5
250 0 7260, | O° 738.0. |) 0° 7266.4) Osa
500 1 + 548 15564 I Or aii | O =4782 |
750 2-123 2°223 | 0° 708 | (0.°745leeaee
| 1,000 2° 474 3° 015 | 0° 674 0: 754
| 1,250 Br25o | 9B 492 || 0 6b: 0 - 698
| 1,500 4:107 fe eeg ail | O° 684 0 + 653
1,750 4 +555 4-056 0 + 650 LO ra 7/09)
2,000 De oo 4 4° 284 0 - 669 0: 536
2,250 6: 021 — 0 + 669 a
2.500 6° 817 at 0 =682: | wae
For 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.
I 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. VIL.
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°. 4C. 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 —38°6C. 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°6C.- 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. VI. | 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 Gulf-stream 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 (—3°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. xvii. 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 long. 73° 12’ W.; andmon
Lieutenant Dayman, who found the temperature
at 1,000 fathoms, in lat. 51° N. and long. 30° W.,
to be 0°4 C., 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
greatest 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 39° 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 line remains constant to the bottom.
CHAP. VII.] DEEP-SEA TEMPERATURES. 303
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°65 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 SEA. [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-poiut, which is, when kept
perfectly still, about — 3°67 C. (25°4 F.), 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
Staff-Commander May for his temperature obser-
vations. There was an opportunity of testing these
thermometers, however, on the return of the vessel,
1 Recherches sur le Maximum de Densité des Dissolutions aqueuses.
Loc. cit.
CHAP. VIL. ] 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, I 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
llth of August, 1868, and directing our course
towards the Froe banks, we sounded in 500 fathoms
about 60 miles to the north-west of the Butt
of the Lews, and took a bottom 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°8 C.
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°5 C., 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, [cHAP. VII.
channel between Scotland and the F&éroe plateau;
and giving, respectively, the temperatures of — 1°1,
—1':2, —0°7, and —0°5 C. 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 Zerebratula
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° Weim
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’ N., long, 7 29° Wowaue
gave a bottom temperature of 9°6 C. The three
soundings, Nos. 138, 14, and 17, at the depths 650,
570, and 629 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 Froe 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-
eating 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 Féroe 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 proxi-
x 2
308 THE DEPTHS OF THE SEA. [cHAP, VII.
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 paleeonto-
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. Se:
SOD © ,, S20
200 _ =C«ssy, fataats)
250M ws 5) Oa)
500s. ; OG
384 (Bottom) O58
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 580 fathoms, the index stand-
ing so low as —1°3C. On Saturday the 21st we took
a sounding in 187 fathoms, on the edge of the F&roe
a 10 THE DEPTHS OF THE SEA. [CHAP. VI.
plateau, and about twenty miles north of the pre-
vious station, with a temperature of 6°9 C., and so
found that we had passed the limits of the cold
basin.
Our first two soundings after leaving Thorshavn
(Stations 61 and 62) were in shallow water on the
Feroe Bank, 114 and 125 fathoms, with a tempera-
ture of 7-2 and 7-0 C. respectively; but the next
Station, No. 63, after a run of eighty miles, gave
317 fathoms and 0°9C., 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 :—
SUPEACE) oy. Sc a ees hae oe ee
S0fathonmis’.< 2° 0.25 7-5 eae ee
100). 3 we AG a Ts a a
LO ae rill cass APO cee ee Ge
200i? ve. 4-4
2505 er ee a ee OE
OOK we. oat fg 8) im Re A es
SKU mare . aw ee Sees
400 Pe DAs!) oo eee ORS
450, 0-8
500 Es -1:0
Ho Ouower., ee ee a tL
AUC), rar ene LE ET Tt
640 a OS ER ee aa ae eo,
cuar. vi] DEEP-SEA TEMPERATURES. eal
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, Fig. 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 southern 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
Fwéroe Channel gives for the same depth a tempera-
ture of about 8°8 C. 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
JJ
iia
~Servial Sounding, Station G4.
FIG
96, —Serial Sounding,
Station 87.
CHAP, VII. ] DEEP-SEA TEMPERATURES. ale
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 500 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.
RAC ORMOAEE 00 tata aa Se ol Mog" ee ALG.
SOGEVUIMOMIS, sj... Seale Sk hier
HOO >, opnoms
M5O= 4 os
200... Oye
a0 Uae» s, toler aL
400 ; (RS
D00y (Panes)
600 —,, 61
BOTs ‘sy ae!
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 Feroe Bank close to the western
opening of the Fiéroe Channel, and that one of these
chains, including Stations 52, 53, 54, and 86, is in
the cold area, while the other chain of Stations, 48,
314 THE DEPTHS OF THE SEA. [CHAP, VIT.
47, 90, 49, 50, and 51, is 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 Féroe 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
Féroe 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
soundings 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
, PUL .-ULIVA, OI[} UL SSULPUNOS [BIS ULOIy popon.AysuC
201M Y PUB PULBTJODS W9aM Jaq [OUUKYO 9} UL , S¥aTE-plOD
316 THE DEPTHS OF THE SEA. (CHAP. VII.
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 300 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 Féroe 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. VU.] DEEP-SEA TEMPERATURES. BLE
continuous with the general basin of the North
Atlantic.
The temperature of this ocean valley was investi-
gated with great care during the first and second
eruises of the ‘ Porcupine’ in 1869, 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 6380
fathoms, No. 28, a little to the south of Rockall,
gave a temperature of 6°4 C., almost exactly the
same as the temperature of a like depth in the warm
area off the entrance of the Féroe Channel; and a
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 8°5 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.
SUDRYGO. 6 Soe ig a og b0 5 Pe a Oe
DAVIN 6 ceo 6 oe 8 oe eon oS 9:0
500 Way oc, 5, ee es, 8 Sirs
”
5
HO one Be i lor ES EO) on 2 OR
318 THE DEPTHS OF THE SEA. {CHAP. VIL.
12000 tathontsws: JAS GE) Oa Ee Roane
1a ae hh oni aL ee
LANG. 25 Aparna Geran sree a OL
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 Féroe 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
ereatly 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
creat, indeed, as probably to represent the average
depth of the great ocean basins—it may be well to
describe the methods of observation and the condi-
tions of temperature somewhat in detail.
320 THE DEPTHS OF THE SEA. (CHAP. VII.
The sounding at Station No. 37, 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°°1 C., 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°05 C. 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 lght
upon the physical conditions of a hitherto unknown
world.
CHAP. vIn] DEEP-SEA TEMPERATURES. 39]
A series of temperature soundings, at depths m-
creasing progressively by 250 fathoms, was taken to a
depth of 2,090 fathoms, on the 24th of July, lat.
A 39 N., lone. 11° 33’ W.
Surface . . 17°: 08C.
250 fathoms. 10° 28 less than Surface . . 7°: 5C.
500 &; 738 53 250 fathoms. 1° 5
(3) aeer VON rg 5 500, 3)-.6
L000 ,; 3° 5 , 750R t. tO
1250) —., 3-17 - 1,000). 0:3
1,500 ,, 2+9 2 eneee 0-3
G50. 25 P61 sf 1500) 3) OLS
7 UE) ee 2°4 - bE) ok 0-2
The same two Miller-Casella thermometers were
employed as in the previous observation.
Another serial sounding was taken a few days later
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 tempera-
ture, and the exact position of the most marked
irregularities.
Suniace, = .. 17-2 22.C.
1Ofathoms., 16° 72 less than surface . Uae &-
74 a Hoel 22 less than 10 fathoms. 1° 5
2; Uae ye linseOer is: r 2005 2. cele
OE 2 AD ad a 30> 3 = 0,59
Sve. eee) Mea cri oes e cy) ees
LOODs es. EO. 6 ; Ose ae de
50) git. ees Lome ., 0-1
200! = me hOR 3 3 150 = LOGsS
DO eo etl a 2007 age (ea
300" ~ 5; a Ee eS . 250, .) ORNS
Wisp)
Fre. 60.—Diagram representing the
relation between depth and tent-
perature in the Atlantic basin.
Fic. 59.—Diagram representing the
relation between depth and tem
perature off Rockall
$e: Se
Pirate VI.—Diagram of the § Porcupine’ soundings in the Allantic and in the Faeroe Channel, showing the relation between temperature and depth,—the serial soundings reduced to curves,
The numbers refer to the stations on the Charts, Plates II, IITI., and IV.
Ti 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 - 1500 1600 1700 1800 1900
emp.
2000 — 2100 2200 2300 2400 Fathoms
———= T
C
o
|
| | 2
_ 2100 2200 2300 2400 FKathoms
0 50 =: 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 $700 {800 1900 2000 ed
00
——L
cHaP. vil.] DEEP-SEA TEMPERATURES. 393
350 fathoms 9°-5C. lessthan 300 fathoms. 0°: 3C.
400, 25-47 , 350, 0-3
eae 8-7 ; oe sO 5
500, 8-55 E 450 , . 0°15
550, 8-0 2 500, 0-55
600, 7:4 : ee oe
650, 6-83 a ene 66
MG? ee 4h, 650, 0-4
50 , -Med- 83 = 700, 0-6
300... ,,. utr aD DS e 750 0-3
862 (Bottom) 4°3 f 800 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 3°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°38 C. for every 250 fathoms.
The most singular feature in this decrease of tem-
y 2
1 jULTLV et} Ul sSuipunos sinqzeredure4 u | PUB [VILLAS WOIJ paJNASMOD SAAIND—"T9 ‘OI
CHAP. VII. ] DEEP-SHEA TEMPERATURES. oe
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, Mr. 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 PI. 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 :—
DUTlace. <7 0 era se ae eee ea ee 252° OIC:
De fat NOINS ie ws 2), ee eet mn ne heal
OAS. Fae RG aie UND Mey fic) me INL)
DP) & >, Sahel NS ORT EA chee 1a BER Mle:
30m, CN ian 20 eel teh ae elon
40 em Seman re ey eee Lor
50 ms Ne TRS fk oy ec LG
LOO ray eg. ye ay Ria (0)
and Dr. Carpenter made the remarkable observa-
tion that “whatever the temperature was at 100
Fic. 62.—Diagram representing the relation between depth and temperature, from the tempera-
ture observations taken between Cape Finisterre and Cape St. Vincent, August 1570.
>
328 THE DEPTHS OF THE SEA. [CHAP, VII.
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 138°C. (55°5° 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.
VAAY CHURCH IN SUDERO.
CHAP. VII. } DEEP-SEA TEMPERATURES.
APPENDIX A.
329
Surface Temperatures observed on board HMMS. ‘ Porcupine’
during the Summers of 1869 and 1870.
I. TEMPERATURES OBSERVED IN 1869.
| 2 | seell Sa Be he eal aes
| Date and Position. iS ae 2% | Date and Position. = 25 oe
| > Bo .| &3 | fo ao | 33
| Be | Be | oT es
Deg. Deg. Deg. Deg.
Cent. Cent. || Cent. Cent.
May 28th . . 2 | 100 94 | May 30th 4 | 100 9°4
4+ 10°;0 |} 102 6 10°8 | 10°8
6 8 122 | 11-1
| 8 10 T5507 |
| 10 | 10:0 | 10°5 || In Valentia . Noon.| 15°0 | 12-7
| Of the Great ; Ze S| eo
Skelligs ee eee 4 | 195 | 11-4
2 11°9 6 114 | lil
| 4 LCG lalla 8
6 11°4 || LO) | 10:0) |) 1-7
8 | Midn.| 9°4 | 11°1
10 116. | 10°2 | May 31st. 2 9°4 | 10°8
Midn.| 10:0 | 10°5 4 OSO ete:
May 29th . . 2 ] 6 ia | a1
4 (7% | 8 13°3 j Ill
6 116 | 102 10 133; ) VET
| 8 | Wy | 108 Gat. 51°52’ NN.) | ;
| 10 |-13:3 | 12-7 || Long, 11°34 w. 5 | Noom-| 189 | 11°6
In Dingle Bay . | Noon | 13°99 | 11°6 | 2 | 139 | 114
2 13°9 11-4 | 4 12°7
4 1257 11°4 6 12:2 | 11°9
6 10°5 8 122 >|) EG
8 1070 | 10°5 10 Loy LIENS
| ROS let | Midn.| 11°9 | 11°9
Midn.| 1171 | June ist . De | DSO ll 2
7 4 Zia lee,
May 30th . .. 2 |) VEG
330 THE DEPTHS OF THE SEA. [CHAP. VII.
@ ae |i © od
5 Bs £5 5 Be Ee
Date and Position iS 24 Bie | Date and Position. iS = z%
ED Sel eee BP | ee
Deg. Deg. || Deg Deg.
Cent Cent. || Cent. Cent.
June Ist . 6 | 122 | 11:9 || June 4th . 2 | TS Se eee
8 SiO atalOin|| 4 Nei} jf Ib)
10 SOM elo || 6 IPs) |] UES)
iaite ollie: 22MIN): Ate : 8 1258. 2e2
Long. 12° 26 W. SSE UE TIED 10 | 122 | 11-4
2 144 | 122 || Midn.| 11'9 | 11:9
4 12°2 | 11°6 || June Sth . 2) lO lS
6 13°3 | 11:9 4 1E6 116
8 [22 169") 6. | 127 eel
LOD RO esa 8 | 12 eee
Midn.| 11°6 | 119 || 10 Ue |) AIG
June 2nd, 2 | 119 | 11:9 || In Galway Dock | Noon.| 1671 | 13°3
4 ila 11°9 2 ists) |) Hay,
6 10°5 | 11°9 4 139
8 116 6 155
10 22 | D2 8 13°3
Lat. 52° 8 N. | 10 | 13°3
Long. 12°50’ W. (| Noon) 150 | 122 Midn. 13-9
2 | 144 | 122 || June 6th. 2 eee
4 Is (0) 11 4 Py
6 ISH). | Ie 6
8 iil 11:9 8
10 11°4 | 11°9 10 14°4
| Midn.} 111 | 11°9 || In Galway Dock | Noon.| 12:2
June 3rd . | 2 iibeil 11°6 2 172
| 4 KOS} |) WLS 4 19°4
6 ILA 11°9 6 19°4
8 a7 ales 8
10 15:0 | 11:9 10 13°9
Tat. 52.260 IN) Ss er Midn.} 13°3
Long. 11°41’ W. § Noon ty 3) tee. |) sane 7th 2 lars
2 W471) 11-9 || t WAT
4 13°0 | 12°2 6
6 THE |) PA 8
8 111 11°8 10 1671
10 | 111 | 11°6 || In Galway Dock | Noon.| 18°3
Midn.| 10°8 | 11°6 2 yg
June 4th . | Waleik |) Tales AS el Tia
4 tal 11°6 6 17:2
6 iyi 11°6 8 150
8 10°8 | 11°6 10 13°9
7 10 10°5 | 116 Midn.| 12°2
ats, "52. 140 oN : . June 8th . 2°. | ot
Tone, ease jcon| 205) 14 4 | 10:0
CHAP. VII. | DEEP-SEA TEMPERATURES. 331
4 | £2 | £8 H | Ze | #5
Date and Position. e aS 27 Date and Position. g ae are
Fed Bu ES £5
& ere & apa
Deg. Deg. Deg. Deg
Cent. Cent. Cent Cent.
June 8th . 6 | 10:0 June 11th 6 | 119 | 12-7
8 8 NO) 7
10 A/S 10 ites 12°2
In Galway Dock | Noon.} 21°1 | | Midn.| 10°0 | 12°2
2 | 905 June 12th 2 | 100 | 12°9
4 20°5 Wefeeh Ih 4 10°2 12°3
6 20°0 6 Lita 12°9
8 166 | 15:0 8 Aes eiltess(
10 IEG ea 3 N) MO ae 22 7/
Midna) ices suai at. 53°24" Ni aoe ;
June 9th . 2 rico |) be Long. 15° 24 W. {| Noon.) 12°2 | 12°7
4 for) 11°6 2 SN 1ST
6 10°5 DD, 4 14) IP 7/
8 19-7 | Bib 6 1O38> |) 130
10 16°1 13°3 8 atales 12°9
In Galway Dock | Noon.| 19:4 | 13°9 LOW) dae 1a -5
2 17-4 | 139 Midn) 10:5) | 12:3
4 17:2 | 13°6 || June 13th Ph |) ARS, I, alee.
6 15:0 | 12°5 4 NOOR alo)
8 Iie |) ee 6 eal | Tee
10 10°55 | 12°5 8 9°7 | 11°9
‘ Midn.| 10°5 | 12°5 = 10 9°4 | 12°0
June 10t 2 | 1070) |) 11°6) |) Lat. 537287 Ne) ; .
4 | 10:5 | 11°6 || Long. 15°08’ W. 5 | Noom-| 10°8 | 12°2
6 16:2 | 1o32 2 10°5 E25)
8 OJ 12°5 4 11°4 | 12°2
7 = 10 ISG eles 6 Tey LE,
at. 53° 16'N. 8 | 10:7 | 123
Long. 11° 52° W. Noon.| 127 | 125 10 | 111 | 12°2
2 NES} 4) RY Midn.| 11°1 12:2
4 122 | 12°2 || June 14th 2 Aiee> |) 119-9;
6 IGG ale 4 TCS aD)
8 LO) -\) Lass 6 Tee tet 9)
10 10:0 | 12:3 8 1D9) 2:5
j Midn.} 10:0 12°3 10 qlee 1D,
une 11th 2 | LOO | reel Eat: 53°40 N. ) < oe
4 | 100 | 122% || Long. 13°49’ W, }|Noom-} 133 | 12°2
6 WAPI VAs: 2, 7 sy
8 Hl TDS 4 130 12°2
= Sone 10 12°5 12°5 6 EF 12°2
ate os 22 Ni : a 8.) | dale As
Long. 13° 23’ W. § Noon.| 15:0 | 122 UIC O ag fl Bs hae STEP
2, Bee | alee | Midn.| 11°] 11°4
4 | 144 | 12°7 || June 15th 2. 108 Plast
332 THE DEPTHS OF THE SEA. [CHAP. VI.
Date and Position. 3 Spe oe Date and Position. = ed r=
eal gee B° | Ba
B ss = nite
Deg. Deg. | Deg. Deg.
June 15th 4 | tos | 116 | Lat. 54°10°N. ) ee
une lv ite i | at, Vv . | 9: Dee
6 | 111 | 11°6 || Long. 10°59’ W. 5 | Noon.| 125 | 122
8 144) 6 | 2 ae |. 129)
10 12:3 |) L1s6 4 127s ret
Lat. 53°47 N. ae yi 6 NERY || Wile
Long. 13° 14 W. Noons| as 0G g | 11-9 | 118
2 13:6) sG 10 LAA eIcG
AL | 13:0") E156: | Midn.| 11°4 | 11°4
6 139 | 11°8 || June 19th 2 LT SSL tbls
8 LOS) Es 4 ET SIL
10 10°8 | 116 6 ANOS} Ts)
Midn.| 10°5 | 11:1 8 MAL ay |) Wee.
June 16th 294 NOs ea a 10> | 13;9) aes
4 | 102 | 11:4 | At Killibegs. Noon.| 13°9 | 11:9
6 157 | eo 2 13°3 | 12:2
8 12509) co 4 12:2 | 122
z 7 10 1359) EG 6 116 | 123
at. 54° 2 N. a ee 8 | 130 | 12°7
Tere, Toe ee | || Le) se 10 | 111 | 122
2 13:9) 119" |i) Midn.| 10°5 | 122
4 13°3. | 12°1 || June 20th 2 LOSS a HES
6 PE ILIIEG: 4 Vs) 5) EG
8 NO De ey 6 NLS) |) JUTE
10 TANG) eabile4s 8 12°77 | 12:2
Midn.| 11-4 | 114 | 10 TSO ES
June 17th 2 | 116 | 116 | At Killibegs. Noon.| 13°9 | 12:2
4 11-6 | DEG fll 2 ASO) || 2A
6 1 Ns 4 144 | 12°5
8 1356S els6 6 14°4 | 12°5
10 2 ela: 8 12°2 | 12°5
Lat. 54°27'N. )| 10 | 10:0 | 12°2
Tone mae epi ty (OB | ales) 'Midn.) 10°8 | 12°5
2 | 133 | 119 || June 2ist | 2 4) Piet See
4 13739) 119 4 able || alsa
6 Wey) TL) 6 aS 3) |) ZF 2
8 22 als 8 POs2 We Mee
10 19> | 116 - || 10 13:0 |-12°2
Midn.| 122 | 11°6 | At Killibegs. Noon.) 15°0 | 12°5
June 18th 2 16. }) 161} 2 153 | 12°2
+ TAG L250. 4 144 | 12°5
6 122 | 12°0 6 13-0 ee
Seal22) |) 19 | & |-11-6.| as
10 1252) |) 12:2 10 Waites |) IIL}
CRAP. VII. ]
DEEP-SEA TEMPERATURES.
5 Be
a oS sy Se}
Date and Position 3 24 one | Date and Position.
| a =5 es |
) oN
| = |
Deg. Deg. |
Cent Cent. |
June 21st Midn.| 10° | 12°22 | June 25th
June 22nd ie Dn OL ay) dels
4 lil 119
6 WET 116
b> Sida o-000
| 10 | 133 | 122 | June 26th
At Killibegs. | Noon.| 13°3 | 12:2
2 13°99 | 12:3
4 PSS 22
6 12°2° | 12:2
8 | In Donegal Bay
| 10 1A | 125
Mubeolny)) Teil |) anes)
June 23rd Fetal ORS | EY
4 TMH 12°2
6 12°4 | 12:2
8 13:9 | 12:2 ||
10 | 155 | 125 || June 27th
At Kaillibegs. Noon.| 16°6 | 12°5
| 2 15°5 PS)
[eee lee icrzae | peal
) 6 Wee) a3: ||
8 13°3 | 13:0 | At Killibegs.
10 136 | 13:3 ||
| Midn.| 12°7 | 130 |
June 24th ee 2 MO TSS
40 | 184) 133M
6 ae SE |
8 tay} IRS 4]
10 | 166 | 135 || June 28th
At Killibegs. Noon.| 17°5 | 13°5 |
9 Ne | Aso 4
4 viral | 141
6 Li7fPAe |) IUESRO)
8 161 14:1 That: 54°54" Ni
10 | 147 | 15°0 || Long. 10°59’ W.
| Midn.| 14°7 | 15°3 ||
June 25th | Deira aes
4 14°] 14°4 |
6 | 139 | 136 |]
8 18°3 | 144 ||
10 20°0 | 13°9 |
At Bundoran | Noon.| 20°5 | 16°6°|| June 29th
lp 8 23:9 | 166
—
by 2h a
°
Deg. | Deg. |
Cent. | Cent.
4 | 15:0 | 15:0
6 | 1671 | 13:9
S| 15:0 ie
108 | 1555165. |
Midn | 14°4 L535 |
Oe eka eras: |
4--| 13:9 | 15-0
6} 139 N83
§ (1s3. | 136
10 | 180 | 14-4
Noon. Oso s9
Q | 99°2 | 153
4 | 194 | 161
6 | 166 | 155
8 | 155 | 155
LOS T2e0 | Woes
'Midn.| 12°5 | 15:0
98 | Dil | ia ||
Ah Sea aaa |
6 lee 139) |
8 | 136 | 13:9
10 | ob: | 142 4
Noon.| 16°6 | 14:4 |
2 | 20:0 | 15-0 |
4 | 172 | 144
6.1331 183
g | 133 | 133
10) sles | 1354
Mirdnsintso i 33
Pa OT dln daa
4 | 127 | 12:9
6 wer |eoe7
gs 13-2 (piso
10 | 139 | 133
Noon.| 14°7 | 13°3
9 | 14 Nese
4 | 139 | 133 |
6. | 13: s90
8 | 13-6 13-0
!. 10> «| 19°72 |) 1333
| Midn.| 129 | 13°6
2 | 12°7 13°3
a Oe ey:
304 THE DEPTHS OF THE SEA. [cuAP. VI.
ao- ee
Date and Position. e . 26 am Date and Position ie ae z4
= aS =o =»
| a are ! | = Bs
| (Se | | eas a
Deg Deg. i Deg. Deg
Cent Cent. |] tent. Ceut
June 29th . . 6 | 136 | 13:3 || July 2nd . 4 162 2)5 | a2
8 14:4 113333} 6 ays) 14°5
10 16°6 13°9 8 147 14-4
Deke, fay Wa NYS 7) e rel 10 15: O26
Morena we yhoo) Lee es Midn.| 14:4 | 139
9 | 16m | wero. || July srdicr.. 2 13:9) | U39
4 15°5 14°4 | 4 13°3 13°9
6 15°5 14-4 6 14:9 141
San lis Oe aa ee 8") sss a eee
1) 13°6 139 L = 10 161 140
| Midn.| 13°3 | 13°9 at. 56° 58’ N. ( :
| June 30th’. . 9 | 13:0 (| wat |) bong: ls air’ Wes Noon.| 153 | 13°9
4 13'°3 14:0 2 16°99 | 14:4
6 16:6" | V9 4 ASL || SHY)
8 SOM Seo 6 14:7 | 136
7 7 10 161 14-4 8 139 12°5
at. 55°44’ vi 10 13°3 12°5
Long. 12°53’ W Noon.| 16'4 | 14°4 Midn.| 12°7 | 12-2
2 \177 | 145 || July 4th. . . 2 | 13-4 | 136
4 Welz 14°4 || 4 13°9 | 139
6 15°8 1550) 6 13°6 14:0
8 TSSOP SEO: 8 14:1 13°6
10 144 | 15:3 || x 10 14°7 14:7
Midn.| 13°6 | 14:4 || Lat. 56°47 N. }| :
| July Ist... 2 | 127 | 13-9 |) Long. 12° 49° W. Noon. |b 05 aee
4 13°3 13°9 || 2 144 laa
6 15°5 14°4 4 144 | 148
8 16°3 14°4 6 139 | 14:8
10 ys |) We e7 8 13°9 | 149
Noon.| 172 | 14:8 10 139 | 1
2 IPA |) lise Midn.| 13°3 | 14°7
4 1656. 15:0 || Sully bth Se 2 | V2) ae
6 15:0 14°4 4 13:3) 15:0
8 14:4 14-4 6 13°9 14°7
| LOU | Ws) a 8 | 139 cae
Midn.| 1471 14:1 a 10 14:4 | 14:7
| duliye2indie 7 acs De t4at. |) 13:9) ||| Tat. (56: 4p '
| 4 | 141 | 140 || Long. 12° 56 W. Neon. eae
| 6 WoO) Was 2 144 | 15:0
8 155 | 141 | 4 11353) doo
10 155 14°4 6 12°7 14°4
|| Hat: “562 19/ Ne) 3 8 12°2 14:1
| Long 14° 10’ W. \ Noon 17 Ul 14°4
Bi 174-147 || Midn.| 125 | 14-4
| 10 | 12:5 | 14:4
CHAP. VII. ]
DEEP-SEA TEMPERATURES.
io)
oS
or
Date and Position
July 6th .
Matenn6 22% IN.
Long. 11°37’ W. §
July 7th .
Ones
Lat. 55°55’ N. )
Long. 10° 17' W. §
July 8th .
tate 56° 6 N. |)
Long 9° 36’ W. ||
July 9th .
|
|
| 2 zo i 2 2g
S zo ae 1 Date and Position | e ae Ba
) on || | D ow
a Be || a Bs
|
Deg. Deg Deg. | Deg
Cent Cent : ‘ent Cent
2 | 12:2 | 13:9 || In Lough Swilly | Noon.| 15°8 | 13:3
AO W127 9) Be Teale) sis
6 | 124 | 138 | A 55 1 13°0
Si jel3'9) nasi 6 5" | 13:3
LO | Pat W13-9 8 | 13°99 | 133
a LOO Poets:
Noon. 13 | Midn.|-11°6 | 12-7
25-0 | July 10th 9 Deis 1:6
4 \el5:3 |) 4-7 1) 47 | 19:9= 1 13:6
6° | 13-9) | 144 Go see 13-0
Sela ete S: || UGe ie ela!
10 12°0 | 13°9 10 1671 | ia-4
Midn.| 11°1 | 13°3 || In Lough Foyle | Noon.| 17°7 | 14:4
P77 3) TSS tt 2 Die Tao
Ai | 14 ses AY 1853 lees
6 | 1470 | 1333 | 6 | 161 | 144
8 | 147 | 133 | 8) tea aS-6
LO) | DSO tS (= 10! aso. 333
ae Ye | | Midn.| 14:4 | 13:9
Noon.) 15°0 | 13°31! July vith | 2 | 150 | 14-4
2 ESO) TBS) } az 13:9) 4) 144!
4 | 150 | 136 | | = siGe eaacs* | Oisee)
6 |. 15:0 1) 18:9 || 8. | di63 (13:9
8 | 15:0 | 139 || | 10 | 166 | 136
10 | 144 | 13:3 || At: Moville, aie f ;
Midn.| 14-4 | 13°3 || Lough Foyle § Noee ae ie
2 | deal | 53°97 Gy) 2 | 205 | 15°5
A | 4-4 13:6 lel 50
6 | 155 | 13:9 6 | 189 | 14:4
8: 1 15a kiSo Se (80) | 1454
10 | 150: _|-13°9 10 |} 15:8 |: 13-9
ee eal Midn.| 15°8 | 14°4
NGO TOS ACrea rally Wott | 2 | 15:3 | 15-0
2 147 13-64 Ads [pkey
AR Oe Ss6i i Gee Sole | ae:
6 183) Sou Pes. Weiss. | ara
Cele Bie ai erene| f 10) | 16) 4 LOS
10 Mpsey |) 13x) Off Belfast | | oe :
| Midn. | NPAs ea Lough. . . | Noone 1a OF peas
|; 9 | 1972 | 13:9 2 Ge jeri
AS TDs 9-7 V4) Pongo acs
6 | 6 | 144 | 144
Ce RES Nee e | | (8 | W4s4e aor
TO! Vous ones LO.) 12°7-|| 1272:
336
THE DEPTHS OF THE SEA.
Date and Position.
Hour.
Temperature
of Air.
Temperature
of Sea-Surface,
Date and Position.
Hour.
Temperature
of Air.
[CHAP, VIL.
Temperature
of Sea-Surface.
| July 12th
| July 13th
| At Belfast .
July 14th
At Belfast
July 15th
At Belfast
July 16th
At Belfast
SCO b
A
of
CaOrNS
—
~
~—
10
Midn.
2
4
6
8
10
Noon.
2
a ee
Ss
bo bo tw DO WD bY aT bP
! July 16th
|
| July 17th
| July 18th
| July 19th
| July 20th
| Ati Belfast
Off Tuskar L. H.
} At Haulbowline
10
Midn.
10
Midn.
2
17°4
16°6
16°6
IEF
18°0
18°3
CHAP. VII. ]
DEEP-SEA TEMPERATURES.
337
Date and Position.
Hour.
Temperature
of Air.
July 20th . . 8
Tat. 50° 28’ N. j
Long. 9° 37’ W.
July 2ist. . . 2
10
Lat. 48° BIEN.
Long. 11 8 W.
July 22nd . . 2
10
Lat. 47°38’ N. }
Long. 12° 11' W. § |
~ 4
July 23rd... 2
10
Lat. 47°39’ N.
Long. 11° 52’ W.
2
Noon.
Noon.
Noon.
Temperature
of Sea-Surface.
Date and Position.
July 23rd
July 24th
Lat. 47°40'N. j
Long. 11°34 W. §
July 25th
Lat. 49° 1'N. )
|| Long. 12° 22’ W. §
July 26th
Lat. 49° O'N.
Long. 11°58’ W.
Hour.
8
10
Midn.
Temperature
of Air
Temperature
of Sea-Surface.
Deg. Deg.
Cent Cent.
17-2 18°3
189 | 183
ilgaais |ralfs gs:
lez, 18°3
166 | 18°3
Wea | AES?
Tree hers
17°5
186 | 18:0
189 | 183
183 | 183
19°4 | 18°3
189 | 183
SiO leisd
SHOT AUS)
18°3 | 18:3
N7Ceh || teks}
17-2 180
169 | 183
NGG al eliza
eC) ART
LBiOF |) Wa7
189 | 17°7
1823) | aes
UScoaa alee ardh
ugS¥33. || alyiee
194 | 183
Sima liven
189 | 17°5
161 172
1671 eee,
ego | alge
16°71 17°5
1S-9e VW ahe?
ISI al) sa be(Sr/
ig} HN Velez
16°9 iid
1G oe living
LG | Wied
1671 Wiha
L5:8melidad
338
Hour.
Date and Position.
July 27th
Lat. 49°10’ N.
Long. 12°45’ W.
July 28th 9". 2
10
Lat. 49°59’ N.
Long. 12° 22’ W. :
July 29th ,. . 2
Lat. 50°24’ N.
Long. 11° 42’ W.
July 30th
\ Noon.
Noon.
2
THE DEPTHS OF THE SEA.
[CHAP, VIL
i) ov 2 oo
e. | ge | 2:
BH B58 j eI &
a 5h Date and Position. E Ae) pag
B° | Ba B° | 83
B Een i) ai
Deg. Deg Deg. Deg.
Cent. Tea Lat, 51° 5 N Cent Cent
155 | 17° at. ;
15:0 | 17:2 |] Long. 11°22’ W. Noon.| 17°7 | 15°8
LOA |) ees 2 ale se7/
146 Ia: 4 175 16°71
18°9 17°5 6 17:2) | 1636
; ber 8 16°6 | 16°6
SUS 10 | 166 | 15:5
Wide a eauiiee Midn.| 16°6 | 15°8
18°9 Wey July 3lst. 2 16°3 | 15:5
18°3 lez 4 15°5 15:5
1671 iLSY 6 15 Se ees
NGL aed, 8 ye |) ze7
15°8 WT 10 18°9 12°5
15°3 | 17°5 || Near Cork Har- ; ;
150 | 166 || “bour (et. . Neen ee
15°5 169 2
186 | 166 4 18°3 | 1671
ied 656 6 1621) | 15:8
; f 8 14:4 | 144
NO 6:9 Mids 2a/anlelelei:
183 | 171 || August Ist 2 | 12:2
16°6 16°9 4 12-2
15:5 16°9 6 13°9
15°8 iro 8 16°6
161 | 16°6 10 pis) || ay
161 | 17°2 || At Queenstown. | Noon.| 19°1 | 14°7
15°5 W7/Sz 2 18°9 1%}
15'°8 169 4 2:9) Was
164 | 16:9 6
16°6 16°6 8 1359) | Lows
d ‘ 10 12°2 15°0
BAZ Ges Midn.) 12°5 | 14-7
161 | 163 |} August 2nd . 2 | 122 | 144
Iy27/ 16°3 4 11°9 15°0
17°7 | 16°6 6 | 127 | 155.
16S le, 8 15:0 | 15:3
16°1 16°6 10 14:7
16°1 At Queenstown. | Noon
CHAP. Vu. ]
Hour.
Date and Position.
August 2nd .
August 3rd... 2
Blackwater,
Lat. N. 11 miles.
Lat. 52° 22’ N.
August 4th . . 2
10
At Copeland Is- Noun:
andes? «2
2
August 5th .. 2
At Belfast
August 6th .
Temperature
of Air.
Temperature
of Sea-Surface.
DEEP-SEA TEMPERATURES.
Date and Position.
August 6th .
At Belfast
August 7th.
At Belfast
August 8th .
At Belfast
August 9th .
At Belfast
Hour.
10
Midn.
10
Midn.
339
Temperature
of Air
Temperature
of Sea-Surface,
3140 THE DEPTHS OF THE SEA. (CHAP. VII.
2 oe 2 2s
z zs z as
4 es es A ie a
Date and Position, 5 ae oe Date and Position. 3 hs oe
= a | a Sc
Deg Deg. Deg.
Cent. Ceut. Cent.
August 10th. 2 | 111 | 139 || August 13th. 2 | 125
4 105 | 14°7 + 127
6 10°55 | 14:4 6 13°3
} 8 | dia | 144 8 | 12-0
10 13°9 10 114
At Belfast Noon.| 15°5 | 15°0 Midn.| 11°1
2 15:0 | August 14th. 2 116
A | Va7 ie 4 | 114
6 IDET | 6 11:4
8 11°9 | 15:0 8 13°3
10 TGS hehe) 10 12°7
Midn.| 11°6 | 13°9 || At Stornoway Noon.| 15°5
August llth, . 2 | 105 | 13°9 2° | GH
4 17 also -t 150
6 1232 | 13i6 6 14-7
8 ieka3_ i) We) 8 13°3
| 10 | 144 10 | 13:3:
| In Belfast Lough | Noon.| 14:4 | 14:4 Midn.| 12°7
| 2 | 153 | 122 || August 15th. 2 | 133
4 15:0 | 13°0 4 13°3
6 139) 2 6 | 133
Ss) 12:2) 12:2 8 | _1s9
10 MEZA |) alee 10 139
Midn.} 12°0 | 11°7 || At Stornoway Noon.| 14°4
Angust 12th. . Ze W222 2 | 158
4 VET | ah hey 4 1671
6 11°4 | 12°0 6 15°5
8 13°3 | 12:5 8 13°3
10 172 | 12°7 10 12°7
Yoll Island, N., ) y os Midn.| 13:0
3 miles . . j Nocona) 183) 12 August 16th. 2 lo
2 153 | 13°3 4 EF;
at 144 | 12°2 6 13°3
6 DEE | 8 13°3
8 12:2 | 12°0 10 13°6
10 WiE7/ 12°2 Lat. 59° 21’ N. :
Midn.| 12:0 | 12-2 || Long. 6° 58’ W. ¢|No™-| 183
August 13th. . 2 NOPE || ALIS ih 2 13°0
4d WR) |) VULNS) | 4 13°3
6 Le e209 | 6 13°3
8 E210) LZ:0N)) 8 12°7
10 14a | WaeG 10 12°5
Shiant Islands, } | ae ; Midn.| 12°2
N.N.W. 6 miles § | NGG) ese eae August 17th. . 277 Nie
cup. vu. ]
Date and Position.
Hour.
August 17th. . 4
6
Lat. 59° 36 N.
Long. 7° 12’ W.
August 18th. . 2
Lat.
Long.
60° 25’ N.
8° 9 W.
August 19th.
Lat. 60° 13'N. )|
Long. 6° 41 W. § |
| 4
August 20th. . | 2
DELP-SEA TEMPERATURES. 341
Se 7°35 J Sees
9 < as ‘| Date and Position. = | a< Pia
ae EG m | gS Ea
a | cal | i= Ei
Deg Deg. | | Deg | Deg
122 | 119 || Lat. Gur 2578. Seay
122) UNO) Hone Ge Wy ph NOON) ASS" ETS
12:2 1) Qe Moy eels
13°9 | 12:2 A | 122 | 116
: Dn 6 | 94 | 14
es he 8 | O94 | 105
13°6 | 11:9 10 9°7 | 10:0
eS Meee ea, Midn.| 10:0 | 974
130 | 11°9 || August 21st. . 2/100 9°4
12°5 | 11°4 4 94 | 9-4
12-7) Wat 6 | 100 | 9-4
193 ole 8 | 10:0 | 100
12°2 | 10°5 | 10 | 13°6 9°7
12:2) dd 9) Of) Sander iniy) - <
127 |, Vast | Feerve Islands § Noon.| .13°3 a
13-91% | 9 | Wasa S38
136 | 108 | AS Mele ha Oat
: ; Got ee 9A
136 | 11:4 | ae aa
127 |, decom 10 | 108 | 94
125, | 10:84 Midn | 105 | 9:4
122 | 11:1 || August 22nd . 9 1105 | 91
Toe Maule 4 |108 | 9:4
Poe iad 6 | tied 9a
12 eit 8 | ir6-| 9:4
122. Nai 9) 10: ieee |e oe
12-2 | 111 || At Thorshavn Noon.| 144 | 94
ey ale 9 A SS | 69:7
ie al a oe 4 | 122 | 100
13:3) || Ta 6 ass 9:7
fe en 8 1105 | 94
re ca Na 10 | 100 | 9-4
POeSy 4 total Midn.| 10°0 | 9:4
139 | Augnst 23rd, 2 9°4 9°4
12°77; | Sue | A
1 e7a ot} ate 6 | 108°] 9-4
127 | lee 8 | 10°5 9°4
122 | 105 | 10 | 197 | 97
12°2 | 10°5 || At Thorshavn Noon.| 12°7 9°7
120 | 10°0 | 2 | 1o-7, 1) 94
12°2 | 10°8 || AL 17 oe
12°5 | 10°5 | 6 |'12De)) 94
12°5 | 103 8: alikee alee
Date and Position.
August 23rd
August 24th.
About 10 miles i
East of Haalso §
August 25th.
Lat. 61° 36’ N.
Long. 3° 45’ W.
August 26th.
Lat. 61°14’ N. }
Long. 1° 58’ W. §
August 27th.
THE DEPTHS OF THE SEA.
Hour.
10
10
“=
4
6
Midn.
Midn.
2
Temperature
of Air
eS:
Temperature
ot Sea-Surface.
|
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.
Temperature
of Air
EE a, ee Oe OOD STIRS (CO CO) 6S OR ST Tt TCO ce
tow 0 0 70 SAT AT BB AT ~7 709 1 HD AT
a ee
~J
~JI
Temperature
of Sea-Surface.
CHAP. VII. ]
Date and Position.
Hour.
August 30th.
August 31st.
At Lerwick .
September Ist .
Lat. 60° 27’ N.
Long. 3° 11’ W.
September 2nd .
Lat.
September 3rd .
60° 29’ N. ) |
Long. 4°38’ W. §
10
Midn.
10
Midn.
| Midn. |
2
.| 114
DEEP-SEA TEMPERATURES. 343
HI
24 22 || Date and Position. 8 =<
Ee | FS Bi | BS
= Eis i=
Deg Deg Deg Dee
Cent Cent. Cent Cent
ie an Een 44 3. LO AlmlSeOicn EasleG
66 | 111 || Lat. 602 8 N. 2)
72 | 105 || Long. 5° 10’ W. EDS ea | IEE:
TSTiae Nei (ORS) 2 125 | Lie6
10°0 NEI 4 TsO seo enlelic6
10:0) |) tiled G yale | Ine
11°6 10°8 8 71-112°5 11-4
12°2 1 LEI 10 WF 116
13:6 |) 11a! Midns; 1277 | 19-2
111 | 11:1 || September 4th . DO e.| Wee?
LOS: aint AN (MBS | doo
ala: eT 6 13°9 12°5
10°8 10°8 8 13°9 12°5
10°5 1 < 10 14-4 | 129
IEUESH on Lat. 59° 43’ N. , y
11:1 | 11°6 | Long. 6° 35 Wf Noon.| 13°3 | 12°2
116 11°6 2 133 | 1272
SGT WW eISG 4 TSO 22
iti 114 6 QE 2:2.
: , 8 LO A EG
ce gtr 10 | 122 | 11-6
122 | WEG Midn, | 12°5. | 12:0
13°3 | 11°4 || September 5th . 2) 2-20 | 12-0
TAG ntST 4 1275 IEG
11°4 1S 6 1257) NGG
Ta 11°6 8 D237) Si a6
Tei 11°6 10 13°3 12°0
10°38 | 10°8 || Lat. 59°38’ N. : 99
10°38 | 10°5 || Long. 8°25 W. § BRED) SE Ue:
1a 10°3 2 13°6 11°6
sei 10°3 4 TAO SEG
ea | 10°3 | Gis | uel 11°6
10: 8 111 11°6
10°0 10 10°8 11°4
1 Ee es esl Gs} Midn.} 11:1 | 11°4
116 | 105 | September 6th . 2 seDis| wake
1 JEG Toei 4 en 114
as: Wa LSIL 6 12°2 11°6
11°6 11°4 8 13°0 N63
aS LEG 10 1257 We
11°6 Taal Tat. 59°37 N. : 96
111 | 111 || Long. 9° awit CE ate
Pee anise 2 | 13-0 |
11°6 11°6 4 17 el D2
ODD
344
Date and Position.
September 6th .
September 7th .
Lat. 59° 41’ N.
Long. 7° 32' W.
September 8th .
Lat. 59° 7 N.
Long. 6° 35’ W.
September 9th .
At Stornoway
September 10th
|
THE DEPTHS UF THE SEA.
Hour.
8
10
10
Noon.
2
4
6
8
10
Midn.
2
4
Midn.
Temperature
of Air
Temperature
of Sea-Surtace.
Q
ey
cot
12°0
12°2
12°2
116
116
116
EY)
116
TLS)
12:2
12°2
12°2
122
12°5
12°2
122
11°6
19
IS
12°2
12°7
12°7
12°7
12°77 .
12°5
125
13°0
13°0
12°7
12°7
Ref
12°7
12°7
12°7
12°7
12°7
12°7
13°3
12°7
17
12°7
03
| In Loch
Date and Position.
| September 10th
At Stornoway
September 11th
At Stornoway
September 12th
At Stornoway .
September 13th
Dany,
dae nie = hil
Hour.
[CHAP. VII.
Temperature
of Air.
14:4
13°9
Temperature
of Sea-Surface
12°2
12:2
CHAP. VII.]
Date and Position.
Hour.
September 13th 8
September 14th 2
Il. Surrace TEMPERATURES
Temperature
of Air
DiLP-SEA
Temperature
of Sea-Surtace
TiMPERATURES.
Date and Position
Abreast of Mull
345
= ao | &3
ow om
B Bee
°o
Deg. Deg.
Cent Cent
Noon.| 12°7 | 13°0
2 144 | 13°3
4 AF AS S333
6 SiG; | L2s7
8 TSO} alsa
10 12c5) 4) 1350
Midn.; 12°0 | 13°0
OBSERVED DURING THE SUMMER OF 1870.
5 ES
4 SH | BB
Date and Position. 5 as 3a
B | ge | Es
Deg. Deg
Cent, Cent.
July 6th . 2 139 es
4 14°4 | 1257
6 13°9 12°5
8 14°7 Ae 7
10 L553" WP 1356
Off Scilly Islands | Noon.| 18°6 | 18°3
2 19°7 | 17°4
4 19°4 | 18°3
6 18°9 | 18°3
8 AE Wh Al7/e7/
10 16:6 | 17:2
Midn. | 16°1 17°2
July 7th . 2 | 166 | 166
4 166 | 16°6
6 16°6 | 16°6
8 169 | 16°9
7 ; = 10 17°7 | 16°4
at. 48° 49° N. ) :
Long. 9° 35’ W. f Noon.| 18°3 | 16°4
2 19°4 | 16°4
4 18°9 | 17:2
|
i
Date and Position.
July 7th .
July 8th .
Lat. 48°31’ N.
Long. 10° 6’ W.
July 9th .
Hour.
Temperature
of Air
Temperature
of Sea-Surface.
346
THE DEPTHS OF THE SEA.
[CHAP. VIL.
Date and Position.
Hour.
July 9th. .
Lat. 48° 26’ N.
Long. 9° 43’ W.
July 10th
July 11th
Lat. 48° 8 N.
Long. 9° 18° W.
July 12th ,. .
Lat. 46° 26’ N.
| Long. 9° 31’ W.
10
Midn.
10
Midn.
Temperature
of Air
Temperature
of Sea-Surtface.
93
_
eel
Qe
Date and Position.
July 12th
July 13th
Lat. 44°59’ N. )
Long. 9° 33' W. §
July 14th
E. N.N.
Cape Finisterre, )
10 miles .
July 15th
That. (42010 Nt
Long. 9°13’ W.
2 es RS =
oO ee ee
Shee gee
H Fric=
Deg. Deg.
Cent Cent.
6 17:9 | 18:0
8 16°6 | 18°0
10 16°6 | 17:2
Midn.| 16°6 | 17°7
2 Wee | ez
4 y/o} 18:3
6 Weep || azz
8 ISHS |) alz/°5)
10 18:9) led
Noon.| 19°7 | 18:2
2 PAA |) aS)
4 22:5 18°9
6 PAIL © || IUs333
8 UpAay. |p sks)
10 Ils) |) ASO)
Midn.| 17°2 | 18°0
2 iiz(27/ 17:9
4 WA SA |)
6 169 | 161
8 iss} |) ileal
10 18:6 | Wass
Noon.| 18°6 | 15°8
Y 18°6 15°8
4 ISLS |) ists)
6 alfa | TLS
8 1676 || 155
10 16°6 | 158
Midn.| 16°6 | 1671
2 166 | 161
4 16°6 | 16°6
6 Lid || U6
8 18°3 | 16°9
10 18°9 | 17:2
Noon.| 20:0 | 16°4
O22 3a live
4 D2 17°9
6 19°0 189
8 179 | 189
10 ICZAN |jaillS39)
PH USD 19°3
CHAP. Vil. ] DEEP-SEA TEMPERATURES. Bu OE
ae |
‘ti Boe ecal - Boe ee
Date and Position. S Big, a Date and Position, S a! Be
AE aes Sane se:
& a = Be
|
Deg. Deg. | Deg. Deg
Cent. Cent. || Cent. Cent
July 16th 2 | 155 | 190 | July 19th 2 | 203 | 180
4 72 |2118:9 4 20°3 | 18:0
6 16) io 6 19:5 | 17:9
8 | 20°r | 19°4 8 19°4 | 18°3
10 eB) |) 17/9) 10 18°9 | 184
At Vigo . Noon.| 23°6 | 17°8 Midn.| 18°6 | 18°4
2 | 236 | 17-9 || July 20th . . 2 | 4:3) |.18:3
t 23°4 | 18°0 4 18°3 | 183
6 DAG; 8) Ahie 6 19°4 | 18°4
8 18°4 | 1671 | 8 24°4 | 18°9
10 177 | 166%) | 10 23°3 | 20°5
| Midn.| 17°2 | 16:9 -|| Lat. 40° 0’ N. din Bye
July 7th . 2, | 77 (“1611 tnete, 9749 Warp on] 244 | AED
| a 17°55 | 165 2 \\25sbeale ile
| 6 LT, |eliGi6 4 26°3 | 21°8
8 19°7 | 16°4 66 23°3 | 21°8
10 29-2) | V6e 8 216) | 1937
At Vigo...» |Noon.| 32°2 | 16°4 10 | 21:3 | 20°8
2 26°6 | 16°9 Midn.| 21:3 | 20°5
4 | 25°38 | 15°38)! July Qistes . 2 2 | 210i I) 20s
6 22°5 | 16°4 4 21:5 | 19°7
8 20°8 | 16°4 6 23:3 18:9
10 20°0 | 16°5 8 22°7 | 19°4
Midn.| 18°6 | 16°2 7 ni 10 24°5 -| 19°4
Suly 18the . ¢ 2 18°3 | 16°4 ats 39°39" N; ae
y A. Nae Long. 9°36’ W. Noon.| 25°5 | 19°4
6 18:9) 16rd 2 | 25:0 | 19°4
8 19°4 | 166 4 | 23°99 | 197
10 18°9 6 21°8 | 19°4
Bat: 41°55 N. : . 8 20°1 | 19°4
Long. 9° 30' W. Noon!) 191) 162 10 | 196 | 19-4
2 186 | 16°3 Midn.| 19°5 | 19°1
4 | 189 | 163 || July22nd:.. . 2 | 19°4 | 189
6 189 | 16°4 4 18°9 | 18:9
8 18°3 | 166 6 20:0 | 18:2
10 18°3 | 16°6 8 212s Sis
Midn.| 17°7 | 16°4 10) | 25:0: | 19:4
July 19th 2 |17°7 | 169 || The Farilhoes, are
4 A OW TC 1639 8.S.E. 5 miles Noon: | 200)5) 12.3
6 19°4 | 169 2 23:9 | 19°1
8 20°8 | 17°5 4 23°3 | 20°5
10 201 | ited 6 | 23°9 | 19°4
Lat. 40° 16' N. nee 8 | 20:0 | 19-4
Tiong, 9° a3'tw. | Noon.) 2085) Ere 10 | 189 | 183
318
Date and Position.
July 22nd
July 23rd
At Lisbon
July 24th
At Lisbon
July 25th
Lat. 38°10’ N.
Long. 9° 29’ W.
| July 26th ..
THE DEPTHS OF THE SEA.
Hour,
Temperature
of Air
[o)
oo
503
19°1
18°9
19°3
20°5
23°3
24°7
22°5
23°6
21°6
23°0
20°5
19°5
20°1
19°4
19°4
20°1
20°8
21°2
24°]
23°0
22°1
22°2
20°5
20°0
19°4
19°1
19°0
20°3
20°4
20°8
21°8
21°1
20°8
21°6
20°0
18°6
18:0
18°3
18°3
19°1
19°4
20°3
Temperature
of Sea-Surtace.
c
om
i)
Cent.
aa
CON
[> i)
Date and Position.
Hour.
[CHAP. VI.
Temperature
of Air
|
|
|
Temperature
of Sea-Surface.
Tat. 38°17 N Plage
Long. 9° 23’ W. { oe
July 27th
Lat. 37° 18’ N.
|| Long. 9° 12' W.
| July 28th
Lat. 36° 55’ N.
|| Long. 8° 44’ W.
July 29th
Lat. 36° 45’ N.
Long. 8° 8 W.
G
ef
Bo
20°0
20°0
20°0
20°0
19°4
20°0
20°0
19°4
19°4
19°4
20°0
21°3
2171
23°3
21-1
20°0
20°0
19°4
19°5
19°4
19°4
TOR
pA ea |
21°1
21°8
21°6
21°6
20°5
18°9
18°9
18°6
18°3
18°3
21°1
22°1
23°0
23°3
23°3
24°8
CHAP. VII. |
Date and Position.
July 29th
July 30th
Lat. 36° 27’ N.
Long 6° 39 W.
July 31st.
At Cadiz .
August Ist .
At Cadiz .
August 2nd .
DEEP-SEA TEMPERATURES.
Hour.
10
Noon.
Temperature
of Ail
Temperature
of Sea-Surface.
|
Co}
Ee
Eos
349
Lat. 35° 39’
Long. 7° 4’
August 4th .
|| Lat. 35° 35° N.
| Long. 6° 24 W.
October Ist .
In Strait
Gibraltar .
=} eS
K eS a=
Date aud Position. iS 25 Pea
a es SS:
= Be
| Deg Deg.
Cent Cent.
August 2nd . We Se 2) Bie D359
ls 10 | 22°8 | 94-4
| Lat. 36° 18’ N. : .
I eaten Ww | Noon. 22°83 | 23-0
| 2 | 99:5; | 93-0
| A) 227 1230
6 21°8 | 22°8
8 21°2 | 22°2
10 21°3 | 22°5
Midns|) 2s 17229
August 3rd . 2 | 20°5 | 22:0
350 THE DEPTHS OF THE SEA.
2 23
J = £¢ 2
Date and Position. 3S Bo ae Date and Position |
= ape
Deg. Deg
Cent Cent
October Ist . 4 | 22°5 | 99:8 || October 5th . - 9
6 22°0 22°6 4
8 Dial: 22°5 6
10 Ales) 92°92 8
Midn.| 20°8 | 22°6 10
October 2nd . 2 | 2171 | 22°8 || Lat. 43° 33’ N. N
4 | 22:3 | 23:3 || Long. 9° 3’ W. oon.
6 22°6 92°9 2)
8 Q4°7 Dey 4
= 10 94°7 23°3 6
at. 36° 27° N. 8
| Long. 8° 31’ W. 4 oO aa eae 10
Ve 22°6 93°4 Midn
4 PBT 23°0 October 6th. . 2
6 20°5 92°5 4
8 20°5 20°5 6
10 20°5 20°8 8
Midn.| 20°5 21°6 10
October 3rd . 2 20:0 | 21°71 || Lat. 46°12’ N. N
4 | 19:4 | 18:3 || Long. 8° 8’ W. oon
6 19°1 20°5 2
8 18°3 20°8 4
- [ 10 18°6 20°5 6
Lat. 38° 39’ N. j , 8
Long. 9° 30 W. {| Noon.) 22°2 | 20°3 10
2g 21°6 20°5 Midn
4 | 21-1 | 21:1 || October 7th . . 2,
6 20°5 20°6 4
8 20°0 19°8 6
10 20°6 2073 8
Midn.| 20°5 20°5 10
October 4th. . 2 20: Sue Lat. 48° 51’ N. N
A | 20°6 | 2171 || Long. 5° 54’ W. oom.
6 Oileil: OALIL 2
' 8 21°6 D5 4
10 22°29, 21°0 6
Lat. 40°57’ N. bg 8
Long. 9° 29’ W. Noon. 922 21°9 10
2 22°9 Heil Midn
4 222, 21°0 October 8th. . 2
6 20°0 20°5 4
8 20°3 90°4 6
10 189 19°4 8
Midn.| 19:3 19°4 10
[CHAP. VII.
Temperature
of Air,
Temperature
of Sea-Surface.
CHAP. VII. ] DEEP-SEA TEMPERATURES.
© oo
I oo es
AC 3 nad Ese) ARG
Date aud Position. Ss ice AS Date and Position.
si © =
o FS) 2
= °
Deg. Deg
Cent. Cent
October 8th .
English Chan- >| Noon.| 18°6 | 16:2
nel . oa
St. Alban’s Hd., !
9 19°5 | 16:0 || At Cowes
Co
or
—
Hour.
Midn.
Temperature
of Air
Temperature
of Sea-Surface.
352 THE DEPTHS OF THE SEA. [cHAP. VII.
APPENDIX. 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.
SERIAL SOUNDINGS. Botrom SOUNDINGS. |
Tempe- lTempe- |Tempe-| ‘Tempe-/ Tempe- 'Tempe- |'Tempe- Sta- Surface | Bottom
Depth | rature.| rature.| rature | rature. ‘ature. | ' 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. | Cent. | Cent. | Fms. Cent. Cent. |
0 | 14:0 O 13°8 | 12°6 | 13°0 | 13:4 | 17°7 oe ee oe os |
50 ao : : ;
34 75 | 18-9 98 |
6 90 12:2 10-0 |
35 | 96| 17-4 | 107 |
100 9-1 | 10°6 8 106 12°3 10-6
24 109 14°3 8-0 |
150 10°5 159 11°8 10:2
14 173 118 9-7
18 183 | 11°8 9-6
200 8°9 | 10:2 13 208 | 12:0 9-7
250 a ao Q-] 89 | 91 9-0 | 10°2 4 fe a aa
300 5 26 4 .
350 9°5 1 370 13:2 9-4
400 6 9-1 | 15 422 ile, 8:3
50 8-6 45 458 15:9 8-9
500 hls ae 81 Sele S35 8&6 8°8 || sy ad oe el
550 axe : E
600 ae 75 4] 584 17°4 8-0
630 ‘
650 6°8 | 23) | 664 | 1441 53 |
700 6-4 12 | 670| 11:2 | 5:9 |
3 723 125 61
36 | 725| 17-7 | 66 |
oes | eek eee ol teal gos | 123 | 5-2 |
OU Bes ci ee 2° ;
| 16 816 11°6 4°]
862 4°3 | 44 865 | 16:2 4-1
oe ae] ee) PT 98) oe ee
2 ; A
17 1230 11°8 a2
1250 | cs) | sc I) Geo) wo | SD] 18-2) 081 | a9 || 1268! is eee
1300 82 1320 13°3 3°0
1360 3°0 30 | 13880 | 13°3 2°8
1400
1443 |... oe a0 oct 2-7 | |
14760) ese hs tec as ae 27 |
1500 ee Foe con cco cee Su 2-9
ie fy
2°4 | |
| s7 | 2435 | 186 | 2:5
CHAP. vit.] DEEP-SEA TEMPERATURES. 393
APPENDIX. 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.
STATION 42. STATION 23. StTaTIOn 87.
Lat. 49° 12". Lat. 56° 13°. Lat. 59° 35’.
Depth. ————— 2 SSE = = = ; ==
sar aa Difference. cy as Difference. | pe Difference.
Fathous. |
Surface.) 17° 0C. 14°01: hee ee
7 AC ALAC. eo VO
LOO) i LOG 9:1 8:5
O°: 4 Or Ones
200 iope 8° 9 Si?
Ose 5: 0°2 2
300 ONT rocky |
OIG O°] | 0:3
409 yal 8°6 Toa
10 10 OD
500 Siow 4,8 isis
0°6 ory 2
600 eee) 6°9 Gx
leo
790 ay O83 0:9
767 Dio,
as
354
THE DEPTHS OF THE SEA.
APPENDIX D.
[CHAP. VII.
Temperature of the Sea at different Depths in the Warm and
Cold Areas lying between the North of Scotland, the Shetland
Islands, and the Féroe Islands ; as ascertained by Serial and
by Bottom Soundings.
N.B.—The Roman numerals indicate the ‘Lightning’ Temperature Soundings,
corrected for pressure.
| WarRM ARHA, CoLp AREA,
(aa ee ee ee eee 3
|
| | |
ieee Sta- | Surface Bottom pee Ser. 52. Sta- Surface) Bottom
ji tion. | Depth.)|Tempe- Tempe- ia e tion: Depth. pa AIDE
empe- v | rature. rature, | empe- | Tempe- | No. rature.| rature,
Depth. ature, phi ue | Depth. ratace. | fataie,
Deg. | Deg. Deg Deg. Deg. | Deg. Deg
Fms. | Cent Fms. | Cent. | Cent. || Fms Cent. Cent Fms. | Cent Cent
11-4 | | 0 os |r
50 3-9 73 84 TU bess [p= 48583 50 eo) 9-1 70 66 | 11:9 ts
80 | 92 | 11:8] 9-6 || 69 | 67 | 119| 6%
100 8°5 100 7:2 8:5 68 75 114 6°6
71 103 116 9-2 || 61 114 10°Z te
81 142 11°8 9°5 | 62 125 9°7 7:0
150 8:3 84 | 155 123 9-5 || 150 6:2 8-0 60 | 167 9°77 6°8
85 190 12 9-2 IX. | 170 ileal 5:0
200 8:2 200 4:2 iGo
74 203 11°4 8:7
250 1159, oy
300 8-1 , 300 0-2 —0°7
63 | 317 9-4 | —1:0
65 345 1-1.) =162
76 344 UP |) 1183
50 3855 11°4 7:9 350 | —0°3 54 363 11-4 | —0:3
46 | 374 IARI (OF 384 —0°8
400 Ras | 400 = | 86 | 445 12:0 | —1-1
89 445 IALe7/ 7:5 || 450 —0°8
90 458 U9 to 56 480 11:4) —0:7
49 475 12:0 C4 || 53 490 NIE) |= Li
500 72 500 -1:1 X. 500 KOs yan ee Oy
XII. | 530 11°4 hall 58 540 10:8 | —0°7
47 542 ZZ 6°5 || VIII. | 550 Gaps
ROVER OO 19 Gl 6°3 550 | 11 77 560 10°5 | —1°3
59 580 11:5 || =1:3
600 | 61 600 SH |
XVIE,| 620 111 6:3 || 55 | 605 | 11-4 | —1°3
XIV.) 650 11°6 5°8 57 632 11°1 | —0:8
| 640 —1°4
700 |
88 705 11°9 5:9 ||
767 | 52 |
} |
CHAP, Vu. | DEEP-SEA TEMPERATURES. 300
APPENDIX E.
Intermediate Bottom Temperatures, showing the Intermiature of
Warm and Cold Currents on the Borders of the Warm and
Cold Areas,
] 1 !
| | | | |
P | Surface Bottom P Surface | Bottom |
| puation. Depth. | Tempera- | Tempera- Station: | Depth. | Tempera- | Tempera-
: | ture. GUT Suk rua ture.» | ture!
| | : E E
Deg. Deg. "Dea Deg.
| Fathoms. | Cent. Cent. Fathoms. | Cent Cent.
72 76 11°3 9°3 75 250° | 108 | 55
79 76 Ie, 9°3 ee We PNY) IS | 5°3
73 84 TCS al G:3RR >| Sone eek sete iammiol
| | |
eee lO 11°6 9:2 83 362 11°8 3°0
|
+ 74 203 11°4 87 ||
66 267 114 Won. ||" 15 440 10°9 B°6
| |
CHA PPE, ELE.
THE GULF-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. Carpeuter.—
()pinion 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.
AL the temperature investigations carried on in
H.M.SS. ‘ 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 Féroe
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-STREAM. 357
the eastern Border of the North Atlantic fringing
Western Europe. A small but very interesting por-
tion of it forms the channel between the Féroe
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 iieiaaee
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, liowever, 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
398 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
Pacifie :'—
TEMPERATURES OF THE ATLANTIC.
Temperature. | |
: Depth |
Latitude. Longitude. in ; Observer and Date. |
| Faths. | surface. | Bottom. |
42° o'N. | 34°40’ W.| 780 | 16°7°C.| 6°6°C.| Chevalier . 1837
29 0 3450 | 1400 | 24-4 6'1 ‘ . 1837
7 21 20 40 | 505 | 26°6 2°2 Lenz . . 1832
4 25 26 6 | 1006 | 27°0 3°2 Tessan « SE
15 358. 23 14 | 1200 | 25:0 4°1 “ - 1841 ~|
25 10 7 59 EK. 886 | 19°6 3°0 = . 1841
29 323 10 57 1051 | 1971 2°0 ~ . 1841
32 20 4350 | 1074 | 21°6 2°4 Lenz . . 1832
38 12 54 80 W. | 333 | 168 30 | Tessan - 184i |
TEMPERATURES OF THE PACIFIC.
| |
Temperature.
Depth |
Latitude. | Longitude. in | Observer and Date. |
aoe Surface. Bottom.
FiOS Niele 4 Bay 957) | ts8e'Ce |) -95°'Cal essan: , tz |
98 52 Nicer o 600 | 25°5 50 Beechey . . 1828
18 5 | 174 10 ANO | QAe7 4°8 =p «~ ) 836
4 32 134 24W.! 2045 | 97°2 iE, The ‘ Bonite’ 1837
Fquator. | 179 34 1000 | 30°0 2°5 Kotzebue . 1824
21 148. | 196 1 916 | 272 |-. 2e Lenz . - 1834
3 ST | 176 42 E. 782 | 16°4 54 “ > LBS
1066 13°0 ee Tessan . 1841
43 47 | 80 6W.
|
1 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. 359
To these may be added the observations of Lieu-
tenant 8. P. Lee, of the United States Coast Survey,
who, in August 1847, recorded a temperature of
2°°7 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°4C., 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°9 C. 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 1°6 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
? 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. VI11.
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 tie 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 light 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 accumulation of the almost infinite number
1 Fragments de Géol. et de Climatol. Asiat., 1831.
Geological Society of London, 1571,
ee
CHAP. VIII. ] THE GULF-STREAM. 361
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
862 THE DEPTHS OF THE SEA. [CHAP, VIIL.
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. C:, while, that of Dublin, lat. 53°21" N.,
is 9°6C.; and the temperature of Boston (Mass.),
Jat. 42° 21’ N., is exactly the same as that of
Dublin.
564 THE DEPTHS OF THE SEA. [cHAP. VI,
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 infer-
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.
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
eround; but 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. VI.
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 fillmg 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. 403
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 intertropteal
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.
Di DZ
404 THE DEPTHS OF THE SEA. [CHAP. VILL
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 Queen’s College, Belfast, at the close of
the Summer Session 1870, by Professor Wyville Thomson. (ature,
July 28th, 1870.)
CHAP. 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. As a 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 eall the Gulf-stream, the reflux of the
ereat 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.—‘ Coccoliths,’ 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.—Rhizo-
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.
THe 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
ereat 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
invertebrate 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
Universitat 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-
sehleim,’ 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 homopencous 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-like structures which
most of them secrete, and the poe groups may be
taken together.
The dredging at 2,435 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 ewt. of calcareous 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. IX.
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
eradually 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 caleareous mud, structureless and
in a fine state of division, is in greatly preponderat-
ing 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 —
elobigerina—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. 1X] THE DEEP-SEA FAUNA. en
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 im 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
AT THE DEPTHS OF THE SEA. (CHAP. 1X.
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
trangen.” (x. 700.) 1
‘ Biologische Studien. Von Dr. Ernst Haeckel, Professor an der
Universitat Jena. Leipzig, 1870.
CHAP. 1x.] 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
* Quarterly Journal of Microscopical Science, 1868, p. 203.
2 Proceedings of the Sheffield Literary and Philosophical Society,
October 1860. 3" Op. eit.
4 Ann. and Mag. Nat. Hist. 1871, p. 184.
5 Jahrbuch Miinch. 1870, p. 753.
A414 THE DEPTHS OF THE SEA. [CHAP, 1X.
bodies seem to have been taken in to the JMyxro-
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-
sareous Shields or spines falling gradually through
Fia. 64.—‘ Coecosphere.’ (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
eroups. ‘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
eristellarians, with their sand-grains bound 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.
In the cold area, and in the paths of cold currents,
foraminifera with sandy tests are more numerous;
some of those of the genera