BERKElerN
LIBRARY
UNIVERSITY OF
CALIFORNIA
EAKTH
SCIENCES
LIBRARY
J
THE
GLACIERS OF THE ALPS,
BEING
A NARRATIVE OF EXCURSIONS AND ASCENTS,
AN ACCOUNT OF THE OKIGIN AND PHENOMENA OF GLACIERS,
AND
AN EXPOSITION OF THE PHYSICAL PRINCIPLES
TO WHICH THEY ARE RELATED.
BY JOHN TYNDALL, F.B.S.
WITH ILLUSTRATIONS.
NEW EDITION.
LONGMANS, GREEN, AND CO.
LONDON, NEW YORK, AND BOMBAY.
1896.
All rights reserved
EARTH
SCIENCES
LIBRARY
TO
MICHAEL FAKADAY,
THIS BOOK
IS AFFECTIONATELY INSCRIBED.
1860.
MS601QO
PEE FACE.
IN the following work I have not attempted to mix
Narrative and Science, believing that the mind once
interested in the one, cannot with satisfaction pass abruptly
to the other. The book is therefore divided into Two
Parts : the first chiefly narrative, and the second chiefly
scientific.
In Part I. I have sought to convey some notion of the
life of an Alpine explorer, and of the means by which his
knowledge is acquired. In Part II. an attempt is made
to classify su^h knowledge, and to refer the observed
phenomena to their physical causes.
The Second Part of the work is written with a desire to
interest intelligent persons who may not possess any spe-
cial scientific culture. For their sakes I have dwelt more
fully on principles than I should have done in presence of a
purely scientific audience. The brief sketch of the nature
of Light and Heat, with which Part II. is commenced, will
not, I trust, prove uninteresting to the reader for whom it
is more especially designed.
Should any obscurity exist as to the meaning of the
viii PREFACE.
terms Structure, Dirt-bands, Regelation, Interference, and
others, which occur in Part I., it will entirely disappear
in the perusal of Part II.
Two ascents of Mont Blanc and two of Monte Rosa are
recorded ; but the aspects of nature, and other circum-
stances which attracted my attention, were so different
in the respective cases, that repetition was scarcely
possible.
The numerous interesting articles on glaciers which
have been published during the last eighteen months, and
the various lively discussions to which the subject has
given birth, have induced me to make myself better
acquainted than I had previously been with the historic
aspect of the question. In some important cases I
have stated, with the utmost possible brevity, the results
of my reading, and thus, I trust, contributed to the forma-
tion of a just estimate of men whose labours in this
field were long anterior to my own.
J. T.
Royal Institution, June, 1860.
PREFATORY NOTE.
"GLACIERS of the Alps" was published nearly six and thirty
years ago, and has been long out of print, its teaching in a
condensed form having been embodied in the little book
called " Forms of Water.'* The two books are, however,
distinct in character ; each appears to me to supplement
the other ; and as the older work is still frequently asked
for, I have, at the suggestion of my husband's Publishers,
consented to the present reprint, which may be followed
later on by a reprint of " Hours of Exercise."
Before reproducing a book written so long ago, I
sought to assure myself that it contained nothing touching
the views of others which my husband might have wished
at the present time to alter or omit. With this object I
asked Lord Kelvin to be good enough to read over for
me the pages which deal with the history of the subject
and with discussions in which he himself took an active
part. In kind response he writes : — ' . . . After carefully
going through all the passages relating to those old differ-
ences I could not advise the omission of any of them from
the reprint. There were, no doubt, some keen differences
of opinion and judgement among us, and other friends
now gone from us, but I think the statements on contro-
x PEEFATOKY NOTE.
versial points in this beautiful and interesting book of your
husband's are all thoroughly courteous and considerate of
feelings, and have been felt to be so by those whose views
were contested or criticised in them."
The current spelling of Swiss names has changed con-
siderably since " Glaciers of the Alps " was written, but,
except in the very few cases where an obvious oversight
called for correction, the text has been left unaltered.
Only the Index has been made somewhat fuller than it was.
L. C. T.
January, 1896.
CONTENTS.
PART I.
, 1 .—INTRODUCTORY.
Visit to Penrhyn ; the Cleavage of Slate Rocks; Sedgwick's theory— its
difficulties ; Sharpe's observations ; Sorby's experiments ; Lecture at
the Eoyal Institution ; Glacier Lamination ; arrangement of an expe-
dition to Switzerland Page 1
2.— EXPEDITION OF 1856 : THE OBERLAND.
Valley of Lauterbrunnen ; Pliability of rocks ; the Wengern Alp ; the
Jungfrau and Silberhorn ; Ice avalanches ; Glaciers formed from them ;
Scene from the Little Scheideck ; the Lower Grind elwald Glacier ;
the Heisse Platte— its Avalanches ; Ice Minarets and Blocks ; Echoes
of the Wetterhorn ; analogy with the Reflection of Light from angular
mirrors ; the Reichenbach Cascade ; Handeck Fall ; the Grimsel ; the
Unteraar Glacier ; hut of M. Dollfuss ; Hotel des Neufchatelois ; the
Rhone glacier from the Mayenwand ; expedition up the glacier ;
Coloured Rings round the sun ; crevasses of the n6v& ; extraordinary
meteorological phenomenon ; Spirit of the Brocken . . . 9
3.— THE TYROL.
Kaunserthal and the Gebatsch Alp ; Senner or Cheesemakers ; Gebatsch
Glacier ; a night in a cowshed ; passage to Lantaufer ; a chamois on
the rocks ; my Guide ; the atmospheric snow-line ; passage of the
Stelvio ; Colour of fresh snow ; Bormio ; the pass recrossed by night ;
aspect of the mountains ; Meran to Unserfrau ; passage of the Hock-
jochtoFend; singular hailstorm; wild glacier region; hidden cre-
vasses ; First Paper presented to the Royal Society . . . 23
xii CONTENTS.
4. — EXPEDITION OF 1857 : THE LAKE OF GENEVA.
Blueness of the water ; the head of the Lake ; appearance of the Rhone ;
subsidence of particles ; Mirage Page 33
5. — CHAMOUNI AND THE MONTANVERT.
Arrival ; Coloured Shadows on the snow ; Source of the Arveiron ; fall of
the Vault ; " Sunrise in the Valley of Chamouni ; " Scratched Rocks ;
quarters at the Montanvert . • . . . . . 37
6.— THE MER DE GLACE.
Not a Sea but a River of ice ; Wave-forms on its surface ; their explanation ;
Structure and Strata ; Glacier Tables ; first view of the Dirt Bands ;
influence of Illumination in rendering them visible ; the Eye in-
capable of detecting differences between intense lights . . 42
7.
Measurements commenced ; the " Cleft Station " at Trelaporte ; Regelation
of snow granules ; two chamois ; view of the Mer de Glace and its Tri-
butaries ; Seracs of the Col du Geant ; Sliding and Viscous theories ;
Rending of the ice ; Striae on its surface ; White Ice-seams . 4G
Alone upon the glacier ; Lakes and Rivulets ; parallel between Glacier
and Geological disturbance ; splendid rainbow ; aspect of the glacier
at the base of the Seracs ; visit to the Chief Guide at Chamouni ;
Liberties granted . .... . ; . . . . .57
9. — THE JARDIN.
Glacier du Talef re ; Jardin divides the n6ve ; Blue Veins near the summit ;
surrounding scene ; Moraines and Avalanches ; Cascade du Talefre ;
dangers on approaching it from above 61
10.
Lightning and Rain ; Spherical hailstones ; an evening among the cre-
vasses ; Dangerous Leap ; ice-practice ; preparations for an ascent of
Mont Blanc .... 64
CONTENTS. xiii
11. — FIRST ASCENT OF MONT BLANC (1857).
Across the mountain to the Glacier des Bossons; its crevasses ; Ladder left
behind ; consequent difficulties ; the Grands Mulets ; Twinkling and
change of Colour of the Stars ; moonlight on the mountains ; start
with one guide ; difficulties among the crevasses ; the Petit Plateau ;
Seracs of the Dome du Gouter ; bad condition of snow ; the Grand
Plateau ; Coloured Spectra round the sun ; the lost Guides ; the Route
missed ; dangerous ice-slope ; Guide exhausted ; cutting steps ; cheer-
less prospect ; the Corridor ; the Mur de la Cote ; the Petits Mulets ;
food and drink disappear ; Physiological experiences on the Calotte ;
Summit attained ; the Clouds and Mountains ; experiment on Sound ;
colour of the snow ; the descent ; a solitary prisoner ; second night at
the Grands Mulets ; Inflammation of eyes ; a blind man among the
crevasses ; descent to Chamouni ; thunder on Mont Blanc Page 68
12.
Life at the Montanvert ; glacier " Blower ; " Cascade of the Talefre ;
difficulties in setting out lines ; departure from the Montanvert ; my
hosts ; prospect from the Glacier des Bois ; Edouard Simond . 86
13. — EXPEDITION OF 1858.
Origin and aim of the expedition ; Laminated Structure of the ice 92
14. — PASSAGE OF THE STRAHLECK.
Unpromising weather ; appearance of the glacier and of the adjacent
mountains ; Transverse Protuberances ; Dirt Bands ; Structure ; a Slip
on a snow slope ; the Finsteraarhorn ; the Schreckhorn ; extraordinary
Atmospheric Effects ; Summit of the Strahleck ; Grand Amphitheatre ;
mutations of the clouds ; descent of the rocks ; a Bergschrund ; fog in
the valley ; descent to the Grimsel 93
15.
Ancient Glaciers in the valley of Hasli ; Bounded, Polished, and Striated
Rocks ; level of the ancient ice ; Groovings on the Grimsel Pass ; glacier
of the Rhone ; descent of the Rhone valley ; the ^Eggischhorn ;
Cloud Iridescences ; the Aletsch glacier ; the Marjelen See ; Icebergs ;
Tributaries of the Aletsch ; Grand glacier-region ; crevasses; a chamois
deceived , 99
XIV CONTENTS.
16. — ASCENT OF THE FINSTERAARHORN.
Character of my Guide ; iridescent cloud ; evening on the Faulberg ; the
Jungf rau and her neighbours ; a Mountain Cave ; the Jungf rau before
dawn ; contemplated visit ; the Griinhorn Liicke ; Magnificent Cor-
ridor ; sunrise ; nev6 of the Viesch glacier ; halt at the base of the
Finsteraarhorn ; Spurs and Couloirs of the mountain; Pyramidal
Crest ; scene of Agassiz's observations ; a hard climb ; discipline of
such an ascent ; Boiling Point ; Registering Thermometer, its fate ;
daring utterance ; descent by glissades ; the Viesch glacier ; hidden
crevasses ; a brave and competent guide .... Page 104
17.
Subsequent days at the /Eggischhorn ; Afloat on the Icebergs ; Bedding
and Structure ; Ancient Moraines of the Aletsch ; Scratched Rocks ;
passage of the mountains to the end of the glacier ; a wild gorge ;
arrival at Zermatt ; the Rift'elberg 119
18. — FIRST ASCENT OF MONTE ROSA.
The ascent new to myself and my guide ; directions; Ulrich Lauener ;
Ominous Clouds ; passage of the Gorner Glacier ; Roches Moutonnees ;
Avalanche from the Twins ; gradual advance of clouds ; bridged
chasms ; Scene from a cliff; apparent atmospheric struggle ; Sound of
the snow ; Dangerous Edge ; Overhanging Cornice ; staff driven
through it ; increased obscurity ; Rocky Crest ; loss of pocket-book ;
Summit attained ; Boiling Point ; fall of snow ; exquisite forms of the
Snow Crystals ; a shower of frozen blossoms ; the descent ; mode of
attachment ; Startling Avalanche ; Blue Light emitted from the fissures
of the fresh snow ; Stifling Heat ; return to the Riffel . . 122
19.
The Rothe Kumm ; pleasant companions ; difficult descent ; temperatures
of rock, air, and grass ; Singular Cavern in the ice ; Structure and
Stratification 133
20.— THE GORNER GRAT AND THE RIFFELHORN ; MAGNETIC
PHENOMENA.
Formation and Dissipation of clouds ; Scene from the Gorner Grat ; Mag-
netism of the Rocks ; the Compass and Sun at variance ; ascent of the
Riffelhorn ; Magnetic effects ; places of most intense action ; Scratched
CONTENTS. XV
and Polished Kocks ; Exfoliation of crust produced by the sliding of
ancient glaciers ; Magnetic Polarity ; Consequent Points ; Bearings
from the Biffelhorn ; action on a Distant Needle . . Page 137
21.
Fog on the Biffelberg ; its dissipation ; Sunset from the Gorner Grat ;
Cloud-wreaths on the Matterhorn ; Streamers of Flame ; grand Inter-
ference Phenomenon ; investigation of Structure ; the Gornerhorn
glacier ; Western glacier of Monte Eosa ; the Schwarze, Trifti, and
Theodule glaciers ; welding of the Tributaries to parallel Strips ;
Temptation 145
22. — SECOND ASCENT OF MONTE ROSA (1858).
A Light Scrip ; my Guide lent ; a substitute ; a party on the mountain ;
across the glacier and up the rocks ; the guide expostulates ; among
the crevasses ; the guide halts ; left alone ; beauty of the mountain ;
splendid effects of Diffraction ; Cheer from the summit ; on the
Kamm; climbers meet; among the rocks; Alone on the Summit;
the Axe slips ; the prospect ; the descent ; serious accident ; a word on
climbing alone 151
23.
The Furgge glacier ; thunder and lightning ; the Weissthor given up ;
excursion by Stalden to Saas ; Herr Imseng ; the Mattmark See and
Hotel ; ascent of a boulder ; Snow-storm ; cold quarters ; the Monte
Moro ; the Allalein glacier ; a noble vault ; Structure and Dirt-bands ;
stormy weather ; Avalanches at Saas ; the Fee glacier ; Frozen dust
on the Mischabelhorner ; Snow, Vapour, and Cloud; curious effect on
the hearing ; " a Terrible Hole ; " singular group ; a Song from ' The
Bobbers ' . 160
24.
Need of observations on Alpine Temperature ; Balmat's intention ; aid
from the Boyal Society; Difficulties at Chamouni in 1858; the In-
tendant memorialised ; his response ; the Seracs revisited ; Crevasses
and Crumples ; bad weather ; thermometers placed at the Jardin ;
Avalanches of the Talefre ; wondrous sky .... 168
xvi CONTENTS.
25.— SECOND ASCENT OF MONT BLANC (1858).
Shadows of the Aiguilles ; Silver Trees at sunrise ; M. Necker's letter ;
Birds as Sparks and Stars against the sky ; crevasse bridged ; ladder
rejected ; a hunt for a pont ; crevasses crossed ; Magnificent Sunset ;
illuminated clouds ; Storm on the Grands Mulcts ; a Comet discovered ;
start by starlight ; the Petit Plateau a reservoir for avalanches ; Bal-
mat'a warning ; the Grand Plateau at dawn ; blue of the ice ; Balmat
in danger ; Clouds upon the Calotte ; the Summit ; wind and snow-
dust ; Balmat frostbitten ; halt on the Calotte ; descent to Chamouni ;
good conduct of porters „ Page 177
26.
Hostility of Chief Guide ; Proces Verbal ; the British Association ; appli-
cation to the Sardinian authorities ; President's Letter ; Koyal Society;
Testimonial to Balmat . 192
27. — WINTER EXPEDITION TO THE MER DE GLACE, 1859.
First defeat and fresh attempt ; Geneva to Chamouni ; deep snow ; Deso-
lation ; slow progress ; a horse in the snow ; a struggle ; Chamouni on
Christmas night ; mountains hidden ; Climb to the Montanvert ; Snow
on the Pines ; debris of avalanches ; Breaking of snow ; Atmospheric
Changes; the mountains concealed and revealed ; colour of the snow ;
the Montanvert in Winter ; footprints in the snow ; wonderful frost
figures ; Crystal Curtain ; the Mer de Glace in Winter ; the first night ;
" arose of dawn; " Crimson Banners of the Aiguilles ; the stakes fixed;
a Hurricane on the glacier ; the second night ; Wild Snow-storm ; a
man in a crevasse ; calm ; Magnificent Snow Crystals ; Sound through
the falling snow; swift descent ; Source of the Arveiron ; Crystal Cave ;
appearance of water ; westward from the vault ; Majestic Scene; Fare-
well . 195
CONTENTS. xvii
PART II.
1. — LIGHT AND HEAT.
What is Light ? — notion of the ancients ; requires Time to pass through
Space ; Komer, Bradley, Fizeau ; Emission Theory supported by New-
ton, opposed by Huyghens ; the Wave Theory established by Young
and Fresnel ; Theory explained ; nature of Sound ; of Music ; of Pitch ;
nature of Light ; of Colour ; two sounds may produce silence ; two rays
of light may produce darkness ; two rays of heat may produce cold ;
Length and Number of waves of light ; Liquid Waves ; Interference ;
Diffraction ; Colours of Thin Plates ; applications of the foregoing to
cloud iridescences, luminous trees, twinkling of stars, the Spirit of the
Brocken, &c Page 223
2. — RADIANT HEAT.
The Sun emits a multitude of Non -luminous Eays ; Kays of Heat differ
from rays of Light as one colour differs from another ; the same ray
may produce the sensations of light and heat . . . .39
3. — QUALITIES OF HEAT.
Heat a kind of Motion; system of exchanges ; Luminous and Obscure Heat;
Absorption by Gases ; gases may be transparent to light, but opaque
to heat ; Heat selected from luminous sources ; the Atmosphere acts
the part of a Eatchet-wheel ; possible heat of a Distant Planet ; causes
of Cold in the upper strata of the Earth's Atmosphere . . 241
4. — ORIGIN OF GLACIERS.
Application of principles ; the Snow-line ; its meaning ; waters piled annu-
ally in a solid form on the summits of the hills ; the Glaciers furnish
the chief means of escape ; superior and inferior snow-line . 248
o.
.Whiteness of snow ; whiteness of ice ; Bound air-bubbles ; melting and
freezing ; Conversion of snow into ice by Pressure . . . 249
a
xviii CONTENTS.
6. — COLOUR OF WATER AND ICE.
Waves of Ether not entangled ; they are separated in the prism ; they are
differently absorbed ; Colour due to this ; Water and Ice blue ; water
and ice opaque to radiant heat ; Long Waves shivered on the mole-
cules ; Experiment ; Grotto of Capri ; theLaugs of Iceland Page 253
7. — COLOURS OF THE SKY.
Newton's idea ; Goethe's Theory ; Clausius and Briicke ; Suspended
Particles ; singular effect on a painting explained by Goethe ; Light
separated without Absorption ; Keflected and Transmitted light ;
blueness of milk and juices; the Sun through London smoke;
Experiments; Blue of the Eye; Colours of Steam; the Lake of
Geneva . 257
8. — THE MORAINES.
Glacier loaded along its edges by the ruins of the mountains ; Lateral
Moraines ; Medial Moraines ; their number one less than the number
of Tributaries ; Moraines of the Mer de Glace ; successive shrinkings ;
Glacier Tables explained ; ' Dip ' of stones upon the glacier enables
us to draw the Meridian Line ; type ' Table ; ' Sand Cones ; moraines
engulfed and disgorged ; transparency of ice under the moraines 263
9 . — GLACIER MOTION, — PRELIMINARY.
Neve and Glacier; First Measurements; HugiandAgassiz; Escher's defeat
on the Aletsch ; Piles fixed across the Aar glacier by Agassiz in 1841 ;
Professor Forbes invited by M. Agassiz ; Forbes's first observations on
the Mer de Glace in 1842 ; motion of Agassiz 's piles measured by M.
Wild ; Centre of the glacier moves quickest ; State of the Question 2G9
10.— MOTION OF THE MER DE GLACE.
The Theodolite ; mode of measurement ; first line ; Centre Point not the
quickest ; second line : former result confirmed ; Law of Motion sought ;
the glacier moves through a Sinuous Valley ; effect of Flexure; Western
half of glacier moves quickest ; Point of Maximum Motion crosses axis ;
CONTENTS. xix
Eastern half moves quickest; Locus of Point of Maximum Motion ; New
Law ; Motion of the Geant ; motion of the Lechaud ; Squeezing of the
Tributaries through the Neck of the valley at Trelaporte ; the Lechaud
a Driblet . ... Page 275
11. — ICE WALL AT THE TACUL, — VELOCITIES OF TOP
AND BOTTOM.
First attempt by Mr. Hirst; second attempt, stakes fixed at Top, Bottom,
and Centre ; dense fog ; the stakes lost ; process repeated ; Velocities
determined .... , 289
12. — WINTER MOTION OF THE MER DE GLACE.
First line, Above the Montanvert ; second line, Below the Montanvert ;
Eatio of winter to summer motion 294
13. — CAUSE OF GLACIER MOTION, — DE SAUSS ORE'S
THEORY.
First attempt at a Theory by Scheuchzer in 1705 ; Charpentier's theory, or
the Theory of Dilatation ; Agassiz's theory ; Altmann and Griiner ;
theory of De Saussure, or the Sliding Theory ; in part true ; strained
interpretation of this theory 296
14. — RENDU'S THEORY.
Character of Kendu; his Essay entitled ' Theorie des Glaciers de la
Savoie; ' extracts from the essay; he ascribes "circulation" to natural
forces; classifies glaciers; assigns the cause of the conversion of
snow into ice; notices Veined Structure; "time and affinity;"
notices Kegelation ; diminution of glaciers reservoirs ; Kemarkable
Passage ; announces Swifter Motion of Centre ; North British Keview ;
Discrepancies explained by Eendu ; Liquid Motion ascribed to glacier ;
all the phenomena of a Eiver reproduced upon the Mer de Glace ; Eatio
of Side and Central velocities ; Errors removed . . . 299
15.
Anticipations of Eendu confirmed by Agassiz and Forbes; analogies
with Liquid Motion established by Forbes ; his Measurements in 1842 ;
measurements in 1844 and 1846 ; Measurements of Agassiz and Wild
XX CONTENTS.
in 1842, 1843, 1844, and 1845 ; Agassiz notices the " migration " of the
Point of Swiftest Motion ; true meaning of this observation ; Summary
of contributions on this part of the question . . . Page 308
16. — FORBES'S THEORY.
Discussions as to its meaning ; Facts and Principles ; definition of theory ;
Some Experiments on the Mer de Glace to test the Viscosity of the
Ice .311
17. — THE CREVASSES.
Caused by the Motion ; Ice Sculpture ; Fantastic Figures ; beauty of the
crevasses of the highest glaciers ; Birth of a crevasse ; Mechanical
Origin ; line of greatest strain ; Marginal Crevasses ; Transverse Cre-
rasses ; Longitudinal Crevasses ; Bergschrunds ; Influence of Flexure ;
why the Convex Sides of glaciers are most crevassed . . 315
18.
Further considerations on Viscosity ; Numerical Test ; formation of cre-
vasses opposed to viscosity 325
19. — HEAT AND WORK.
Connexion of Natural Forces ; Equivalence of Heat and Work ; heat
produced by Mechanical Action ; heat consumed in producing work ;
Chemical Attractions ; Attraction of Gravitation ; amount of heat
which would be produced by the stoppage of the Earth in its Orbit ;
amount produced by the falling of the Earth into the Sun ; shifting of
Atoms ; heat consumed in Molecular Work ; Specific Heat ; Latent
Heat; 'friability' of ice near its melting point; Kotten Ice and
softened Wax . .... . . . . . 328
20.
Papers presented to the Koyal Society by Prof essor Forbes in 1846 ; Capil-
lary Hypothesis of glacier motion ; hypothesis examined . . 334
21. — THOMSON'S THEORY.
Statement of theory; influence of Pressure on the Melting Point of
Ice ; difficulties of theory ; Calculation of requisite Pressure ; Actual
pressure insufficient 340
CONTENTS. xxi
22. — PRESSURE THEORY.
Pressure and Tension ; possible experiments ; Ice may be moulded into
Vases and Statuettes or coiled into Knots ; this no proof of Viscosity ;
Actual Experiments ; a sphere of ice moulded to a lens ; a lens moulded
to a cylinder ; a lump of ice moulded to a cup ; straight bars of ice
bent ; ice thus moulded incapable of being sensibly stretched ; when
Tension is substituted for Pressure, analogy with viscous body breaks
down . . . . ..... . . Page 346
23. — REGELATION.
Faraday's first experiments ; Freezing together of pieces of ice at 32° ;
Freezing in Hot Water ; Faraday's recent experiments ; Kegelation not
due to Pressure nor to Capillary Attraction ; it takes place in vacuo ;
fracture and regelation ; no viscidity discovered . . .351
24. — CRYSTALLIZATION AND INTERNAL LIQUEFACTION.
How crystals are 'nursed;' Snow-Crystals; Crystal Stars formed in
Water ; Arrangement of Atoms of Lake Ice ; dissection of ice by a
sunbeam ; Liquid Flowers formed in ice ; associated Vacuous Spots ;
curious sounds ; their explanation ; Cohesion of water when free from
air ; liquid snaps like a broken spring ; Ebullition converted into
Explosion ; noise of crepitation ; Water-cells in glacier ice ; Vacuous
Spots mistaken for Bubbles ; not Flattened by Pressure ; experiments ;
Cause of Kegelation 353
25. — THE MOULINS.
Their character ; Depth of Moulin on Grindelwald Glacier ; Explanation
the Grand Moulin of the Mer de Glace ; Motion of moulins . 362
26. — DIRT-BANDS OF THE MER DE GLACE.
Their discovery by Professor Forbes ; view of Bands from a point near the
F16gere ; Bands as seen from Les Charmoz ; Skew Surface of glacier ;
aspect of Bands from the Cleft Station ; Origin of bands ; tendency to
become straight ; differences between Observers . . • 367
27. — VEINED STRUCTURE OF GLACIERS.
General appearance ; Grooves upon the glacier ; first observations ; de-
scription by M. Guyot ; observations of Professor Forbes ; Structure
xxii CONTENTS.
and Stratification ; subject examined ; Marginal Structure ; Transverse
Structure ; Longitudinal Structure ; experimental illustrations ; the
Structure Complementary to the Crevasses ; glaciers of the Oberland,
Valais, and Savoy examined with reference to this question Page 376
28. — THE VEINED STRUCTURE AND DIFFERENTIAL MOTION.
Marginal Structure Oblique to sides ; Drag towards the centre ; diffi-
culties of theory which ascribes the structure to Differential Sliding ;
it persists across the lines of maximum sliding . . . 395
29. — THE RIPPLE THEORY OF THE VEINED STRUCTURE.
Hippies in Water supposed to correspond to Glacier Structure ; analysis
of theory ; observation of the MM. Weber ; water dropping from an
4 oar ; stream cleft by an obstacle ; Two Divergent lines of Eipple ;
Single Line produced by Lateral Obstacle ; Direction of ripples com-
pounded of Eiver's motion and Wave motion ; Structure and Eipples
due to different causes ; their positions also different . . 398
30. — THE VEINED STRUCTURE AND PRESSURE.
Supposed case of pressed prism of glass ; Experiments of Nature ; Quartz-
pebbles flattened and indented ; Pressure would produce Lamination ;
Tangential Action 404
31. — THE VEINED STRUCTURE AND THE LIQUEFACTION OF
ICE BY PRESSURE.
Influence of pressure on Melting and Boiling points ; some substances
swell, others shrink in melting ; effects of pressure different on the two
classes of bodies ; Theoretic Anticipation by Mr. James Thomson ;
Melting point of Ice lowered by pressure ; Internal Liquefaction of a
prism of solid ice by pressure ; Liquefaction in Layers ; appplication to
the Veined Structure 408
32. — WHITE ICE-SEAMS OF THE GLACIER DU GEANT.
Aspect of Seams ; they sweep across the glacier concentric with Struc-
ture ; Structure at the base of the Talefre cascade ; Crumples ; Scaling
off by pressure ; Origin of seams of White Ice . . . 413
CONTENTS. xxiii
33.
Glacier du Geant in a state of Longitudinal Compression ; Measurements
which prove that its hinder parts are advancing upon those in front ;
Shortening of its Undulations ; Squeezing of white Ice-seams ; develop-
ment of Veined Structure Page 419
SUMMARY . . . . . . . .422
APPENDIX 427
INDEX . 441
ILLUSTRATIONS.
The Mer de Glace.— Showing the Cleft Station at Trelaporte, the
Echelets, the Tacul, the Periades, and the Grand Jorasse. Frontispiece
Fig. Page
1. Ice Minaret .... . ... 14
2. Diagram of an angular reflector . 16
4" i Boats' sails inverted by Atmospheric Refraction ... 35
5. Wave-like forms on the Mer de Glace . . . . . . 43
6. Glacier Table . . . . . . .• . . . .44
7. Tributaries of the Mer de Glace ........ 53
8. Magnetic Boulder of the Riffelhorn . . ... . .143
jj' r Luminous Trees projected against the sky at sunrise 180, 181
12j
13. Snow on the Pines . 201
Snow Crystals 214
16. Chasing produced by waves . . . . * . . . . 233
17. Diagram explanatory of Interference 234
18. Interference Spectra, produced by Diffraction . . To face 235
19. Moraines of the. Mer de Glace .... . „ 264
20. Typical section of a glacier Table ... * . . 266
21. Locus of the Point of Maximum Motion 286
22. Inclinations of ice cascade of the Glacier des Bois . . . 313
23. Inclinations of Mer de Glace above 1'Angle ... •• • • 314
24. Fantastic Mass of ice 316
25. Diagram explanatory of the mechanical origin of Crevasses . 318
20. Diagram showing the line of Greatest Strain .... 319
27 A. ] Section and Plan of a portion of the Lower Grindelwald
27B. f Glacier , . 322
XXVI ILLUSTRATIONS.
Fig. Page
28. Diagram illustrating the crevassing of Convex Sides of glacier 323
29. Diagram illustrating test of viscosity 326
30.^
01 f
32' r Moulds used in experiments with ice . . . . 346-348
33.)
34. Liquid Flowers in lake ice . . . . . . . 355
35. Dirt-bands of the Mer de Glace, as seen from a point near the
Flegere . . . ... V . .To face 367
36. Ditto, as seen from les Charmoz . .-.- *, . „ 368
37. Ditto, as seen from the Cleft Station, Trelaporte . . „ 369
38. Plan of Dirt-bands taken from Johnson's ' Physical Atlas ' . 374
39. Veined Structure on the walls of crevasses .... 381
40. Figure explanatory of the Marginal Structure . ... 383
41. Plan of part of icefall, and of glacier below it (Glacier of the
Ehone) . . 386
42. Section of ditto . . . . ... . . . 386
43. Figure explanatory of Longitudinal Structure .... 388
44. Structure and bedding on the Great Aletsch Glacier . . . 391
4g | Structure and Stratification on the Furgge glacier . . 394
47. Diagram illustrating Differential Motion . . . , . . 395
A C\ ~\
4Q I Diagrams explanatory of the formation of Eipples . 400, 403
59" j Appearance of a prism of ice partially liquefied by Pressure . 410
5?" 1 Figures illustrative of compression and liquefaction of ice . 411
oo. J <•
^:' i Sections of White Ice-seams . . . . ' . . . 414
oo. J
5S* } Variations in the Dip of the Veined Structure . . 414, 415
58. Section of three glacier Crumples 416
59. Wall of a crevasse, with incipient crumpling . ... 416
60. Plan of a Stream on the Glacier du Geant . . ... 418
61. Plan of a Seam of White Ice on ditto ... . . 418
PART I.
CHIEFLY NAKKATIVE,
Ages are your days,
Ye grand expressors of the present tense
And types of permanence ;
Firm ensigns of the fatal Being
Amid these coward shapes of joy and grief
That will not bide the seeing.
Hither we bring
Our insect miseries to the rocks,
And the whole flight with pestering wing
Vanish and end their murmuring,
Vanish beside these dedicated blocks.
EMEBSON
GLACIEES OF THE ALPS.
INTRODUCTORY.
(I-)
IN the autumn of 1854 I attended the meeting of the
British Association at Liverpool ; and, alter it was over,
availed myself of my position to make an excursion into
North Wales. Guided by a friend who knew the country,
I became acquainted with its chief beauties, and concluded
the expedition by a visit to Bangor and the neighbouring
slate quarries of Penrhyn.
From my boyhood I had been accustomed to handle
slates ; had seen them used as roofing materials, and had
worked the usual amount of arithmetic upon them at
school ; but now, as I saw the rocks blasted, the broken
masses removed to the sheds surrounding the quarry, and
there cloven into thin plates, a new interest was excited,
and I could not help asking after the cause of this extra-
ordinary property of cleavage. It sufficed to strike the
point of an iron instrument into the edge of a plate of rock
to cause the mass to yield and open, as wood opens in
advance of a wedge driven into it. I walked round the
quarry and observed that the planes of cleavage were
everywhere parallel ; the rock was capable of being split
in one direction only, and this direction remained perfectly
constant throughout the entire quarry.
I was puzzled, and, on expressing my perplexity to my
companion, he suggested that the cleavage was nothing
2 CLEAVAGE OF SLATE ROCKS.
more than the layers in which the rock had been origin-
ally deposited, and which, by some subsequent disturbance,
had been set on end, like the strata of the sandstone rocks
and chalk cliffs of Alum Bay. But though I was too igno-
rant to combat this notion successfully, it by no means
satisfied me. I did not know that at the time of my visit
this very question of slaty cleavage was exciting the
greatest attention among English geologists, and I quitted
the place with that feeling of intellectual discontent which,
however unpleasant it may be for a time, is very useful as
a stimulant, and perhaps as necessary to the true appre-
ciation of knowledge as a healthy appetite is to the enjoy-
ment of food.
On inquiry I found that the subject had been treated
by three English writers, Professor Sedgwick, Mr. Daniel
Sharpe, and Mr. Sorby. From Professor Sedgwick I
learned that cleavage and stratification were things totally
distinct from each other ; that in many cases the strata
could be observed with the cleavage passing through them
at a high angle ; and that this was the case throughout vast
areas in North Wales and Cumberland. I read the lucid
and important memoir of this eminent geologist with great
interest : it placed the data of the problem before me, as
far as they were then known, and I found myself, to some
extent at least, in a condition to appreciate the value of a
theoretic explanation.
Everybody has heard of the force of gravitation, and of
that of cohesion ; but there is a more subtle play of forces
exerted by the molecules of bodies upon each other when
these molecules possess sufficient freedom of action. In
virtue of such forces, the ultimate particles of matter are
enabled to build themselves up into those wondrous edifices
which we call crystals. A diamond is a crystal self-erected
from atoms of carbon ; an amethyst is a crystal built up
from particles of silica ; Iceland spar is a crystal built
CRYSTALLIZATION THEORY. 3
by particles of carbonate of lime. By artificial means we
can allow the particles of bodies the free play necessary to
their crystallization. Thus a solution of saltpetre exposed
to slow evaporation produces crystals of saltpetre ; alum
crystals of great size and beauty may be obtained in a
similar manner ; and in the formation of a bit of common
sugar-candy there are agencies at play, the contemplation
of which, as mere objects of thought, is sufficient to make
the wisest philosopher bow down in wonder, and confess
himself a child.
The particles of certain crystalline bodies are found to
arrange themselves in layers, like courses of atomic ma-
sonry, and along these layers such crystals may be easily
cloven into the thinnest laminae. Some crystals possess
one such direction in which they may be cloven, some
several ; some, on the other hand, may be split with dif-
ferent facility in different directions. Rock salt may be
cloven with equal facility in three directions at right angles
to each other ; that is, it may be split into cubes ; calcspar
may be cloven in three directions oblique to each other ;
that is, into rhomboids. Heavy spar may also be cloven
in three directions, but one cleavage is much more perfect,
or more eminent as it is sometimes called, than the rest.
Mica is a crystal which cleaves very readily in one di-
rection, and it is sufficiently tough to furnish films of ex-
treme tenuity : finally, any boy, with sufficient skill, who
tries a good crystal of sugar-candy in various directions
with the blade of his penknife, will find that it possesses
one direction in particular, along which, if the blade of the
knife be placed and struck, the crystal will split into
plates possessing clean and shining surfaces of cleavage.
Professor Sedgwick was intimately acquainted with all
these facts, and a great many, more, when he investigated
the cleavage of slate rocks ; and seeing no other expla-
nation open to him, he ascribed to slaty cleavage a crystal-
B 2
4 POLAR FOECES.
line origin. He supposed that the particles of slate rock
were acted on, after their deposition, by " polar forces," which
so arranged them as to produce the cleavage. According
to this theory, therefore, Honister Crag and the cliffs of
Penrhyn are to be regarded as portions of enormous
crystals ; a length of time commensurate with the vast-
ness of the supposed action being assumed to have elapsed
between the deposition of the rock and its final crystal-
lization.
When, however, we look closely into this bold and beau-
tiful hypothesis, we find that the only analogy which exists
between the physical structure of slate rocks and of crystals
is this single one of cleavage. Such a coincidence might
fairly give rise to the conjecture that both were due to
a common cause ; but there is great difficulty in accepting
this as a theoretic truth. When we examine the structure
of a slate rock, we find that the substance is composed of
the debris of former rocks ; that it was once a fine mud,
composed of particles of sensible magnitude. Is it meant
that these particles, each taken as a whole, were re-arranged
after deposition ? If so, the force which effected such an
arrangement must be wholly different from that of crystalli-
zation, for the latter is essentially molecular. What is this
force ? Nature, as far as we know, furnishes none com-
petent, under the conditions, to produce the effect. Is it
meant that the molecules composing these sensible particles
have re-arranged themselves ? We find no evidence of
such an action in the individual fragments : the mica is
still mica, and possesses all the properties of mica ; and so
of the other ingredients of which the rock is composed.
Independent of this, that an aggregate of heterogeneous
mineral fragments should, without any assignable external
cause, so shift its molecules %as to produce a plane of
cleavage common to them all, is, in my opinion, an
assumption too heavy for any theory to bear.
MECHANICAL THEOKY. 5
Nevertheless, the paper of Professor Sedgwick invested
the subject of slaty cleavage with an interest not to be
forgotten, and proved the stimulus to further inquiry.
The structure of slate rocks was more closely examined ;
the fossils which they contained were subjected to rigid
scrutiny, and their shapes compared with those of the same
species taken from other rocks. Thus proceeding, the late
Mr. Daniel Sharpe found that the fossils contained in slate
rocks are distorted in shape, being uniformly flattened out
in the direction of the planes of cleavage. Here, then, was
a fact of capital importance, — the shells became the indi-
cators of an action to which the mass containing them had
been subjected ; they demonstrated the operation of pres-
sure acting at right angles to the planes of cleavage.
The more the subject was investigated, the more clearly
were the evidences of pressure made out. Subsequent to
Mr. Sharpe, Mr. Sorby entered upon this field of inquiry.
With great skill and patience he prepared sections of slate
rock, which he submitted to microscopic examination, and
his observations showed that the evidences of pressure could
be plainly traced, even in his minute specimens. The sub-
ject has been since ably followed up by Professors Haughton,
Harkness, and others ; but to the two gentlemen first
mentioned we are, I think, indebted for the prime facts on
which rests the mechanical theory of slaty cleavage.*
The observations just referred to showed the co-existence
of the two phenomena, but they did not prove that pressure
and cleavage stood to each other in the relation of cause
and effect. " Can the pressure produce the cleavage ? "
was still an open question, and it was one which mere rea-
soning, unaided by experiment, was incompetent to answer.
* Mr. Sorby has drawn my attention to an able and interesting paper
by M. Bauer, in Karsten's ' Archiv ' for 1846 ; in which it is announced
that cleavage is a tension of the mass produced by pressure. The author
refers to the experiments of Mr. Hopkins as bearing upon the question.
6 LECTUKE AT THE BOYAL INSTITUTION
Sharpe despaired of an experimental solution, regarding
our means as inadequate, and our time on earth too short
to produce the result. Mr. Sorby was more hopeful. Sub-
mitting mixtures of gypsum and oxide of iron scales to
pressure, he found that the scales set themselves approxi-
mately at right angles to the direction in which the pres-
sure was applied. The position of the scales resembled
that of the plates of mica which his researches had dis-
closed to him in slate rock, and he inferred that the pre-
sence of such plates, and of flat or elongated fragments
generally, lying all in the same general direction, was the
cause of slaty cleavage. At the meeting of the British
Association at Glasgow, in 1855, I had the pleasure of
seeing some of Mr. Sorby 's specimens, and, though the
cleavage they exhibited was very rough, still, the tendency
to yield at right angles to the direction in which the pres-
sure had been applied, appeared sufficiently manifest.
At the time now referred to I was engaged, and had
been for a long time previously, in examining the effects
of pressure upon the magnetic force, and, as far back as
1851, I had noticed that some of the bodies which I had
subjected to pressure exhibited a cleavage of surpassing
beauty and delicacy. The bearing of such facts upon
the present question now forcibly occurred to me. I fol-
lowed up the observations ; visited slate yards and quarries,
observed the exfoliation of rails, the fibres of iron, the struc-
ture of tiles, pottery, and cheese, and had several practical
lessons in the manufacture of puff-paste and other lami-
nated confectionery. My observations, I thought, pointed
to a theory of slaty cleavage different from any previously
given, and which, moreover, referred a great number of
apparently unrelated phenomena to a common cause. On
the 10th of June, 1856, I made them the subject of a
Friday evening's discourse at the Eoyal Institution.*
* See Appendix.
OKIGIN OF KESEAKCHES. 7
Such are the circumstances, apparently remote enough,
under which my connexion with glaciers originated. My
friend Professor Huxley was present at the lecture re-
ferred to : he was well acquainted with the work of Pro-
fessor Forbes, entitled ' Travels in ^ the Alps,' and he
surmised that the question of slaty cleavage, in its new
aspect, might have some bearing upon the laminated struc-
ture of glacier-ice discussed in the work referred to. He
therefore urged me to read the i Travels,' which I did with
care, and the book made the same impression upon me
that it had produced upon my friend. We were both
going to Switzerland that year, and it required but a slight
modification of our plans to arrange a joint excursion over
some of the glaciers of the Oberland, and thus afford our-
selves the means of observing together the veined structure
of the ice.
Had the results of this arrangement been revealed to me
beforehand, I should have paused before entering upon an
investigation which required of me so Jong a renunciation
of my old and more favourite pursuits. But no man knows
when he commences the examination of a physical problem
into what new and complicated mental alliances it may
lead him. No fragment of nature can be studied alone ;
each part is related to every other part ; and hence it is,
that, following up the links of law which connect pheno-
mena, the physical investigator often finds himself led far
beyond the scope of his original intentions, the danger in
this respect augmenting in direct proportion to the wish of
the inquirer to render his knowledge solid and complete.
When the idea of writing this book first occurred to me,
it was not my intention to confine myself to the glaciers
alone, but to make the work a vehicle for the familiar ex-
planation of such general physical phenomena as had come
under my notice. Nor did I intend to address it to a cul-
tured man of science, but to a youth of average intelligence,
8 A BOY'S BOOK.
and furnished with the education which England now offers
to the young. I wished indeed to make it a boy's class-
book, which should reveal the mode of life, as well as the
scientific objects, of an explorer of the Alps. The incidents
of the past year have, caused me to deviate, in some degree,
from this intention, but its traces will be sufficiently mani-
fest; and this reference to it will, I trust, excuse an
occasional liberty of style and simplicity of treatment
which would be out of place if intended for a reader of
riper years.
1856.] THE OBERLAND. 9
EXPEDITION OF 1856.
THE OBERLAND.
(2.)
ON the 16th of August, 1856, I received my Alpenstock
from the hands of Dr. Hooker, in the garden of the Pension
Ober, at Interlaken. It bore my name, not marked, how-
ever, by the vulgar brands of the country, but by the solar
beams which had been converged upon it by the pocket
lens of my friend. I was the companion of Mr. Huxley,
and our first aim was to cross the Wengern Alp. Light
and shadow enriched the crags and green slopes as we
Ivanced up the valley of Lauterbrunnen, and each
occupied himself with that which most interested him.
My companion examined the drift, I the cleavage, while
both of us looked with interest at the contortions of the
strata to our left, and at the shadowy, unsubstantial aspect
of the pines, gleaming through the sunhaze to our right.
What was the physical condition of the rock when it was
thus bent and folded like a pliant mass ? Was it neces-
sarily softer than it is at present ? I do not think so. The
shock which would crush a railway carriage, if communi-
cated to it at once, is harmless when distributed over the
interval necessary for the pushing in of the buffer. By
suddenly stopping a cock from which water flows you may
burst the conveyance pipe, while a slow turning of the cock
keeps all safe. Might not a solid rock by ages of pressure
be folded as above ? It is a physical axiom that no body is
perfectly hard, none perfectly soft, none perfectly elastic.
The hardest body subjected to pressure yields, however
little, and the same body when the pressure is removed
10 FOLDED EOCKS. [1856.
cannot return to its original form. If it did not yield in
the slightest degree it would be perfectly hard ; if it could
completely return to its original shape it would be perfectly
elastic.
Let a pound weight be placed upon a cube of granite ;
the cube is flattened, though in an infinitesimal degree.
Let the weight be removed, the cube remains a little
flattened; it cannot quite return to its primitive condition.
Let us call the cube thus flattened No. 1. Starting with
No. 1 as a new mass, let the pound weight be laid upon it ;
the mass yields, and on removing the weight it cannot
return to the dimensions of No. 1 ; we have a more flat-
tened mass, No. 2. Proceeding in this manner, it is manifest
that by a repetition of the process we should produce a
series of masses, each succeeding one more flattened than
the former. This appears to be a necessary consequence
of the physical axiom referred to above.
Now if, instead of removing and replacing the weight in
the manner supposed, we cause it to rest continuously upon
the cube, the flattening, which above was intermittent, will
be continuous ; no matter how hard the cube may be,
there will be a gradual yielding of its mass under the
pressure. Apply this to squeezed rocks — to those, for
example, which form the base of an obelisk like the
Matterhorn; that this base must yield, seems a certain
consequence of the physical constitution of matter : the
conclusion seems inevitable that the mountain is sinking
by its own weight. Let two points be fixed, one near
the summit, the other near the base of the obelisk ; next
year these points will have approached each other. Whether
the amount of approach in a human lifetime be measure-
able we know not ; but it seems certain that ages would
leave their impress upon the mass, and render visible to
the eye an action which at present is appreciable by the
imagination only.
1856.] THE JUNGFRAU AND SILBERHOKN. 11
We halted on the night of the 16th at the Jungfrau
Hotel, and next morning we saw the beams of the rising
sun fall upon the peaked snow of the Silberhorn. Slowly
and solemnly the pure white cone appeared to rise higher
and higher into the sunlight, being afterwards mottled with
gold and gloom, as clouds drifted between it and the sun.
I descended alone towards the base of the mountain,
making my way through a rugged gorge, the sides of
which were strewn with pine-trees, splintered, broken
across, and torn up by the roots. I finally reached the
end of a glacier, formed by the snow and shattered ice
which fall from the shoulders of the Jungfrau. The view
from this place had a savage magnificence such as I had
not previously beheld, and it was not without some slight
feeling of awe that I clambered up the end of the glacier.
It was the first I had actually stood upon. The lone-
liness of the place was very impressive, the silence being
only broken by fitful gusts of wind, or by the weird rattle
of the debris which fell at intervals from the melting ice.
Once I noticed what appeared to be the sudden and
enormous augmentation of the waters of a cascade, but the
sound soon informed me that the increase was due to an
avalanche which had chosen the track of the cascade for
its rush. Soon afterwards my eyes were fixed upon a white
slope some thousands of feet above me; I saw the ice
give way, and, after a sensible interval, the thunder of
another avalanche reached me. A kind of zigzag chan-
nel had been worn on the side of the mountain, and
through this the avalanche rushed, hidden at intervals, and
anon shooting forth, and leaping like a cataract down the
precipices. The sound was sometimes continuous, but
f sometimes broken into rounded explosions which seemed
to assert a passionate predominance over the general level
of the roar. These avalanches, when they first give way,
usually consist of enormous blocks of ice, which are more
12 AVALANCHES. [1856.
and more shattered as they descend. Partly to the echoes
of the first crash, but mainly, I think, to the shock of the
harder masses which preserve their cohesion, the explosions
which occur during the descent of the avalanche are to
be ascribed. Much of the ice is crushed to powder ; and
thus, when an avalanche pours cataract-like over a ledge,
the heavier masses, being less influenced by the atmo-
spheric resistance, shoot forward like descending rockets,
leaving the lighter powder in trains behind them. Such is
the material of which a class of the smaller glaciers in the
Alps is composed. They are the products of avalanches,
the crushed ice being recompacted into a solid mass, which
exhibits on a smaller scale most of the characteristics of
the large glaciers.
After three hours' absence I reascended to the hotel,
breakfasted, and afterwards returned with Mr. Huxley to
the glacier. While we were engaged upon it the weather
suddenly changed ; lightning flashed about the summits ot
the Jungfrau, and thunder u leaped " among her crags.
Heavy rain fell, but it cleared up afterwards with magical
speed, and we returned to our hotel. Heedless of the
forebodings of many prophets of evil weather we set out for
Grindelwald. The scene from the summit of the Little
Scheideck was exceedingly grand. The upper air ex-
hibited a commotion which we did not experience ; clouds
were wildly driven against the flanks of the Eiger, the
Jungfrau thundered behind, while in front of us a magni-
ficent rainbow, fixing one of its arms in the valley ol
Grindelwald, and, throwing the other right over the crown
of the Wetterhorn, clasped the mountain in its embrace.
Through jagged apertures in the clouds floods of golden
light were poured down the sides of the mountain. On
the slopes were innumerable chalets, glistening in the
sunbeams, herds browsing peacefully and shaking their
mellow bells ; while the blackness of the pine-trees, crowded
556.] THE HEISSE PLATTE. 13
ito woods, or scattered in pleasant clusters over alp and
lley, contrasted forcibly with the lively green of the
ields.
At Grindelwald, on the 18th, we engaged a strong and
competent guide, named Christian Kaufmann, and pro-
ceeded to the Lower Glacier. After a steep ascent, we
gained a point from which we could look down upon the
frozen mass. At first the ice presented an appearance of
utter confusion, but we soon reached a position where the
mechanical conditions of the glacier revealed themselves,
and where we might learn, had we not known it before,
that confusion is merely the unknown intermixture of laws,
and becomes order and beauty when we rise to their com-
prehension. We reached the so-called Eismeer — Ice Sea.
In front of us was the range of the Viescherhorner, and a
vast snow slope, from which one branch of the glacier
was fed. Near the base of this neve, and surrounded on
all sides by ice, lay a brown rock, to which our attention
was directed as a place noted for avalanches ; on this
rock snow or ice never rests, and it is hence called the
ffeisse Platte — the Hot Plate. At the base of the rock,
and far below it, the glacier was covered with clean crushed
ice, which had fallen from a crown of frozen cliffs en-
circling the brow of the rock. One obelisk in particular
signalised itself from all others by its exceeding grace and
beauty. Its general surface was dazzling white, but from
its clefts and fissures issued a delicate blue light, which
deepened in hue from the edges inwards. It stood upon a
pedestal of its own substance, and seemed as accurately
fixed as if rule and plummet had been employed in its
erection. Fig. 1 represents this beautiful minaret of ice.
While we were in sight of the Heisse Platte, a dozen
avalanches rushed downwards from its summit. In most
cases we were informed of the descent of an avalanche by
the sound, but sometimes the white mass was seen gliding
14
ICE MINABET.
[1856.
down the rock, and scattering its smoke in the air, long
before the sound reached us. It is difficult to reconcile the
insignificant appearance presented by avalanches, when seen
from a distance, with the volume of sound which they
Fig. 1.
generate ; but 011 this day we saw sufficient to account for
the noise. One block of solid ice which we found below
the Heisse Platte measured 7 feet 6 inches in length, 5 feet
8 inches in height, and 4 feet 6 inches in depth. A second
mass was 10 feet long, 8 feet high, and 6 feet wide. It
contained therefore 480 cubic feet of ice, which had been
cast to a distance of nearly 1000 yards down the glacier.
The shock of such hard and ponderous projectiles against
rocks and ice, reinforced by the echoes from the surrounding
1856.] ECHOES OF THE WETTERHOEN. 15
-
mountains, will appear sufficient to account for the peals
by which their descent is accompanied.
A second day, in company with Dr. Hooker, completed
ihe examination of this glacier in 1856 ; after which I
parted from my friends, Mr. Huxley intending to rejoin me
at the Grimsel. On the morning of the 20th of August I
strapped on my knapsack and ascended the green slopes
from Grindelwald towards the Great Scheideck. Before
reaching the summit I frequently heard the wonderful
echoes of the Wetterhorn. Some travellers were in advance
of me, and to amuse them an alpine horn was blown. The
direct sound was cut off from me by a hill, but the echoes
talked down to me from the mountain walls. The sonorous
waves arrived after one, two, three, and more reflections,
diminishing gradually in intensity, but increasing in soft-
ness, as if in its wanderings from crag to crag the sound
had undergone a kind of sifting process, leaving all its
grossness behind, and returning in delightful flute notes to
the ear.
Let us investigate this point a little. If two looking-
glasses be placed perfectly parallel to each other, with a
lighted candle between them, an infinite series of images of
the candle will be seen at both sides, the images diminishing
in brightness the further they recede. But if the looking-
glasses, instead of being parallel, enclose an angle, a limited
number of images only will be seen. The smaller the
angle which the reflectors make with each other, or, in
other words, the nearer they approach parallelism, the
greater will be the number of images observed.
To find the number of images the following is the rule : —
Divide 360, or the number of degrees in a circle, by the
number of degrees in the angle enclosed by the two mirrors,
the quotient will be one more than the number of images ;
or, counting the object itself, the quotient is always equal
to the number of images plus the object. In Fig. 2 1 have
16
ECHOES EXPLAINED.
[1856.
Fig. 2.
given the number and position of the images produced by
two mirrors placed at an angle of 45°. A B and B c mark
the edges of the mirrors,
and o represents the can-
dle, which, for the sake
of simplicity, I have
placed midway between
them. Fix one point of
a pair of compasses at
B, and with the distance
B o sweep a circle : — all
the images will be ranged
upon the circumference of
this circle. The number
of images found by the
foregoing rule is 7, and
their positions are marked in the figure by the numbers 1,
2, 3, &c.
Suppose the ear to occupy the place of the eye, and
that a sounding body occupies the place of the luminous
one, we should then have just as many echoes as we had
images in the former case. These echoes would diminish
in loudness just as the images of the candle diminish in
brightness. At each reflection a portion both of sound and
light is lost ; hence the oftener light is reflected the dimmer
it becomes, and the oftener sound is reflected the fainter
it is.
Now the cliffs of the Wetterhorn are so many rough
angular reflectors of the sound : some of them send it back
directly to the listener, and we have a first echo ; some of
them send it on to others from which it is again re-
flected, forming a second echo. Thus, by repeated reflec-
tion, successive echoes are sent to the ear, until, at length,
they become so faint as to be inaudible. The sound, as
it diminishes in intensity, appears to come from greater
1856.] KEICHENBACH AND HANDECK. 17
and greater distances, as if it were receding into the moun-
tain solitudes ; the final echoes being inexpressibly soft and
pure.
After crossing the Scheideck I descended to Meyringen,
visiting the Reichenbach waterfall on my way. A pecu-
liarity of the descending water here is, that it is broken up
in one of the basins into nodular masses, each of which in
falling leaves the light foaming mass which surrounds it as
a train in the air behind ; the effect exactly resembles
that of the avalanches of the Jungfrau, in which the more
solid blocks of ice shoot forward in advance of the lighter
debris, which is held back by the friction of the air.
Next day I ascended the valley of Hasli, and observed
upon the rocks and mountains the action of ancient glaciers
which once filled the valley to the height of more than a
thousand feet above its present level. I paused, of course,
at the waterfall of Handeck, and stood for a time upon
the wooden bridge which spans the river at its top. The
Aar comes gambolling down to the bridge from its parent
glacier, takes one short jump upon a projecting ledge,
boils up into foam, and then leaps into a chasm, from the
bottom of which its roar ascends through the gloom. A
rivulet named the Aarlenbach joins the Aar from the left
in the very jaws of the chasm : falling, at first, upon a
projection at some depth below the edge, and, rebound-
ing from this, it darts at the Aar, and both plunge
together like a pair of fighting demons to the bottom of
the gorge. The foam of the Aarlenbach is white, that
of the Aar is yellow, and this enables the observer to trace
the passage of the one cataract through the other. As I
stood upon the bridge the sun shone brightly upon the
spray and foam ; my shadow was oblique to the river, and
'hence a symmetrical rainbow could not be formed in the
spray, but one half of a lovely bow, with its base in the
chasm, leaned over against the opposite rocks, the colours
c
18 HUT OF M. DOLLFUSS. [1856.
advancing and retreating as the spray shifted its position.
I had been watching the water intently for some time,
when a little Swiss boy, who stood beside me, observed,
in his trenchant German, u There plunge stones ever
downwards." The stones were palpable enough, carried
down by the cataract, and sometimes completely breaking
loose from it, but I did not see them until my attention
was withdrawn from the water.
On my arrival at the Grimsel I found Mr. Huxley already
there, and, after a few minutes' conversation, we decided to
spend a night in a hut built by M. Dollfuss in 1846, beside
the Unteraar glacier, about 2000 feet above the Hospice.
We hoped thus to be able to examine the glacier to its
origin on the following day. Two days' food and some
blankets were sent up from the Hospice, and, accompanied
by our guide, we proceeded to the glacier.
Having climbed a great terminal moraine, and tramped
for a considerable time amid loose shingle and boulders,
we came upon the ice. The finest specimens of " tables "
which I have ever seen are to be found upon this glacier
—huge masses of clean granite poised on pedestals of ice.
Here are also " dirt-cones " of the largest size, and nume-
rous shafts, the forsaken passages of ancient " moulins,"
some filled with water, others simply with deep blue light.
I reserve the description and explanation of both cones
and moulins for another place. The surfaces of some of
the small pools were sprinkled lightly over with snow,
which the water underneath was unable to melt ; a coating
of snow granules was thus formed, flexible as chain armour,
but so close that the air could not escape through it.
Some bubbles which had risen through the water had lifted
the coating here and there into little rounded domes,
which, by gentle pressure, could be shifted hitherand thither,
and several of them collected into one. We reached the
hut, the floor of which appeared to be of the original moun-
1856.] H6TEL DES NEUFCHATELOIS. 19
tain slab ; there was a space for cooking walled off from
the sleeping-room, half of which was raised above the floor,
and contained a quantity of old hay. The number 2404
metres, the height, I suppose, of the place above the sea,
was painted on the door, behind which were also the names
of several well-known observers — Agassiz, Forbes, Desor,
Dollfuss, Ramsay, and others — cut in the wood. A loft con-
tained a number of instruments for boring, a surveyor's
chain, ropes, and other matters. After dinner I made my
way alone towards -the junction of the Finsteraar and
Lauteraar glaciers, which unite at the Abschwung to form
the trunk stream of the Unteraar glacier. Upon the great
central moraine which runs between the branches were
perched enormous masses of rock, and, under the over-
hanging ledge of one of these, M. Agassiz had his Hotel
des Neufchdtelois. The rock is still there, bearing traces of
names now nearly obliterated by the weather, while the
fragments around also bear inscriptions. There in the
wilderness, in the gray light of evening, these blurred and
faded evidences of human activity wore an aspect of sad-
ness. It was a temple of science now in ruins, and I a
solitary pilgrim to the desecrated blocks. As the day de-
clined, rain began to fall, and I turned my face towards
my new home ; where in due time we betook ourselves to
our hay, and waited hopefully for the morning.
But our hopes were doomed to disappointment. A vast
[uantity of snow fell during the night, and, when we arose,
found the glacier covered, and the air thick with the
descending flakes. We waited, hoping that it might clear
up, but noon arrived and passed without improvement;
our fire-wood was exhausted, the weather intensely cold,
and, according to the men's opinion, hopelessly bad ;
they opposed the idea of ascending further, and we had
therefore no alternative but to pack up and move down-
wards. What was snow at the higher elevations changed
c 2
20 THE RHONE GLACIEE. [1856
to rain lower down, and drenched us completely before we
reached the Grimsel. But though thus partially foiled in
our design, this visit taught us much regarding the struc-
ture and general phenomena of the glacier.
The morning of the 24th was clear and calm : we rose
with the sun, refreshed and strong, and crossed the Grimsel
pass* at an early hour. The view from the summit of the
pass was lovely in the extreme ; the sky a deep blue, the
surrounding summits all enamelled with the newly-fallen
snow, which gleamed with dazzling whiteness in the sun-
light. It was Sunday, and the scene was itself a Sabbath,
with no sound to disturb its perfect rest. In a lake which
we passed the mountains were mirrored without distortion,
for there was no motion of the air to ruffle its surface. From
the summit of the Mayenwand we looked down upon the
Ehone glacier, and a noble object it seemed, — I hardly
know a finer of its kind in the Alps. Forcing itself
through the narrow gorge which holds the ice cascade in
its jaws, and where it is greatly riven and dislocated, it
spreads out in the valley below in such a manner as
clearly to reveal to the mind's eye the nature of the
forces to which it is subjected. Longfellow's figure is quite
correct ; the glacier resembles a vast gauntlet, of which the
gorge represents the wrist ; while the lower glacier, cleft
by its fissures into finger-like ridges, is typified by the hand.
Furnishing ourselves with provisions at the adjacent inn,
we devoted some hours to the examination of the lower
portion of the glacier. The dirt upon its surface was
arranged in grooves as fine as if produced by the passage
of a rake, while the laminated structure of the deeper ice
always corresponded to the superficial grooving. We
found several shafts, some empty, some filled with water.
At one place our attention was attracted by a singular noise,
evidently produced by the forcing of air and water through
passages in the body of the glacier ; the sound rose and
KINGS AROUND THE SUN. 21
fell for several minutes, like a kind of intermittent snore, re-
minding one of Hugi's hypothesis that the glacier was alive.
We afterwards climbed to a point from which the whole
glacier was visible to us from its origin to its end. Adjacent
to us rose the mighty mass of the Finsteraarhorn, the
monarch of the Oberland. The Galenstock was also at
hand, while round about the neve of the glacier a mountain
wall projected its jagged outline against the sky. At a
distance was the grand cone of the Weisshorn, then, and I
believe still, unsealed ; * further to the left the magnificent
peaks of the Mischabel ; while between them, in savage
isolation, stood the obelisk of the Matterhorn. Near us was
the chain of the Furca, all covered with shining snow, while
overhead the dark blue of the firmament so influenced
the general scene as to inspire a sentiment of wonder
approaching to awe. We descended to the glacier, and
proceeded towards its source. As we advanced an unusual
light fell upon the mountains, and looking upwards we
saw a series of coloured rings, drawn like a vivid cir-
cular rainbow quite round the sun. Between the orb
and us spread a thin veil of cloud on which the circles
were painted; the western side of the veil soon melted
away, and with it the colours, but the eastern half remained
a quarter of an hour longer, and then in its turn disap-
peared. The crevasses became more frequent and dan-
gerous as we ascended. They were usually furnished with
overhanging eaves of snow, from which long icicles de-
pended, and to tread on which might be fatal. We were
near the source of the glacier, but the time necessary to
reach it was nevertheless indefinite, so great was the entan-
glement of fissures. We followed one huge chasm for some
hundreds of yards, hoping to cross it ; but after half an
hour's fruitless effort we found ourselves baffled and forced
to retrace our steps.
* [The Weisshorn was first scaled, by Tyndall, in 1861.— L. C. T.J
22 SPIRIT OF THE BKOCKEN. [1856.
The sun was sloping to the west, and we thought it wise
to return ; so down the glacier we went, mingling our
footsteps with the tracks of chamois, while the frightened
marmots piped incessantly from the rocks. We reached
the land once more, and halted for a time to look upon
the scene within view. The marvellous blueness of the
sky in the earlier part of the day indicated that the air was
charged, almost to saturation, with transparent aqueous
vapour. As the sun sank the shadow of the Finsteraar-
horn was cast through the adjacent atmosphere, which,
thus deprived of the direct rays, curdled up into visible
fog. The condensed vapour moved slowly along the flanks
of the mountain, and poured itself cataract-like into the
valley of the Ehone. Here it met the sun again, which
reduced it once more to the invisible state. Thus, though
there was an incessant supply from the generator behind,
the fog made no progress ; as in the case of the moving
glacier, the end of the cloud-river remained stationary
where consumption was equal to supply. Proceeding along
the mountain to the Furca, we found the valley at the
further side of the pass also filled with fog, which rose, like
a wall, high above the region of actual shadow. Once on
turning a corner an exclamation of surprise burst simul-
taneously from my companion and myself. Before each
of us and against the wall of fog, stood a spectral image
of a man, of colossal dimensions ; dark as a whole, but
bounded by a coloured outline. We stretched forth our
arms ; the spectres did the same. We raised our alpen-
stocks ; the spectres also flourished their batons. All our
actions were imitated by these fringed and gigantic shades.
We had, in fact, the Spirit of the Brocken before us in per-
fection.
At the time here referred to I had had but little expe-
rience of alpine phenomena. I had been through the
Oberland in 1850, but was then too ignorant to learn
1856.] THE TYROL. 23
much from my excursion. Hence the novelty of this day's
experience may have rendered it impressive : still even
now I think there was an intrinsic grandeur in its phenomena
which entitles the day to rank with the most remarkable
that I have spent among the Alps. At the Furca, to my
great regret, the joint ramblings of my friend and myself
ended ; I parted from him on the mountain side, and
watched him descending, till the gray of evening finally
hid him from my view,
THE TYROL.
(3.) '
MY subsequent destination was Vienna ; but I wished to
associate with my journey thither a visit to some of the
glaciers of the Tyrol. At Landeck, on the 29th of August,
I learned that the nearest glacier was that adjacent to the
Gebatsch Alp, at the head of the Kaunserthal ; and on
the following morning I was on my way towards this valley.
I sought to obtain a guide at Kaltebrunnen, but failed ;
and afterwards walked to the little hamlet of Feuchten,
where I put up at a very lonely inn. My host, I believe,
had never seen an Englishman, but he had heard of such,
and remarked to me in his patois with emphasis, " Die
Englcinder sind die Mhnsten Leute in dieser Welt." Through
his mediation I secured a chamois -hunter, named Johann
Auer, to be my guide, and next morning I started with this
man up the valley. The sun, as we ascended, smote the
earth and us with great power ; high mountains flanked
us on either side, while in front of us, closing the view, was
the mass of the Weisskugel, covered with snow. At three
24 THE GEBATSCH ALP. [1856.
o'clock we came in sight of the glacier, and soon afterwards
I made the acquaintance of the Senner or cheesemakers of
the Gebatsch Alp.
The chief of these was a fine tall fellow, with free, frank
countenance, which, however, had a dash of the mountain
wildness in it. His feet were bare, he wore breeches, and
fragments of stockings partially covered his legs, leaving
a black zone between the upper rim of the sock and the
breeches. His feet and face were of the same swarthy
hue ; still he was handsome, and in a measure pleasant
to look upon. He asked me what he could cook for me,
and I requested some bread and milk ; the former was a
month old, the latter was fresh and delicious, and 011 these
I fared sumptuously. I went to the glacier afterwards
with my guide, and remained upon the ice until twilight,
when we returned, guided by no path, but passing amid
crags grasped by the gnarled roots of the pine, through
green dells, and over bilberry knolls of exquisite colouring.
My guide kept in advance of me singing a Tyrolese
melody, and his song and the surrounding scene revived
and realised all the impressions of my boyhood regarding
the Tyrol.
Milking was over when we returned to the chalet, which
now contained four men exclusive of myself and my guide.
A fire of pine logs was made upon a platform of stone,
elevated three feet above the floor ; there was no chimney,
as the smoke found ample vent through the holes and
fissures in the sides and roof. The men were all intensely
sunburnt, the legitimate brown deepening into black with
beard and dirt. The chief senner prepared supper, break-
ing eggs into a dish, and using his black fingers to empty
the shell when the albumen was refractory. A fine
erect figure he was as he stood in the glowing light of the
fire. All the men were smoking, and now and then a
brand was taken from the fire to light a renewed pipe, and
1856.] AN ALPINE CHALET. 25
a ruddy glare flung thereby over the wild countenance of
the smoker. In one corner of the chalet, and raised high
above the ground, was a large bed, covered with clothes
of the most dubious black-brown hue ; at one end was a
little water-wheel turned by a brook, which communi-
cated motion to a churndash which made the butter. The
beams and rafters were covered with cheeses, drying in the
warm smoke. The senner, at my request, showed me his
storeroom, and explained to me the process of making
cheese, its interest to me consisting in its bearing upon
the question of slaty cleavage. Three 'gigantic masses of
butter were in the room, and I amused my host by calling
them butter-glaciers. Soon afterwards a bit of cotton was
stuck in a lump of grease, which was placed in a lantern,
and the wick ignited ; the chamois-hunter took it, and led
the way to our resting-place, I having previously declined
a good-natured invitation to sleep in the big black bed
already referred to.
There was a cowhouse near the chalet, and above it,
raised on pillars of pine, and approached by a ladder, was
a loft, which contained a quantity of dry hay : this my
guide shook to soften the lumps, and erected an eminence
for my head. I lay down, drawing my plaid over me, but
Auer affirmed that this would not be a sufficient protec-
tion against the cold ; he therefore piled hay upon me to
the shoulders, and proposed covering up my head also.
This, however, I declined, though the biting coldness of
the air, which sometimes blew in upon us, afterwards
proved to me the wisdom of the suggestion. Having set
me right, my chamois-hunter prepared a place for himself,
and soon his heavy breathing informed me that he was
in a state of bliss which I could only envy. One by one
the stars crossed the apertures in the roof. Once the
Pleiades hung above me like a cluster of gems ; I tried to
admire them, but there was no fervour in my admiration.
26 THE GEBATSCH GLACIEK. [1856.
Sometimes I dozed, but always as this was about to deepen
into positive sleep it was rudely broken by the cla-
mour of a group of pigs which occupied the ground-floor
of our dwelling. The object of each individual of the
group was to secure for himself the maximum amount of
heat, and hence the outside members were incessantly
trying to become inside ones. It was the struggle of
radical and conservative among the pachyderms, the politics
being determined by the accident of position.
I rose at five o'clock on the 1st of September, and after
a breakfast of black bread and milk ascended the glacier
as far as practicable. We once quitted it, crossed a pro-
montory, and descended upon one of its branches, which
was flanked by some fine old moraines. We here came
upon a group of seven marmots, which with yells of
terror scattered themselves among the rocks. The points
of the glacier beyond my reach I examined through a
telescope ; along the faces of the sections the lines of stra-
tification were clearly shown ; and in many places where
the mass showed manifest signs of lateral pressure, I
thought I could observe the cleavage passing though the
strata. The point, however, was too important to rest
upon an observation made from such a distance, and I
therefore abstained from mentioning it subsequently. I
examined the fissures and the veining, and noticed how
the latter became most perfect in places where the pres-
sure was greatest. The effect of ollique pressure was also
finely shown : at one place the thrust of the descending
glacier was opposed by the • resistance offered by the side
of the valley, the direction of the force being oblique to
the side ; the consequence was a structure nearly parallel
to the valley, and consequently oblique to the thrust which
I believe to be its cause.
After five hours' examination we returned to our chalet,
where we refreshed ourselves, put our things in order, and
1856.] A CHAMOIS ON THE ROCKS. 27
faced a nameless " Joch," or pass ; our aim being to cross
the mountains into the valley of Lantaufer, and reach
Graun that evening. After a rough ascent over the alp
we came to the dead crag, where the weather had broken
up the mountains into ruinous heaps of rock and shingle.
We reached the end of a glacier, the ice of which was
covered by sloppy snow, and at some distance up it came
upon an islet of stones and debris, where we paused to rest
ourselves. My guide, as usual, ranged over the summits
with his telescope, and at length exclaimed, " I see a
chamois." The creature stood upon a cliff some hundreds
of yards to our left, and seemed to watch our movements.
It was a most graceful animal, and its life and beauty stood
out in forcible antithesis to the surrounding savagery and
death.
On the steep slopes of the glacier I was assisted by the
hand of my guide. In fact, on this day I deemed places
dangerous, and dreaded them as such, which subsequent
practice enabled ine to regard with perfect indifference ;
so much does what we call courage depend upon habit, or
on the fact of knowing that we have really nothing to fear.
Doubtless there are times when a climber has to make up
his mind for very unpleasant possibilities, and even gather
calmness from the contemplation of the worst ; but in most
cases I should say that his courage is derived from the
latent feeling that the chances of safety are immensely in
his favour.
After a tough struggle we reached the narrow row of
crags which form the crest- of the pass, and looked into
the world of mountain and cloud on the other side. The
scene was one of stern grandeur — the misty lights and
deep cloud-glooms being so disposed as to augment the
impression of vast-ness which the scene conveyed. The
breeze at the summit was exceedingly keen, but it gave
our muscles tone, and we sprang swiftly downward
28 PASSAGE OF A JOCH. [1856.
through the yielding debris which here overlies the moun-
tain, and in which we sometimes sank to the knees.
Lower down we came once more upon the ice. The
glacier had at one place melted away from its bounding
cliff, which rose vertically to our right, while a wall of ice
60 or 80 feet high was on our left. Between the two was
a narrow passage, the floor of which was snow, which
I knew to be hollow beneath : my companion, however,
was in advance of me, and he being the heavier man,
where he trod I followed without hesitation. On turn-
ing an angle of the rock I noticed an expression of
concern upon his countenance, and he muttered audibly,
" I did not expect this." The snow-floor had, in fact,
given way, and exposed to view a clear green lake, one
boundary of which was a sheer precipice of rock, and the
other the aforesaid wall of ice ; the latter, however, curved
a little at its base, so as to form a short steep slope
which overhung the water. My guide first tried the slope
alone ; biting the ice with his shoe-nails, and holding on
by the spike of his baton, he reached the other side. He
then returned, and, divesting myself of all superfluous
clothes, as a preparation for the plunge which I fully
expected, I also passed in safety. Probably the conscious-
ness that I had water to fall into instead of pure space,
enabled me to get across without anxiety or mischance ;
but had I, like my guide, been unable to swim, my feelings
would have been far different.
This accomplished, we went swiftly down the valley,
and the more I saw of my g.uide the more I liked him.
He might, if he wished, have made his day's journey
shorter by stopping before he reached Graun, but he
would not do so. Every word he said to me regarding
distances was true, and there was not the slightest desire
shown to magnify his own labour. I learnt by mere acci-
dent that the day's work had cut up his feet, but his
1856.] THE STELVIO. 29
cheerfulness and energy did not bate a jot till he had landed
me in the Black Eagle at Graun. Next morning he came
to my room, and said that he felt sufficiently refreshed
to return home. I paid him what I owed him, when
he took my hand, and, silently bending down his head,
kissed it ; then, standing erect, he stretched forth his
right hand, which I grasped firmly in mine, and bade him
farewell ; and thus I parted from Johann Auer, my brave
and truthful chamois-hunter.
On the following day I met Dr. Frankland in the Finster-
muntz pass, and that night we bivouacked together at
Mais. Heavy rain fell throughout the night, but it came
from a region high above that of liquidity. It was first
snow, which, as it descended through the warmer strata
of the atmosphere, was reduced to water. Overhead, in
the air, might be traced a surface, below which the preci-
pitate was liquid, above which it was solid ; and this sur-
face, intersecting the mountains which surround Mais,
marked upon them a beautifully-defined snow-line, below
which the pines were dark and the pastures green, but
above which pines and pastures and crags were covered
with the freshly-fallen snow.
On the 2nd of September we crossed the Stelvio. The
brown cone of the well-known Madatschspitze was clear, but
the higher summits were clouded, and the fragments of sun-
shine which reached the lower world wandered like gleams
of fluorescent light over the glaciers. Near the snow- line
the partial melting of the snow had rendered it coarsely
granular, but as we ascended it became finer, and the light
emitted from its cracks and cavities a pure and deep
blue. When a staff was driven into the snow low down
the mountain, the colour of the light in the orifice was
scarcely sensibly blue, but higher up this increased in a
wonderful degree, and at the summit the effect was mar-
vellous. I struck my staff into the snow, and turned it
30 COLOUR OF FRESH SNOW. [1856.
round and round ; the surrounding snow cracked repeat-
edly, and flashes of blue light issued from the fissures.
The fragments of snow that adhered to the staff were, by
contrast, of a beautiful pink yellow, so that, on moving the
staff with such fragments attached to it up and down, it
was difficult to resist the impression that a pink flame was
ascending and descending in the hole. As we went down
the other side of the pass, the effect became more and
more feeble, until, near the snow-line, it almost wholly dis-
appeared.
We remained that night at the baths of Bormio, but the
following afternoon being fine we wished to avail ourselves
of the fair weather to witness the scene from the summit of
the pass. Twilight came on before we reached Santa Maria,
but a gorgeous orange overspread the western horizon, from
which we hoped to derive sufficient light. It was a little
too late when we reached the top, but still the scene was
magnificent. A multitude of mountains raised their crowns
towards heaven, while above all rose the snow-white cone
of the Ortler. Far into the valley the giant stretched his
granite limbs, until they were hid from us by darkness. As
this deepened, the heavens became more and more crowded
with stars, which blazed like gems over the heads of the
mountains. At times the silence was perfect, unbroken
save by the crackling of the frozen snow beneath our own
feet ; while at other times a breeze would swoop down
upon us, keen and hostile, scattering the snow from the roofs
of the wooden galleries in frozen powder over us. Long
after night had set in, a ghastly gleam rested upon the
summit of the Ortler, while the peaks in front deepened to
a dusky neutral tint, the more distant ones being lost in
gloom. We descended at a swift pace to Trafoi, which we
reached before 1 1 P.M.
Meran was our next resting-place, whence we turned
through the Schnalzerthal to Unserfrau, and thence over
1856.] SINGULAE HAILSTOEM. 31
the Hochjoch to Fend. From a religious procession we
took a guide, who, though partly intoxicated, did his duty
well. Before reaching the summit of the pass we were
assailed by a violent hailstorm, each hailstone being a
frozen cone with a rounded end. Had not their motion
through the air something to do with the shape of these
hailstones? The theory of meteorites now generally
accepted is that they are small planetary bodies drawn to
the earth by gravity, and brought to incandescence by
friction against the earth's atmosphere. Such a body
moving through the atmosphere must have condensed hot
air in front of it, and rarefied cool air behind it ; and the
same is true to a small extent of a hailstone. This distri-
bution of temperature must, I imagine, have some influence
on the shape of the stone. Possibly also the stratified ap-
pearance of some hailstones may be connected with this
action.*
The hail ceased and the heights above us cleared as we
ascended. At the top of the pass we found ourselves on
the verge of a great neve, which lay between two ranges of
summits, sloping down to the base of each range from a
high and rounded centre : a wilder glacier scene I have
scarcely witnessed. Wishing to obtain a more perfect
view of the region, I diverged from the track followed by
Dr. Frankland and the guide, and climbed a ridge of snow
about half a mile to the right of them. A glorious expanse
* I take the following account of a grander storm of the above charac-
ter from Hooker's ' Himalayan Journals,' vol. ii. p. 405.
" On the 20th (March, 1849) we had a change in the weather : a violent
storm from the south-west occurred at noon, with hail of a strange form,
the stones being sections of hollow spheres, half an inch across and up-
wards, formed of cones with truncated apices and convex bases : these
cones were aggregated together with their bases outwards. The large
masses were followed by a shower of the separate conical pieces, and that
by heavy rain. On the mountains this storm was most severe : the stones
lay at Darjeeling for seven days, congealed into masses of ice several feet
long and a foot thick in sheltered places : at Purneah, fifty miles south,
stones one and two inches across fell, probably as whole spheres."
32 THE HOCHJOCH AND FEND. [1856.
was before me, stretching itself in vast undulations, and
heaping itself here and there into mountainous cones,
white and pure, with the deep blue heaven behind them.
Here I had my first experience of hidden crevasses, and to
niy extreme astonishment once found myself in the jaws of
a fissure of whose existence I had not the slightest notice.
Such accidents have often occurred to me since, but the
impression made by the first is likely to remain the
strongest. It was dark when we reached the wretched '
Wirthshaus at Fend, where, badly fed, badly lodged, and
disturbed by the noise of innumerable rats, we spent
the night. Thus ended my brief glacier expedition of
1856 ; and on the observations then made, and on subsequent
experiments, was founded a paper presented to the Royal
Society by Mr. Huxley and myself.*
* [' Phil. Trans.' 1857, pp. 327-346.— L. C. T.]
1857.J THE LAKE OF GENEVA. 33
EXPEDITION OF 1857.
THE LAKE OF GENEVA,
(4.)
THE time occupied in the observations of 1856 embraced
about five whole days ; and though these days were labo-
rious and instructive, still so short a time proved to be
wholly incommensurate with the claims of so wide a pro-
blem. During the subsequent experimental treatment of
the subject, I had often occasion to feel the incompleteness
of my knowledge, and hence arose the desire to make a
second expedition to the Alps, for the purpose of expand-
ing, fortifying, or, if necessary, correcting first impressions.
On Thursday, the 9th of July, 1857, 1 found myself upon
the Lake of Geneva, proceeding towards Vevey. I had
long wished to see the waters of this renowned inland sea,
the colour of which is perhaps more interesting to the man
of science than to the poets who have sung about it. Long
ago its depth of blue excited attention, but no systematic
examination of the subject has, so far as I know, been
attempted. It may be that the lake simply exhibits the
colour of pure water. Ice is blue, and it is reasonable to
suppose that the liquid obtained from the fusion of ice is
of the same colour ; but still the question presses — " Is the
blue of the Lake of Geneva to be entirely accounted for
in this way ? " The attempts which have been made to
explain it otherwise show that at least a doubt exists as to
the sufficiency of the above explanation.
It is only in its deeper portions that the colour of the
lake is properly seen. Where the bottom comes into view
the pure effect of the water is disturbed ; but where the
D
34 BLUENESS OF THE WATER. [1857.
water is deep the colour is deep : between Rolle and
Nyon for example, the blue is superb. Where the blue
was deepest, however, it gave me the impression of turbidity
rather than of deep transparency. At the upper portion of
the lake the water through which the steamer passed was
of a blue green. Wishing to see the place where the Rhone
enters the lake, I walked on the morning of the 10th
from Villeneuve to Novelle, and thence through the woods
to the river side. Proceeding along an embankment,
raised to defend the adjacent land from the incursions of
the river, an hour brought me to the place where it
empties itself into the lake. The contrast between the
two waters was very great : the river was almost white
with the finely divided matter which it held in suspension ;
while the lake at some distance was of a deep ultramarine.
The lake in fact forms a reservoir where the particles
held in suspension by the river have time to subside, and
its waters to become pure. The subsidence of course takes
place most copiously at the head of the lake ; and here
the deposit continues to form new land, adding year by
year to the thousands of acres which it has already left
behind it, and invading more and more the space occupied
by the water. Innumerable plates of mica spangled the
fine sand which the river brought down, and these, mixing
with the water, and flashing like minute mirrors as the sun's
rays fell upon them, gave the otherwise muddy stream a
silvery appearance. Had I an opportunity I would make
the following experiments :—
(a.) Compare the colour of the light transmitted by a
column of the lake water fifteen feet long with that trans-
mitted by a second column, of the same length, derived
from-the melting of freshly fallen mountain snow.
(b.) Compare in the same manner the colour of the ordi-
nary water of the lake with that of the same water after
careful distillation.
1857.]
ATMOSPHERIC KEFEACTION.
35
(c.) Strictly examine whether the light transmitted by
the ordinary water contains an excess of red over that
transmitted by the distilled water : this latter point, as
will be seen farther on, is one of peculiar interest.
The length is fixed at fifteen feet, because I have found
this length extremely efficient in similar experiments.
On returning to the pier at Villeneuve, a peculiar
flickering motion was manifest upon the surface of the dis-
tant portions of the lake, and I soon noticed that the
coast line was inverted by atmospheric refraction. It
required a long distance to produce the effect : no trace
of it was seen about the Castle of Chillon, but at Vevey
and beyond it, the whole coast was clearly inverted ; and
the houses on the margin of the lake were also imaged to
a certain height. Two boats at a considerable distance pre-
sented the appearance sketched in Figs. 3 and 4 ; the hull
A
Fig. 4.
of each, except a small portion at the end, was invisible,
but the sails seemed lifted up high in the air, with their
inverted images below; as the boats drew nearer the
hulls appeared inverted, the apparent height of the vessel
above the surface of the lake being thereby nearly doubled,
36 MIRAGE. [1857.
while the sails and higher objects, in these cases, were
almost completely cut away. . When viewed through a
telescope the sensible horizon of the lake presented a bil-
lowy tumultuous appearance, fragments being incessantly
detached from it and suspended in the air.
The explanation of this effect is the same as that of the
mirage of the desert, which may be found in almost any
book on physics, and which so tantalized the French
soldiers in Egypt. They often mistook this aerial inversion
for the reflection from a lake, and on trial found hot and
sterile sand at the place where they expected refreshing
waters. The effect was shown by Monge, one of the
learned men who accompanied the expedition, to be due
to the total reflection of very oblique rays at the upper
surface of the layer of rarefied air which was nearest to the
heated earth. A sandy plain, in the early part of the day,
is peculiarly favourable for the production of such effects ;
and on the extensive flat strand which stretches between
Mont St. Michel and the coast adjacent to Avranches in
Normandy, I have noticed Mont Tombeline reflected as if
glass instead of sand surrounded it and formed its mirror.
1857.] CHAMOUNI AND THE MONTANVERT. 37
CHAMOUNI AND THE MONTANVERT.
(5.)
ON the evening of the 12th of July I reached Chamouni ;
the weather was not quite clear, but it was promising ;
white cumuli had floated round Mont Blanc during the
day, but these diminished more and more, and the light of
the setting sun was of that lingering rosy hue which bodes
good weather. Two parallel beams of a purple tinge were
drawn by the shadows of the adjacent peaks, straight across
the Glacier des Bossons, and the Glacier des Pelerins was
also steeped for a time in the same purple light. Once
when the surrounding red illumination was strong, the
shadows of the Grands Mulets falling upon the adjacent
snow appeared of a vivid green.
This green belonged to the class of subjective colours, or
colours produced by contrast, about which a volume might
be written. The eye received the impression of green,
but the colour was not external to the eye. Place a red
wafer on white paper, and look at it intently, it will be
surrounded in a little time by a green fringe : move the
wafer bodily away, and the entire space which it occupied
upon the paper will appear green. A body may have its
proper colour entirely masked in this way. Let a red
wafer be attached to a piece of red glass, and from a
moderately illuminated position let the sky be regarded
through the glass ; the wafer will appear of a vivid green.
If a strong beam of light be sent through a red glass and
caused to fall upon a screen, which at the same time is
moderately illuminated by a separate source of white light,
an opaque body placed in the path of the beam will cast
a green shadow upon the screen which may be seen by
38 COLOURED SHADOWS. [1857.
several hundred persons at once. If a blue glass be used,
the shadow will be yellow, which is the complementary
colour to blue.
When we suddenly pass from open sunlight to a mode-
rately illuminated room, it appears dark at first, but after
a little time the eye regains the power of seeing objects dis-
tinctly. Thus one effect of light upon the eye is to render
it less sensitive, and light of any particular colour falling
upon the eye blunts its appreciation of that colour. Let us
apply this to the shadow upon the screen. This shadow
is moderately illuminated by a jet of white light; but the
space surrounding it is red, the effect of which upon
the eye is to blind it in some degree to the perception of
red. Hence, when the feeble white light of the shadow
reaches the eye, the red component of this light is, as it
were, abstracted from it, and the eye sees the residual
colour, which is green. A similar explanation applies to
the shadows of the Grands Mulcts.
On the 13th of July I was joined by my friend Mr.
Thomas Hirst, and on the 14th we examined together the
end of the Mer de Glace. In former times the whole volume
of the Arveiron escaped from beneath the ice at the
end of the glacier, forming a fine arch at its place of
issue. This year a fraction only of the water thus found
egress ; the greater portion of it escaping laterally from the
glacier at the summit of the rocks called Les Mottets, down
which it tumbled in a fine cascade. The vault at the
end of the glacier was nevertheless respectable, and rather
tempting to a traveller in search of information regard-
ing the structure of the ice. Perhaps, however, Nature
meant to give me a friendly warning at the outset, for,
while speculating as to the wisdom of entering the cavern,
it suddenly gave way, and, with a crash which rivalled
thunder, the roof strewed itself in ruins upon the floor.
Many years ago I had read with delight Coleridge's
1857.] SUNEISE AT CHAMOUNI. 89
poem entitled ' Sunrise in the Valley of Chamouni,' and
to witness in all perfection the scene described by the poet,
I waited at Chamouni a day longer than was otherwise
necessary. On the morning of Wednesday, the 1 5th of July,
I rose before the sun ; Mont Blanc and his wondrous staff of
Aiguilles were without a cloud ; eastward the sky was of a
pale orange which gradually shaded off to a kind of rosy
violet, and this again blended by imperceptible degrees
with the deep zenithal blue. The morning star was still
shining to the right, and the moon also turned a pale face
towards the rising day. The valley was full of music ;
from the adjacent woods issued a gush of song, while the
sound of the Arve formed a suitable bass to the shriller me-
lody of the birds. The mountain rose for a time cold and
grand, with no apparent stain upon his snows. Suddenly the
sunbeams struck his crown and converted it into a boss of
gold. For some time it remained the only gilded summit
in view, holding communion with the dawn while all the
others waited in silence. These, in the order of their
heights, came afterwards, relaxing, as the sunbeams struck
each in succession, into a blush and smile.
On the same day we had our luggage transported to the
Montanvert, while we clambered along the lateral moraine
of the glacier to the Chapeau. The rocks alongside the
glacier were beautifully scratched and polished, and I paid
particular attention to them, for the purpose of furnishing
myself with a key to ancient glacier action. The scene
to my right was one of the most wonderful I had ever wit-
nessed. Along the entire slope of the Glacier des Bois, the
ice was cleft and riven into the most striking and fantastic
forms. It had not yet suffered much from the wasting in-
fluence of the summer weather, but its towers and minarets
sprang from the general mass with clean chiselled outlines.
Some stood erect, others leaned, while the white debris,
strewn here and there over the srlacier, showed where the
o
40 GLACIER DES BOIS. [1857.
wintry edifices had fallen, breaking themselves to pieces,
and grinding the masses on which they fell to powder.
Some of them gave way during our inspection of the place,
and shook the valley with the reverberated noise of their
fall. I endeavoured to get near them, but failed ; the
chasms at the margin of the glacier were too dangerous, and
the stones resting upon the heights too loosely poised to
render persistence in the attempt excusable.
We subsequently crossed the glacier to the Montanvert,
and I formally took up my position there. The rooms of
the hotel were separated from each other by wooden
partitions merely, and thus the noise of early risers in one
room was plainly heard in the next. For the sake of
quiet, therefore, I had my bed placed in the chateau next
door, — a little octagonal building erected by some
kind and sentimental Frenchman, and dedicated " a la
Nature" My host at first demurred, thinking the place
not " fyrvpre" but I insisted, and he acquiesced. True the
stone floor was dark with moisture, and On the walls a
glistening was here and there observable, which suggested
rheumatism, and other penalties, but I had had no expe-
rience of rheumatism, and trusted to the strength which
mountain air and exercise were sure to give me, for
power to resist its attacks. Moreover, to dispel some of
the humidity, it was agreed that a large pine fire should
be made there on necessary occasions.
Though singularly favoured on the whole, still our resi-
dence at the Montanvert was sufficiently long to give us
specimens of all kinds of weather ; and thus my chateau
derived an interest from the mutations of external nature.
Sometimes no breath disturbed the perfect serenity of the
night, and the moon, set in a black-blue sky, turned a, face
of almost supernatural brightness to the mountains, while
in her absence the thick-strewn stars alone flashed and
twinkled through the transparent air. Sometimes dull
1857.] QUARTERS AT THE MONTANVERT. 41
dank fog choked the valley, and heavy rain plashed upon
the stones outside. On two or three occasions we were
favoured by a thunderstorm, every peal of which broke
into a hundred echoes, while the seams of lightning which
ran through the heavens produced a wonderful intermittence
of gloom and glare. And as I sat within, musing on the.
experiences of the day, with my pine logs crackling, and
the ruddy fire-light gleaming over the walls, and lending
animation to the visages sketched upon them with charcoal
by the guides, I felt that my position was in every way
worth v of a student of nature.
42 A RIVER OF ICE. [1857.
THE MEE DE GLACE.
(6.)
THE name " Mer de Glace " lias doubtless led many who
have never seen this glacier to a totally erroneous concep-
tion of its character. Misled probably by this term, a
distinguished writer, for example, defines a glacier to be
a sheet of ice spread out upon the slope of a mountain ;
whereas the Mer de Glace is indeed a river, and not a sea
of ice. But certain forms upon its surface, often noticed
and described, and which I saw for the first time from the
window of our hotel on the morning of the 16th of July,
suggest at once the origin of the name. The glacier here
has the appearance of a sea which, after it had been tossed
by a storm, had suddenly stiffened into rest. The ridges
upon its surface accurately resemble waves in shape, and
this singular appearance is produced in the following
way : —
Some distance above the Montanvert — opposite to the
Echelets — the glacier, in passing down an incline, is rent
by deep fissures, between each two of which a ridge of
ice intervenes. At first the edges of these ridges are sharp
and angular, but they are soon sculptured off by the action
of the sun. The bearing of the Mer de Glace being
approximately north and south, the sun at mid-day shines
down the glacier, or rather very obliquely across it;
and the consequence is, that the fronts of the ridges, which
look downward, remain in shadow all the day, while the
backs of the ridges, which look up the glacier, meet the
direct stroke of the solar rays. The ridges thus acted
upon have their hindmost angles wasted off and converted
1857.]
FROZEN WAVES.
43
into slopes which represent the back of a wave, while the
opposite sides of the ridges, which are protected from the
sun, preserve their steepness, and represent the front of the
wave. Fig. 5 will render my meaning at once plain.
The dotted lines are intended to represent three of the
ridges into which the glacier is divided, with their inter-
posed fissures ; the dots representing the boundaries of the
ridges when the glacier is first broken. The parallel
shading lines represent the direction of the sun's rays,
which, falling obliquely upon the ridges, waste away the
right-hand corners, and finally produce wave-like forms.
We spent a day or two in making the general acquaint-
ance of the glacier. On the 16th we ascended till we came
to the rim of the Talefre basin, from which we had a good
view of the glacier system of the region. The lami-
nated structure of the ice was a point which particularly
interested me ; and as I saw the exposed sections of the
neve, counted the lines of stratification, and compared
these with the lines upon the ends of the secondary
44
GLACIER TABLES.
[1857.
glaciers, I felt the absolute necessity either of connecting
the veined structure with the strata by a continuous chain
of observations, or of proving by ocular evidence that
they were totally distinct from each other. I was well
acquainted with the literature of the subject, but nothing
that I had read was sufficient to prove what I required.
Strictly speaking, nothing that had been written upon the
subject rose above the domain of opinion >, while I felt that
without absolute demonstration the question would never
be set at rest.
On this day we saw some fine glacier tables ; flat masses
of rock, raised high upon columns of ice : Fig. 6 is a
sketch ol one of the finest of them. Some of them fell
from their pedestals while we were near them, and the
clean ice-surfaces which they left behind sparkled with
minute stars as the small bubbles of air ruptured the film
of water by which they were overspread. I also noticed that
" petit bruit de crepitation/ to which M. Agassiz alludes,
and which he refers to the rupture of the ice by the ex-
1857.] FIRST SIGHT OF THE DIRT-BANDS. 45
tnsion of the air-bubbles contained within it. When I
first read Agassiz's account of it, I thought it might be
produced by the rupture of the minute air-bubbles which
incessantly escape from the glacier. This, doubtless, pro-
duces an effect, but there is something in the character of
the sound to be referred, I think,- to a less obvious cause,
which I shall notice further on.
At six P.M. this day I reached the Montanvert ; and the
same evening, wrapping my plaid around me, I wandered
up towards Charmoz, and from its heights observed, as
they had been observed fifteen years previously by Pro-
fessor Forbes, the dirt-bunds of the Mer de Glace. They
were different from any I had previously seen, and I felt
a strong desire to trace them, to their origin. Content,
however, with the performance of the day, and feeling
healthily tired by it, I lay down upon the bilberry bushes
and fell asleep. It was dark when I awoke, and I experi-
enced some difficulty and risk in getting down from the
petty eminence referred to.
The illumination of the glacier, as remarked by Pro-
fessor Forbes, has great influence upon the appearance of
the bands ; they are best seen in a subdued light, and I
think for the following reasons : —
The dirt-bands are seen simply because they send less
light to the eye than the cleaner portions of the glacier
which lie between them ; two surfaces, differently illumi-
nated, are presented to the eye, and it is found that this
difference is more observable when the light is that of
evening than when it is that of noon.
It is only within certain limits that the eye is able to
perceive differences of intensity in different lights ; beyond
a certain intensity, if I may use the expression, light ceases
to be light, and becomes mere pain. The naked eye can
detect no difference in brightness between the electric light
46 BANDS SEEN BEST BY TWILIGHT. [1857.
and the lime light, although, when we come to strict mea-
surement, the former may possess many times the inten-
sity of the latter. It follows from this that we might
reduce the ordinary electric light to a fraction of its in-
tensity, without any perceptible change of brightness to
the naked eye which looks at it. But if we reduce the
lime light in the same proportion the effect would be very
different. This light lies much nearer to the limit at which
the eye can appreciate differences of brightness, and its
reduction might bring it quite within this limit, and
make it sensibly dimmer than before. Hence we see
that when two sources of intense light are presented
to the eye, by reducing both the lights in the same pro-
portion, the di/erence between them may become more
perceptible.
Now the dirt-bands and the spaces between them re-
semble, in some measure, the two lights above mentioned.
By the full glare of noon both are so strongly illuminated
that the difference which the eye perceives is very small ;
as the evening advances the light of both is lowered in the
same proportion, but the differential effect upon the eye
is thereby augmented, and the bands are consequently
more clearly seen.
(7-)
On Friday, the 17th of July, we commenced our mea-
surements. Through the kindness of Sir Eoderick Mur-
chison, I found myself in the possession of an excellent
five-inch theodolite, an instrument with the use of which
both my friend Hirst and myself were perfectly familiar.
1857.] THE CLEFT STATION. 47
We worked in concert for a few days to familiarize our
assistant with the mode of proceeding, but afterwards it
was my custom to simply determine the position where a
measurement was to be made, and to leave the execu-
tion of it entirely to Mr. Hirst and our guide.
On the 20th of July I made a long excursion up the
glacier, examining the moraines, the crevasses, the struc-
ture, the moulins, and the disintegration of the surface.
I was accompanied by a boy named Edouard Balmat,* and
found him so good an iceman that I was induced to take
him with me on the following day also.
Looking upwards from the Montanvert to the left of
the Aiguille de Charrnoz, a singular gap is observed in
the rocky mountain wall, in the centre of which stands a
detached column of granite. Both cleft and pillar are
shown in. the frontispiece, to the right. The eminence to
the left of this gap is signalised by Professor Forbes as one
of the best stations from which to view the Mer de Glace,
and this point, which I shall refer to hereafter as the Cleft
Station, it was now my desire to attain. From the Mon-
tanvert side a steep gully leads to the cleft; up this
couloir we proposed to try the ascent. At a considerable
height above the Mer de Glace, and closely hugging
the base of the Aiguille de Charm oz, is the small Gla-
cier de Tendue, shown in the frontispiece, and from
which a steep slope stretches down to the Mer de Glace.
This Tendue is the most talkative glacier I have ever
known ; the clatter of the small stones which fall from it
is incessant. Huge masses of granite also frequently fall
upon the glacier from the cliffs above it, and, being slowly
borne downwards by the moving ice, are at length seen
toppling above the terminal face of the glacier. The
> ice which supports them being gradually melted, they are
* " Le petit Balmat " my host always called him.
48 KOUGH ASCENT. [1857.
at length undermined, and sent bounding down the slope
with peal and rattle, according as the masses among which
they move are large or small. The space beneath the
glacier is cumbered with blocks thus sent clown ; some of
them of enormous size.
The danger arising from this intermittent cannonade,
though in reality small, has caused the guides to swerve
from the path which formerly led across the slope to the
promontory of Trelaporte. I say " small," because, even
should a rock choose the precise moment at which a tra-
veller is passing to leap down, the boulders at hand are so
large and so capable of bearing a shock that the least
presence of mind would be sufficient to place him in safety.
But presence of mind is not to be calculated on under
such circumstances, and hence the guides were right to
abandon the path.
Reaching the mouth of our gully after a rough ascent,
we took to the snow, instead of climbing the adjacent
rocks. It was moist and soft, in fact in a condition alto-
gether favourable for the "regelation" of its granules.
As the foot pressed upon it the particles became cemented
together. A portion of the pressure was transmitted
laterally, which produced attachments beyond the bound-
ary of the foot ; thus as the latter sank, it pressed upon
a surface which became continually wider and more rigid,
and at length sufficiently strong to bear the entire
weight of the body ; the pressed snow formed in fact a
virtual camel's foot, which soon placed a limit to the sink-
ing. It is this same principle of regelation which enables
men to cross snow bridges in safety. By gentle cautious
pressure the loose granules of the substance are cemented
into a continuous mass, all sudden shocks which might
cause the frozen surfaces to snap asunder being avoided.
In this way an arch of snow fifteen or twenty inches in
1857.] CHAMOIS ON THE MOUNTAINS. 49
thickness may be rendered so firm that a man will cross
it, although it may span a chasm one hundred feet in
depth.
As we ascended, the incline became very steep, and
once or twice we diverged from the snow to the adjacent
rocks ; these were disintegrated, and the slightest dis-
turbance was sufficient to bring them down ; some fell,
and from one of them I found it a little difficult to escape ;
for it grazed my leg, inflicting a slight wound as it passed.
Just before reaching the cleft at which we aimed, the snow
for a short distance was exceedingly steep, but we sur-
mounted it ; and I sat for a time beside the granite pillar,
pleased to find that I could permit my legs to dangle over
a precipice without prejudice to my head.
While we remained here a chamois made its appear-
ance upon the rocks above us. Deeming itself too near,
it climbed higher, and then turned round to watch us.
It was soon joined by a second, and the two formed a
very pretty picture : their attitudes frequently changed,
but they were always graceful; with head erect and
horns curved back, a light limb thrown forward upon a
ledge of rock, looking towards us with wild and earnest
gaze, each seemed a type of freedom and agility.
Turning now to the left, we attacked the granite tower,
from which we purposed to scan the glacier, and were
soon upon its top. My companion was greatly pleased
— he was " tres-content " to have reached the place — he
felt assured that many old guides would have retreated
from that ugly gully, with its shifting shingle and debris,
and his elation reached its climax in the declaration that,
if I resolved to ascend Mont Blanc without a guide, he
was willing to accompany me.
From the position which we had attained, the prospect
was exceedingly fine, both of the glaciers and of the
mountains. Beside us was the Aiguille de Charmoz,
E
50 SCENE FKOM THE STATION. [1857.
piercing with its spikes of granite the clear air. To my
mind it is one of the finest of the Aiguilles, noble in mass,
with its summits singularly cleft and splintered. In some
atmospheric colourings it has the exact appearance of a
mountain of cast copper, and the manner in which some of
its highest pinnacles are bent, suggesting the idea of ducti-
lity, gives strength to the illusion that the mass is metallic.
At the opposite side of the glacier was the Aiguille Verte,
with a cloud poised upon its point : it has long been the
ambition of climbers to scale this peak, and on this day it
was attempted by a young French count with a long
retinue of guides. He had not fair play, for before we
quitted our position we heard the rumble of thunder upon
the mountain, which indicated the presence of a foe more
terrible than the avalanches themselves. Higher to the
right, and also at the opposite side of the glacier, rose the
Aiguille du Moine; and beyond was the basin of the
Talefre, the ice cascade issuing from which appeared, from
our position, like the foam of a waterfall. Then came the
Aiguille de Lechaud, the Petite Jorasse, the Grande Jorasse,
and the Mont Tacul ; all of which form a cradle for the
Glacier de Lechaud. Mont Mallet, the Periades, and the
Aiguille Noire, came next, and then the singular obelisk of
the Aiguille du Geant, from which a serrated edge of
cliff descends to the summit of the " Col."
Over the slopes of the Col du Geant was spread a cover-
let of shining snow, at some places apparently as smooth
as polished marble, at others broken so as to form pre-
cipices, on the pale blue faces of which the horizontal lines
of bedding were beautifully drawn. As the eye approaches
the line which stretches from the Rognon to the Aiguille
Noire, the repose of the neve becomes more and more dis-
turbed. Vast chasms are formed, which however are still
merely indicative of the trouble in advance. If the gla-
cier were lifted off we should probably see that the line
1857.] SEKACS OF THE COL DU GEANT. 51
just referred to would lie along the summit of a steep
gorge ; over this summit the glacier is pushed, and has its
back periodically broken, thus forming vast transverse
ridges which follow each other in succession down the slope.
At the summit these ridges are often cleft by fissures
transverse to them, thus forming detached towers of ice of
the most picturesque and imposing character.* These
towers often fall ; and while some are caught upon the
platforms of the cascade, others struggle with the slow
energy of a behemoth through the debris which opposes
them, reach the edges of the precipices which rise in suc-
cession along the fall, leap over, and, amid ice-smoke and
thunder-peals, fight their way downwards.
A great number of secondary glaciers were in sight
hanging on the steep slopes of the mountains, and from
them streams sped downwards, falling over the rocks, and
filling the valley with a low rich music. In front of me,
for example, was the Glacier du Moine, and I could not
help feeling as I looked at it, that the arguments drawn
from the deportment of such glaciers against the " sliding
theory," and which are still repeated in works upon the
Alps, militate just as strongly against the " viscous theory."
" How," demands the antagonist of the sliding theory,
" can a secondary glacier exist upon so steep a slope ? why
does it not slide down as an avalanche ? " " But how," the
person addressed may retort, " can a mass which you as-
sume to be viscous exist under similar conditions ? If it be
viscous, what prevents it from rolling down ? " The sliding
theory assumes the lubrication of the bed of the glacier,
but on this cold height the quantity melted is too small
* To such towers the name Seracs is applied. In the chalets of Savoy,
after the richer curd has been precipitated by rennet, a stronger acid is
used to throw down what remains ; an inferior kind of cheese called Sdrac
is thus formed, the shape and colour of which have suggested the applica-
tion of the term to the cubical masses of ice.
E 2
52 GLACIEK MOTION. [1857.
to lubricate the bed, and hence the slow motion of these
glaciers. Thus a sliding-theory man might reason, and, if
the external deportment of secondary glaciers were to de-
cide the, question, De Saussure might perhaps have the
best of the argument.
And with regard to the current idea, originated by M.
de Charpentier, and adopted by Professor Forbes, that if a
glacier slides it must slide as an avalanche, it may be
simply retorted that, in part, it does so ; but if it be asserted
that an accelerated motion is the necessary motion of an
avalanche, the statement needs qualification. An avalanche
on passing through a rough couloir soon attains a uni-
form velocity — its motion being accelerated only up to the
point when the sum of the resistances acting upon it is
equal to the force drawing it downwards. These resistances
are furnished by the numberless asperities which the mass
encounters, and which incessantly check its descent, and
render an accumulation of motion impossible. The motion
of a man walking down stairs may be on the whole uniform,
but it is really made up of an aggregate of small motions,
each of which is accelerated ; and it is easy to conceive
how a glacier moving over an uneven bed, when released
from one opposing obstacle will be checked by another, and
its motion thus rendered sensibly uniform.
From the Aiguille du Geant and Les Periades a glacier
descended, which was separated by the promontory of La
Noire from the glacier proceeding from the Col du Geant.
A small moraine was formed between them, which is marked
a upon the diagram, Fig. 7. The great mass of the glacier
descending from the Col du Geant came next, and this was
bounded on the side nearest to Trelaporte by a small
moraine ft, the origin of which I could not see, its upper
portion being shut out by a mountain promontory. Between
the moraine b and the actual side of the valley was another
little glacier, derived from some of the lateral tributaries.
1857.]
MOKAINES.
It was, however, between the moraines a and b that the
great mass of the Glacier du Geant really lay. At the
Fig. 7.
promontory of the Tacul the lateral moraines of the Gla-
cier des Periades and of the Glacier de Lechaud united to
54 TKIBUTAEIES OF THE MER DE GLACE. [1857.
form the medial moraine c of the Mer de Glace. Carry-
ing the eye across the Lechaud, we had the moraine d
formed by the union of the lateral moraines of the Lechaud
and Talefre ; further to the left was the moraine e, which
came from the Jardin, and beyond it was the second lateral
moraine of the Talefre. The Mer de Glace is formed by
the confluence of the whole of the glaciers here named ;
being forced at Trelaporte through a passage, the width of
which appears considerably less than that of the single
tributary, the Glacier du Geant.
In the ice near Trelaporte the blue veins of the glacier
are beautifully shown ; but they vary in distinctness accord-
ing to the manner in which they are looked at. When
regarded obliquely their colour is. not so pronounced as
when the vision plunges deeply into them. The weathered
ice of the surface near Trelaporte could be cloven with great
facility ; I could with ease obtain plates of it a quarter of
an inch thick, and possessing two square feet of surface. On
the 28th of July I followed the veins several times from
side to side across the Geant portion of the Mer de Glace ;
starting from one side, and walking along the veins, my
route was directed obliquely downwards towards the axis
of the tributary. At the axis I was forced to turn, in
order to keep along the veins, and now ascended along
a line which formed nearly the same angle with the axis
at the other side. Thus the veins led me as it were
along the two sides of a triangle, the vertex of which was
near the centre of the glacier. The vertex was, however,
in reality rounded off, and the figure rather resembled a
hyperbola, which tended to coincidence with its asymp-
totes. This observation corroborates those of Professor
Forbes with regard to the position of the veins, and, like
him, I found that at the centre the veining, whose normal
direction would be transverse to the glacier, was contorted
and confused.
1857.] WASTING O.F ICE. 55
Near the side of the Glacier du Geant3 above the pro-
montory of Trelaporte, the ice is rent in a remarkable
manner. Looking upwards from the lower portions of the
glacier, a series of vertical walls, rising apparently one
above the other, face the observer. I clambered up among
these singular terraces, and now recognise, both from my
sketch and memory, that their peculiar forms are due to
the same action as that which has given their shape to the
" billows " of the Mer de Glace. A series of profound
crevasses is first formed. The Glacier du Geant deviates
14° from the meridian line, and hence the sun shines
nearly down it during the middle portion of each day.
The backs of the ridges between the crevasses are thus
rounded off, one boundary of each fissure is destroyed, or
at least becomes a mere steep declivity, while the other
boundary being shaded from the sun preserves its ver-
ticality ; and thus a very curious series of precipices is
formed.
Through all this dislocation, the little moraine on
which I have placed the letter b in the sketch maintains
its right to existence, and under it the laminated struc-
ture of this portion of the glacier appears to reach its
most perfect development. The moraine was generally
a mere dirt track, but one or two immense blocks of
granite were perched upon it. I examined the ice under-
neath one of these, being desirous of seeing whether the
pressure resulting from its enormous weight would pro-
duce a veining, but the result was not satisfactory.
Veins were certainly to be seen in directions different
from the normal ones, but whether they were due to
the bending of the latter, or were directly owing to the
pressure of the block, I could not say. The sides of a
stream which had cut a deep gorge in the clean ice
of the Glacier du Geant afforded a fine opportunity of
observing the structure. It was very remarkable — highly
56 GEOOVES ON THE SURFACE. [1857.
significant indeed in a theoretic point of view. Two long
and remarkably deep blue veins traversed the bottom of
the stream, and bending upwards at a place where the
rivulet curved, drew themselves like a pair of parallel lines
upon the clean white ice. But the general structure was
of a totally different character ; it did not consist of long
bars, but approximated to the lenticular form, and was,
moreover, of a washy paleness, which scarcely exceeded in
depth of colouring the whitish ice around.
To the investigator of the structure nothing can be Hner
than the appearance of the glacier from one of the ice
terraces cut in the Glacier du Geant by its passage round
Trelaporte. As far as the vision extended the dirt upon
the surface of the ice was arranged in striae. These striae
were not always straight lines, nor were they unbroken
curves. Within slight limits the various parts into which
a glacier is cut up by its crevasses enjoy a kind of inde-
pendent motion. The grooves, for example, on two ridges
which have been separated by a small fissure, may one
day have their striae perfect continuations of each other,
but in a short time this identity of direction may be
destroyed by a, difference of motion between the ridges.
Thus it is that the grooves upon the surface above Trela-
porte are bent hither and thither, a crack or seain always
marking the point where their continuity is ruptured.
This bending occurs, however, within limits sufficiently
small to enable the striae to preserve the same genera]
direction.
My attention had often been attracted this day by pro-
jecting masses of what at first appeared to be pure white
snow, rising in seams above the general surface of the
glacier. On examination, however, I found them to be
compact ice, filled with innumerable air-cells, and so
resistant as to maintain itself in some places at a height of
four feet above the general level. When amongst the
1857.] SEAMS OF WHITE ICE. 57
ridges they appeared discontinuous and confused, being
scattered apparently at random over the glacier ; but when
viewed from a sufficient distance, the detached parts
showed themselves to belong to a system of white seams
which swept quite across the Glacier du Geant, in a direc-
tion concentric with the structure. Unable to account for
these singular seams, I climbed up among the tributary
glaciers on the Rognon side of the Glacier du Geant, and
remained there until the sun sank behind the neighbour-
ing peaks, and the fading light warned me that it was
time to return.
(8.)
Early on the following day I was again upon the ice.
I first confined myself to the right side of the Glacier du
Geant, and found that the veins of white ice which I had
noticed on the previous day were exclusively confined to
this glacier, or to the space between the moraines a and
I (Fig. 7), bending up so that the moraine a between
the Glacier du Geant and the Glacier des Periades was
tangent to them. At a good distance up the glacier I
encountered a considerable stream rushing across it
almost from side to side. I followed the rivulet, examin-
ing the sections which it exposed. At a certain point
three other streams united, and formed at their place
of confluence a small green lake. From this a rivulet
rushed, which was joined by the stream whose track I had
pursued, and at this place of junction a second green lake
was formed, from which flowed a stream equal in volume
to the sum of all the tributaries. It entered a crevasse,
and took the bottom of the fissure for its bed. Standing
at the entrance of the chasm, a low muffled thunder
58 A LAKE SET FREE. [1857.
resounding through the valley attracted my attention. I
followed the crevasse, which deepened and narrowed, and,
by the blue light of the ice, could see the stream gam-
bolling along its bottom, and flashing as it jumped over
the ledges which it encountered in its way. The fissure
at length came to an end : placing a foot on each side
of it, and withholding the stronger light from my eyes,
I looked down between its shining walls, and saw the
stream plunge into a shaft which carried it to the bottom
of the glacier.
Slowly, and in zigzag fashion, as the crevasses demanded,
I continued to ascend, sometimes climbing vast humps of
ice from which good views of the surrounding glacier
were obtained ; sometimes hidden in the hollows between
the humps, in which also green glacier tarns were often
formed, very lonely and very beautiful.
While standing beside one of these, and watching the
moving clouds which it faithfully mirrored, I heard the
sound of what appeared to be a descending avalanche, but
the time of its continuance surprised me. Looking through
my opera-glass in the direction of the sound, I saw issuing
from the end of a secondary glacier on the Tacul side a tor-
rent of what appeared to me to be stones and mud. I could
see the stones and finer debris jumping down the declivi-
ties, and shaping themselves into singular cascades. The
noise continued for a quarter of an hour, after which the
torrent rapidly diminished, until, at length, the ordinary
little stream due to the melting of the glacier alone
remained. A subglacial lake had burst its boundary, and
carried along with it in its rush downwards the debris
which it met with in its course.
In some places I found the crevasses difficult, the ice
being split in a very singular manner. Vast plates of
it not more than a foot in thickness were sometimes de-
tached from the sides of the crevasses, and stood alone.
1857.] IMPEESSIVE SCENE. 59
I was now approaching the base of the seracs, and the
glacier around me still retained a portion of the turbu-
lence of the cascade. I halted at times amid the ruin and
confusion, and examined with my glass the cascade itself.
It was a wild and wonderful scene, suggesting throes of
spasmodic energy, though, in reality, all its dislocation had
been sloidij and gradually produced. True, the stratified
blocks which here and there cumbered the terraces sug-
gested debacles, but these were local and partial, and did
not affect the general question. There is scarcely a case
of geological disturbance which could not be matched with
its analogue upon the glaciers, — contortions, faults, fissures,
joints, and dislocations, — but in the case of the ice we can
prove the effects to be due to slowly-acting causes; how
reasonable is it then to ascribe to the operation of similar
causes, which have had an incomparably longer time to
work, many geological effects which at first sight might
suggest sudden convulsion !
Wandering slowly upwards, successive points of attrac-
tion drawing me almost unconsciously on, I found myself
as the day was declining deep in the entanglements of the
ice. A shower commenced, and a splendid rainbow threw
an oblique arch across the glacier. I was quite alone ; the
scene was exceedingly impressive, and the possibility of
difficulties on which I had not calculated intervening
between me and the lower glacier, gave a tinge of
anxiety to my position. I turned towards home ; crossed
some bosses of ice and rounded others : I followed the
tracks of streams which were very irregular on this portion
of the glacier, bending hither and thither, rushing through
deep-cut channels, falling in cascades and expanding here
and there to deep green lakes ; they often plunged into the
depths of the ice, flowed under it with hollow gurgle, and
reappeared at some distant point. I threaded my way
cautiously amid systems of crevasses, scattering with my
60 CHAMOUNI RULES. [1857.
axe, to secure a footing, the rotten ice of the sharper crests,
which fell with a ringing sound into the chasms at either
side. Strange subglacial noises were sometimes heard,
as if caverns existed underneath, into which blocks of
ice fell at intervals, transmitting the shock of their fall
with a dull boom to the surface of the glacier. By the
steady surmounting ot difficulties one after another, I at
length placed them all behind me, and afterwards hastened
swiftly along the glacier to my mountain home.
On the 30th incessant rain confined us to indoor work ;
on the 31st we determined the velocity with which the
glacier is forced through the entrance of the trunk valley
at Trelaporte, and also the motion of the Grand Moulin.
We also determined both the velocity and the width of the
Glacier du Geant. The 1st of August was spent by me at the
cascade of the Talefre, examining the structure, crumpling,
and scaling off of the ice. Finding that the rules at Cha-
mouni put an unpleasant limit to my demands on my
guide Simond, I visited the Guide Chef on the 2nd of
August, and explained to him the object of my expedition,
pointing out the inconvenience which a rigid application
of the rules made for tourists would impose upon me.
He had then the good sense to acknowledge the reason-
ableness of my remarks, and to grant me the liberty I
requested. The 3rd of August was employed in deter-
mining the velocity and width of the Glacier de Lech and,
and in observations on the lamination of the glacier.
1857.] THE JARDIN. 61
THE JARDIN.
ON the 4th of August, with a view of commencing a
series of observations on the inclinations of the Mer de
Glace and its tributaries, we had our theodolite transported
to the Jardin, which, as is well known, lies like an island
in the middle of the Glacier du Talefre. We reached the
place by the usual route, and found some tourists reposing
on the soft green sward which covers the lower portion, and
to which, and the flowers which spangle it, the place owes its
name. Towards the summit of the Jardin, a rock jutted
forward, apparently the very apex of the place, or at least
hiding by its prominence everything that might exist be-
hind it ; leaving our guide with the instrument, we aimed
at this, and soon left the grass and flowers behind us.
Stepping amid broken fragments of rock, along slopes of
granite, with fat felspar crystals which gave the boots a
hold, and crossing at intervals patches of snow, which
continued still to challenge the summer heat, I at length
found myself upon the peak referred to ; and, although it
was not the highest, the unimpeded view which it com-
manded induced me to get astride it. The Jardin was com-
pletely encircled by the ice of the glacier, and this was
held in a mountain basin, which was bounded all round
by a grand and cliffy rim. The outline of the dark brown
crags — a deeply serrated and irregular line — was forcibly
drawn against the blue heaven, and still more strongly
against some white and fleecy clouds which lay here and
there behind it ; while detached spears and pillars of
rock, sculptured by frost and lightning, stood like a kind of
defaced statuary along the ridge. All round the basin the
62 A EESEEVOIK OF ICE. [1857.
snow reared itself like a buttress against the precipitous
cliffs, being streaked and fluted by the descent of blocks
from the summits. This mighty tub is the collector of one
of the tributaries of the Mer de Glace. According to Pro-
fessor Forbes, its greatest diameter is 4200 yards, and out
of it the half-formed ice is squeezed through a precipitous
gorge about 700 yards wide, forming there the ice cascade
of the Talefre. Bounded on one side by the Grande
Jorasse, and on the other by Mont Mallet, the principal
tributary of the Glacier de Lechaud lay white and pure
upon the mountain slope. Bound further to the right we
had the vast plateau whence the Glacier du Geant is fed,
fenced on the left by the Aiguille du Geant and the
Aiguille Noire, and on the right by the MontsMaudits and
Mont Blanc. The scene was a truly majestic one. The
mighty Aiguilles piercing the sea of air, the soft white
clouds floating here and there behind them ; the shining
snow with its striped faults and precipices ; the deep blue
firmament overhead ; the peals of avalanches and the
sound of water ; — all conspired to render the scene glori-
ous, and our enjoyment of it deep.
A voice from, above hailed me as I moved from my
perch ; it was my friend, who had found a lodgment
upon the edge of a rock which was quite detached from
the Jardin, being the first to lift its head in opposition to
the descending neve. Making a detour round a steep
concave slope of the glacier, I reached the flat summit of
the rock. The end of a ridge of ice abutted against it,
which was split and bent by the pressure so as to form a
kind of arch. I cut steps in the ice, and ascended until I got
beneath the azure roof. Innumerable little rills of pellucid
water descended from it. Some came straight down, clear
for a time, and apparently motionless, rapidly tapering at
first, and more slowly afterwards, until, at the point of maxi-
mum contraction, they resolved themselves into strings of
1857.] MOEAINES OF THE TALEFKE. 63
liquid pearls which pattered against the ice floor under-
neath. Others again, owing to the directions of the little
streamlets of which they were constituted, formed spiral
figures of great beauty : one liquid vein wound itself round
another, forming a spiral protuberance, and owing to the
centrifugal motion thus imparted, the vein, at its place
of rupture, scattered itself laterally in little liquid
spherules.* Even at this great elevation the structure of
the ice was fairly developed, not with the sharpness to be
observed lower down, but still perfectly decided. Blue
bands crossed the ridge of ice to which I have referred,
at right angles to the direction of the pressure.
I descended, and found my friend beneath an over-
hanging rock. Immediately afterwards a peal like that
of thunder shook the air, and right in front of us an
avalanche darted down the brown cliffs, then along a steep
slope of snow which reared itself against the mountain wall,
carrying with it the debris of the rocks over which it
passed, until it finally lay a mass of sullied rubbish at the
base of the incline : the whole surface of the Talefre is
thus soiled. Another peal was heard immediately after-
wards, but the avalanche which caused it was hidden
from us by a rocky promontory. From this same pro-
montory the greater portion of the medial moraine which
descends the cascade of the Talefre is derived, forming
at first a gracefully winding curve, and afterwards stretch-
ing straight to the summit of the fall. In the chasms of
the cascade its boulders are engulfed, but the lost moraine
is restored below the fall, as if disgorged by the ice which
had swallowed it. From the extremity of the Jardin itself
a mere driblet of a moraine proceeds, running parallel to
the former, and like it disappearing at the summit of the
cascade.
* The recent hydraulic researches of Professor Magnus furnish some
beautiful illustrations of this action.
64 AMONG THE CREVASSES. [1857.
We afterwards descended towards the cascade, but long
before this is attained the most experienced iceman would
find himself in difficulty. Transverse crevasses are formed,
which follow each other so speedily as to leave between
them mere narrow ridges of ice, along which we moved
cautiously, jumping the adjacent fissures, or getting round
them, as the case demanded. As we approached the jaws
of the gorge, the ridges dwindled to mere plates and wedges,
which being bent and broken by the lateral pressure, added
to the confusion, and warned us not to advance. The
position was in some measure an exciting one. Our guide
had never been here before ; we were far from the beaten
track, and the riven glacier wore an aspect of treacherous
hostility. As at the base of the semes, a subterranean
noise sometimes announced the falling of ice-blocks into
hollows underneath, the existence of which the resonant
concussion of the fallen mass alone revealed. There was
thus a dash of awe mingled with our thoughts ; a stirring
up of the feelings which troubled the coolness of the intel-
lect. We finally swerved to the right, and by a process
the reverse of straightforward reached the Couvercle.
Nightfall found us at the threshold of our hotel.
(10.)
On the 5th we were engaged for some time in an im-
portant measurement at the Tacul. We afterwards ascended
towards the seracs, and determined the inclinations of the
Glacier du Geant downwards. Dense cloud-masses gathered
round the points of the Aiguilles, and the thunder bellowed
at intervals from the summit of Mont Blanc. As we de-
scended the Mer de Glace the valley in front of us was
filled with a cloud of pitchy darkness. Suddenly from side
1857.] ROUND HAILSTONES. 65
to side this field of gloom was riven by a bar of light-
ning of intolerable splendour ; it was followed by a peal of
commensurate grandeur, the echoes of which leaped from
cliff to cliff long after the first sound had died away. The
discharge seemed to unlock the clouds above us, for they
showered their liquid spheres down upon us with a mo-
mentum like that of swan-shot : all the way home we were
battered by this pellet-like rain. On the 6th the rain con-
tinued with scarcely any pause ; on the 7th I was engaged
all day upon the Glacier du Geant ; on the morning of the
8th heavy hail had fallen there, the stones being perfect
spheres ; the rounded rain-drops had solidified during then*
descent without sensible change of form. When this hail
was squeezed together, it exactly resembled a mass of
oolitic limestone which I had picked up in 1853 near
Blankenburg in the Hartz. Mr. Hirst and myself were en-
gaged together this day taking the inclinations : he struck
his theodolite at the Angle, and went home accompanied
by Simond, and the evening being extremely serene, I pur-
sued my way down the centre of the glacier towards the
Echelets. The crevasses as I advanced became more
deep and frequent, the ridges of ice between them becom-
ing gradually narrower. They were very fine, their down-
ward faces being clear cut, perfectly vertical, and in many
cases beautifully veined. Vast plates of ice moreover
often stood out midway between the walls of the chasms,
as if cloven from the glacier and afterwards set on edge.
The place was certainly one calculated to test the skill
and nerve of an iceman; and as the day drooped, and
the shadow in the valley deepened, a feeling approach-
ing to awe took possession of me. My route was an exag-
gerated zigzag ; right and left amid the chasms wherever
a hope of progress opened ; and here I made the experience
which I have often repeated since, and laid to heart as
regards intellectual work also, that enormous difficulties
F
66 A DANGEROUS LEAP. [1857.
may be overcome when they are attacked in earnest.
Sometimes I found myself so hedged in by fissures that
escape seemed absolutely impossible ; but close and resolute
examination so often revealed a means of exit, that I felt
in all its force the brave verity of the remark of Mirabeau,
that the word " impossible " is a mere blockhead of a word.
It finally became necessary to reach the shore, but I found
this a work of extreme difficulty. At length, however, it be-
came pretty evident that, if I could cross a certain crevasse,
my retreat would be secured. The width of the fissure
seemed to be fairly within jumping distance, and if I could
have calculated on a safe purchase for my foot I should
have thought little of the spring ; but the ice on the edge
from which I was to leap was loose and insecure, and hence
a kind of nervous thrill shot through me as I made the
bound. The opposite side was fairly reached, but an invo-
luntary tremor shook me all over after I felt myself secure.
I reached the edge of the glacier without further serious
difficulty, and soon after found myself steeped in the crea-
ture comforts of our hotel.
On Monday, August 10th, I had the great pleasure of
being joined by my friend Huxley ; and though the weather
was very unpromising, we started together up the glacier,
he being desirous to learn something of its general features,
and, if possible, to reach the Jardin. We reached the
Couvercle, and squeezed ourselves through the Egralets ;
but here the rain whizzed past us, and dense fog settled
upon the cascade of the Talefre, obscuring all its parts.
We met Mr. Galton, the African traveller, returning
from an attempt upon the Jardin ; and learning that his
guides had lost their way in the fog, we deemed it prudent
to return.
The foregoing brief notes will have informed the reader
that at the period of Mr. Huxley's arrival I was not with-
out due training upon the ice ; I may also remark, that on
1857.] PKEPAKATIONS FOR A CLIMB. 67
the 25th of July I reached the sum-rait of the Col du
Geant, accompanied by the boy Balmat, and returned to
Montanvert on the same day. My health was perfect,
and incessant practice had taught me the art of dealing
with the difficulties of the ice. From the time of my
arrival at the Montanvert the thought of ascending Mont
Blanc, and thus expanding my knowledge of the glaciers,
had often occurred to me, and I think I was justified in
feeling that the discipline which both my friend Hirst
and myself had undergone ought to enable us to accom-
plish the journey in a much more modest way than ordi-
nary. I thought a single guide sufficient for this purpose,
and I was strengthened in this opinion by the fact that
Simond, who was a man of the strictest prudence, and who
at first declared four guides to be necessary, had lowered
his demand first to two, and was now evidently willing to
try the ascent with us alone.
On mentioning the thing to Mr. Huxley he at once
resolved to accompany us. On the llth of August the
weather was exceedingly fine, though the snow which had
fallen during the previous days lay thick upon the glacier.
At noon we were all together at the Tacul, and the subject
of attempting Mont Blanc was mooted and discussed. My
opinion was that it would be better to wait until the fresh
snow which loaded the mountain had- disappeared ; but the
weather was so exquisite that my friends thought it best to
take advantage of it. We accordingly entered into an
agreement with our guide, and immediately descended to
make preparations for commencing the expedition on the
following morning.
F 2
68 SCENE FEOM THE CHARMOZ. [1857.
FIRST ASCENT OF MONT BLANC, 1857.
(11.)
ON Wednesday, the 12th of August, we rose early, after a
very brief rest on my part. Simond had proposed to go down
to Chamouni, and commence the ascent in the usual way,
but we preferred crossing the mountains from the Montan -
vert, straight to the Glacier des Bossons. At eight o'clock
we started, accompanied by two porters who were to carry
our provisions to the Grands Mulets. Slowly and silently
we climbed the hill-side towards Charmoz. We soon
passed the limits of grass and rhododendrons, and reached
the slabs of gneiss which overspread the summit of the
ridge, lying one upon the other like coin upon the table of
a money-changer. From the highest point I turned to
have a last look at the Mer de Glace ; and through a pair
of very dark spectacles I could see with perfect distinct-
ness the looped dirt-bands of the glacier, which to the
naked eye are scarcely discernible except by twilight.
Flanking our track to the left rose a series of mighty
Aiguilles — the Aiguille de Charmoz, with its bent and
rifted pinnacles ; the Aiguille du Grepon, the Aiguille de
Blaitiere, the Aiguille du Midi, all piercing the heavens
with their sharp pyramidal summits. Far in front of us
rose the grand snow-cone of the Dome du Gouter, while,
through a forest of dark pines which gathered like a
cloud at the foot of the mountain, gleamed the white
minarets of the Glacier des Bossons. Below us lay the
Valley of Chamouni, beyond which were the Brevent and
the chain of the Aiguilles Rouges ; behind us was the
granite obelisk of the Aiguille du Dru, while close at hand
science found a corporeal form in a pyramid of stones
1857.] PASSAGE TO THE PIEERE A L'ECHELLE. 69
used as a trigonometrical station by Professor Forbes.
Sound is known to travel better up hill than down, be-
cause the pulses transmitted from a denser medium to a
rarer, suffer less loss of intensity than when the transmis-
sion is in the opposite direction ; and now the mellow voice
of the Arve came swinging upwards from the heavier air
of the valley to the lighter air of the hills in rich deep
cadences.
The way for a time was excessively rough, our route
being overspread with the fragments of peaks which had
once reared themselves to our left, but which frost and
lightning had shaken to pieces, and poured in granite
avalanches down the mountain. We were sometimes
among huge angular boulders, and sometimes amid lighter
shingle, which gave way at every step, thus forcing us
to shift our footing incessantly. Escaping from these, we
crossed the succession of secondary glaciers which lie at
the feet of the Aiguilles, and having secured firewood
found ourselves after some hours of hard work at the
Pierre a 1'Echelle. Here we were furnished with leggings
of coarse woollen cloth to keep out the snow ; they were
tied under the knees and quite tightly again over the
insteps, so that the legs were effectually protected. We
had some refreshment, possessed ourselves of the ladder,
and entered upon the glacier.
The ice was excessively fissured : we crossed crevasses
and crept round slippery ridges, cutting steps in the ice
wherever climbing was necessary. This rendered our pro-
gress very slow. Once, with the intention of lending a
helping hand, I stepped forward upon a block of granite
which happened to be poised like a rocking stone upon the
ice, though I did not know it; it treacherously turned
under me ; I fell, but my hands were in instant requisition,
and I escaped with a bruise, from which, however, the
blood oozed angrily. We found the ladder necessary in
70 LADDER LEFT BEHIND. [1857.
crossing some of the chasms, the iron spikes at its end
being firmly driven into the ice at one side, while the
other end rested on the opposite side of the fissure. The
middle portion of the glacier was not difficult. Mounds of
ice rose beside us right and left, which were sometimes
split into high towers and gaunt-looking pyramids, while
the space between was unbroken. Twenty minutes' walk-
ing brought us again to a fissured portion of the glacier,
and here our porter left the ladder on the ice behind him.
For some time I was not aware of this, but we were soon
fronted by a chasm to pass which we were in consequence
compelled to make a long and dangerous circuit amid
crests of crumbling ice. This accomplished, we hoped
that no repetition of the process would occur, but we
speedily came to a second fissure, where it was neces-
sary to step from a projecting end of ice to a mass of soft
snow which overhung the opposite side. Simond could
reach this snow with his long-handled axe ; he beat it
down to give it rigidity, but it was exceedingly tender,
and as he worked at it he continued to express his fears
that it would not bear us. I was the lightest of the
party, and therefore tested the passage first ; being par-
tially lifted by Simond on the end of his axe, I crossed
the fissure, obtained some anchorage at the other side, and
helped the others over. We afterwards ascended until
another chasm, deeper and wider than any we had hitherto
encountered, arrested us. We walked alongside of it in
search of a snow bridge, which we at length found, but the
keystone of the arch had unfortunately given way, leaving
projecting eaves of snow at both sides, between which we
could look into the gulf, till the gloom of its deeper por-
tions cut the vision short. Both sides of the crevasse were
sounded, but no sure footing was obtained ; the snow was
beaten and carefully trodden down as near to the edge as
possible, but it finally broke away from the foot and fell
18,57.] DIFFICULT CKEVASSES. 71
into the chasm. One of our porters was short-legged and
a bad iceman ; the other was a daring fellow, and he now
threw the knapsack from his shoulders, came to the edge
of the crevasse, looked into it, but drew back again. After
a pause he repeated the act, testing the snow with his feet
and staff. I looked at the man as he stood beside the
chasm manifestly undecided as to whether he should take
the step upon which his life would hang, and thought it
advisable to put a stop to such perilous play. I accord-
ingly interposed, the man withdrew from the crevasse, and
he and Simond descended to fetch the ladder.
While they were away Huxley sat down upon the ice,
with an expression of fatigue stamped upon his counte-
nance : the spirit and the muscles were evidently at war,
and the resolute will mixed itself strangely with the sense
of peril and feeling of exhaustion. He had been only two
days with us, and, though his strength is great, he had had
no opportunity of hardening himself by previous exercise
upon the ice for the task which he had undertaken. The
ladder now arrived, and we crossed the crevasse. I was
intentionally the last of the party, Huxley being immedi-
ately in front of me. The determination of the man dis-
guised his real condition from everybody but myself, but
I saw that the exhausting journey over the boulders and
debris had been too much for his London limbs. Con-
verting my waterproof havresack into a cushion, I made
him sit down upon it at intervals, and by thus breaking the
steep ascent into short stages we reached the cabin of the
Grands Mulets together. Here I spread a rug on the
boards, and placing my bag for a pillow, he lay down, and
after an hour's profound sleep he rose refreshed and well ;
but still he thought it wise not to attempt the ascent
farther. Our porters left us : a baton was stretched across
the room over the stove, and our wet socks and leggings
were thrown across it to dry; our boots were placed
7*2 STAR TWINKLING. [1857.
around the fire, and we set about preparing our evening
meal. A pan was placed upon the fire, and filled with
snow, which in due time melted and boiled ; I ground some
chocolate and placed it in the pan, and afterwards ladled
the beverage into the vessels we possessed, which con-
sisted of two earthen dishes and the metal cases of our
brandy flasks. After supper Simond went out to inspect
the glacier, and was observed bj Huxley, as twilight
fell, in a state of deep contemplation beside a crevasse.
Gradually the stars appeared, but as yet no moon. Be-
fore lying down we went out to look at the firmament, and
noticed, what I suppose has been observed to some extent
by everybody, that the stars near the horizon twinkled
busily, while those near the zenith shone with a steady
light. One large star in particular excited our admira-
tion ; it flashed intensely, and changed colour incessantly,
sometimes blushing like a ruby, and again gleaming like
an emerald. A determinate colour would sometimes re-
main constant for a sensible time, but usually the flashes
followed each other in very quick succession. Three planks
were now placed across the room near the stove, and
upon these, with their rugs folded round them, Huxley
and Hirst stretched themselves, while I nestled on the
boards at the most distant end of the room. We rose at
eleven o'clock, renewed the fire and warmed ourselves,
after which we lay down again. I at length observed a
patch of pale light upon the wooden wall of the cabin,
which had entered through a hole in the end of the edifice,
and rising found that it was past one o'clock. The cloud-
less moon .was shining over the wastes of snow, and the
scene outside was at once wild, grand, and beautiful.
Breakfast was soon prepared, though not without diffi-
culty ; we had no candles, they had been forgotten ; but I
fortunately possessed a box of wax matches, of which Huxley
took charge, patiently igniting them in succession, and
1857.] START FROM THE GRANDS MULETS. 73
thus giving us a tolerably continuous light. We had some
tea, which had been made at the Montanvert, and carried
to the Grands Mulets in a bottle. My memory of that
tea is not pleasant ; it had been left a whole night in con-
tact with its leaves, and smacked strongly of tannin. The
snow-water, moreover, with which we diluted it was not
pure, but left a black residuum at the bottom of the dishes
in which the beverage was served. The few provisions
deemed necessary being placed in Simond's knapsack, at
twenty minutes past two o'clock we scrambled down the
rocks, leaving Huxley behind us.
The snow was hardened by the night's frost, and we
were cheered by the hope of being able to accomplish
the ascent with comparatively little labour. We were
environed by an atmosphere of perfect purity ; the larger
stars hung like gems above us, and the moon, about half
full, shone with wondrous radiance in the dark firmament.
One star in particular, which lay eastward from the moon,
suddenly made its appearance above one of the Aiguilles,
and burned there with unspeakable splendour. We turned
once towards the Mulets, and saw Huxley's form projected
against the sky as he stood upon a pinnacle of rock ; he
gave us a last wave of the hand and descended, while we
receded from him into the solitudes.
The evening previous our guide had examined the glacier
for some distance, his progress having been arrested by a
crevasse. Beside this we soon halted : it was spanned at
one place by a bridge of snow, which was of too light a
structure to permit of Simond's testing it alone ; we there-
fore paused while our guide uncoiled a rope and tied us
all together. The moment was to me a peculiarly solemn
one. Our little party seemed so lonely and so small amid
the silence and the vastness of the surrounding scene. We
were about to try our strength under unknown conditions,
and as the various possibilities of the enterprise crowded on
74 A WKONG- TUEN. [1857.
the imagination, a sense of responsibility for a moment
oppressed me. But as I looked aloft and saw the glory of
the heavens, my heart lightened, and I remarked cheerily
to Hirst that Nature seemed to smile upon our work.
" Yes," he replied, in a calm and earnest voice, " and, God
willing, we shall accomplish it."
A pale light now overspread the eastern sky, which
increased, as we ascended, to a daffodil tinge ; this after-
wards heightened to orange, deepening at one extremity
into red, and fading at the other into a pure ethereal hue
to which it would be difficult to assign a special name.
Higher up the sky was violet, and this changed by insen-
sible degrees into the darkling blue of the zenith, which
had to thank the light of moon and stars alone for its exist-
ence. We wound steadily for a time through valleys of
ice, climbed white and slippery slopes, crossed a num-
ber of crevasses, and after some time found ourselves
beside a chasm of great depth and width, which extended
right and left as far as we could see. We turned to the
left, and marched along its edge in search of a pout ; but
matters became gradually worse : other crevasses joined
on to the first one, and the further we proceeded the more
riven and dislocated the ice became. At length we
reached a place where further advance was impossible.
Simond in his difficulty complained of the want of
light, and wished us to wait for the advancing day ; I,
on the contrary, thought that we had light enough and
ought to make use of it. Here the thought occurred to me
that Simond, having been only once before to the top of the
mountain, might not be quite clear about the route ; the
glacier, however, changes within certain limits from year
to year, so that a general knowledge was all that could be
expected, and we trusted to our own muscles to make good
any mistake in the way of guidance. We now turned and
retraced our steps along the edges of chasms where the ice
1857.] SEKACS OF THE D6ME DU GOITER 75
was disintegrated and insecure, and succeeded at length in
finding a bridge which bore us across the crevasse. This
error caused us the loss of an hour, and after walking for this
time we could cast a stone from the point we had attained
to the place whence we had been compelled to return.
Our way now lay along the face of a steep incline of
snow, which was cut by the fissure we had just passed, in a
direction parallel to our route. On the heights to our
right, loose ice-crags seemed to totter, and we passed two
tracks over which the frozen blocks had rushed some short
time previously. We were glad to get out of the range of
these terrible projectiles, and still more so to escape the
vicinity of that ugly crevasse. To be killed in the open air
would be a luxury, compared with having the life squeezed
out of one in the horrible gloom of these chasms. The blush
of the coming day became more and more intense ; still the
sun himself did not appear, being hidden from us by the
peaks of the Aiguille du Midi, which were drawn clear
and sharp against the brightening sky. Right under this
Aiguille were heaps of snow smoothly rounded and consti-
tuting a portion of the sources whence the Glacier du
Geant is fed ; these, as the day advanced, bloomed with a
rosy light. We reached the Petit Plateau, which we found
covered with the remains of ice avalanches ; above us upon
the crest of the mountain rose three mighty bastions,
divided from each other by deep vertical rents, with clean
smooth walls, across which the lines of annual bedding
were drawn like courses of masonry. From these, which
incessantly renew themselves, and from the loose and
broken ice-crags near them, the boulders amid which we
now threaded our way had been discharged. When they
fall their descent must be sublime.
The snow had been gradually getting deeper, and the
ascent more wearisome, but superadded to this at the Petit
Plateau was the uncertainty of the footing between the
76 THE LOST GUIDES. [1857.
blocks of ice. In many places the space was merely
covered by a thin crust, which, when trod upon, instantly
yielded, and we sank with a shock sometimes to the hips.
Our way next lay up a steep incline to the Grand Plateau,
the depth and tenderness of the snow augmenting as we
ascended. We had not yet seen the sun, but, as we
attained the brow which forms the entrance to the Grand
Plateau, he hung his disk upon a spike of rock to our
left, and, surrounded by a glory of interference spectra
of the most gorgeous colours, blazed down upon us. On
the Grand Plateau we halted and had our frugal refresh-
ment. At some distance to our left was the crevasse into
which Dr. Hamel's three guides were precipitated by an
avalanche in 1820 ; they are still entombed in the ice,
and some future explorer may perhaps see them disgorged
lower down, fresh and undecayed. They can hardly reach
the surface until they pass the snow-line of the glacier, for
above this line the quantity of snow that annually falls
being in excess of the quantity melted, the tendency would
be to make the ice-covering above them thicker. But it
is also possible that the waste of the ice underneath may
have brought the bodies to the bed of the glacier, where
their very bones may have been ground to mud by an
agency which the hardest rocks cannot withstand.
As the sun poured his light upon the Plateau the little
snow-facets sparkled brilliantly, sometimes with a pure
white light, and at others with prismatic colours. Con-
trasted with the white spaces above and around us were
the dark mountains on the opposite side of the valley of
Chamouni, around which fantastic masses of cloud were
beginning to build themselves. Mont Buet, with its cone
of snow, looked small, and the Brevent altogether mean ;
the limestone bastions of the Fys, however, still pre-
sented a front of gloom and grandeur. We traversed
the Grand Plateau, and at length reached the base of an
1857.] THE GUIDE TIRED. 77
extremely steep incline which stretched upwards towards
the Corridor. Here, as if produced by a fault, consequent
upon the sinking of the ice in front, rose a vertical preci-
pice, from the coping of which vast stalactites of ice de-
pended. Previous to reaching this place I had noticed a
haggard expression upon the countenance of our guide,
which was now intensified by the prospect of the ascent
before him. Hitherto he had always been in front, which
was certainly the most fatiguing position. I felt that I
must now take the lead, so I spoke cheerily to the man
and placed him behind me. Marking a number of points
upon the slope as resting places, I went swiftly from one
to the other. The surface of the snow had been partially
melted by the sun and then refrozen, thus forming a super-
ficial crust, which bore the weight up to a certain point,
and then suddenly gave way, permitting the leg to sink
to above the knee. The shock consequent on this, and the
subsequent effort necessary to extricate the leg, were ex-
tremely fatiguing. My motion was complained of as too
quick, and my tracks as imperfect; I moderated the
former, and, to render my footholes broad and sure, I
stamped upon the frozen crust, and twisted my legs in the
soft mass underneath, — a terribly exhausting process. I
thus led the way to the base of the Rochers Rouges, up to
which the fault already referred to had prolonged itself as
a crevasse, which was roofed at one place by a most dan-
gerous-looking snow-bridge. Simond came to the front ;
I drew his attention to the state of the snow, and proposed
climbing the Rochers Rouges ; but, with a promptness un-
usual with him, he replied that this was impossible ; the
bridge was our only means of passing, and we must try it.
We grasped our ropes, and dug our feet firmly into the snow
to check the man's descent if the pont gave way, but to our
astonishment it bore him, and bore us safely after him.
The slope which we had now to ascend had the snow swept
78 A PERILOUS SLOPE. [1857.
from its surface, and was therefore firm ice. It was most
dangerously steep, and, its termination being the fretted
coping of the precipice to which I have referred, if we
slid downwards we should shoot over this and be dashed
to pieces upon the ice below.* Simond, who had come to
the front to cross the crevasse, was now engaged in cutting
steps, which he made deep and large, so that they might
serve us on our return. But the listless strokes of his
axe proclaimed his exhaustion ; so I took the implement
out of his hands, and changed places with him. Step after
step was hewn, but the top of the Corridor appeared ever
to recede from us. Hirst was behind unoccupied, and could
thus turn his thoughts to the peril of our position : he felt
the angle on which we hung, and saw the edge of the pre-
cipice, to which less than a quarter of a minute's slide
would carry us, and for the first time during the journey he
grew giddy. A cigar which he lighted for the purpose
tranquilized him.
I hewed sixty steps upon this slope, and each step had
cost a minute, by Hirst's watch. The Mur de la Cote
was still before us, and on this the guide-books in-
formed us two or three hundred steps were sometimes found
necessary. If sixty steps cost an hour, what would be the
cost of two hundred ? The question was disheartening in
the extreme, for the time at which we had calculated on
reaching the summit was already passed, while the chief
difficulties remained unconquered. Having hewn our way
along the harder ice we reached snow. I again resorted to
stamping to secure a footing, and while thus engaged be-
came, for the first time, aware of the drain of force to
which I was subjecting myself. The thought of being
* Those acquainted with the mountain will at once recognise the grave
error here committed. In fact, on starting from the Grands Mulcts we
had crossed the glacier too far, and throughout were much too close to the
Dome du Gouter.
1857.] WILL AND MUSCLE. 79
absolutely exhausted had never occurred to me, and from
first to last I had taken no care to husband my strength. I
always calculated that the will would serve me even should
the muscles fail, but I now found that mechanical laws rule
man in the long run ; that no effort of will, no power of
spirit, can draw beyond a certain limit upon muscular force.
The soul, it is true, can stir the body to action, but its
function is to excite and apply force, and not to create it.
While stamping forward through the frozen crust I was
compelled to pause at short intervals ; then would set out
again apparently fresh, to find, however, in a few minutes
that my strength was gone, and that I required to rest
once more. In this way I gained the summit of the Cor-
ridor, when Hirst came to the front, and I felt some relief
in stepping slowly after him, making use of the holes into
which his feet had sunk. He thus led the way to the base
of the Mur de la Cote, the thought of which had so long
cast a gloom upon us ; here we left our rope behind us,
and while pausing I asked Simond whether he did not feel
a desire to go to the summit — " Bien sur" was his reply,
" mais ! " Our guide's mind was so constituted that the
u mais" seemed essential to its peace. I stretched my
hand towards him, and said, " Simond, we must do it."
One thing alone I felt could defeat us : the usual time of
the ascent had been more than doubled, the day was
already far spent, and if the ascent would throw our sub-
sequent descent into night it could not be contemplated.
We now faced the Mur, which was by no means so bad
as we had expected. Driving the iron claws of our boots
into the scars made by the axe, and the spikes of our
batons into the slope above our feet, we ascended steadily
until the summit was attained, and the top of the moun-
tain rose clearly above us. We congratulated ourselves
upon this; but Simond, probably fearing that our joy
might become too full, remarked, " Mais le sommet est
80 A DOZE ON THE CALOTTE. [1857.
encore Hen loin ! " It was, alas ! too true. The snow be-
came soft again, and our weary limbs sank in it as
before. Our guide went on in front, audibly muttering
his doubts as to our ability to reach the top, and at length
he threw himself upon the snow, and exclaimed, " II faiit
y renoncer ! " Hirst now undertook the task of rekindling
the guide's enthusiasm, after which Simoiid rose, ex-
claiming, "Ah! comme qa me fait mat aux genoux" and
went forward. Two rocks break through the snow between
the summit of the Mur and the top of the mountain ;
the first is called the Petits Mulets, and the highest the
Derniers Rochers. At the former of these we paused to
rest, and finished our scanty store of wine and provisions.
We had not a bit of bread nor a drop of wine left ; our
brandy flasks were also nearly exhausted, and thus we had
to contemplate the journey to the summit, and the subse-
quent descent to the Grands Mulets, without the slightest
prospect of physical refreshment. The almost total loss
of two nights' sleep, with two days' toil superadded, made
me long for a few minutes' doze, so I stretched myself
upon a composite couch of snow and granite, and imme-
diately fell asleep. My friend, however, soon aroused me.
"You quite frighten me," he said; "I have listened for
some minutes, and have not heard you breathe once." I
had, in reality, been taking deep draughts of the moun-
tain air, but so silently as not to be heard.
I now filled our empty wine-bottle with snow and placed
it in the sunshine, that we might have a little water on
our return. We then rose ; it was half-past two o'clock ;
we had been upwards of twelve hours climbing, and I cal-
culated that, whether we reached the summit or not, we
could at all events work towards it for another hour. To
the sense of fatigue previously experienced, a new pheno-
menon was now added — the beating of the heart. We
were incessantly pulled up by this, which sometimes be-
1857.] THE SUMMIT ATTAINED. 81
came so intense as to suggest danger. I counted the
number of paces which we were able to accomplish with-
out resting, and found that at the end of every twenty,
sometimes at the end of fifteen, we were compelled to
pause. At each pause my heart throbbed audibly, as I
leaned upon my staff, and the subsidence of this action
was always the signal for further advance. My breathing
was quick, but light and unimpeded. I endeavoured to
ascertain whether the hip-joint, on account of the dimi-
nished atmospheric pressure, became loosened, so as to
throw the weight of the leg upon the surrounding liga-
ments, but could not be certain about it. I also sought a
little aid and encouragement from philosophy, endeavour-
ing to remember what great things had been done by the
accumulation of small quantities, and I urged upon my-
self that the present was a case in point, and that
the summation of distances twenty paces each must finally
place us at the top. Still the question of time left the
matter long in doubt, and until we had passed the Derniers
Rochers we worked on with the stern indifference of men
who were doing their duty, and did not look to conse-
quences. Here, however, a gleam of hope began to brighten
our souls ; the summit became visibly nearer, Simond
showed more alacrity ; at length success became certain,
and at half-past three P.M. my friend and I clasped hands
upon the top.
The summit of the mountain is an elongated ridge,
which has been compared to the back of an ass. It
was perfectly manifest that we were dominant over all
other mountains ; as far as the eye could range Mont
Blanc had no competitor. The summits which had looked
down upon us in the morning were now far beneath us.
The Dome du Gouter, which had held its threatening semes
above us so long, was now at our feet. The Aiguille du
Midi, Mont Blanc du Tacul, and the Monts Maudits, the
Gr
82 CLOUDS FEOM THE SUMMIT. [1857.
Talefre with its surrounding peaks, the Grand Jorasse, Mont
Mallet, and the Aiguille du Geant, with our own familial-
glaciers, were all below us. And as our eye ranged over
the broad shoulders of the mountain, over ice hills and
valleys, plateaux and far-stretching slopes of snow, the
conception of its magnitude grew upon us, and impressed
us more and more.
The clouds were very grand — grander indeed than any-
thing I had ever before seen. Some of them seemed to
hold thunder in their breasts, they were so dense and dark ;
others, with their faces turned sunward, shone with the
dazzling whiteness of the mountain snow ; while others
again built themselves into forms resembling gigantic elm
trees, loaded with foliage. Towards the horizon the luxury
of colour added itself to the magnificent alternations of
light and shade. Clear spaces of amber and ethereal green
embraced the red and purple cumuli, and seemed to form
the cradle in which they swung. Closer at hand squally
mists, suddenly engendered, were driven hither and thither
by local winds ; while the clouds at a distance lay " like
angels sleeping on the wing," with scarcely visible motion.
Mingling with the clouds, and sometimes rising above them,
were the highest mountain heads, and as our eyes wandered
from peak to peak, onwards to the remote horizon, space
itself seemed more vast from the manner in which the
objects which it held were distributed.
I wished to repeat the remarkable experiment of
De Saussure upon sound, and for this purpose had requested
Simond to bring a pistol from Chamouni ; but in the mul-
titude of his cares he forgot it, and in lieu of it my host at
the Montanvert had placed in two tin tubes, of the same
size and shape, the same amount of gunpowder, securely
closing the tubes afterwards, and furnishing each of them
with a small lateral aperture. We now planted one of
them upon the snow, and bringing a strip of amadou into
1857.] INTENSITY OF SOUND. 83
communication with the touchhole, ignited its most distant
end : it failed ; we tried again, and were successful, the
explosion tearing asunder the little case which contained
the powder. The sound was certainly not so great as I
should have expected from an equal quantity of powder at
the sea level.*
The snow upon the summit was indurated, but of an
exceedingly fine grain, and the beautiful effect already
referred to as noticed upon the Stelvio was strikingly
manifest. The hole made by driving the baton into the
snow was filled with a delicate blue light ; and, by manage-
ment, its complementary pinky yellow could also be pro-
duced. Even the iron spike at the end of the baton made
a hole sufficiently deep to exhibit the blue colour, which
certainly depends on the size and arrangement of the snow
crystals. The firmament above us was without a cloud, and
of a darkness almost equal to that which surrounded the
moon at 2 A.M. Still, though the sun was shining, a breeze,
whose tooth had been sharpened by its passage over the
snow-fields, searched us through and through. The day
was also waning, and, urged by the warnings of our ever
prudent guide, we at length began the descent.
Gravity was now in our favour, but gravity could not
entirely spare our wearied limbs, and where we sank in the
snow we found our downward progress very trying. I
suffered from thirst, but after we had divided the liquefied
snow at the Petits Mulets amongst us we had nothing to
drink. I crammed the clean snow into my mouth, but the
process of melting was slow and tantalizing to a parched
* I fired the second case in a field in Hampshire, and, as far as my
memory enabled me to make the comparison, found its sound considerably
denser, if I may use the expression. In 1859 I had a pistol fired at the
summit of Mont Blanc : its sound was sensibly feebler and shorter than in
the valley ; it resembled somewhat the discharge of a cork from a cham-
pagne bottle, though much louder, but it could not be at all compared to
the sound of a common cracker.
84 AN UNEXPECTED GLISSADE. [1857.
throat, while the chill was painful to the teeth. We marched
along the Corridor, and crossed cautiously the perilous slope
on which we had cut steps in the morning, breathing more
freely after we had cleared the ice-precipice before de-
scribed. Along the base of this precipice we now wound,
diverging from our morning's track, in order to get surer
footing in the snow ; it was like flour, and while descending
to the Grand Plateau we sometimes sank in it nearly to
the waist. When I endeavoured to squeeze it, so as to fill
my flask, it at first refused to cling together, behaving
like so much salt ; the heat of the hand, however, soon
rendered it a little moist, and capable of being pressed into
compact masses. The sun met us here with extraordinary
power ; the heat relaxed my muscles, but when fairly im-
mersed in the shadow of the Dome du Gouter, the coolness
restored my strength, which augmented as the evening
advanced. Simond insisted on the necessity of haste, to
save us from the perils of darkness. " On pent perir " was
his repeated admonition, and he was quite right. We
reached the region of ponts, more weary, but, in compensa-
tion, more callous, than we had been in the morning, and
moved over the , soft snow of the bridges as if we had been
walking upon eggs. The valley of Chamouni was filled with
brown-red clouds, which crept towards us up the mountain ;
the air around and above us was, however, clear, and the
chastened light told us that day was departing. Once as
we hung upon a steep slope, where the snow was exceed-
ingly soft, Hirst omitted to make his footing sure ; the soft
mass gave way, and he fell, uttering a startled shout as he
went down the declivity. I was attached to him, and, fixing
my feet suddenly in the snow, endeavoured to check his
fall, but I seemed a mere feather in opposition to the force
with which he descended.* I fell, and went down after him ;
and we carried quite an avalanche of snow along with us,
* I believe that I could stop him now (1860).
1857.] BLIND AMID THE CKEVASSES. 85
in which we were almost completely hidden at the bottom
of the slope. All further dangers, however, were soon
past, and we went at a headlong speed to the base of the
Grands Mulets ; the sound of our batons against the rocks
calling Huxley forth. A position more desolate than his
had been can hardly be imagined. For seventeen hours
he had been there. He had expected us at two o'clock in
the afternoon ; the hours came and passed, and till seven
in the evening he had looked for us. " To the end of my
life," he said, " I shall never forget the sound of those
batons." It was his turn now to nurse me, which he did,
repaying my previous care of him with high interest. We
were all soon stretched, and, in spite of cold and hard
boards, I slept at intervals ; but the night, on the whole,
was a weary one, and we rose next morning with muscles
more tired than when we lay down.
Friday, 14^ August. — Hirst was almost blind this morn-
ing; and our guide's eyes were also greatly inflamed.
We gathered our things together, and bade the Grands
Mulets farewell. It had frozen hard during the night,
and this, on the steeper slopes, rendered the footing very
insecure. Simond, moreover, appeared to be a little bewil-
dered, and I sometimes preceded • him in cutting the
steps, while Hirst moved among the crevasses like a blind
man ; one of us keeping near him, so that he might feel for
the actual places where our feet had rested, and place his own
in the same position. It cost us three hours to cross from
the Grands Mulets to the Pierre a 1'Echelle, where we dis-
carded our leggings, had a mouthful of food, and a brief
rest. Once upon the safe earth Simond's powers seemed to
be restored, and he led us swiftly downwards to the little
auberge beside the Cascade du Tard, where we had some
excellent lemonade, equally choice cognac, fresh straw-
berries and cream. How sweet they were, and how beau-
tiful we thought the peasant girl who served them ! Our
86 HAPPY EVENINGS. [1857.
guide kept a little hotel, at which we halted, and found it
clean and comfortable. We were, in fact, totally unfit to
go elsewhere. My coat was torn, holes were kicked
through my boots, and I was altogether ragged and shabby.
A warm bath before dinner refreshed all mightily. Dense
clouds now lowered upon Mont Blanc, and we had not
been an hour at Chamouni when the breaking up of the
weather was announced by a thunder-peal. We had
accomplished our journey just in time.
(12.)
After our return we spent every available hour upon the
ice, working at questions which shall be treated under
their proper heads, each daj's work being wound up by
an evening of perfect enjoyment. Roast mutton and fried
potatoes were our incessant fare, for which, after a little
longing for a change at first, we contracted a final and
permanent love. As the year advanced, moreover, and
the grass sprouted with augmented vigour on the slopes of
the Montanvert, the mutton, as predicted by our host,
became more tender and juicy. We had also some capital
Sallenches beer, cold as the glacier water, but effervescent
as champagne. Such were our food and drink. After din-
ner we gathered round the pine-fire, and I can hardly think
it possible for three men to be more happy than we then
were. It was not the goodness of the conversation, nor any
high intellectual element, which gave the charm to our
gatherings ; the gladness grew naturally out of our own
perfect health, and out of the circumstances of our posi-
tion. Every fibre seemed a repository of latent joy, which
the slightest stimulus sufficed to bring into conscious action.
On the 1 7th I penetrated with Simond through thick
gloom to the Tacul ; on the 1 8th we set stakes at the same
1857.] A GLACIER " BLOWEE." 87
place : on the same day, while crossing the medial moraine
of the Taldfre, a little below the cascade, a singular noise
attracted my attention ; it seemed at first as if a snake
were hissing about my feet. On changing my position the
sound suddenly ceased, but it soon recommenced. There
was some snow upon the glacier, which I removed, and
placed my ear close to the ice, but it was difficult
to fix on the precise spot from which the sound issued.
I cut away the disintegrated portion of the surface, and
at length discovered a minute crack, from which a
stream of air issued, which I could feel as a cold blast
against my hand. While cutting away the surface fur-
ther, I stopped the little " blower." A marmot screamed
near me, and while I paused to look at the creature
scampering up the crags, the sound commenced again,
changing its note variously — hissing like a snake, sing-
ing like a kettle, and sometimes chirruping intermittently
like a bird. On passing my fingers to and fro over
the crack, I obtained a succession of audible puffs ; the
current was sufficiently strong to blow away the corner
of a gauze veil held over the fissure. Still the crack
was not wide enough to permit of the entrance of my
finger nail ; and to issue with such force from so minute a
rent the air must have been under considerable pressure.
The origin of the blower was in all probability the follow-
ing : — When the ice is recompacted after having descended
a cascade, it is next to certain that chambers of air will be
here and there enclosed, which, being powerfully squeezed
afterwards, will issue in the manner described whenever a
crack in the ice furnishes it with a means of escape. In
my experiments on flowing mud, for example, the air
entrapped in the mass while descending from the sluice
into the trough, bursts in bubbles from the surface at
a short distance downwards.
I afterwards examined the Talefre cascade from summit
88 A DIFFICULT LINE. [1857.
to base, with reference to the structure, until at the close
of the day thickening clouds warned me off. I went down
the glacier at a trot, guided by the boulders capped with
little cairns which marked the route. The track which I
had pursued for the last five weeks amid the crevasses near
FAngle was this day barely passable. The glacier had
changed, my work was drawing to a close, and, as I looked
at the objects which had now become so familiar to me,
I felt that, though not viscous, the ice did not lack the
quality of " adhesiveness," and I felt a little sad at the
thought of bidding it so soon farewell.
At some distance below the Montanvert the Mer de
Glace is riven from side to side by transverse crevasses :
these fissures indicate that the glacier where they occur is
in a state of longitudinal strain which produces transverse
fracture. I wished to ascertain the amount of stretch-
ing which the glacier here demanded, and which the
ice was not able to give ; and for this purpose desired to
compare the velocity of a line set out across the fissured
portion with that of a second line staked out across the ice
before it had become thus fissured. A previous inspection of
the glacier through the telescope of our theodolite induced
us to fix on a place which, though much riven, still did not
exclude the hope of our being able to reach the other side.
Each of us was, as usual, armed with his own axe ; and
carrying with us suitable stakes, my guide and myself
entered upon this portion of the glacier on the morning
of the 19th of August.
I was surprised on entering to find some veins of white
ice, which from their position and aspect appeared to be
derived from the Glacier du Geant ; but to these I shall
subsequently refer. Our work was extremely difficult;
we penetrated to some distance along one line, but
were finally forced back, and compelled to try another.
Right and left of us were profound fissures, and once
1857.] "NOUS NOUS THOUVERONS PERDUS ! " 89
a cone of ice forty feet high leaned quite over our track.
In front of us was a second leaning mass borne by a
mere stalk, and so topheavy that one wondered why the
slight pedestal on which it rested did not suddenly crack
across. We worked slowly forwards, and soon found our-
selves in the shadow of the topheavy mass above referred
to; and from which I escaped with a wounded hand,
caused by over-haste. Simond surmounted the next
ridge and exclaimed, " Nous nous trouverons perdus!" I
reached his side, and on looking round the place saw that
there was no footing for man. The glacier here, as shown
in the frontispiece, was cut up into thin wedges, separated
from each other by profound chasms, and the wedges were
so broken across as to render creeping along their edges
quite impossible. Thus brought to a stand, I fixed a
stake at the point where we were forced to halt, and
retreated along edges of detestable granular ice, which fell
in showers into the crevasses when struck by the axe. At
one place an exceedingly deep fissure was at our left,
which was joined, at a sharp angle, by another at our
right, and we were compelled to cross at the place of
intersection : to do this we had to trust ourselves to a
projecting knob of that vile rotten ice which I had learned
to fear since my experience of it on the Col du Geant.
We finally escaped, and set out our line at another place,
where the glacier, though badly cut, was not impassable.
On the 20th we made a series of final measurements at
the Tacul, and determined the motion of two lines which
we had set out the previous day. On the 21st we
quitted the Montanvert ; I had been there from the 1 5th
of July, and the longer I remained the better I liked the
establishment and the people connected with it. It was
then managed by Joseph Tairraz and Jules Charlet, both
of whom showed us every attention. In 1858 and 1859 I
had occasion to revisit the establishment, which was then
90 FAREWELL TO THE MONTANVERT. [1857.
managed by Jules and his brother, and found in it the
same good qualities. During my winter expedition of
1859 I also found the same readiness to assist me in every
possible way ; honest Jules expressing his willingness to
ascend through the snow to the auberge if I thought his
presence would in any degree contribute to my comfort.
We crossed the glacier, and descended by the Chapeau
to the Cascade des Bois, the inclination of which and of
the lower portion of the glacier we then determined. The
day was magnificent. Looking upwards, the Aiguilles de
Charmoz and du Dru rose right and left like sentinels of
the valley, while in front of us the ice descended the steep,
a bewildering mass of crags and chasms. At the other
side was the pine-clad slope of the Montanvert. Further
on the Aiguille du Midi threw its granite pyramid between
us and Mont Blanc ; on the Dome du Gouter the seracs of
the mountain were to be seen, while issuing as if from a
cleft in the mountain side the Glacier des Bossons thrust
through the black pines its snowy tongue. Below us was
the beautiful valley of Chamouni itself, through which
the Arve and Arveiron rushed like enlivening spirits. We
finally examined a grand old moraine produced by a Mer
de Glace of other ages, when the ice quite crossed the
valley of Chamouni and abutted against the opposite moun-
tain-wall.
Simond had proved himself a very valuable assistant ;
he was intelligent and perfectly trustworthy ; and though
the peculiar nature of my work sometimes caused me to
attempt things against which his prudence protested, he
lacked neither strength nor courage. On reaching Cha-
mouni and adding up our accounts, I found that I had not
sufficient cash to pay him ; money was waiting for me at
the post-office in Geneva, and thither it was arranged that
my friend Hirst should proceed next morning, while I was
to await the arrival of the money at Chamouni. My guide
1857.] EDOUAED SIMOND. 91
heard of this arrangement, and divined its cause : he came
to me, and in the most affectionate manner begged of me
to accept from him the loan of 500 francs. Though I did
not need the loan, the mode in which it was offered to
me augmented the kindly feelings which I had long enter-
tained towards Simond, and I may add that my intercourse
with him since has served only to confirm my first estimate
of his worthiness.
92 DOUBTS KEGAEDING STKUCTUKE. [1858.
EXPEDITION OF 1858.
(13.)
I HAD confined myself during the summer of 1857 to the
Mer de Glace and its tributaries, desirous to make my
knowledge accurate rather than extensive. I had made
the acquaintance of all accessible parts of the glacier, and
spared no pains to master both the details and the meaning
of the laminated structure of the ice, but I found no fact
upon which I could take my stand and say to an advocate
of an opposing theory, " This is unassailable." In experi-
mental science we have usually the power of changing the
conditions at pleasure ; if Nature does not reply to a ques-
tion we throw it into another form ; a combining of condi-
tions is, in fact, the essence of experiment. To meet the
requirements of the present question, I could not twist the
same glacier into various shapes, and throw it into different
states of strain and pressure ; but I might, by visiting
many glaciers, fincj. all needful conditions fulfilled in detail,
and by observing these I hoped to confer upon the subject
the character and precision of a true experimental inquiry.
The summer of 1858 was accordingly devoted to this
purpose, when I had the good fortune to be accompanied
by Professor Ramsay, the author of some extremely in-
teresting papers upon ancient glaciers. Taking Zurich,
Schaffhausen, and Lucerne in our way, we crossed the
Briinig on the 22nd of July, and met my guide, Christian
Lauener, at Meyringen. On the 23rd we visited the
glacier of Rosenlaui, and the glacier of the Schwartz-
wald, and reached Grindelwald in the evening of the same
day. My expedition with Mr. Huxley had taught me
that the Lower Grindelwald Glacier was extremely in-
1858.] A GLOOMY PKOSPECT. 93
str active, and I was anxious to see many parts of it once
more ; this I did, in company with Ramsay, and we also
spent a day upon the upper glacier, after which our path
lay over the Strahleck to the glaciers of the Aar and of
the Rhone.
PASSAGE OF THE STRAHLECK.
(14.)
ON Monday, the 26th of July, we were called at 4 A.M.,
and found the weather very unpromising, but the two
mornings which preceded it had also been threatening
without any evil result. There was, it is true, something
more than usually hostile in the aspect of the clouds
which sailed sullenly from the west, and smeared the air
and mountains as if with the dirty smoke of a manufac-
turing town. We despatched our coffee, went down to the
bottom of the Grindelwald valley, up the opposite slope,
and were soon amid the gloom of the pines which partially
cover it. On emerging from these, a watery gleam on
the mottled head of the Eiger was the only evidence of
direct sunlight in that direction. To our left was the
Wetterhorn surrounded by wild and disorderly clouds,
through the fissures of which the morning light glared
strangely. For a time the Heisse Platte was seen, a dark
brown patch amid the ghastly blue which overspread the
surrounding slopes of snow. The clouds once rolled up, and
revealed for a moment the summits of the Viescherhorner ;
but they immediately settled down again, and hid the
mountains from top to base. Soon afterwards they drew
themselves partially aside, and a patch of blue over the
Strahleck gave us hope and pleasure. As we ascended, the
94 ICE CASCADE AND PROTUBERANCES. [1858.
prospect in front of us grew better, but that behind us —
and the wind came from behind — grew worse. Slowly and
stealthily the dense neutral-tint masses crept along the
sides of the mountains, and seemed to dog us like spies ;
while over the glacier hung a thin veil of fog, through which
gleamed the white minarets of the ice.
When we first spoke of crossing the Strahleck, Lauener
said it would be necessary to take two guides at least ; but
after a day's performance on the ice he thought we might
manage very well by taking, in addition to himself, the
herd of the alp, over the more difficult part of the pass.
He had further experience of us on the second day,
and now, as we approached the herd's hut, I was amused
to hear him say that he thought any assistance beside his
own unnecessary. Kelying upon ourselves, therefore, we
continued our route, and were soon upon the glacier, which
had been rendered smooth and slippery through the re-
moval of its disintegrated surface by the warm air. Cross-
ing the Strahleck branch of the glacier to its left side, we
climbed the rocks to the grass and flowers which clothe the
slopes above them. Our way sometimes layover these, some-
times along the beds of streams, across turbulent brooks,
and once around the face of a cliff, which afforded us
about an inch of ledge to stand upon, and some protrud-
ing splinters to lay hold of by the hands. Having reached
a promontory which commanded a fine view of the glacier,
and of the ice cascade by which it was fed, I halted, to
check the observations already made from the side of the
opposite mountain. Here, as there, cliffy ridges were seen
crossing the cascade of the glacier, with interposed spaces
of dirt and debris — the former being toned down, and the
latter squeezed towards the base of the fall, until finally
the ridges swept across the glacier, in gentle swellings, from
side to side ; while the valleys between them, holding the
principal share of the superficial impurity, formed the
1858.] DIET-BANDS OF THE STEAHLECK BEANCH. 95
cradles of the so-called Dirt-Bands. These swept con-
centric with the protuberances across the glacier, and
remained upon its surface even after the swellings had
disappeared. The swifter flow of the centre of the glacier
tends of course incessantly to lengthen the loops of the
bands, and to thrust the summits of the curves which they
form more and more in advance of their lateral portions.
The depressions between the protuberances appeared to
be furrowed by minor wrinkles, as if the ice of the depres-
sions had yielded more than that of the protuberances.
This, I think, is extremely probable, though it has never
yet been proved. Three stakes, placed, one on the summit,
another on the frontal slope, and another at the base of a
protuberance, would, I think, move with unequal velocities.
They would, I think, show that, upon the large and gene-
ral motion of the glacier, smaller motions are superposed,
as minor oscillations are known to cover parasitically the
large ones of a vibrating string. Possibly, also, the dirt-
bands may owe something to the squeezing of impuri-
ties out of the glacier to its surface in the intervals
between the swellings. From our present position we
could also see the swellings on the Viescherhorner branch
of the glacier, in the valleys between which coarse shingle
and debris were collected, which would form dirt-bands if
they could. On neither branch, however, do the bands
attain the definition and beauty which they possess upon
the Mer de Glace.
After an instructive lesson we faced our task once more,
passing amid crags and boulders, and over steep moraines,
from which the stones rolled down upon the slightest dis-
turbance. While crossing a slope of snow with an inclina-
tion of 45°, my footing gave way, I fell, but turned promptly
on my face, dug my staff deeply into the snow, and arrested
the motion before I had slid a dozen yards. Eamsay
was behind me, speculating whether he should be able to
96 ICE CLIFFS THROUGH THE FOG. [1858.
pass the same point without slipping ; before he reached
it, however, the snow yielded, he fell, and slid swiftly
downwards. Lauener, whose attention had been aroused
by my fall, chanced to be looking round when Kamsay's
footing yielded. With the velocity of a projectile he threw
himself upon my companion, seized him, and brought him
to rest before he had reached the bottom of the slope. The
act made a very favourable impression upon me, it was so
prompt and instinctive. An eagle could not swoop upon its
prey with more directness of aim and swiftness of execution.
While this went on the clouds were playing hide and
seek with the mountains. The ice-crags and pinnacles to our
left, looming through the haze, seemed of gigantic propor-
tions, reminding one of the Hades of Byron's ' Cain.'
" How sunless and how vast are these dim realms ! "
We climbed for some time along the moraine which
flanks the cascade, and on reaching the level of the brow
Lauener paused, cast off his knapsack, and declared for
breakfast. While engaged with it the dense clouds which
had crammed the gorge and obscured the mountains, all
melted away, and a scene of indescribable magnificence
was revealed. Overhead the sky suddenly deepened to
dark blue, and against it the Finsteraarhorn projected his
dark and mighty mass. Brown spurs jutted from the
mountain, and between them were precipitous snow-slopes,
fluted by the descent of rocks and avalanches, and broken
into ice-precipices lower down. Right in front of us, and
from its proximity more gigantic to the eye. was the
Schreckhorn, while from couloirs and mountain-slopes
the matter of glaciers yet to be was poured into the
vast basin on the rim of which we now stood.
This it was next our object to cross; our way lying
in part through deep snow-slush, the scene changing
perpetually from blue heaven to gray haze which massed
itself at intervals in dense clouds about the nioun-
1858.] MUTATIONS OF THE CLOUDS. 97
tains. After crossing the basin our way lay partly over
slopes of snow, partly over loose shingle, and at one place
along the edge of a formidable precipice of rock. We sat
down sometimes to rest, and during these pauses, though
they were very brief, the scene had time to go through
several of its Protean mutations. At one moment all would
be perfectly serene, no cloud in the transparent air to tell
us that any portion of it was in motion, while the blue
heaven threw its flattened arch over the magnificent am-
phitheatre. Then in an instant, from some local cauldron,
the vapour would boil up suddenly, eddying wildly in the
air, which a moment before seemed so still, and envelop-
ing the entire scene. Thus the space enclosed by the
Finsteraarhorn, the Viescherhorner, and the Shreckhorn,
would at one moment be filled with fog to the mountain
heads, every trace of which a few minutes sufficed to sweep
away, leaving the unstained blue of heaven behind it,
and the mountains showing sharp and jagged outlines
in the glassy air. One might be almost led to imagine
that the vapour molecules endured a strain similar to
that of water cooled below its freezing point, or heated
beyond its boiling point ; and that, on the strain being re-
lieved by the sudden yielding of the opposing force, the
particles rushed together, and thus filled in an instant the
clear atmosphere with aqueous precipitation.
I had no idea that the Strahleck was so fine a pass.
Whether it is the quality of my mind to take in the glory
of the present so intensely as to make me forgetful of the
glory of the past, I know not, but it appeared to me that I
had never seen anything finer than the scene from the
summit. The amphitheatre formed by the mountains
seemed to me of exceeding magnificence ; nor do I think
that my feeling was subjective merely; for the simple
magnitude of the masses which built up the spectacle
would be sufficient to declare its grandeur. Looking down
H
98 DESCENT OF THE CRAGS. [1858.
towards the Glacier of the Aar, a scene of wild beauty
and desolation presented itself. Not a trace of vegetation
could be seen along the whole range of the bounding
mountains ; glaciers streamed from their shoulders into
the valley beneath, where they welded themselves to form
the Finsteraar affluent of the Unteraar glacier.
After a brief pause, Lauener again strapped on his knap-
sack, and tempered both will and muscles by the remark,
that our worst piece of work was now before us. From the
place where we sat, the mountain fell precipitously for seve-
ral hundred feet ; and down the weathered crags, and over
the loose shingle which encumbered their ledges, our route
now lay. Lauener was in front, cool and collected, lending
at times a hand to Kamsay, and a word of encouragement
to both of us, while I brought up the rear. I found my
full haversack so inconvenient tha,t I once or twice thought
of sending it down the crags in advance of me, but
Lauener assured me that it would be utterly destroyed
before reaching the bottom. My complaint against it was,
that at critical places it sometimes came between me and
the face of the cliff, pushing me away from the latter so
as to throw my centre of gravity almost beyond the base
intended to support it. We came at length upon a snow-
slope, which had for a time an inclination of 50° ; then
once more to the rocks ; again to the snow, which was both
steep and deep. Our batons were at least six feet long :
we drove them into the snow to secure an anchorage,
but they sank to their very ends, and we merely retained
a length of them sufficient for a grasp. This slope was
intersected by a so-called Bergschrund, the lower portion
of the slope being torn away from its upper portion so as
to form a crevasse that extended quite round the head of
the valley. We reached its upper edge ; the chasm was
partially filled with snow, which brought its edges so near
that we cleared it by a jump. The rest of the slope was
1858.] THROUGH GLOOM TO THE GRIMSEL. 99
descended by a glissade. Each sat down upon the snow,
and the motion, once commenced, swiftly augmented to
the rate of an avalanche, and brought us pleasantly to
the bottom.
As we looked from the heights, we could see that the
valley through which our route lay was filled with gray fog :
into this we soon plunged, and through it we made our way
towards the Abschwung. The inclination of the glacier
was our only guide, for we could see nothing. Eeaching
the confluence of the Finsteraar and Lauteraar branches,
we went downwards with long swinging strides, close
alongside the medial moraine of the trunk glacier. The
glory of the morning had its check in the dull gloom of
the evening. Across streams, amid dirt-cones and glacier-
tables, and over the long reach of shingle which covers
the end of the glacier, we plodded doggedly, and reached
the Grimsel at 7 P.M., the journey having cost a little more
than 14 hours.
(15.)
100 ANCIENT GLACIER ACTION. [1858.
has worked its channel into the ancient rocks. In some
cases the road from Guttanen to the Grimsel lay right
over the polished rocks, asperities being supplied by the
chisel of man in order to prevent travellers from slipping
on their slopes. Here and there also huge protuberant
crags were rounded into domes almost as perfect as if
chiselled by art. To both my companion and myself this
walk was full of instruction and delight.
On the 28th of July we crossed the Grimsel pass, and
traced the scratchings to the very top of it. Kamsay
remarked that their direction changed high up the pass,
as if a tributary from the summit had produced them,
while lower down they merged into the general direc-
tion of the glacier which had filled the principal valley.
From the summit of the May en wand we had a clear view
of the glacier of the Rhone ; and to see the lower portion
of this glacier to advantage no better position can be
chosen. The dislocation of its cascade, the spreading out
of the ice below, its system of radial crevasses, and the
transverse sweep of its structural groovings, may all be
seen. A few hours afterwards we were among the wild
chasms at the brow of the ice-fall, where we worked our
way to the centre of the ice, but were unable to attain the
opposite side.
Having examined the glacier both above and below the
cascade, we went down the valley to Viesch, and ascended
thence, on the 30th of July, to the Hotel Jungfrau on the
slopes of the ^Eggischhorn. On the following day we
climbed to the summit of the mountain, and from a
sheltered nook enjoyed the glorious prospect which it
commands. The wind was strong, and fleecy clouds flew
over the heavens ; some of which, as they formed and
dispersed themselves about the flanks of the Aletschhorn,
showed extraordinary iridescences.
The sunbeams called us early on the morning of the 1st
1858.] THE MARJELEN SEE. 101
of August. No cloud rested on the opposite range of the
Valais mountains, but on looking towards the ^Eggischhorn
we found a cap upon its crest ; we looked again — the cap
had disappeared and a serene heaven stretched overhead.
As we breasted the alp the moon was still in the sky,
paling more and more before the advancing day ; a single
hawk swung in the atmosphere above us ; clear streams
babbled from the hills, the louder sounds reposing on a
base of music ; while groups of cows with tinkling bells
browsed upon the green alp. Here and there the grass
was dispossessed, and the flanks of the mountain were
covered by the blocks which had been cast down from the
summit. On reaching the plateau at the base of the final
pyramid, we rounded the mountain to the right and came
over the lonely and beautiful Marjelen See. No doubt the
hollow which this lake fills had been scooped out in former
ages by a branch of the Aletsch glacier ; but long ago
the blue ice gave place to blue water. The glacier
bounds it at one side by a vertical wall of ice sixty feet
in height : this is incessantly undermined, a roof of crystal
being formed over the water, till at length the projecting
mass, becoming too heavy for its own rigidity, breaks and
tumbles into the lake. Here, attacked by sun and air,
its blue surface is rendered dazzlingly white, and several
icebergs of this kind now floated in the sunlight ; the water
was of a glassy smoothness, and in its blue depths each ice
mass doubled itself by reflection.*
The Aletsch is the grandest glacier in the Alps : over it
we now stood, while the bounding mountains poured vast
feeders into the noble stream. The Jungfrau was in
front of us without a cloud, and apparently so near that I
proposed to my guide to try it without further preparation.
He was enthusiastic at first, but caution afterwards got the
* A painting of this exquisite lake has been recently executed by Mr.
George Barnard,
102 THE ALETSCH GLACIER. [1858.
better of his courage. At some distance up the glacier the
snow-line was distinctly drawn, and from its edge upwards
the mighty shoulders of the hills were heavy laden with
the still powdery material of the glacier.
Amid blocks and debris we descended to the ice : the
portion of it which bounded the lake had been sapped,
and a space of a foot existed between ice and water :
numerous chasms were formed here, the mass being thus
broken, preparatory to being sent adrift upon the lake.
We crossed the glacier to its centre, and looking down it
the grand peaks of the Mischabel, the noble cone of the
Weisshorn, and the dark and stern obelisk of the Matter-
horn, formed a splendid picture. Looking upwards, a
series of most singularly contorted dirt-bands revealed
themselves upon the surface of the ice. I sought to trace
them to their origin, but was frustrated by the snow which
overspread the upper portion of the glacier. Along this
we marched for three hours, and came at length to the
junction of the four tributary valleys which pour their
frozen streams into the great trunk valley. The glory
of the day, and that joy of heart which perfect health
confers, may have contributed to produce the impression,
but I thought I had never seen anything to rival in
magnificence the region in the heart of which we now
found ourselves. We climbed the mountain on the right-
hand side of the glacier, where, seated amid the riven and
weather-worn crags, we fed our souls for hours on the
transcendent beauty of the scene.
We afterwards redescended to the glacier, which at this
place was intersected by large transverse crevasses, many
of which were apparently filled with snow, while over
others a thin and treacherous roof was thrown. In some
cases the roof had broken away, and revealed rows of
icicles of great length and transparency pendent from the
edges. We at length turned our faces homewards, and
1858.] A CHAMOIS DECEIVED. 103
looking down the glacier I saw at a great distance something
moving on the ice. I first thought it was a man, though
it seemed strange that a man should be there alone. On
drawing my guide's attention to it he at once pronounced
it to be a chamois, and I with my telescope immediately
verified his statement. The creature bounded up the gla-
cier at intervals, and sometimes the vigour of its spring
showed that it had projected itself over a crevasse. It
approached us sometimes at full gallop : then would stop,
look toward us, pipe loudly, and commence its race once
more. It evidently made the reciprocal mistake to my
own, imagining us to be of its own kith and kin. We
sat down upon the ice the better to conceal our forms,
and to its whistle our guide whistled in reply. A joyous
rush was the creature's first response to the signal ; but
it afterwards began to doubt, and its pauses became more
frequent. Its form at times was extremely graceful, the
head erect in the air, its apparent uprightness being
augmented by the curvature which threw its horns back.
I watched the animal through my glass until I could see
the glistening of its eyes ; but soon afterwards it made a
final pause, assured itself of its error, and flew with the
speed of the wind to its refuge in the mountains.
104 MY GUIDE, [1858.
ASCENT OF THE FINSTERAARHORN, 1858.
(16.)
SINCE my arrival at the hotel on the 30th of July I had
once or twice spoken about ascending the Finsteraarhorn,
and on the 2nd of August my host advised me to avail
myself of the promising weather. A guide, named Bennen,
was attached to the hotel, a remarkable-looking man, be-
tween 30 and 40 years old, of middle stature, but very
strongly built. His countenance was frank and firm, while
a light of good-nature at times twinkled in his eye. Alto-
gether the man gave me the impression of physical strength,
combined with decision of character. The proprietor had
spoken to me many times of the strength and courage of
this man, winding up his praises of him by the assurance
that if I -were killed in Bennen's company there would
be two lives lost, for that the guide would assuredly sacri-
fice himself in the effort to save his Herr.
He was called, and I asked him whether he would accom-
pany me alone to the top of the Finsteraarhorn. To this he
at first objected, urging the possibility of his having to
render me assistance, and the great amount of labour
which this might entail upon him ; but this was overruled
by my engaging to follow where he led, without asking him
to render me any help whatever. He then agreed to make
the trial, stipulating, however, that he should not have
much to carry to the cave of the Faulberg, where we were
to spend the night. To this I cordially agreed, and sent
on blankets, provisions, wood, and hay, by two porters.
My desire, in part, was to make a series of observations
at the summit of the mountain, while a similar series was
made by Professor Ramsay in the valley of the Rhone, near
1858.] IRIDESCENT CLOUD. 105
Viesch, with a view to ascertaining the permeability of the
lower strata of the atmosphere to the radiant heat of the
sun. During the forenoon of the 2nd I occupied myself
with my instruments, and made the proper arrangements
with Ramsay. I tested a mountain-thermometer which
Mr. Casella had kindly lent me, and found the boiling
point of water on the dining-room table of the hotel to be
199-29° Fahrenheit. At about three o'clock in the after-
noon we quitted the hotel, and proceeded leisurely with
our two guides up the slope of the ^ggischhorn. We
once caught a sight of the topmost pinnacle of the Fin-
steraarhorn ; beside it was the Rothhorn, and near this
again the Oberaarhorn, with the Yiescher glacier streaming
from its shoulders. On the opposite side we could see,
over an oblique buttress of the mountain on which we
stood, the snowy summit of the Weisshorn ; to the left of
this was the ever grim and lonely Matterhorn ; and farther
to the left, with its numerous snow-cones, each with
its attendant shadow, rose the mighty Mischabel. We
descended, and crossed the stream which flows from the
Marjelen See, into which a large mass of the glacier had
recently fallen, and was now afloat as an iceberg. We passed
along the margin of the lake, and at the junction of water
and ice I bade Ramsay good-bye. At the commencement
of our journey upon the ice, whenever we crossed a cre-
vasse, I noticed Bennen watching me ; his vigilance, how-
ever, soon diminished, whence I gathered that he finally
concluded that I was able to take care of myself. Clouds
hovered in the atmosphere throughout the whole time of
our ascent ; one smoky-looking mass marred the glory of
the sunset, but at some distance was another which exhi-
bited colours almost as rich and varied as those of the
solar spectrum. I took the glorious banner thus unfurled
as a sign of hope, to check the despondency which its
gloomy neighbour was calculated to produce.
106 EVENING- NEAR THE JUNGFRAU. [1858.
Two hours' walking brought us near our place of rest ;
the porters had already reached it, and were now returning.
We deviated to the right, and, having crossed some ice-
ravines, reached the lateral moraine of the glacier, and
picked our way between it and the adjacent mountain- wall.
We then reached a kind of amphitheatre, crossed it, and
climbing the opposite slope, came to a triple grotto formed
by clefts in the mountain. In one of these a pine-fire
was soon blazing briskly, and casting its red light upon
the surrounding objects, though but half dispelling the
gloom from the deeper portions of the cell. I left the
grotto, and climbed the rocks above it to look at the heavens.
The sun had quitted our firmament, but still tinted the
clouds with red and purple ; while one peak of snow ' in
particular glowed like fire, so vivid was its illumination.
During our journey upwards the Jungfrau never once
showed her head, but, as if in ill temper, had wrapped her
vapoury veil around her. She now looked more good-
humoured, but still she did not quite remove her hood ;
though all the other summits, without a trace of cloud to
mask their beautiful forms, pointed heavenward. The
calmness was perfect; no sound of living creature, no
whisper of a breeze, no gurgle of water, no rustle of
debris, to break the deep and solemn silence. Surely, if
beauty be an object of worship, those glorious mountains,
with rounded shoulders of the purest white — snow-crested
and star-gemmed — were well calculated to excite senti-
ments .of adoration.
I returned to the grotto, where supper was prepared and
waiting for me. The boiling point of water, at the level
of the " kitchen " floor, I found to be 196° Fahr. Nothing
could be more picturesque than the aspect of the cave
before we went to rest. The fire was gleaming ruddily. I
sat upon a stone bench beside it, while Bennen was in front
with the red light glimmering fitfully o^er him. My
1858.] THE CAVE OF THE FAULBERG. 107
boiling-water apparatus, which had just been used, was in
the foreground ; and telescopes, opera-glasses, haversacks,
wine-keg, bottles, and mattocks, lay confusedly around.
The heavens continued to grow clearer, the thin clouds,
which had partially overspread the sky, melting gradually
away. The grotto was comfortable; the hay sufficient
materially to modify the hardness of the rock, and my posi-
tion at least sheltered and warm. One possibility re-
mained that might prevent me from sleeping — the snoring
of my companion ; he assured me, however, that he did
not snore, and we lay down side by side. The good fellow
took care that I should not be chilled ; he gave me the
best place, by far the best part of the clothes, and may have
suffered himself in consequence ; but, happily for him,
he was soon oblivious of this. Physiologists, I believe, have
discovered that it is chiefly during sleep that the muscles
are repaired ; and ere long the sound I dreaded announced
to me at once the repair of Bennen's muscles and the
doom of my own. The hollow cave resounded to the deep-
drawn snore. I once or twice stirred the sleeper, breaking
thereby the continuity of the phenomenon; but it in-
stantly pieced itself together again, and went on as before.
I had not the heart to wake him, for I knew that upon
him would devolve the chief labour of the coming day.
At half-past one he rose and prepared coffee, and at two
o'clock I was engaged upon the beverage. We afterwards
packed up our provisions and instruments. Bennen bore
the former, I the latter, and at three o'clock we set out.
We first descended a steep slope to the glacier, along
which we walked for a time. A spur of the Faulberg jutted
out between us and the ice-laden valley through which we
must pass ; this we crossed in order to shorten our way
and to avoid crevasses. Loose shingle and boulders over-
laid the mountain; and here and there walls of rock
opposed our progress, and rendered the route far from
108 "SHALL WE TEY THE JUNGFEAU ? " [1858.
agreeable. We then descended to the Griinhorn tributary,
which joins the trunk glacier at nearly a right angle, being
terminated by a saddle which stretches across from moun-
tain to mountain, with a curvature as graceful and as
perfect as if drawn by the instrument of a mathematician.
The unclouded moon was shining, and the Jungfrau was
before us so pure and beautiful, that the thought of visiting
the " Maiden " without further preparation occurred to me.
I turned to Bennen, and said, " Shall we try the Jungfrau ? "
I think he liked the idea well enough, though he cau-
tiously avoided incurring any responsibility. " If you de-
sire it, I am ready," was his reply. He had never made
the ascent, and nobody knew anything of the state of the
snow this year ; but Lauener had examined it through a
telescope on the previous day, and pronounced it dan-
gerous. In every ascent of the mountain hitherto made,
ladders had been found indispensable, but we had none.
I questioned Bennen as to what he thought of the proba-
bilities, and tried to extract some direct encouragement
from him ; but he said that the decision rested altogether
with myself, and it was his business to endeavour to carry
out that decision. " We will attempt it, then," I said, and
for some time we actually walked towards the Jungfrau.
A gray cloud drew itself across her summit, and clung
there. I asked myself ' why I deviated from my ori-
ginal intention ? The Finsteraarhorn was higher, and
therefore better suited for the contemplated observa-
tions. I could in no wise justify the change, and finally
expressed my scruples. A moment's further conversation
caused us to " right about," and front the saddle of the
Griinhorn.
The dawn advanced. The eastern sky became illumi-
nated and warm, and high in the air across the ridge in
front of us stretched a tongue of cloud like a red flame,
and equally fervid in its hue. Looking across the trunk
18-58.] MAGNIFICENT SCENE. 109
glacier, a valley which is terminated by the Lotsch saddle
was seen in a straight line with our route, and I often
turned to look along this magnificent corridor. The
mightiest mountains in the Oberland form its sides ; still,
the impression which it makes is not that of vastness or
sublimity, but of loveliness not to be described. The sun
had not yet smitten the snows of the bounding moun-
tains, but the saddle carved out a segment of the heavens
which formed a background of unspeakable beauty. Over
the rim of the saddle the sky was deep orange, pass-
ing upwards through amber, yellow, and vague ethereal
green to the ordinary firmamental blue. Right above
the snow-curve purple clouds hung perfectly motionless,
giving depth to the spaces between them. There was
something saintly in the scene. Anything more exquisite
I had never beheld.
We marched upwards over the smooth crisp snow to the
crest of the saddle, and here I turned to take a last look
along that grand corridor, and at that wonderful " daffodil
sky." The sun's rays had already smitten the snows of the
Aletschhorn ; the radiance seemed to infuse a principle of
life and activity into the mountains and glaciers, but still
that holy light shone forth, and those motionless clouds
floated beyond, reminding one of that eastern religion whose
essence is the repression of all action and the substitution
for it of immortal calm. The Finsteraarhorn now fronted
us ; but clouds turbaned the head of the giant, and hid it
from our view. The wind, however, being north, inspired
us with a strong hope that they would melt as the day ad-
vanced. I have hardly seen a finer ice-field than that
which now lay before us. Considering the neve which
supplies it, it appeared to me that the Viescher glacier
ought to discharge as much ice as the Aletsch ; but
this is an error due to the extent of neve which is here
at once visible : since a glance at the map of this portion
110 THE MOITNTAIK ASSAILED. [ 18-58.
of the Oberland shows at once the great superiority of
the mountain treasury from which the Aletsch glacier
draws support. Still, the ice-field before us was a most
noble one. The surrounding mountains were of imposing
magnitude, and loaded to their summits with snow. Down
the sides of some of them the half-consolidated mass fell in
a state of wild fracture and confusion. In some cases the
riven masses were twisted and overturned, the ledges bent,
and the detached blocks piled one upon another in heaps ;
while in other cases the smooth white mass descended
from crown to base without a wrinkle. The valley
now below us was gorged by the frozen material thus
incessantly poured into it. We crossed it, and reached the
base of the Finsteraarhorn, ascended the mountain a little
way, and at six o'clock paused to lighten our burdens and
to refresh ourselves.
The north wind had freshened, we were in the shade,
and the cold was very keen. Placing a bottle of tea
and a small quantity of provisions in the knapsack, and
a few figs and dried prunes in our pockets, we com-
menced the ascent. The Finsteraarhorn sends down a
number of cliffy buttresses, separated from each other by
wide couloirs filled with ice and snow. We ascended
one of these buttresses for a time, treading cautiously
among the spiky rocks ; afterwards we went along the
snow at the edge of the spine, and then fairly parted
company with the rock, abandoning ourselves to the neve
of the couloir. The latter was steep, and the snow was
so firm that steps had to be cut in it. Once I paused
upon a little ledge, which gave me a slight footing, and
took the inclination. The slope formed an angle of 45°
with the horizon ; and across it, at a little distance be-
low me, a gloomy fissure opened its jaws. The sun now
cleared the summits which had before cut off his rays, and
burst upon us with great power, compelling us to resort to
1858.] THE CREST OF BOOKS. Ill
our veils and dark spectacles. Two years before, Bennen
had been nearly blinded by inflammation brought on by
the glare from the snow, and he now took unusual care in
protecting his eyes. The rocks looking more practicable,
we again made towards them, and clambered among them
till a vertical precipice, which proved impossible of ascent,
fronted us. Bennen scanned the obstacle closely as we
slowly approached it, and finally descended to the snow,
which wound at a steep angle round its base : on this the
footing appeared to me to be singularly insecure, but I
marched without hesitation or anxiety in the footsteps of
my guide.
We ascended the rocks once more, continued along
them for some time, and then deviated to the couloir
on our left. This snow-slope is much dislocated at its
lower portion, and above its precipices and crevasses our
route now lay. The snow was smooth, and sufficiently
firm and steep to render the cutting of steps necessary.
Bennen took the lead : to make each step he swung his
mattock once, and his hindmost foot rose exactly at the
moment the mattock descended ; there was thus a kind of
rhythm in his motion, the raising of the foot keeping
time to the swing of the implement. In this manner we
proceeded till we reached the base of the rocky pyramid
which caps the mountain.
One side of the pyramid had been sliced off, thus
dropping down almost a sheer precipice for some thousands
of feet to 'the Finsteraar glacier. A wall of rock, about
10 or 15 feet high, runs along the edge of the moun-
tain, and this sheltered us from the north wind, which
surged with the sound of waves against the tremendous
barrier at the other side. " Our hardest work is now
before us," said my guide. Our way lay up the steep
and splintered rocks, among which we sought out the
spikes which were closely enough wedged to bear our
112 THE SUMMIT GAINED. [1858.
weight. Each had to trust to himself, and I fulfilled
to the letter my engagement with Bennen to ask no
help. My boiling- water apparatus and telescope were
on my back, much to my annoyance, as the former was
heavy, and sometimes swung awkwardly round as I twisted
myself among the cliffs. Bennen offered to take it, but he
had his own share to carry, and I was resolved to bear
mine. Sometimes the rocks alternated with spaces of
ice and snow, which we were at intervals compelled to
cross ; sometimes, when the slope was pure ice and very
steep, we were compelled to retreat to the highest cliffs.
The wall to which I have referred had given way in
some places, and through the gaps thus formed the
wind rushed with a loud, wild, wailing sound. Through
these spaces I could see the entire field of Agassiz's obser-
vations; the junction of the Lauteraar and Finsteraar
glaciers at the Abschwung, the medial moraine between
them, on which stood the Hotel des Neufchatelois, and the
pavilion built by M. Dollfuss, in which Huxley and myself
had found shelter two years before. Bennen was evidently
anxious to reach the summit, and recommended all obser-
vations to be postponed until after our success had been
assured. I agreed to this, and kept close at his heels.
Strong as he was, he sometimes paused, laid his head upon
his mattock, and panted like a chased deer. He com-
plained of fearful thirst, and to quench it we had only my
bottle of tea : this we shared loyally, my guide praising
its virtues, as well he might. Still the summit loomed
above us ; still the angry swell of the north wind, beating
against the torn battlements of the mountain, made wild
music. Upward, however, we strained ; and at last, on
gaining the crest of a rock, Bennen exclaimed, in a jubilant
voice, l( Die hochste Spitze ! " — the highest point. In a
moment I was at his side, and saw the summit within a
few paces of us. A minute or two placed us upon
1858.] THERMOMETER PLACED. 113
the topmost pinnacle, with the blue dome of heaven
above us, and a world of mountains, clouds, and glaciers
beneath.
A notion is entertained by many of the guides that if
you go to sleep at the summit of any of the highest moun-
tains, you will
" Sleep the sleep that knows no waking."
Bennen did not appear to entertain this superstition ; and
before starting in the morning, I had stipulated for ten
minutes' sleep on reaching the summit, as part compensa-
tion for the loss of the night's rest. My first act, after
casting a glance over the glorious scene beneath us, was
to take advantage of this agreement ; so I lay down and
had five minutes' sleep, from which I rose refreshed
and brisk. The sun at first beat down upon us with
intense force, and I exposed my thermometers ; but thin
veils of vapour soon drew themselves before the sun, and
denser mists spread over the valley of the Khone, thus
destroying all possibility of concert between Ramsay and
myself. I turned therefore to my boiling-water apparatus,
filled it with snow, melted the first charge, put more in,
and boiled it ; ascertaining the boiling point to be 187°
Fahrenheit. On a sheltered ledge, about two or three
yards south of the highest point, I placed a minimum-
thermometer, in the hope that it would enable us in future
years to record the lowest winter temperatures at the
summit of the mountain.*
* The following note describes the single observation made with this
thermometer. Mr. B. informs me that on finding the instrument Bennen
swung it in triumph round his head. I fear, therefore, that the obser-
vation gives'us no certain information regarding the minimum winter-
temperature.
" St. Nicholas, 1859, Aug. 25.
" Sir,— On Tuesday last (the 23rd inst.) a party, consisting of Messrs.
B., H., R. L., and myself, succeeded in reaching the summit of the
Finsteraarhorn under the guidance of Bennen and Melchior Anderegg.
I
114 SCENE FKOM THE SUMMIT. [1858.
It is difficult to convey any just impression of the scene
from the summit of the Fiiisteraarhorn : one might, it is
true, arrange the visible mountains in a list, stating their
heights and distances, and leaving the imagination to fur-
nish them with peaks and pinnacles, to build the precipices,
polish the snow, rend the glaciers, and cap the highest
summits with appropriate clouds. But if imagination did
its best in this way, it would hardly exceed the reality,
and would certainly omit many details which contribute
to the grandeur of the scene itself. The various shapes
of the mountains, some grand, some beautiful, bathed
in yellow sunshine, or lying black and riven under the
frown of impervious cumuli ; the pure white peaks, cor-
nices, bosses, and amphitheatres ; the blue ice rifts, the
We made it an especial object to observe and reset the minimum -
thermometer which you left there last year. On reaching the summit,
before I had time to stop him, Bennen produced the instrument, and it
is just possible that in moving it he may have altered the position
of the index. However, as he held the instrument horizontally, and did
not, as far as I saw, give it any sensible jerk, I have great confidence that
the index remained unmoved.
" The reading of the index was - 32° Cent.
" A portion of the spirit extending over about 10|° (and standing
tween 33° and 43^°) was separated from the rest, but there appeared to
be no data for determining when the separation had taken place. As it
appeared desirable to unite the two portions of spirit before again setting
the index to record the cold of another winter, we endeavoured to effect
this by heating the bulb, but unfortunately, just as we were expecting to
see them coalesce, the bulb burst, and I have now to express my great
regret that my clumsiness or ignorance of the proper mode of setting the
instrument in order should have interfered with the continuance of obser-
vations of so much interest. The remains of the instrument, together
with a note of the accident, I have left in the charge of Wellig, the land-
lord of the hotel on the /Eggischhorn.
" We reached the summit about 10.40 A.M. and remained there till noon ;
the reading of a pocket thermometer in the shade was 41° F.
" Should there be any further details connected with our ascent on which
you would like to have information, I shall be happy to supply them to
the best of my recollection. Meanwhile, with a farther apology for my
clumsiness, I beg to subscribe myself yours respectfully,
" Professor Tyndall." " H."
1858.] "HAVE NO FEAR." 115
stratified snow-precipices, the glaciers issuing from the
hollows of the eternal hills, and stretching like frozen
serpents through the sinuous valleys ; the lower cloud
field — itself an empire of vaporous hills — shining with
dazzling whiteness, while here and there grim summits,
brown by nature, and black by contrast, pierce through it
like volcanic islands through a shining sea, — add to this
the consciousness of one's position which clings to one
unconsciously, that undercurrent of emotion which sur-
rounds the question of one's personal safety, at a height of
more than 14,000 feet above the sea, and which is increased
by the weird strange sound of the wind surging with the
full deep boom of the distant sea against the precipice
behind, or rising to higher cadences as it forces itself
through the crannies of the weatherworn rocks, — all
conspire to render the scene from the Finsteraarhorn
worthy of the monarch of the Bernese Alps.
My guide at length warned me that we must be moving ;
repeating the warning more impressively before I attended
to it. We packed up, and as we stood beside each other
ready to march he asked me whether we should tie our-
selves together, at the same time expressing his belief that
it was unnecessary. Up to this time we had been separate,
and the thought of attaching ourselves had not occurred to
me till he mentioned it. I thought it, however, prudent to
accept the suggestion, and so we united our destinies by a
strong rope. " Now," said Bennen, " have no fear ; no matter
how you throw yourself, I will hold you." Afterwards, on
another perilous summit, I repeated this saying of Bennen's
to a strong and active guide, but his observation was that it
was a hardy untruth, for that in many places Bennen could
not have held me. Nevertheless a daring word strengthens
the heart, and, though I felt no trace of that sentiment
which Bennen exhorted me to banish, and was determined,
as far as in me lay, to give him no opportunity of trying
i 2
116 DISCIPLINE. [18;>8.
his strength in saving me, I liked the fearless utterance of
the man, and sprang cheerily after him. Our descent was
rapid, apparently reckless, amid loose spikes, boulders,
and vertical prisms of rock, where a false step would
assuredly have been attended with broken bones ; but the
consciousness of certainty in our movements never forsook
us, and proved a source of keen enjoyment. The senses
were all awake, the eye clear, the heart strong, the limbs
steady, yet flexible, with power of recovery in store, and
ready for instant action should the footing give way. Such
is the discipline which a perilous ascent imposes.
We finally quitted the crest of rocks, and got fairly
upon the snow once more. We first went downwards
at a long swinging trot. The sun having melted the
crust which we were compelled to cut through in the
morning, the leg at each plunge sank deeply into the
snow ; but this sinking was partly in the direction of the
slope of the mountain, and hence assisted our progress.
Sometimes the crust was hard enough to enable us to glide
upon it for long distances while standing erect ; but the end
of these glissades was always a plunge and tumble in the
deeper snow. Once upon a steep hard slope Bennen's footing
gave way ; he fell, and went down rapidly, pulling me after
him. I fell also, but turning quickly, drove the spike of
my hatchet into the ice, got good anchorage, and held
both fast ; my success assuring me that I had improved
as a mountaineer since my ascent of Mont Blanc. We
tumbled so often in the soft snow, and our clothes and
boots were so full of it, that we thought we might
as well try the sitting posture in gliding down. We
did so, and descended with extraordinary velocity, being
checked at intervals by a bodily immersion in the softer
and deeper snow. I was usually in front of Bennen, shooting
down with the speed of an arrow and feeling the check of the
rope when the rapidity of my motion exceeded my guide's
1858.] DESCENT BY GLISSADES. 117
estimate of what was safe. Sometimes I was behind him,
and darted at intervals with the swiftness of an avalanche
right upon him ; sometimes in the same transverse line with
him, with the full length of the rope between us ; and here
I found its check unpleasant, as it tended to make me roll
over. My feet were usually in the air, and it was only
necessary to turn them right or left, like the helm of a
boat, to change the direction of motion and avoid a diffi-
culty, while a vigorous dig of leg and hatchet into the
snow was sufficient to check the motion and bring us to
rest. Swiftly, yet cautiously, we glided into the region of
crevasses, where we at last rose, quite wet, and resumed
our walking, until we reached the point where we had left
our wine in the morning, and where I squeezed the water
from my wet clothes, and partially dried them in the sun.
We had left some things at the cave of the Faulberg,
and it was Bennen's first intention to return that way and
take them home with him. Finding, however, that we
could traverse the Viescher glacier almost to the ^Eggisch-
horn, I made this our highway homewards. At the place
where we entered it, and for an hour or two afterwards,
the glacier was cut by fissures, for the most part covered
with snow. We had packed up our rope, and Bennen ad-
monished me to tread in his steps. Three or four times he
half disappeared in the concealed fissures, but by clutch-
ing the snow he rescued himself and went on as swiftly as
before. Once my leg sank, and the ring of icicles some
fifty feet below told me that I was in the jaws of a cre-
vasse; my guide turned sharply — it was the only time
that I had seen concern on his countenance :—
" Gott's Donner ! 8ie haben meine Tritte nicht gefolgt."
il Dock ! " was my only reply, and we went on. He
scarcely tried the snow that he crossed, as from its form
and colour he could in most cases judge of its condition.
For a long time we kept at the left-hand side of the
118 THE VIESCH GLACIER [1858.
glacier, avoiding the fissures which were now permanently
open. We came upon the tracks of a herd of chamois,
which had clambered from the glacier up the sides of the
Oberaarhorn, and afterwards crossed the glacier to the
right-hand side, my guide being perfect master of the
ground. His eyes went in advance of his steps, and his
judgment was formed before his legs moved. The glacier
was deeply fissured, but there was no swerving, no retreat-
ing, no turning back to seek more practicable routes ;
each stride told, and every stroke of the axe was a pro-
fitable investment of labour.
We left the glacier for a time, and proceeded along the
mountain side, till we came near the end of the Trift
glacier, where we let ourselves down an awkward face of
rock along the track of a little cascade, and came upon
the glacier once more. Here again I had occasion to
admire the knowledge and promptness of my guide. The
glacier, as is well known, is greatly dislocated, and has
once or twice proved a prison to guides and travellers,
but Bennen led me through the confusion without a pause.
We were sometimes in the middle of the glacier, sometimes
on the moraine, and sometimes on the side of the flanking
mountain. Towards the end of the day we crossed what
seemed to be the consolidated remains of a great ava-
lanche ; on this my foot slipped, there was a crevasse at
hand, and a sudden effort was necessary to save me from
falling into it. In making this effort the spike of my
axe turned uppermost, and the palm of my hand came
down upon it, thus receiving a very ugly wound. We were
soon upon the green alp, having bidden a last farewell
to the ice. Another hour's hard walking brought us to our
hotel. No one seeing us crossing the alp would have sup-
posed that we had laid such a day's work behind us ; the
proximity of home gave vigour to our strides, and our pro-
gress was much more speedy than it had been on starting in
1858.] A ROTATING ICEBEKG. 119
the morning. I was affectionately welcomed by Ramsay,
had a warm bath, dined, went to bed, where I lay fast
locked in sleep for eight hours, and rose next morning as
fresh and vigorous as if I had never scaled the Finster-
aarhorn.
(17.)
On the 6th of August there was a long fight between
mist and sunshine, each triumphing by turns, till at length
the orb gained the victory and cleansed the mountains
from every trace of fog. We descended to the Marjelen
See, and, wishing to try the floating power of its icebergs,
at a place where masses sufficiently large approached
near to the shore, I put aside a portion of my clothes,
and retaining my boots stepped upon the floating ice. It
bore me for a time, and I hoped eventually to be able to
paddle myself over the water. On swerving a little,
however, from the position in which I first stood, the
mass turned over and let me into the lake. I tried a
second one, which served me in the same manner ; the
water was too cold to continue the attempt, and there
was also some risk of being unpleasantly ground between
the opposing surfaces of the masses of ice. A very large
iceberg which had been detached some short time pre-
viously from the glacier lay -floating at some distance
from us. Suddenly a sound like that of a waterfall drew
our attention towards it. We saw it roll over with the
utmost deliberation, while the water which it carried along
with it rushed in cataracts down its sides. Its previous
surface was white, its present one was of a lovely blue, the
* submerged crystal having now come to the air. The
summerset of this iceberg produced a commotion all over
the lake ; the floating masses at its edge clashed together,
120 END OF THE ALETSCH GLACIER. [1858.
and a mellow glucking sound, due to the lapping of the
undulations against the frozen masses, continued long
afterwards.
We subsequently spent several hours upon the glacier ;
and on this day I noticed for the first time a contempo-
raneous exhibition of bedding and structure to which I shall
refer at another place. We passed finally to the left bank
of the glacier, at some distance below the base of the
^Eggischhorn, and traced its old moraines at intervals along
the flanks of the bounding mountain. At the summit of
the ridge we found several fine old rocJies moutonnees, on
some of which the scratchings of a glacier long departed
were well preserved ; and from the direction of the
scratchings it might be inferred that the ice moved down
the mountain towards the valley of the Rhone. A plunge
into a lonely mountain lake ended the day's excursion;
On the 7th of August we quitted this noble station.
Sending our guide on to Viesch to take a conveyance and
proceed with our luggage down the valley, Ramsay and
myself crossed the mountains obliquely, desiring to trace
the glacier to its termination. We had no path, but it was
hardly possible to go astray. We crossed spurs, climbed and
descended pleasant mounds, sometimes with the soft grass
under our feet, and sometimes knee-deep in rhododendrons.
It took us several hours to reach the end of the glacier,
and we then looked down upon it merely. It lay
couched like a reptile in a wild gorge, as if it had split
the mountain by its frozen snout. We afterwards de-
scended to Morill, where we met our guide and driver ;
thence down the valley to Visp ; and the following evening
saw us lodged at the Monte Rosa hotel in Zermatt.
The boiling point of water on the table of the salle cl
manger, I found to be 202-58° Fahr.
On the following morning I proceeded without my friend
to the Gomer glacier. As is well known, the end of this
1858.] MEADOWS INVADED BY ICE. 121
glacier has been steadily advancing for several years, and
when I saw it, the meadow in front of it was partly
shrivelled up by its irresistible advance. I was informed
by my host that within the last sixty years forty-four chalets
had been overturned by the glacier, the ground on which
they stood being occupied by the ice ; at present there
are others for which a similar fate seems imminent.
In thus advancing the glacier merely takes up ground
which belonged to it in former ages, for the rounded
rocks which rise out of the adjacent meadow show that it
once passed over them.
I had arranged to meet Kamsay this morning on the
road to the Kiffelberg. The meeting took place, but I then
learned that a minute or two after my departure he had
received intelligence of the death of a near relative. Thus
was our joint expedition terminated, for he resolved to
return at once to England. At my solicitation he accom-
panied me to the Eiffel hotel. We had planned an ascent
of Monte Eosa together, but the arrangement thus broke
clown, and I was consequently thrown upon my own re-
sources. Lauener had never made the ascent, but he
nevertheless felt confident that we should accomplish it
together.
122 THE RIFFELBERO. [1858.
FIRST ASCENT OF MONTE ROSA, 1858.
(18.)
ON Monday, the 9tli of August, we reached the Eiffel,
and, by good fortune, on the evening of the same day, my
guide's brother, the well-known Ulrich Lauener, also arrived
at the hotel on his return from Monte Rosa. From him we
obtained all the information possible respecting the ascent,
and he kindly agreed to accompany us a little way the
next morning, to put us on the right track. At three A.M.
the door of my bedroom opened, and Christian Lauener
announced to me that the weather was sufficiently good to
justify an attempt. The stars were shining overhead ; but
Ulrich afterwards drew our attention to some heavy clouds
which clung to the mountains on the other side of the
valley of the Visp ; remarking that the weather might
continue fair throughout the day, but that these clouds
were ominous. At four o'clock we were on our way, by
which time a gray stratus cloud had drawn itself across
the neck of the Matterhorn, and soon afterwards another
of the same nature encircled his waist. We proceeded
past the Riffelhorn to the ridge above the Gorner glacier,
from which Monte Rosa was visible from top to bottom,
and where an animated conversation in Swiss patois com-
menced. Ulrich described the slopes, passes, and pre-
cipices, which were to guide us ; and Christian demanded
explanations, until he was finally able to declare to me
that his knowledge was sufficient. We then bade Ulrich
good-bye, and went forward. All was clear about Monte
Rosa, and the yellow morning light shone brightly upon
its uppermost snows. Beside the Queen of the Alps
was the huge mass of the Lyskamm, with a saddle
stretching from the one to the other ; next to the Lyskamm
1858.] SOUNDS ON THE GLACIEK. 123
came two white rounded mounds, smooth and pure, the
Twins Castor and Pollux, and further to the right again
the broad brown flank of the Breithorn. Behind us
Mont Cervin gathered the clouds more thickly round him,
until finally his grand obelisk was totally hidden. We
went along the mountain-side for a time, and then de-
scended to the glacier. The surface was hard frozen, and
the ice crunched loudly under our feet. There was a hol-
lowness and volume in the sound which require explana-
tion ; and this, I think, is furnished by the remarks of Sir
John Herschel on those hollow sounds at the Solfaterra,
near Naples, from which travellers have inferred the exist-
ence of cavities within the mountain. At the place where
these sounds are heard the earth is friable, and, when
struck, the concussion is reinforced and lengthened by the
partial echoes from the surfaces of the fragments. The
conditions for a similar effect exist upon the glacier, for
the ice is disintegrated to a certain depth, and from the
innumerable places of rupture little reverberations are
sent, which give a length and hollowness to the sound pro-
duced by the crushing of the fragments on the surface.
We looked to the sky at intervals, and once a meteor
slid across it, leaving a train of sparks behind. The blue
firmament, from which the stars shone down so brightly
when we rose, was more and more invaded by clouds,
which advanced upon us from our rear, while before us the
solemn heights of Monte Rosa were bathed in rich yellow
sunlight. As the day advanced the radiance crept down
towards the valleys ; but still those stealthy clouds ad-
vanced like a besieging army, taking deliberate possession
of the summits, one after the other, while gray skirmishers
moved through the air above us. The play of light and
shadow upon Monte Rosa was at times beautiful, bars of
gloom and zones of glory shifting and alternating from top
to bottom of the mountain.
124 ADVANCE OF THE CLOUDS. [1858.
At five o'clock a gray cloud alighted on the shoulder of
the Lyskamm, which had hitherto been warmed by the
lovely yellow light. Soon afterwards we reached the foot
of Monte Rosa, and passed from the glacier to a slope of
rocks, whose rounded forms and furrowed surfaces showed
that the ice of former ages had moved over them ; the
granite was now coated with lichens, and between the
bosses where mould could rest were patches of tender
moss. As we ascended, a peal to the right announced the
descent of an avalanche from the Twins ; it came heralded
by clouds of ice-dust, which resembled the sphered masses
of condensed vapour which issue from a locomotive. A
gentle snow-slope brought us to the base of a 'precipice
of brown rocks, round which we wound ; the snow was
in excellent order, and the chasms were so firmly bridged
by the frozen mass that no caution was necessary in
crossing them. Surmounting a weathered cliff to our left,
we paused upon the summit to look upon the scene around
us. The snow gliding insensibly from the mountains, or dis-
charged in avalanches from the precipices which it overhung,
filled the higher valleys with pure white glaciers, which were
rifted and broken here and there, exposing chasms and pre-
cipices from which gleamed the delicate blue of the half-
formed ice. Sometimes, however, the neves spread over wide
spaces without a rupture or wrinkle to break the smooth-
ness of the superficial snow. The sky was now for the
most part overcast, but through the residual blue spaces
the sun at intervals poured light over the rounded bosses
of the mountain.
At half-past seven o'clock we reached another precipice
of rock, to the left of which our route lay, and here
Lauener proposed to have some refreshment ; after which
we went on again. The clouds spread more and more,
leaving at length mere specks and patches of blue
between them. Passing some high peaks, formed by
1858.] MONTE KOSA CAPPED. 125
the dislocation of the ice, we came to a place where the
neve was rent by crevasses, on the walls of which the stra-
tification due to successive snow-falls was shown with
great beauty and definition. Between two of these fissures
our way now lay : the wall of one of them was hollowed
out longitudinally midway down, thus forming a roof above
and a ledge below, and from roof to ledge stretched a rail-
ing of cylindrical icicles, as if intended to bolt them to-
gether. A cloud now for the first time touched the
summit of Monte Rosa, and sought to cling to it, but in a
minute it dispersed in shattered fragments, as if dashed
to pieces for its presumption. The mountain remained
for a time clear and triumphant, but the triumph was
short-lived : like suitors that will not be repelled, the dusky
vapours came; repulse after repulse took place, and the
sunlight gushed down upon the heights, but it was mani-
fest that the clouds gained ground in the conflict.
Until about a quarter past nine o'clock our work was
mere child's play, a pleasant morning stroll along the
flanks of the mountain ; but steeper slopes now rose
above us, which called for more energy, and more care in
the fixing of the feet. Looked at from below, some of
these slopes appeared precipitous ; but we were too well
acquainted with the effect of fore-shortening to let this
daunt us. At each step we dug our batons into the deep
snow. When first driven in, the batons* dipped from us, but
were brought, as we walked forward, to the vertical, and
finally beyond it at the other side. The snow was thus
forced aside, a rubbing of the staff against it, and of
the snow-particles against each other, being the conse-
quence. We had thus perpetual rupture and regelation ;
while the little sounds consequent upon rupture, reinforced
by the partial echoes from the surfaces of the granules,
* My staff was always the handle of an axe an inch or two longer
than an ordinary walking-stick.
126 THE "COMB" OE THE MOUNTAIN. [18-58.
were blended together to a note resembling the lowing of
cows. Hitherto I had paused a,t intervals to make notes,
or to take an angle ; but these operations now ceased, not
from want of time, but from pure dislike ; for when the
eye has to act the part of a sentinel who feels that at
any moment the enemy may be upon him ; when the body
must be balanced with precision, and legs and arms, besides
performing actual labour, must be kept in readiness for
possible contingencies ; above all, when you feel that your
safety depends upon yourself alone, and that, if your foot-
ing gives way, there is no strong arm behind ready to be
thrown between you and destruction ; under 'such circum-
stances the relish for writing ceases, and you are willing
to hand over your impressions to the safe keeping of
memory.
From the vast boss which constitutes the lower portion of
Monte Rosa cliffy edges run upwards to the summit. Were
the snow removed from these we should, I doubt not, see
them as toothed or serrated crags, justifying the term
" kamm" or " comb," applied to such edges by the Ger-
mans. Our way now lay along such a kamm, the cliffs
of which had, however, caught the snow, and been com-
pletely covered by it, forming an edge like the ridge of a
house-roof, which sloped steeply upwards. On the Lys-
kamm side of the edge there was no footing, and, if a
human body fell over here, it would probably pass through
a vertical space of some thousands of feet, falling or rolling,
before coming to rest. On the other side the snow-slope
was less steep, but excessively perilous-looking, and inter-
sected by precipices of ice. Dense clouds now enveloped
us, and made our position far uglier than if it had been
fairly illuminated. The valley below us was one vast caul-
dron, filled with precipitated vapour, which came seething
at times up the sides of the mountain. Sometimes this fog
would partially clear away, and the light would gleam
18.58.] ASCENT ALONG A COENICE. 127
upwards from the dislocated glaciers. My guide continu-
ally admonished me to make my footing sure, and to fix
at each step my staff firmly in the consolidated snow. At
one place, for a short steep ascent, the slope became hard
ice, and our position a very ticklish one. We hewed our
steps as we moved upwards, but were soon glad to deviate
from the ice to a position scarcely less awkward. The wind
had so acted upon the snow as to fold it over the edge of
the kamm, thus causing it to form a kind of cornice, which
overhung the precipice on the Lyskamm side of the moun-
tain. This cornice now bore our weight: its snow had
, become somewhat firm, but it was yielding enough to
permit the feet to sink in it a little way, and thus secure us
at least against the danger of slipping. Here also at each
step we drove our batons firmly into the snow, availing
ourselves of whatever help they could render. Once,
while thus securing my anchorage, the handle of my
hatchet went right through the cornice on which we stood,
and, on withdrawing it, I could see through the aper-
ture into the cloud-crammed gulf below. We continued
ascending until we reached a rock protruding from the
snow, and here we halted for a few minutes. Lauener
looked upwards through the fog. " According to all de-
scription," he observed, '" this ought to be the last kamm
of the mountain; but in this obscurity we can see nothing."
Snow began to fall, and we recommenced our journev,
quitting the rocks and climbing again along the edge.
Another hour brought us to a crest of cliffs, at which,
to our comfort, the kamm appeared to cease, and other
climbing qualities were demanded of us.
On the Lyskamm side, as I have said, rescue would be
out of the question, should the climber go over the edge.
On the other side of the edge rescue seemed possible,
though the slope, as stated already, was most dangerously
steep. I now asked Lauener what he would have done,
128 "DIE HOCHSTE SPIT7E." [1858.
supposing my footing to have failed on the latter slope.
He did not seem to like the question, but said that he
should have considered well for a moment and then have
sprung after me; but he exhorted me to drive all such
thoughts away. I laughed at him, and this did more to
set his mind at rest than any formal profession of courage
could have done. We were now among rocks : we climbed
cliffs and descended them, and advanced sometimes with
our feet on narrow ledges, holding tightly on to other ledges
by our fingers ; sometimes, cautiously balanced, we moved
along edges of rock with precipices on' both sides. Once,
in getting round a crag, Lauener shook a book from his
pocket ; it was arrested by a rock about sixty or eighty feet
below us. He wished to regain it, but I offered to supply
its place, if he thought the descent too dangerous. He said
he would make the trial, and parted from me. I thought
it useless to remain idle. A cleft was before me, through
which I must pass ; so, pressing my knees and back against
its opposite sides, I gradually worked myself to the top. I
descended the other face of the rock, and then, through
a second ragged fissure, to the summit of another pinnacle.
The highest point of the mountain was now at hand, sepa-
rated from me merely by a short saddle, carved by wea-
thering out of the crest of the mountain. I could hear
Lauener clattering after me, through the rocks behind. I
dropped down upon the saddle, crossed it, climbed the oppo-
site cliff", and " die hochste Spitze " of Monte Rosa was won.
Lauener joined me immediately, and we mutually con-
gratulated each other on the success of the ascent. The
residue of the bread and meat was produced, and a bottle of
tea was also appealed to. Mixed with a little cognac,
Lauener declared that he had never tasted anything like it.
Snow fell thickly at intervals, and the obscurity was very
great ; occasionally this would lighten and permit the sun
to shed a ghastly dilute light upon us through the gleaming
1858.] GLOOM ON THE SUMMIT. 129
vapour. I put my boiling-water apparatus in order, and
fixed it in a corner behind a ledge ; the shelter was, how-
ever, insufficient, so I placed my hat above the vessel.
The boiling point was 184°- 9 2 Fahr., the ledge on which
the instrument stood being 5 feet below the highest point
of the mountain.
The ascent from the Eiffel hotel occupied us about
seven hours, nearly two of which were spent upon the
kamm and crest. Neither of us felt in the least degree
fatigued ; I, indeed, felt so fresh, that had another Monte
Rosa been planted on the first, I should have continued
the climb without hesitation, and with strong hopes of
reaching the top. I experienced no trace of mountain
sickness, lassitude, shortness of breath, heart-beat, or
headache ; nevertheless the summit of Monte Rosa is
15,284 feet high, being less than 500 feet lower than Mont
Blanc. It is, I think, perfectly certain, that the rarefaction
of the air at this height is not sufficient of itself to pro-
duce the symptoms referred to ; physical exertion must be
superadded.
After a few fitful efforts to dispel the gloom, the sun
resigned the dominion to the dense fog and the descending
snow, which now prevented our seeing more than 15 or
20 paces in any direction. The temperature of the crags
at the summit, which had been shone upon by the un-
clouded sun during the earlier portion of the day, was
60° Fahr. ; hence the snow melted instantly wherever it
came in contact with the rock. But some of it fell upon
my felt hat, which had been placed to shelter the boiling-
water apparatus, and this presented the most remarkable
and beautiful appearance. The fall of snow was in fact a
shower of frozen flowers. All of them were six-leaved ;
some of the leaves threw out lateral ribs like ferns, some
were rounded, others arrowy and serrated, some were close,
others reticulated, but there was no deviation from the six-
is
130 "FROZEN FLOWERS." [1858.
leaved type. Nature seemed determined to make us
some compensation for the loss of all prospect, and thus
showered down upon us those lovely blossoms of the frost ;
and had a spirit of the mountain inquired my choice, the
view, or the frozen flowers, I should have hesitated
before giving up that exquisite vegetation. It was won-
derful to think of, as well as beautiful to behold. Let us
imagine the eye gifted with a microscopic power sufficient
to enable it to see the molecules which composed these
starry crystals ; to observe the solid nucleus formed and
floating in the air ; to see it drawing towards it its allied
atoms, and these arranging themselves as if they moved to
music, and ended by rendering that music concrete. Surely
such an exhibition of power, such an apparent demonstra-
tion of a resident intelligence in what we are accustomed
to call " brute matter," would appear perfectly miracu-
lous. And yet the reality would, if we could see it, tran-
scend the faucy. If the Houses of Parliament were built
up by the forces resident in their own bricks and lithologic
blocks, and without the aid of hodman or mason, there
would be nothing intrinsically more wonderful in the pro-
cess than in the molecular architecture which delighted us
upon the summit of Monte Rosa.
Twice or thrice had my guide warned me that we must
think of descending, for the snow continued to fall heavily,
and the loss of our track would be attended with imminent
peril. We therefore packed upland clambered downward
among the crags of the summit. We soon left these be-
hind us, and as we stood once more upon the kamm, look-
ing into the gloom beneath, an avalanche let loose from
the side of an adjacent mountain shook the air with its
thunder. We could not see it, could form no estimate of
its distance, could only hear its roar, which coming to us
through the darkness, had an undefinable element of
horror in it. Lauener remarked, " I never hear those
1858.] STARTLING AVALANCHE. 131
things without a shudder ; the memory of my brother
comes back to me at the same time." His brother, who
was the best climber in the Oberland, had been literally
broken to fragments by an avalanche on the slopes of the
Jungfrau.
We had been separate coining up, each having trusted
to himself, but the descent was more perilous, because it is
more difficult to fix the heel of the boot than the toe
securely in the ice. Lauener was furnished with a rope,
which he now tied round my waist, and forming a noose
at the other end, he slipped it over his arm. This to me
was a new mode of attachment. Hitherto my guides in
dangerous places had tied the ropes round their waists
also. Simond had done it on Mont Blanc, and Bennen on
the Finsteraarhorn, proving thus their willingness to share
my fate whatever that might be. But here Lauener had
the power of sending me adrift at any moment, should his
own life be imperilled. I told him that his mode of attach-
ment was new to me, but he assured me that it would
give him more power in case of accident. I did not see
this at the time ; but neither did I insist on his attaching
himself in the usual way. It could neither be called
anger nor pride, but a warm flush ran through me as I
remarked, that I should take good care not to test his
power of holding me. I believe I wronged my guide by
the supposition that he made the arrangement with refer-
ence to his own safety, for all I saw of him afterwards
proved that he would at any time have risked his life to
save mine. The flush however did me good, by displacing
every trace of anxiety, and the rope, I confess, was also a
source of some comfort to me. We descended the kamm, I
going first. " Secure your footing before you move," was
,my guide's constant exhortation, " and make your staff firm
at each step." We were sometimes quite close upon the
rim of the kamm on the Lyskamm side, and we also
K 2
132 SPLENDID BLUE OF THE SNOW. [1858.
followed the depressions which marked our track along the
cornice. This I now tried intentionally, and drove the
handle of my axe through it once or twice. At two
places in descending we were upon the solid ice, and
these were some of the steepest portions of the kamm.
They were undoubtedly perilous, and the utmost caution
was necessary in fixing the staff and securing the footing.
These however once past, we felt that the chief danger
was over. We reached the termination of the edge, and
although the snow continued to fall heavily, and obscure
everything, we knew that our progress afterwards was se-
cure. There was pleasure in this feeling ; it was an agreeable
variation of that grim mental tension to which I had been
previously wound up, but which in itself was by no means
disagreeable.
I have already noticed the colour of the fresh snow upon
the summit of the Stelvio pass. Since I observed it there
it has been my custom to pay some attention to this point
at all great elevations. This morning, as I ascended Monte
Rosa, I often examined the holes made in the snow by our
batons, but the light which issued from them was scarcely
perceptibly blue. Now, however, a deep layer of fresh
snow overspread the mountain, and the effect was magnifi-
cent. Along the kamm I was continually surprised and
delighted by the blue gleams which issued from the broken
or perforated stratum of new snow ; each hole made by
the staff was filled with a light as pure, and nearly as deep,
as that of the unclouded firmament. When we reached
the bottom of the kamm, Lauener came to the front, and
tramped before me. As his feet rose out of the snow, and
shook the latter off in fragments, sudden and wonderful
gleams of blue light flashed from them. Doubtless the
blue of the sky has much to do with mountain colouring,
but in the present instance not only was there no blue sky,
but the air was so thick with fog and descending snow-
1858.] STIFLING HEAT. 133
flakes, that we could not see twenty yards in advance of
us. A thick fog, which wrapped the mountain quite
closely, now added its gloom to the obscurity caused by
the falling snow. Before we reached the base of the
mountain the fog became thin, and the sun shone through
it. There was not a breath of air stirring, and, though
we stood ankle-deep in snow, the heat surpassed anything
of the kind I had ever felt : it was the dead suffocating
warmth of the interior of an oven, which encompassed us
on all sides, and from which there seemed no escape.
Our own motion through the air, however, cooled us con-
siderably. We found the snow-bridges softer than in the
morning, and consequently needing more caution ; but
we encountered no real difficulty among them. Indeed
it is amusing to observe the indifference with which a
snow-roof is often broken through, and a traveller im-
mersed to the waist in the jaws of a fissure. The effort
at recovery is instantaneous ; half instinctively hands and
knees are driven into the snow, and rescue is immediate.
Fair glacier work was now before us ; after which we reached
the opposite mountain-slope, which we ascended, and then
went down the flank of the Biffelberg to our hotel.
The excursion occupied us eleven and a half hours.
(19.)
On the afternoon of the llth I made an attempt alone
to ascend the Kiffelhorn, and attained a considerable height ;
but I attacked it from the wrong side, and the fading
light forced me to retreat. I found some agreeable people
at the hotel on my return. One clergyman especially,
with a clear complexion, good digestion, and bad lungs —
of free, hearty, and genial manner — made himself ex-
tremely pleasant to us all. He appeared to bubble over
134 A DIFFICULT DESCENT. [1858.
with enjoyment, and with him and others on the morning
of the 13th I walked to the Gorner Grat, as it lay on
the way to my work. We had a glorious prospect from
the summit : indeed the assemblage of mountains, snow,
and ice, here within view is perhaps without a rival in the
world.* I shouldered my axe, and saying " good-bye "
moved away from my companions.
" Are you going ? " exclaimed the clergyman. " Give
me one grasp of your hand before we part."
This was the signal for a grasp all round ; and the
hearty human kindness which thus showed itself contri-
buted that day to make my work pleasant to me.
We proceeded along the ridge of the Kothe Kumme to
a point which commanded a fine view of the glacier. The
ice had been over these heights in ages past, for, although
lichens covered the surfaces of the old rocks, they did not
disguise the grooves and scratchings. The surface of the
glacier was now about a thousand feet below us, and this
it was our desire to attain. To reach it we had to descend
a succession of precipices, which in general were weathered
and rugged, but here and there, where the rock was
durable, were fluted and grooved. Once or twice indeed
we had nothing to cling to but the little ridges thus
formed. We had to squeeze ourselves through narrow
fissures, and often to get round overhanging ledges, where
our main trust was in our feet, but where these had only
ledges an inch or so in width to rest upon. These cases
were to me the most unpleasant of all, for they compelled
the arms to take a position which, if the footing gave way,
would necessitate a wrench, for which I entertain consider-
able abhorrence. We came at length to a gorge by which
the mountain is rent from top to bottom, and into which
we endeavoured to descend. We worked along its rim for
* In 1858 Mr. E. W. Cooke made a pencil-sketch of this splendid
panorama, which is the best and truest that I have yet seen.
1858.] SINGULAK ICE-CAVE. 135
a time, but found its smooth faces too deep. We retreated ;
Lauener struck into another track, and while he tested
it I sat down near some grass tufts, which flourished on
one of the ledges, and found the temperature to be as
follows : —
Temperature of rock . . . . 42° C.
Of air an inch above the rock . . 32
Of air a foot from rock . . . . 22
Of grass . . . . . . . . 25
The first of these numbers does not fairly represent the
temperature of the rock, as the thermometer could be in
contact with it only at one side at a time. It was differ-
ences such as these between grass and stone, producing a
mixed atmosphere of different densities, that weakened the
sound of the falls of the Orinoco, as observed and explained
by Humboldt.
By a process of "trial and error" we at length reached
the ice, after two hours had been spent in the effort to
disentangle ourselves from the crags. The glacier is
forcibly thrust at this place against the projecting base
of the mountain, and the structure of the ice corre-
spondingly developed. Crevasses also intersect the ice,
and the blue veins cross them at right angles. I as-
cended the glacier to a region where the ice was com-
pressed and greatly contorted, and thought that in some
cases I could see the veins crossing the lines of stra-
tification. Once my guide drew my attention to what he
called " ein sonderbares Loch" On one of the slopes an
archway was formed which appeared to lead into the body
of the glacier. We entered it, and explored the cavern to
its end. The walls were of transparent blue ice, singularly
free from air-bubbles ; but where the roof of the cavern
was thin enough to allow the sun to shine feebly through
it, the transmitted light was of a pink colour. My guide
136 STEUCTUEE AND STEATA. [1858.
expressed himself surprised at " den rotliliclien Schein." At
one place a plate of ice had been placed like a ceiling
across the cavern ; but owing to lateral squeezing it had
been broken so as to form a V. I found some air-bubbles
in this ice, and in all cases they were associated with
blebs of water. A portion of the " ceiling," indeed, was
very full of bubbles, and was at some places reduced, by
internal liquefaction, to a mere skeleton of ice, with water-
cells between its walls.
High up the glacier (towards the old Weissthor) the
horizontal stratification is everywhere beautifully shown.
I drew my guide's attention to it, and he made the
remark that the perfection of the lower ice was due to the
pressure of the layers above it. " The snow by degrees
compressed itself to glacier." As we approached one of
the tributaries on the Monte Rosa side, where great pres-
sure came into play, the stratification appeared to yield
and the true structure to cross it at those places where
it had yielded most. As the place of greatest pressure
was approached, the bedding disappeared more and more,
and a clear vertical structure was finally revealed.
1858.] GENERATION OF CLOUDS. 137
THE GORNER GRAT AND THE RIFFELHORN.
MAGNETIC PHENOMENA.
(20.)
AT an early hour on Saturday, the 14th of August, I
heard the servant exclaim, "Das Wetter ist wunderschon ! "
which good news caused me to spring from my bed and
prepare to meet the morn. The range of summits at the
opposite side of the valley of St. Nicholas was at first
quite clear, but as the sun ascended light cumuli formed
round them, increasing in density up to a certain point ;
below these clouds the air of the valley was transparent ;
above them the air of heaven was still more so ; and thus
they swung midway between heaven and earth, ranging
themselves in a level line along the necks of the moun-
tains.
It might be supposed that the presence of the sun
heating the air would tend to keep it more transparent,
by increasing its capacity to dissolve all visible cloud ; and
this indeed is the true action of the sun. But it is not
the only action. His rays, as he climbed the eastern
heaven, shot more and more deeply into the valley of
St. Nicholas, the moisture of which rose as invisible
vapour, remaining unseen as long as the air possessed
sufficient warmth to keep it in the vaporous state. High
up, however, the cold crags which had lost their heat
by radiation the night before, acted like condensers
upon the ascending vapour, and caused it to curdle into
visible fog. The current, however, continued ascen-
sional, and the clouds were slowly lifted above the tallest
peaks, where they arranged themselves in fantastic forms,
shifting and changing shape as they gradually melted away.
188 THE EOCKS WAKMED. [1858.
One peak stood like a field-officer with his cap raised above
his head, others sent straggling cloud-balloons upwards ;
but on watching these outliers they were gradually seen
to disappear. At first they shone like snow in the sun-
light, but as they became more attenuated they changed
colour, passing through a dull red to a dusky purple hue,
until finally they left no trace of their existence.
As the day advanced, warming the rocks, the clouds
wholly disappeared, and a hyaline air formed the setting
of both glaciers and mountains. I climbed to the Gorner
Grat to obtain a general view of the surrounding scene.
Looking towards the origin of the Gorner glacier the view
was bounded by a wide col, upon which stood two lovely
rounded eminences enamelled with snow of perfect purity.
They shone like burnished silver in the sunlight, as if
their surfaces had been melted and recongealed to frosted
mirrors from which the rays were flung. To the right
of these were the bounding crags of Monte Rosa, and
then the body of the mountain itself, with its crest of
crag and coat of snows. To the right of Monte Kosa,
and almost rivalling it in height, was the vast mass
of the Lyskamm, a rough and craggy mountain, to
whose ledges clings the snow which cannot grasp its
steeper walls, sometimes leaning over them in impending
precipices, which often break, and send wild avalanches
into the space below. Between the Lyskamm and Monte
Kosa lies a large wide valley into which both mountains
pour their snows, forming there the Western glacier of
Monte Rosa * — a noble ice stream, which from its mag-
nitude and permanence deserves to impose its name
upon the trunk glacier. It extends downwards from the
col which unites the two mountains ; riven and broken
at some places, but at others stretching white and pure
* [Now called, in the Federal map, the ' Grenz glacier.'— L. C. T.]
1858.] SCENE FROM THE GORNER GRAT. 139
down to its snow-line, where the true glacier emerges from
the neve. From the rounded shoulders of the Twin Castor
a glacier descends, at first white and shining, then sud-
denly broken into faults, fissures, and precipices, which
are afterwards repaired, and the glacier joins that of
Monte Kosa before the junction of the latter with the
trunk stream. Next came a boss of rock, with a secondary
glacier clinging to it as if plastered over it, and after it
the Schwarze glacier, bounded on one side by the Breithorn,
and on the other by the Twin Pollux. This glacier is of
considerable magnitude. Over its upper portion rise the
Twin eminences, pure and white ; then follows a smooth and
undulating space, after passing which the neve is torn
up into a collection of peaks and chasms; these, how-
ever, are mended lower down, and the glacier moves
smoothly and calmly to meet its brothers in the main
valley. Next comes the Trifti glacier,* embraced on all
sides by the rocky arms of the Breithorn ; its mass is not
very great, but it descends in a graceful sweep, and
exhibits towards its extremity a succession of beautiful
bands. Afterwards we have the glacier of the Petit
Mont Cervin and those of St. Theodule, which latter are
the last that empty their frozen cargoes into the valley
of the Gorner. All the glaciers here mentioned are
welded together to a common trunk which squeezes itself
through the narrow defile at the base of the KifFelhorn.
Soon afterwards the moraines become confused, the glacier
drops steeply to its termination, and ploughs up the
meadows in front of it with its irresistible share.
In a line with the Riffelhorn, and rising over the
latter so high as to make it almost vanish by comparison,
was the Titan obelisk of the Matterhorn, from the base of
which the Furgge glacier struggles downwards. On the
* I take this name from Studer's map. Sometimes, however, I have
called it the " Breithorn glacier."
140 COMPASS AT FAULT. [1858.
other side are the Zmutt glacier, the Schonbiihl, and the
Hochwang, from the Dent Blanche ; the Gabelhorn and
Trift glaciers, from the summits which bear those names.
Then come the glaciers of the Weisshorn. Describing a
curve still farther to the right we alight on the peaks
of the Mischabel, dark and craggy precipices from this side,
though from the ^Eggischhorn they appear as cones of snow.
Sweeping by the Alphubel, the Allaleinhorn, the Rymp-
fischorn, and Strahlhorn — all of them majestic — we reach
the pass of the Weissthor, and the ' Cima di Jazzi. This
completes the glorious circuit within the observer's view.
I placed my compass upon a piece of rock to find the
bearing of the Gorner glacier, and was startled at seeing
the sun and it at direct variance. What the sun declared
to be north, the needle affirmed to be south. I at first
supposed that the maker had placed the S where the N
ought to be, and vice versa. On shifting my position,
however, the needle shifted also, and I saw immediately
that the effect was due to the rock of the Grat. Some-
times one end of the needle dipped forcibly, at other
places it whirled suddenly round, indicating an entire
change of polarity. The rock was evidently to be re-
garded as an assemblage of magnets, or as a single
magnet full of " consequent points." A distance of trans-
port not exceeding an inch was, in some cases, sufficient
to reverse the position of the needle. I held the needle
between the two sides of a long fissure a foot wide.
The needle set along the fissure at some places, while at
others it set across it. Sometimes a little jutting knob
would attract the north end of the needle, while a closely
adjacent little knob would forcibly repel it, and attract
the south end. One extremity of a ledge three feet long
was north magnetic, the other end was south magnetic,
while a neutral point existed midway between the two, the
ledge having therefore the exact polar arrangement of an
1858.] MAGNETISM OF BOOKS. 141
ordinary bar-magnet. At the highest point of the rock
the action appeared to be most intense, but I also found
an energetic polarity in a mass at some distance below the
summit.
Eemembering that Professor Forbes had noticed some
peculiar magnetic effect upon the Eiffelhorn, I resolved to
ascend it. Descending from the Grat we mounted the
rocks which form the base of the horn ; these are soft and
soapy from the quantity of mica which they contain ;
the higher rocks of the horn are, however, very dense and
hard. The ascent is a pleasant bit of mountain practice.
We climbed the walls of rock, and wound round the ledges,
seeking the assailable points. I tried the magnetic condi-
tion of the rocks as we ascended, and found it in general
feeble. In other respects the Biffelhorn is a most re-
markable mass. The ice of the Gorner glacier of former
ages, which rose hundreds, perhaps thousands of feet above
its present level, encountered the horn in its descent, and
was split by the latter, a diversion of the ice along the
sides of the peak being the consequence. Portions of the
vertical walls of the horn are polished by this action as if
they had come from the hands of a lapidary, and the
scratchings are as sharp and definite as if drawn by
points of steel. I never saw scratchings so perfectly
preserved : the finest lines are as clear as the deepest, a
consequence of the great density and durability of the
rock. The latter evidently contains a good deal of iron,
and its surface near the summit is of the rich brown red
due to the peroxide of the metal. When we fairly got
among the precipices we left our hatchets behind us, trust-
ing subsequently to our hands and feet alone. Squeezing,
creeping, clinging, and climbing, in due time we found
ourselves upon the summit of the horn.
A pile of stones had been erected near the point where
we gained the top. I examined the stones of this pile,
142 ASCENT OF THE KIFFELHORN. [1858.
and found them strongly polar. The surrounding rocks
also showed a violent action, the needle oscillating quickly,
and sometimes twirling swiftly round upon a slight change
of position. The fragments of rock scattered about were
also polar. Long ledges showed north magnetism for a
considerable length, and again for an equal length south
magnetism. Two parallel masses separated from each
other by a fissure, showed the same magnetic distribution.
While I was engaged at one end of the horn, Lauener
wandered to the other, on which- stood two or three
hommes de pierres. He was about disturbing some of the
stones, when a yell from me surprised him. In fact,
the thought had occurred to me that the magnetism of
the horn had been developed by lightning striking upon
it, and my desire was to examine those points which were
most exposed to the discharge of the atmospheric electri-
city ; hence my shout to my guide to let the stones alone.
I worked towards the other end of the horn, examining
the rocks in my way. Two weathered prominences, which
seemed very likely recipients of the lightning, acted vio-
lently upon the needle. I sometimes descended a little
way, and found that among the rocks below the summit
the action was greatly enfeebled. On reaching another
very prominent point, I found its extremity all north
polar, but at a little distance was a cluster of consequent
points, among which the transport of a few inches was
sufficient to turn the needle round and round.
The piles of stone at the Zermatt end of the horn did
not seem so strongly polar as the pile at the other end,
which was higher ; still a strong polar action was mani-
fested at many points of the surrounding rocks. Having
completed the examination of the summit, I descended
the horn, and examined its magnetic condition as I went
along. It seemed to me that the jutting prominences
always exhibited the strongest action. I do not indeed
1858.]
MAGNETISM OF THE HORN.
143
remember any case in which a strong action did not ex-
hibit itself at the ends of the terraces which constitute
the horn. In all cases, however, the rock acted as a
number of magnets huddled confusedly together, and not
as if its entire mass was endowed with magnetism of one
kind.
On the evening of the same day I examined the lower
spur of the Riffelhorn. Amid its fissures and gulleys one
feels as if wandering through the ruins of a vast castle or
fortification ; the precipices are so like walls, and the
scratching and polishing so like what might be done by
the hands of man. I found evidences of strong polar
action in some of the rocks low down. In the same con-
tinuous mass the action would sometimes exhibit itself
over an area of small extent, while the remainder of the
rock showed no appreciable action. Some of the boulders
cast down from the summit exhibited a strong and varied
polarity. Fig. 8 is a sketch of one of these ; the barbed
end of each arrow repre-
sents the north end of the
needle, which assumed
the various positions
shown in the figure. Mid-
way down the spur I
lighted upon a trans-.,
verse wall of rock, which
formed in earlier ages
the boundary of a lateral outlet of the Gorner glacier. It
was red and hard, weathered rough at some places, and
polished smooth at others. The lines were drawn finely
upon it, but its outer surface appeared to be peeling off
like a crust ; the polished layer rested upon the rock like
a kind of enamel. The action of the glacier appeared to
resemble that of the break of a locomotive upon rails, both
being cases of exfoliation brought about by pressure and
144 THE MAGNETIC FOKCE. [1858.
friction. This wall measured twenty-eight yards across,
and one end of it, for a distance of ten or twelve yards, was
all north polar ; the other end for a similar distance was
south polar, but there was a pair of consequent points at
its centre.
To meet the case of my young readers, I will here
say a few words about the magnetic force. The common
magnetic needle points nearly north and south ; and if a
bit of iron be brought near to either end of the needle,
they will mutually attract each other. A piece of lead
will not show this effect, nor will copper, gold, nor silver.
Iron, in fact, is a magnetic metal, which the others are not.
It is to be particularly observed, that the bit of iron at-
tracts both ends of the needle when it is presented to them
in succession ; and if a common steel sewing needle be
substituted for the iron it will be seen that it also has the
power of attracting both ends of the magnetic needle. But
if the needle be rubbed once or twice along one end
of a magnet, it will be found that one of its ends will
afterwards repel a certain end of the magnetic needle and
attract the other. By rubbing the needle on the magnet,
we thus develop both attraction and repulsion, and this
double action of the magnetic force is called its polarity ;
thus the steel which was at first simply magnetic, is now
magnetic and polar.
It is the aim of persons making magnets, that each mag-
net should have but two poles, at its two ends; it is, however,
easy to develop in the same piece of steel several pairs of
poles ; and if the magnetization be irregular, this is some-
times done when we wish to avoid it. These irregular
poles are called consequent points.
Now I want my young reader to understand that it is
not only because the rocks of the Gorner Grat and Riffel-
horn contain iron, that they exhibit the action which I
have described. They are not only magnetic, as common
1858.] BEARINGS FROM THE RIFFELHORN. 145
iron is, but, like the magnetized steel needle, they are mag-
netic and polar. And these poles are irregularly dis-
tributed like the " consequent points " to which I have
referred, and this is the reason why I have used the term.
Professor Forbes, as I have already stated, was the first to
notice the effect of the Riffelhorn upon the magnetic needle,
but he seems to have supposed that the entire mass of the
mountain exercised " a local attraction " upon the needle ;
(upon which end he does not say). To enable future observers
to allow for this attraction, he took the bearing of several of
the surrounding mountains from the Eiffelhorn ; but it is
very probable that had he changed his position a few inches,
and perfectly certain had he changed it a few yards, he would
have found a set of bearings totally different from those
which he has recorded. The close proximity and irregular
distribution of its consequent points would prevent the
Riffelhorn from exerting any appreciable influence on a
distant needle, as in this case the local poles would effectu-
ally neutralize each other.
(21.)
On the morning of the 1 5th the Riffelberg was swathed
in a dense fog, through which heavy rain showered inces-
santly. Towards one o'clock the continuity of the gray
mass was broken, and sky-gleams of the deepest blue
were seen through its apertures ; these would close up
again, and others open elsewhere, as if the fog were
fighting for existence with the sun behind it. The sun,
however, triumphed, the mountains came more and more
into view, and finally the entire air was swept clear. I
went up to the Gorner Grat in the afternoon, and examined
more closely the magnetism of its rocks ; here, as on the
Riffelhorn, I found it most pronounced at the jutting
L
146 MONT CERVIN AS CLOUD-MAKEE. [1858.
prominences of the Grat. Can it be that the superior ex-
posure is more favourable to the formation of the magnetic
oxide of iron ? I secured a number of fragments, which I
still possess, and which act forcibly upon a magnetic needle.
The sun was near the western horizon, and I remained
alone upon the Grat to see his last beams illuminate the
mountains, which, with one exception, were without a trace
of cloud. This exception was the Matterhorn, the appear-
ance of which was extremely instructive. The obelisk
appeared to be divided in two halves by a vertical line
drawn from its summit half way down, to the windward of
which we had the bare cliffs of the mountain ; and to the
left of it a cloud which appeared to cling tenaciously to the
rocks. In reality, however, there was no clinging ; the con-
densed vapour incessantly got away, but it was ever
renewed, and thus a river of cloud had been sent from
the mountain over the valley of Aosta. The wind in fact
blew lightly up the valley of St. Nicholas charged with
moisture, and when the air that held it rubbed against the
cold cone of the Matterhorn the vapour was chilled and
precipitated in his lee. The summit seemed to smoke
sometimes like a burning mountain ; for immediately after
its generation, the fog was drawn away in long filaments
by the wind. As the sun sank lower the ruddiness of his
light augmented, until these filaments resembled streamers
of flame. The sun sank deeper, the light was gradually
withdrawn, and where it had entirely vanished it left the
mountain like a desolate old man whose
" hoary hair
Stream'd like a meteor in the troubled air."
For a moment after the sun had disappeared the scene was
amazingly grand. The distant west was ruddy, copious gray
smoke-wreaths were wafted from the mountains, while high
overhead, in an atmospheric region which seemed perfectly
motionless, floated a broad thin cloud, dyed with the richest
1858.] CELLS IN THE ICE. 147
iridescences. The colours were of the same character as
those which I had seen upon the Aletschhorn, being due to
interference, and in point of splendour and variety far
exceeded anything ever produced by the mere coloured
light of the setting sun.
On the 16th I was early upon the glacier. It had frozen
hard during the night, and the partially liberated streams
flowed, in many cases, over their own ice. I took some
clear plates from under the water, and found in them
numerous liquid cells, each associated with an air-bubble
or a vacuous spot. The most common shape of the cells
was a regular hexagon, but there were all forms between
the perfect hexagon and the perfect circle. Many cells
had also crimped borders, intimating that their primitive
form was that of a flower with six leaves. A plate taken
from ice which was defended from the sunbeams by the
shadow of a rock had no such cells ; so that those that I
observed were probably due to solar radiation.
My first aim was to examine the structure of the
Gornerhorn glacier,* which descends the breast of Monte
Rosa until it is abruptly cut off by the great Western glacier
of the mountain.f Between them is a moraine which is at
once terminal as regards the former, and lateral as regards
the latter. The ice is veined vertically along the mo-
raine, the direction of the structure being parallel to the
latter. I ascended the glacier, and found, as I retreated
from the place where the thrust was most violent, that the
structure became more feeble. From the glacier I passed
to the rocks called " aufder Platte" so as to obtain a general
view of its terminal portion. The gradual perfecting of
the structure as the region of pressure was approached
was very manifest : the ice at the end seemed to wrinkle
* [Now called, in the Federal map, the " Monte Eosa glacier." Gorner-
horn is an old local name for the central mass of Monte Eosa.— L.C.T.]
t [See p. 138, footnote.]
L 2
148 STKUCTUBE OF THE ICE. [1858.
up in obedience to the pressure, the structural furrows,
from being scarcely visible, became more and more
decided, and the lamination underneath correspondingly
pronounced, until it finally attained a state of great per-
fection.
I now quitted the rocks and walked straight across
the Western glacier of Monte Eosa to its centre, where
I found the structure scarcely visible. I next faced the
Gorner Grat, and walked down the glacier towards the
moraine which divides it from the Gorner glacier. The
mechanical conditions of the ice here are quite evident ;
each step brought me to a place of greater pressure, and
also to a place of more highly developed structure, until
finally near to the moraine itself, and running parallel to
it, a magnificent lamination was developed. Here the
superficial groovings could be traced to great distances,
and beside the moraine were boulders poised on pedestals
of ice through which the blue veins ran. At some places
the ice had been weathered into laminae not more than
a line in thickness.
I now recrossed the Monte Rosa glacier to its junction
with the Schwartze glacier, which descends between the
Twins and Breithorn. The structure of the Monte Rosa
glacier is here far less pronounced than at the other
side, and the pressure which it endures is also manifestly
less; the structure of the Schwartze glacier is fairly
developed, being here parallel to its moraine. The cliffs ot
the Breithorn are much exposed to weathering action, and
boulders are copiously showered down upon the adjacent
ice. Between the Schwartze glacier and the glacier
which descends from the breast of the Breithorn itselt
these blocks ride upon a spine of ice, and form a moraine
of grand proportions. From it a fine view of the glacier
is attainable, and the gradual development of its structure
as the region of maximum pressure is approached is very
1858.] TEIBUTAKIES EXPLORED. 149
plain. A number of gracefully curved undulations sweep
across the Breithorn glacier, which are squeezed more
closely together as the moraine is approached. All the
glaciers that descend from the flanking mountains of the
Gorner valley are suddenly turned aside where they meet
the great trunk stream, and are reduced by the pressure
to narrow stripes of ice separated from each other by
parallel moraines.
I ascended the Breithorn glacier to the base of an ice-
fall, on one side of which I found large crumples produced
by the pressure, the veined structure being developed at
right angles to the direction of the latter. No such struc-
ture was visible above this place. The crumples were cut
by fissures, perpendicular to which the blue veins ran.
I now quitted the glacier, and clambered up the adjacent
alp, from which a fine view of the general surface was
attainable. As in the case of the Gornerhorn glacier, the
gradual perfecting of the structure was very manifest ;
the dirt, which first irregularly scattered over the surface,
gradually assumed a, striated appearance, and became
more and more decided as the moraine was approached.
Descending from the alp, I endeavoured to measure
some of the undulations; proceeding afterwards to the
junction of the Breithorn glacier with that of St. Theodule.
The end of the latter appears to be crumpled by its
thrust against the former, and the moraine between them,
instead of being raised, runs along a hollow which is
flanked by the crumples on either side. The Breithorn
glacier became more and more attenuated, until finally it
actually vanished under its own moraines. On the sides
of the crevasses, by which the Theodule glacier is here
intersected, I thought I could plainly see two systems of
veins cutting each other at an angle of fifteen or twenty
degrees. Reaching the Gorner glacier, at a place where
its dislocation was very great, I proceeded down it past
150 TEMPTATION. [1858.
the RifFelhorn, to a point where it seemed possible to scale
the opposite mountain wall. Here I crossed the glacier,
treading with the utmost caution along the combs of ice,
and winding through the entanglement of crevasses until
the spur of the Riffelhorn was reached ; this I climbed
to its summit, and afterwards crossed the green alp to
our hotel.
The foregoing good day's work was rewarded by a sound
sleep at night. The tourists were called in succession
next morning, but after each call I instantly subsided
into deep slumber, and thus healthily spaced out the
interval of darkness. Day at length dawned and gradually
brightened. I looked at my watch and found it twenty
minutes to six. My guide had been lent to a party of
gentlemen who had started at three o'clock for the summit
of Monte Rosa, and he had left with me a porter who
undertook to conduct me to one of the adjacent glaciers.
But as I looked from my window the unspeakable beauty
of the morning filled me with a longing to see the world
from the top of Monte Rosa. I was in exceedingly
good condition — could I not reach the summit alone?
Trained and indurated as I had been, I felt that the thing
was possible ; at all events I could try, without attempting
anything which was not clearly within my power.
1858.] A LIGHT SCEIP. 151
SECOND ASCENT OF MONTE EOS A, 1858.
(22.)
WHETHER my exercise be mental or bodily, I am always
most vigorous when cool. During my student life in
Germany, the friends who visited me always complained
of the low temperature of my room, and here among
the Alps it was no uncommon thing for me to wander
over the glaciers from morning till evening in my shirt-
sleeves. My object now was to go as light as possible,
and hence I left my coat and neckcloth behind me, trusting
to the sun and my own motion to make good the calorific
waste. After breakfast I poured what remained of my tea
into a small glass bottle, an ordinary demi-bouteille, in
fact ; the waiter then provided me with a ham sandwich,
and, with my scrip thus frugally furnished, I thought the
heights of Monte Kosa might be won. I had neither
brandy nor wine, but I knew the immense amount of me-
chanical force represented by four ounces of bread and
ham, and I therefore feared no failure from lack of nutri-
ment. Indeed, I am inclined to think that both guides
and travellers often impair their vigour and render them-
selves cowardly and apathetic by the incessant "refreshing"
which they deem it necessary to indulge in on such
occasions.
The guide whom Lauener intended for me was at the
door ; I passed him and desired him to follow me. This
he at first refused to do, as he did not recognise me in my
shirt-sleeves ; but his companions set him right, and he
ran after me. I transferred my scrip to his shoulders, and
led the way upward. Once or twice he insinuated that that
was not the way to the Schwarze-See, and was probably
perplexed by my inattention. From the summit of the
152 THE GUIDE EXPOSTULATES. [1858.
ridge which bounds the Gorner glacier the whole grand
panorama revealed itself, and on the higher slopes of Monte
Rosa — go high, indeed, as to put all hope of overtaking
them, or even coming near them, out of the question — a
row of black dots revealed the company which had started
at three o'clock from the hotel. They had made remark-
ably good use of their time, and I was afterwards informed
that the cause of this was the intense cold, which compelled
them to keep up the proper supply of heat by increased
exertion. I descended swiftly to the glacier, and made for
the base of Monte Rosa, my guide following at some dis-
tance behind me. One of the streams, produced by super-
ficial melting, had cut for itself a deep wide channel in the
ice ; it was not too wide for a spring, and with the aid of
a run I cleared it and went on. Some minutes afterwards
I could hear the voice of my companion exclaiming, in a
tone of expostulation, " No, no, I won't follow you there."
He however made a circuit, and crossed the stream ; I
waited for him at the place where the Monte Rosa glacier
joins the rock, " auf der Platte" and helped him down the
ice-slope. At the summit of these rocks I again waited for
him. He approached me with some excitement of manner,
and said that it now appeared plain to him that I intended
to ascend Monte Rosa, but that he would not go with me.
I asked him to accompany me to the summit of the next
cliff, which he agreed to do ; and I found him of some ser-
vice to me. He discovered the faint traces of the party in
advance, and, from his greater experience, could keep them
better in view than I could. We lost them, however, near
the base of the cliff at which we aimed, and I went on,
choosing as nearly as I could remember the route followed
by Lauener and myself a week previously, while my guide
took another route, seeking for the traces. The glacier
here is crevassed, and I was among the fissures some dis-
tance in advance of my companion. Fear was manifestly
1858.] THE GUIDE HALTS. 153
getting the better of him, and he finally stood still, ex-
claiming, "No man can pass there." At the same mo-
ment I discovered the trace, and drew his attention to it ;
he approached me submissively, said that I was quite
right, and declared his willingness to go on. We climbed
the cliff, and discovered the trace in the snow above it.
Here I transferred the scrip and telescope to my own
shoulders, and gave my companion a cheque for five francs.
He returned, and I went on alone.
The sun and heaven were glorious, but the cold
was nevertheless intense, for it had frozen bitterly the
night before. The mountain seemed more noble and
lovely than when I had last ascended it ; and as I climbed
the slopes, crossed the shining cols, and rounded the vast
snow-bosses of the mountain, the sense of being alone lent
a new interest to the glorious scene. I followed the track
of those who preceded me, which was that pursued by
Lauener and myself a week previously. Once I deviated
from it to obtain a glimpse of Italy over the saddle which
stretches from Monte Rosa to the Lyskamm. Deep be-
low me was the valley, with its huge and dislocated neve,
and the slope on which I hung was just sufficiently steep
to keep the attention aroused without creating anxiety.
I prefer such a slope to one on which the thought of
danger cannot be entertained. I become more weary
upon a dead level, or in walking up such a valley as
that which stretches between Visp and Zermatt, than on
a steep mountain side. The sense of weariness is often
no index to the expenditure of muscular force : the
muscles may be charged with force, and, if the nervous
excitant be feeble, the strength lies dormant, and we
are tired without exertion. But the thought of peril
keeps the mind awake, and spurs the muscles into
action ; they move with alacrity and freedom, and the
time passes swiftly and pleasantly.
154 LEFT ALONE. [1858.
Occupied with my own thoughts as I ascended, I
sometimes unconsciously went too quickly, and felt the
effects of the exertion. I then slackened my pace,
allowing each limb an instant of repose as I drew it out
of the snow, and found that in this way walking became
rest. This is an illustration of the principle which runs
throughout nature — to accomplish physical changes, time
is necessary. Different positions of the limb require
different molecular arrangements; and to pass from one
to the other requires time. By lifting the leg slowly and
allowing it to fall forward by its own gravity, a man may
get on steadily for several hours, while a very slight addi-
tion to this pace may speedily exhaust him. Of course
the normal pace differs in different persons, but in all
the power of endurance may be vastly augmented by the
prudent outlay of muscular force.
The sun had long shone down upon me with intense
fervour, but I now noticed a strange modification of the
light upon the slopes of snow. I looked upwards, and saw
a most gorgeous exhibition of interference-colours. A light
veil of clouds had drawn itself between me and the sun,
and this was flooded with the most brilliant dyes. Orange,
red, green, blue — all the hues produced by diffraction were
exhibited in the utmost splendour. There seemed a ten-
dency to form circular zones of colour round the sun, but
the clouds were not sufficiently uniform to permit of this,
and they were consequently broken into spaces, each
steeped with the colour due to the condition of the cloud
at the place. Three times during my ascent similar veils
drew themselves across the sun, and at each passage the
splendid phenomena were renewed. As I reached the
middle of the mountain an avalanche was let loose from
the sides of the Lyskamm ; the thunder drew my eyes to
the place ; I saw the ice move, but it was only the tail 01
the avalanche ; still the volume of sound told me that it
1858.] GIDDINESS ON THE KAMM. 155
was a huge one. Suddenly the front of it appeared from
behind a projecting rock, hurling its ice-masses with fury
into the valley, and tossing its rounded clouds of ice-dust
high into the atmosphere. A wild long-drawn sound,
multiplied by echoes, now descended from the heights
above me. It struck me at first as a note of lamentation,
and I thought that possibly one of the party which was
now near the summit had gone over the precipice. On
listening more attentively I found that the sound shaped
itself into an English " hurrah ! " I was evidently nearing
the party, and on looking upwards I could see them, but
still at an immense height above me. The summit still
rose before them, and I therefore thought the cheer prema-
ture. A precipice of ice was now in front of me, around
which I wound to the right, and in a few minutes found
myself fairly at the bottom of the Kamm.
I paused here for a moment, and reflected on the work
before me. My head was clear, my muscles in perfect
condition, and I felt just sufficient fear to render me careful.
I faced the Kamm, and went up slowly but surely, and
soon heard the cheer which announced the arrival of the
party at the summit of the mountain. It was a wild, weird,
intermittent sound, swelling or falling as the echoes re-
inforced or enfeebled it. In getting through the rocks
which protrude from the snow at the base of the last spur
of the mountain, I once had occasion to stoop my
head, and, on suddenly raising it, my eyes swam as they
rested on the unbroken slope of snow at my left. The
sensation was akin to giddiness, but I believe it was chiefly
due to the absence of any object upon the snow upon
which I could converge the axes of my eyes. Up to
this point I had eaten nothing. I now unloosed my
scrip, and had two mouthfuls of sandwich and nearly the
whole of the tea that remained. I found here that my
load, light as it was, impeded me. When fine balancing
156 SCRIP LEFT BEHIND. [1858.
is necessary, the presence of a very light load, to which
one is unaccustomed, may introduce an element of
danger, and for this reason I here left the residue of
my tea and sandwich behind me. A long, long edge was
now in front of me, sloping steeply upwards. As I com-
menced the ascent of this, the foremost of those whose
cheer had reached me from the summit some time pre-
viously, appeared upon the top of the edge, aod the whole
party was seen immediately afterwards dangling on the
Kamm. We mutually approached' each other. Peter
Bohren, a well-known Oberland guide, came first, and
after him came the gentleman in his immediate charge.
Then came other guides with other gentlemen, and
last of all my guide, Lauener, with his strong right
arm round the youngest of the party. We met where a
rock protruded through the snow. The cold smote my
naked throat bitterly, so to protect it I borrowed a hand-
kerchief from Lauener, bade my new acquaintances good
bye, and proceeded upwards. I was soon at the place
where the snow-ridge joins the rocks which constitute the
crest of the mountain ; through these my way lay, every
step I took augmenting my distance from all life, and
increasing my sense of solitude. I went up and down the
cliffs as before, round ledges, through fissures, along edges
of rock, over the last deep and rugged indentation, and up
the rocks at its opposite side, to the summit.
A world of clouds and mountains lay beneath me. Switz-
erland, with its pomp of summits, was clear and grand ;
Italy was also grand, but more than half obscured. Dark
cumulus and dark crag vied in savagery, while at other
places white snows and white clouds held equal rivalry.
The scooped valleys of Monte Kosa itself were magni-
ficent, all gleaming in the bright sunlight — tossed and
torn at intervals, and sending from their rents and
walls the magical blue of the ice. Ponderous neves lay
1858.] ALONE ON THE SUMMIT. 157
upon the mountains, apparently motionless, but sug-
gesting motion — sluggish, but indicating irresistible
dynamic energy, which moved them slowly to their doom
in the warmer valleys below. I thought of my position :
it was the first time that a man had stood alone upon
that wild peak, and were the imagination let loose amid
the surrounding agencies, and permitted to dwell upon
the perils which separated the climber from his kind, I
dare say curious feelings might have been engendered.
But I was prompt to quell all thoughts which might lessen
my strength, or interfere with the calm application of it.
Once indeed an accident made me shudder. While taking
the cork from a bottle which is deposited on the top, and
which contains the names of those who have ascended the
mountain, my axe slipped out of my hand, and slid some
thirty feet away from me. The thought of losing it made
my flesh creep, for without it descent would be utterly im-
possible. I regained it, and looked upon it with an affection
which might be bestowed upon a living thing, for it was
literally my staff of life under the circumstances. One
look more over the cloud-capped mountains of Italy, and
I then turned my back upon them, and commenced the
descent.
The brown crags seemed to look at me with a kind of
friendly recognition, and, with a surer and firmer feeling than
I possessed on ascending, I swung myself from crag to crag
and from ledge to ledge with a velocity which surprised
myself. I reached the summit of the Kamm, and saw
the party which I had passed an hour and a half before,
emerging from one of the hollows of the mountain ;
they had escaped from the edge which now lay between
them and me. The thought of the possible loss of my
axe at the summit was here forcibly revived, for with-
out it I dared not take a single step. My first care
was to anchor it firmly in the snow, so as to enable it
158 THE AXE SLIPS. [1858.
to bear at times nearly the whole weight of my body.
In some places, however, the anchor had but a loose
hold ; the " cornice " to which I have already referred
became granular, and the handle of the axe went through
it up to the head, still, however, remaining loose. Some
amount of trust had thus to be withdrawn from the
staff and placed in the limbs. A curious mixture of care-
lessness and anxiety sometimes fills the mind on such
occasions. I often caught myself humming a verse of a
frivolous song, but this was mechanical, and the sub-
stratum of a man's feelings under such circumstances is
real earnestness. The precipice to my left was a continual
preacher of caution, and the slope to my right was hardly
less impressive. I looked down the former but rarely, and
sometimes descended for a considerable time without
looking beyond my own footsteps. The power of a thought
was illustrated on one of these occasions. I had descended
with extreme slowness and caution for some time, when
looking over the edge of the cornice I saw a row of pointed
rocks at some distance below me. These I felt must
receive me if I slipped over, and I thought how before
reaching them I might so break my fall as to arrive at
them unkilled. This thought enabled me to double my
speed, and as long as the spiky barrier ran parallel to my
track I held my staff in one hand, and contented myself
with a slight pressure upon it.
I came at length to a place where the edge was solid ice,
which rose to the level of the cornice, the latter appearing
as if merely stuck against it. A groove ran between the
ice and snow, and along this groove I marched until the
cornice became unsafe, and I had to betake myself to the
ice. The place was really perilous, but, encouraging
myself by the reflection that it would not last long, I care-
fully and deliberately hewed steps, causing them to dip a
little inward, so as to afford a purchase for the heel of mv
1858.] ACCIDENT ON THE KAMM. 159
boot, never forsaking one till the next was ready, and never
wielding my hatchet until my balance was secured. I was
soon at the bottom of the Kamm, fairly out of danger, and
full of glad vigour I bore swiftly down upon the party in
advance of me. It was an easy task to me to fuse myself
amongst them as* if I had been an old acquaintance, and
we joyfully slid, galloped, and rolled together down the
residue of the mountain.
The only exception was the young gentleman in
Lauener's care. A day or two previously he had, I believe,
injured himself in crossing the Gemmi, and long before he
reached the summit of Monte Rosa his knee swelled, and
he walked with great difficulty. But he persisted in
ascending, and Lauener, seeing his great courage, thought
it a pity to leave him behind. I have stated that a
portion of the Kamm was solid ice. On descending this,
Mr. F.'s footing gave way, and he slipped forward.
Lauener was forced to accompany him, for the place was
too steep and slippery to permit of their motion being
checked. Both were on the point of going over the
Lyskamm side of the mountain, where they would have
indubitably been dashed to pieces. " There was no escape
there," said Lauener, in describing the incident to me sub-
sequently, " but I saw a possible rescue at the other side,
so I sprang to the right, forcibly swinging my companion
round ; but in doing so, the baton tripped me up ; we
both fell, and rolled rapidly over each other down the
incline. I knew that some precipices were in advance of
us, over which we should have gone, so, releasing myself
from my companion, I threw myself in front of him,
stopped myself with my axe, and thus placed a barrier before
him." After some vain efforts at sliding down the slopes
on a baton, in which practice I was fairly beaten by some
of my new friends, I attached myself to the invalid, and
walked with him and Lauener homewards. Had I gone
160 DANGER OF CLIMBING ALONE. [1858.
forward witli the foremost of the party, I should have
completed the expedition to the summit and back in a
little better than nine hours.
I think it right to say one earnest word in con-
nexion with this ascent ; and the more so as I believe a
notion is growing prevalent that half -what is said and
written about the dangers of the Alps is mere humbug.
No doubt exaggeration is not rare, but I would emphatically
warn my readers against acting upon the supposition that
it is general. The dangers of Mont Blanc, Monte Bosa,
and other mountains, are real, and, if not properly pro-
vided against, may be terrible. I have been much accus-
tomed to be alone upon the glaciers, but sometimes, even
when a guide was in front of me, I have felt an extreme
longing to have a second one behind me. Less than two
good ones I think an arduous climber ought not to have ;
and if climbing without guides were to become habitual,
deplorable consequences would assuredly sooner or later
ensue.
(23.)
The 18th of August I spent upon the Furgge glacier at
the base of Mont Cervin, and what it taught me shall be
stated in another place. The evening of this day was
signalised by the pleasant acquaintances which it gave
me. It was my intention to cross the Weissthor on the
morning of the 19th, but thunder, lightning, and heavy
rain opposed the project, and with two friends I descended,
amid pitiless rain, to Zermatt. Next day I walked by
way of Stalden to Saas, where I made the acquaintance of
Herr Imseng, the Cure, and on the 21st ascended to the
Distel Alp. Near to this place the Allalein glacier pushes
its huge terminus right across the valley and dams up the
1858.] ASCENT OF A BOULDER 1G1
streams descending from the mountains higher up, thus
giving birth to a dismal lake. At one end of this stands
the Mattmark hotel, which was to be my headquarters for
a few days.
I reached the place in good company. Near to the
hotel are two magnificent boulders of green serpentine,
which have been lodged there by one of the lateral
glaciers ; and two of the ladies desiring to ascend one of
these rocks, a friend and myself helped them to the top.
The thing was accomplished in a very spirited way. In-
deed the general contrast, in regard to energy, between
the maidens of the British Isles and those of the Continent
and of America is extraordinary. Surely those who talk
of this country being in its old age overlook the physical
vigour of its sons and daughters. They are strong, but
from a combination of the greatest forces we may obtain
a small resultant, because the forces may act in opposite
directions and partly neutralize each other. Herein, in
fact, lies Britain's weakness ; it is strength ill-directed ;
and is indicative rather of the perversity of young blood
than of the precision of mature years.
Immediately after this achievement I was forsaken by
my friends, and remained the only visitor in the hotel.
A dense gray cloud gradually filled the entire atmosphere,
from which the rain at length began to gush in torrents.
The scene from the windows of the hotel was of the
most dismal character; the rain also came through the
roof, and dripped from the ceiling to the floor. I en-
deavoured to make a fire, but the air would not let
the smoke of the pine-logs ascend, and the biting of
the hydrocarbons was excruciating to the eyes. On the
whole, the cold was preferable to the smoke. During the
night the rain changed to snow, and on the morning of
the 22nd all the mountains were thickly covered. The
gray delta through which a river of many arms ran
M
162 DISMAL QUARTEKS. [1858:
into the Mattmark See was hidden ; against some of the
windows of the salle d manger the snow was also piled,
obscuring more than half their light. I had sent my guide
to Visp, and two women and myself were the only occu-
pants of the place. It was extremely desolate — I felt, more-
over, the chill of Monte Rosa in my throat, and the
conditions were not favourable to the cure of a cold.
On the 23rd the Allalein glacier was unfit for work ;
I therefore ascended to the summit of the Monte Moro,
and found the Valaisian side of the pass in clear sunshine,
while impenetrable fog met us on the Italian side. I
examined the colour of the freshly fallen snow ; it was
not an ordinary blue, and was even more transparent than
the blue of the firmament. When the snow was broken
the light flashed forth ; when the staff was dug into the
snow and withdrawn, the blue gleam appeared ; when the
staff lay in a hole, although there might be a sufficient
space all round it, the coloured light refused to show
itself.
My cough kept me awake on the night of the 23rd, and
my cold was worse next day. I went upon the Allalein
glacier, but found myself by no means so sure a climber
as usual. The best guides find that their powers vary ; they
are not equally competent on all days. I have heard a cele-
brated Chamouni guide assert that a man's moralew different
on different days. The morale in my case had a physical
basis, and it probably has so in all. The Allalein gla-
cier, as I have said, crosses the valley and abuts against
the opposite mountain ; here it is forced to turn aside,
and in consequence of the thrust and bending it is
crumpled and crevassed. The wall of the Mattmark See is
a fine glacier section : looked at from a distance, the ridges
and fissures appear arranged like a fan. The structure of
the crumpled ice varies from the vertical to the horizontal,
and the ridges are sometimes split along the planes of
1858.] THE VAULT OF THE ALLALEIN. 163
structure. The aspect of this portion of the glacier from
some of the adjacent heights is exceedingly interesting.
On the morning of the 25th I had two hours' clamber-
ing over the mountains before breakfast, and traced the
action of ancient glaciers to a great height. The valley
of Saas in this respect rivals that of Hasli ; the flutings
and polishings being on the grandest scale. After break-
fast I went to the end of the Allalein glacier, where the
Saas Visp river rushes from it : the vault was exceedingly
tine, being composed of concentric arches of clear blue ice.
I spent several hours here examining the intimate struc-
ture of the ice, and found the vacuum disks which I shall
describe at another place, of the greatest service to me.
As at Rosenlaui and elsewhere, they here taught me that
the glacier was composed of an aggregate of small frag-
ments, each of which had a definite plane of crystallization.
Where the ice was partially weathered the surfaces of
division between the fragments could be traced through
the coherent mass, but on crossing these surfaces the direc-
tion of the vacuum disks changed, indicating a similar
change of the planes of crystallization. The blue veins
of the glacier went through its component fragments irre-
spective of these planes. Sometimes the vacuum disks
were parallel to the veins, sometimes across them, some-
times oblique to them.
Several fine masses of ice had fallen from the arch upon
its floor, and these were disintegrated to the core. A
kick, or a stroke of an axe, sufficed to shake masses almost
a cubic yard in size into fragments varying not much on
either side of a cubic inch. The veining was finely pre-
served on the concentric arches of the vault, and some of
them apparently exhibited its abolition, or at least confu-
sion, -and fresh development by new conditions of pressure.
The river being deep and turbulent this day, to reach its
opposite side I had to climb the glacier and cross over
M 2
164 AVALANCHE AT SAAS. [1858.
the crown of its highest arch; this enabled me to get
quite in front of the vault, to enter it, and closely inspect
those portions where the structure appeared to change. I
afterwards ascended the steep moraine which lies between
the Allaleiii and the smaller glacier to the left of it,
passing to the latter at intervals to examine its struc-
ture. I was at length stopped by the dislocated ice ; and
from the heights I could count a system of seven dirt-
bands, formed by the undulations on the surface of the
glacier. On my return to the hotel I found there a number
of well-known Alpine men who intended to cross the
Adler pass on the following day. Herr Imseng was there :
he came to me full of enthusiasm, and asked me whether
I would join him in an ascent of the Dom : we might im-
mediately attack it, and he felt sure that we should succeed.
The Dom is the highest of the Mischabel peaks, and
is one of the grandest of the Alps. I agreed to join the
Cure, and with this understanding we parted for the night.
Thursday, 26th August. — A wild stormy morning after
a wild and rainy night : the Adler pass being impassable,
the mountaineers returned, and Imseng informed me that
the Dom must be abandoned. He gave me the statistics
of an avalanche which had fallen in the valley some years
before. Within the memory of man Saas had never been
touched by an avalanche, but a tradition existed that such
a catastrophe had once occurred. On the 14th of March,
1848, at eight o'clock in the morning, the Cure was in his
room, when he heard the cracking of pine-branches, and
inferred from the sound that an avalanche was descend-
ing upon the village. It dashed in the windows of his house
and filled his rooms with snow ; the sound it produced
being sufficient to mask the crashing of the timbers of an
adjacent house. Three persons were killed. On the 3rd of
April, 1849, heavy snow fell at Saas; the Cure waited
until it had attained a depth of four feet, and then re-
1858.] THE FEE GLACIER. 165
treated to Fee. That night an avalanche descended, and
in the line of its rush was a house in which five or six and
twenty people had collected for safety : nineteen of them
were killed. The Cure afterwards showed me the site of
the house, and the direction of the avalanche. It passed
through a pine wood ; and on expressing my surprise that
the trees did not arrest it, he replied that the snow was
" quite like dust," and rushed among the trees like so much
water. To return from Fee to Saas on the day following
he found it necessary to carry two planks. Kneeling upon
one of them, he pushed the other forward, and transferred
his weight to it, drawing the other after him and repeating
the same act. The snow was like flour, and would not
otherwise bear his weight. Seeing no prospect of fine
weather, I descended to Saas on the afternoon of the 26th.
I was the only guest at the hotel ; but during the evening
I was gratified by the unexpected arrival of my friend
Hirst, who was on his way over the Monte Moro to Italy.
For the last five days it had been a struggle between
the north wind and the south, each edging the other by
turns out of its atmospheric bed, and producing copious
precipitation ; but now the conflict was decided — the north
had prevailed, and an almost unclouded heaven overspread
the Alps. The few white fleecy masses that remained
were good indications of the swift inarch of the wind in
the upper air. My friend and I resolved to have at least
one day's excursion together, and we chose for it the
glacier of the Fee. Ascending the mountain by a well-
beaten path, we passed a number of " Calvaries " filled
with tattered saints and Virgins, and soon came upon the
rim of a flattened bowl quite clasped by the mountains.
In its centre was the little hamlet of Fee, round which
were fresh green pastures, and beyond it the perpetual
ice and snow. It was exceedingly picturesque — a scene
of human beauty and industry where savagery alone
166 SNOW, VAPOUR, AND CLOUD. [1858.
was to be expected. The basin had been scooped by
glaciers, and as we paused at its entrance the rounded
and fluted rocks were beneath our feet. The Alphubel and
the Mischabel raised their crowns to heaven in front of us ;
the newly fallen snow clung where it could to the precipitous
crags of the Mischabel, but on the summits it was the
sport of the wind. Sometimes it was borne straight up-
wards in long vertical striae ; sometimes the fibrous columns
swayed to the right, sometimes to the left ; sometimes the
motion on one of the summits would quite subside ; anon
the white peak would appear suddenly to shake itself to
dust, which it yielded freely to the wind. I could see the
wafted snow gradually melt away, and again curdle up into
true white cloud by precipitation ; this in its turn would
be pulled asunder like carded wool, and reduced a second
time to transparent vapour.
In the middle of the ice of the Fee stands a green
alp, not unlike the Jardin; up this we climbed, halting
at intervals upon its grassy knolls to inspect the glacier. I
aimed at those places ' where on a priori grounds I should
have thought the production of the veined structure most
likely, and reached at length the base of a wall of rock
from the edge of which long spears of ice depended.
Here my friend halted, while Lauener and myself climbed
the precipice, and ascended to the summit of the alp.
The snow was deep at many places, and our immersions
in unseen holes very frequent. From the peak of the
Fee Alp a most glorious view is obtained ; in point of
grandeur it will bear comparison with any in the Alps,
and its seclusion gives it an inexpressible charm. We
remained for half an hour upon the warm rock, and then
descended. It was our habit to jump from the higher
ledges into the deep snow below them, in which we wal-
lowed as if it were flour ; but on one of these occasions I
lighted on a stone, and the shock produced a curious effect
1858.] "A TERRIBLE HOLE." 167
upon my hearing. I appeared suddenly to lose the power
of appreciating deep sounds, while the shriller ones were
comparatively unimpaired. After I rejoined my friend it
required attention on my part to hear him when he spoke
to me. This continued until I approached the end of the
glacier, when suddenly the babblement of streams, and a
world of sounds to which I had been before quite deaf
burst in upon me. The deafness was probably due to a
strain of the tympanum, such as we can produce artificially,
and thus quench low sounds, while shrill ones are scarcely
affected.
I was anxious to quit Saas early next morning, but the
Cure expressed so strong a wish to show us what he called
a schauderhaftes Loch — a terrible hole — which he had him-
self discovered, that I consented to accompany him. We
were joined by his assistant and the priest of Fee. The
stream from the Fee glacier has cut a deep channel through
the rocks, and along the right-hand bank of the stream
we ascended. It was very rough with fallen crags and
fallen pines amid which we once or twice lost our way.
At length we came to an aperture just sufficient to let a
man's body through, and were informed by our conductor
that our route lay along the little tunnel : he lay down upon
his stomach and squeezed himself through it like a marmot.
I followed him ; a second tunnel, in which, however, we
could stand upright, led into a spacious cavern, formed
by the falling together of immense slabs of rock which
abutted against each other so as to form a roof. It was
the very type of a robber den ; and when I remarked this,
it was at once proposed to sing a verse from Schiller's play.
The young priest had a powerful voice — he led and
we all chimed in.
" Ein frohes Leben fiihren wir,
Ein Leben voller Wonne.
Der Wald ist unser Nachtquartier,
Bei Sturm und Wind hanthieren wir,
Der Mond ist unsre Sonne."
168 SONG- OF THE ROBBEKS. [1858.
Herr Imseng wore his black coat ; the others had taken
theirs off, but they wore their clerical hats, black breeches
and stockings. We formed a singular group in a singular
place, and the echoed voices mingled strangely with the
gusts of the wind and the rush of the river.
Soon afterwards I parted from my friend, and descended the
valley to Visp, where I also parted with my guide. He
had been with me from the 22nd of July to the 29th of
August, and did his duty entirely to my satisfaction. He
is an excellent iceman, and is well acquainted both with the
glaciers of the Oberland and of the Valais. He is strong
and good-humoured, and were I to make another expedi-
tion of the kind I don't think that I should take any guide
in the Oberland in preference to Christian Lauener.
(24.)
It is a singular fact that as yet we know absolutely
nothing of the winter temperature of any one of the high
Alpine summits. No doubt it is a sufficient justification of
our Alpine men, as regards their climbing, that they like it.
This plain reason is enough ; and no man who ever
ascended that " bad eminence " Primrose Hill, or climbed
to Hampstead Heath for the sake of a freer horizon, can
consistently ask a better. As regards physical science,
however, the contributions of our mountaineers have as
yet been nil, and hence, when we hear of the scientific
value of their doings, it is simply amusing to the climbers
themselves. I do not fear that I shall offend them in the
least by my frankness in stating this. Their pleasure is
that of overcoming acknowledged difficulties, and of wit-
nessing natural grandeur. But I would venture to urge
that our Alpine men will not find their pleasure lessened
by embracing a scientific object in their doings. They
1858.] CLIMBEKS AND SCIENCE. 169
have the strength, the intelligence, and let them add to
these the accuracy which physical science now demands,
and they may contribute work of enduring value. Mr.
Casella will gladly teach them the use of his minimum-
thermometers ; and I trust that the next seven years
will not pass without making us acquainted with the
winter temperature of every mountain of note in Switzer-
land.*
I had thought of this subject since I first read the con-
jectures of De Saussure on the temperature of Mont
Blanc ; but in 1857 I met Auguste Balmat at the Jardin,
and there learned from him that he entertained the idea
of placing a self- registering thermometer at .the sum-
mit of the mountain. Balmat was personally a stranger
to me at the time, but Professor Forbes's writings had
inspired me with a respect for him, which this un-
prompted idea of his augmented. He had procured a
thermometer, the graduation of which, however, he feared
was not low enough. As an encouragement to Balmat,
and with the view of making his laudable intentions known,
I communicated them to the Royal Society, and obtained
from the Council a small grant of money to purchase ther-
mometers and to assist in the expenses of an ascent.
I had now the thermometers in my possession ; and
having completed my work at Zermatt and Saas, my next
desire was to reach Chamouni and place the instruments
on the top of Mont Blanc. I accordingly descended the
valley of the Rhone to Martigny, crossed the Tete
Noire, and arrived at Chamouni on the 29th of August,
1858.
Balmat was engaged at this time as the guide of Mr.
Alfred Wills, who, however, kindly offered to place him
at my disposal; and also expressed a desire to 'accom-
* I find with pleasure that my friend Mr. John Ball is now exerting
himself in this direction.
170 DIFFICULTIES AT CHAMOUNI. [1858.
pany me himself and assist me in my observations. I
gladly accepted a proposal which gave me for com-
panion so determined a climber and so estimable
a man. But Chamouni was rife with difficulties. In
1857 the Guide Chef had the good sense to give me
considerable liberty of action. Now-his mood was entirely
changed : he had been " molested " for giving me so much
freedom. I wished to have a boy to carry a small instru-
ment for me up the Mer de Glace — he would not allow it ;
I must take a guide. If I ascended Mont Blanc he de-
clared that I must take four guides ; that, in short, I must
in all respects conform to the rules made for ordinary
tourists. I endeavoured to explain to him the advantages
which Chamouni had derived from the labours of men of
science ; it was such men who had discovered it when it
was unknown, and it was by their writings that the atten-
tion of the general public had been called towards it. It
was a bad recompense, I urged, to treat a man of science
as he was treating me. This was urged in vain ; he
shrugged his shoulders, was very sorry, but the thing could
not be changed. I then requested to know his superior,
that I might apply to him ; he informed me that there
were a President and Commission of guides at Chamouni,
who were the proper persons to decide the question, and
he proposed to call them together on the 31st of August,
at seven P.M., on condition that I was to be present to state
my own case. To this I agreed.
I spent that day quite alone upon the Mer de Glace,
and climbed amid a heavy snow-storm to the Cleft station
over Trelaporte. When I reached the Montanvert I was
wet and weary, and would have spent the night there were
it not for my engagement with the Guide Chef. I de-
scended amid the rain, and at the appointed hour went to
his bureau. He met me with a polite sympathetic shrug ;
explained to me that he had spoken to the Commission,
1858.] THE INTENDANT MEMORIALISED. 171
but that it could not assemble pour une chose comme ga ; that
the rules were fixed, and I must abide by them. " Well,"
I responded, u you think you have done your duty ; it is
now my turn to perform mine. If 110 other means are
available I will have this transaction communicated to the
Sardinian Government, and I don't think that it will ratify
what you have done." The Guide Chef evidently did not
believe a word of it.
Previous to taking any further step I thought it right
to see the President of the Commission of Guides, who was
also Syndic of the commune. I called upon him on the
morning of the 1st of September, and, assuming that he
knew all about the transaction, spoke to him accordingly.
He listened to me for a time, but did not seem to under-
stand me, which I ascribed partly to my defective French
pronunciation. I expressed a hope that he did comprehend
me ; he said he understood my words very well, but did
not know their purport. In fact he had not heard a single
word about me or my request. He stated with some indigna-
tion that, so far from its being a subject on which the
Commission could not assemble, it was one which it was
their especial duty to take into consideration. Our con-
ference ended with the arrangement that I was to write
him an official letter stating the case, which he was to for-
ward to the Intendant of the province of Faucigny resi-
dent at Bonneville. All this was done.
I subsequently memorialised the Intendant himself;
and Balmat visited him to secure his permission to accom-
pany me. I have to record, .that from first to last the
Intendant gave me his sympathy and support. He could
not alter laws, but he deprecated a "judaical" inter-
pretation of them. His final letter to myself was as
follows : —
172 THE INTENDANT'S. RESPONSE. [1858.
" Intendance Roy ale de la Province de Faucigny,
" Bonneville, 11 Septembre, 1858.
" Monsieur,—
" J'apprends avec une veritable peine les diffi-
cultes que vous rencontrez de la part de M. le Guide Chef
pour 1'effectuation de votre perilleuse entreprise scienti-
fique, mais je dois vous dire aussi avec regret que ces diffi-
cultes resident dans un reglementfait en vue de la securite
des voyageurs, quel que puisse. etre le but de leurs ex-
cursions.
a Desireux neanmoins de vous etre utile, notamment en
la circonstance, j 'invite aujourd'hui meme M. le Guide
Chef a avoir egard a votre projet, a faire en sa faveur une
exception au reglement ci-devant eu, tant qu'il n'y aura
aucun danger pour votre surete et celle des personnes qui
vous accompagneront, et enfin de se preter dans les liniites
de ses moyens et attributions pour 1'heureux succes de
1'expedition, dont les consequences et resultats n'interessent
pas seulement la science, mais encore la vallee de Cha-
mounix en particulier.
" Agreez, Monsieur,
" 1'assurance de ma consideration trds-distinguee.
" Pour 1'Intendant en conge,
" Le Secretaire,
" DELMLISE."
While waiting for this permission I employed myself in
various .ways. On the 2nd of September I ascended the
Brevent, from which Mont Blanc is seen to great advan-
tage. From Chamouni its vast slopes are so foreshortened
that one gets a very imperfect idea of the extent to be
traversed to reach the summit. What, however, struck
me most on the Brevent was the changed relation of
the Aiguille du Dru and the Aiguille Verte. 'From Mont-
anvert the former appears a most imposing mass, while
1858.] THE "SEKACS" EEVISITED. 173
the peak of the latter appears rather dwarfed behind it ;
but from the Brevent the Aiguille du Dru is a mere
pinnacle stuck in the breast of the grander pyramid of the
Aiguille Verte.
On the 4th I rose early, and, strapping on my telescope,
ascended to the Montanvert, where I engaged a youth to
accompany me up the glacier. The heavens were clear
and beautiful : — blue over the Aiguille du Dru, blue over
the Jorasse and Mont Mallet, deep blue over the pinnacles
of Charmoz, and the same splendid tint stretched grandly
over the Col du Geant and its Aiguille. No trace of con-
densation appeared till towards eleven o'clock, when a
little black balloon of cloud swung itself over the Aiguilles
Rouges. At one o'clock there were two large masses and
a little one between them ; while higher up a white veil,
almost too thin to be visible, spread over a part of the
heavens. At the zenith, however, and south, north, and
west, the blue seemed to deepen as the day advanced. I
visited the ice-wall at the Tacul, which seemed lower
than it was last year ; the cascade of le Geant appeared
also far less imposing. Only in the early part of summer
do we see the ice in its true grandeur : its edges and sur-
faces are then sharp and clear, but afterwards its nobler
masses shrink under the influence of sun and air. The
semes now appeared wasted and dirty, and not the sharp
angular ice-castles which rose so grandly when I first saw
them. Thirteen men had crossed the Col du Geant on the
day previous, and left an ample trace behind them. This
I followed nearly to the summit of the fall. The con-
dition of the glacier was totally different from that of
the opposite side on the previous year. The ice was
riven, burrowed, and honeycombed, but the track amid
all was easy : a vigorous English maiden might have
ascended the fall without much difficulty. My object now
was to examine the structure of the fall ; but the ice was
174 THERMOMETER AT THE JARDIN. [1858.
not in a good condition for such an examination : it was
too much broken. Still a definite structure was in many
places to be traced, and some of them apparently showed
structure and bedding at a high angle to each other, but
I could not be certain of it. I paused at every command-
ing point of view and examined the ice through my opera-
glass ; but the result was inconclusive. I observed that
the terraces which compose the fall do not front the middle
of the glacier, but turn their foreheads rather towards its
eastern side, and the consequence is that the protuberances
lower down, which are the remains of these terraces, are
highest at the same side. Standing at the base of the
Aiguille Noire, and looking downwards where the Glacier
des Periades pushes itself against the Geant, a series of fine
crumples is formed on the former, cut across by crevasses,
on the walls of which a forward and backward dipping of
the blue veins is exhibited. Huge crumples are also
formed by the Glacier du Geant, which are well seen from
a point nearly opposite the lowest lateral moraine of the
Glacier des Periades. In some cases the upper portions
of the crumples had scaled off so as to form arches of
ice — a consequence doubtless of the pressure.
The beauty of some Alpine skies is treacherous ; in fact
the deepest blue often indicates an atmosphere charged
almost to saturation with aqueous vapour. This was the
case on the present occasion. Soon after reaching Chamouni
in the evening, rain commenced and continued with scarcely
any intermission until the afternoon of the 8th. I had
given up all hopes of being able to ascend Mont Blanc ;
and hence resolved to place the thermometers in some
more accessible position. On the 9th accordingly, accom-
panied by Mr. Wills, Balmat, and some other friends, I
ascended to the summit of the Jardin, where we placed
two thermometers : one in the ice, at a depth of three feet
below the surface; another on a ledge of the highest
1858.] EVENING RED. 175
rock.* The boiling point of water at this place was 194'6°
Fahr.
Deep snow was upon the Talefre, and the surrounding
precipices were also heavily laden. Avalanches thundered
incessantly from the Aiguille Verte and the other moun-
tains. Scarcely five minutes on an average intervened
between every two successive peals ; and after the direct
shock of each avalanche had died away the air of the basin
continued to be shaken by the echoes reflected from its
bounding walls.
The day was far spent before we had completed our
work. All through the weather had been fine, and towards
evening augmented to magnificence. As we descended
the glacier from the Couvercle the sun was just disappear-
ing, and the western heaven glowed with crimson, which
crept gradually up the sky until finally it reached the
zenith itself. Such intensity of colouring is exceedingly
rare in the Alps ; and this fact, together with the known
variations in the intensity of the firmamental blue, justify
the conclusion that the colouring must, in a great measure,
be due to some variable constituent of the atmosphere. If
the air were competent to produce these magnificent effects
they would be the rule instead of the exception.
No sooner had the thermometers been thus disposed of
than the weather appeared to undergo a permanent change.
On the 10th it was perfectly fine — not the slightest mist
upon Mont Blanc; on the llth this was also the case.
Balmat still had the old thermometer to which I have
already referred ; it might not do to show the minimum
temperature of the air, but it might show the temperature
at a certain depth below the surface. I find in my own
case that the finishing of work has a great moral value :
* The minimum temperature of the subsequent winter, as shown by this
thermometer, was -6° Fahr., or 38° below the freezing point. The instru-
ment placed in the ice was broken.
176 FINISHED WORK. [1858.
work completed is a safe fulcrum for the performance of
other work ; and even though in the course of our labours
experience should show us a better means of accomplishing
a given end, it is often far preferable to reach the end,
even by defective means, than to swerve from our course.
The habits which this conviction had superinduced no
doubt influenced me when I decided on placing Balmat's
thermometer on the summit; of Mont Blanc.
1858.] SHADOWS OF THE AIGUILLES. 177
SECOND ASCENT OF MONT BLANC, 1858.
Ox the 12th of September, at 5^ A.M. the sunbeams had
already fallen upon the mountain ; but though the sky above
him, and over the entire range of the Aiguilles, was without
a cloud, the atmosphere presented an appearance of tur-
bidity resembling that produced by the dust and thin
smoke mechanically suspended in a London atmosphere on
a dry summer's day. At 20 minutes past 7 we quitted Cha-
mouni, bearing with us the good wishes of a portion of its
inhabitants.
A lady accompanied us on horseback to the point where
the path to the Grands Mulets deviates from that to
the Plan des Aiguilles ; here she turned to the left, and
we proceeded slowly upwards, through woods of pine,
hung with fantastic lichens : escaping from the gloom
of these, we emerged upon slopes of bosky underwood, green
hazel, and green larch, with the red berries of the moun-
tain-ash shining brightly between them. Through the air
above us, like gnomons of a vast sundial, the Aiguilles cast
their fanlike shadows, which moved round as the day ad-
vanced. Slopes of rhododendrons with withered flowers
next succeeded, but the colouring of the bilberry-leaves was
scarcely less exquisite than the freshest bloom of the Alpine
rose. For a long time we were in the cool shadow of the
mountain, catching, at intervals, through the twigs in front
of us, glimpses of the sun surrounded by coloured spectra.
On one occasion a brow rose in front of me ; behind it was
* a lustrous space of heaven, adjacent to the sun, which, how-
ever, was Judder behind the brow ; against this space the
twigs and weeds upon the summit of the brow shone as if
N
178 INTERFERENCE-SPECTRA. [1858.
they were self-luminous, while some bits of thistle-down
floating in the air appeared, where they crossed this portion
of the heavens, like fragments of the sun himself. Once
the orb appeared behind a rounded mass of snow which lay
near the summit of the Aiguille du Midi. Looked at with
the naked eyes, it seemed to possess a billowy motion,
the light darting from it in dazzling curves, — a sub-
jective effect produced by the abnormal action of the
intense light upon the eye. As the sun's disk came more
into view, its rays however still grazing the summit of the
mountain, interference-spectra darted from it on all sides,
and surrounded it with a glory of richly-coloured bars.
Mingling however with the grandeur of nature, we had
the anger and obstinacy of man. With a view to subse-
quent legal proceedings, the Guide Chef sent a spy after us,
who, having satisfied himself of our delinquency, took his
unpleasant presence from the splendid scene.
Strange to say, though the luminous appearance of
bodies projected against the sky adjacent to the rising sun
is a most striking and beautiful phenomenon, it is hardly
ever seen by either guides or travellers ; probably because
they avoid looking towards a sky the brightness of which is
painful to the eyes. In 1859 Auguste Balmat had never
seen the effect ; and the only written description of it which
we possess is one furnished by Professor Necker, in a letter
to Sir David Brewster, which is so interesting that I. do
not hesitate to reproduce it here : —
" I now come to the point," writes M. Necker, " which
you particularly wished me to describe to you ; I mean the
luminous appearance of trees, shrubs, and birds, when
seen from the foot of a mountain a little before sunrise.
The wish I had to see again the phenomenon before at-
tempting to describe it made me detain this letter a few
days, till I had a fine day to go to see it at the Mont
Saleve ; so yesterday I went there, and studied the fact, and
1858.] PROFESSOR NECKER'S LETTER. 179
in elucidation of it I made a little drawing, of which I
give you here a copy : it will, with the explanation and the
annexed diagram (Fig. 9), impart to you, I hope, a correct
idea of the phenomenon. You must conceive the observer
placed at the foot of a hill interposed between him and the
place where the sun is rising, and thus entirely in the
shade ; the upper margin of the mountain is covered with
woods or detached trees and shrubs, which are projected
as dark objects on a very bright and clear sky, except at
the very place where the sun is just going to rise, for
there all the trees and shrubs bordering the margin are
entirely, — branches, leaves, stem and all, — of a pure and
brilliant white, appearing extremely bright and luminous,
although projected on a most brilliant and luminous sky,
as that part of it which surrounds the sun always is. All
the minutest details, leaves, twigs, &c., are most delicately
preserved, and you would fancy you saw these trees and
forests made of the purest silver, with all the skill of the
most expert workman. The swallows and other birds
flying in those particular spots appear like sparks of the
most brilliant white. Unfortunately, all these details,
which add so much to the beauty of this splendid pheno-
menon, cannot be represented in such small sketches.
" Neither the hour of the day nor the angle which the
object makes with the observer appears to have any effect ;
for on some occasions I have seen the phenomenon take
place at a very early hour in the morning. Yesterday it
was 10 A.M., when I saw it as represented in Fig. 10. I
saw it again on the same day at 5 P.M., at a different
place of the same mountain, for which the sun was just
setting. At one time the angle of elevation of the lighted
white shrubs above the horizon of the spectator was about
20°, while at another place it was only 15°. But the
extent of the field of illumination is variable, according to
the distance at which the spectator is placed from it.
N 2
180
SILVER TREES AT SUNRISE.
[1858.
When the object behind which the sun is just going to
rise, or has just been setting, is very near, no such effect
takes place. In the case
represented in Fig. 9 the
distance was about 194
metres, or 636 English
feet, from the spectator in
a direct line, the height
above his level being 60
metres, or 197 English
feet, and the horizontal
line drawn from him to
the horizontal projection
of these points on the
plane of his horizon being
160 metres, or 525 Eng-
lish feet, as will be seen
in the following diagram,
~ig^ Fig. 10.
" In this case only small shrubs and the lower half of the
stem of a tree are illuminated white, and the horizontal
extent of this effect
is also compara-
tively small ; while
at other places when
I was near the edge
behind which the
sun was going to rise no such effect took place. But on
the contrary, when I have witnessed the phenomenon at a
greater distance and at a greater height, as I have seen it
other times on the same and on other mountains of the
Alps, large tracts of forests and immense spruce-firs were
illuminated white throughout their whole length, as I have
attempted to represent in Fig. 11, and the corresponding
diagram, Fig. 12. Nothing can be finer than these silver-
Fig. 10.
%M^%&^^$.
1858. J
BIEDS AS SPARKS OR STARS.
181
looking spruce-forests. At the same time, though at a
distance of more than a thousand metres, a vast number of
large swallows or swifts ":: - -:
(Gypselus cdpinus\ which
inhabit these high rocks,
were seen as small bril-
liant stars or sparks mov-
ing rapidly in the air.
From these facts it ap-
pears to me obvious that
the extent of the illumi-
nated spots varies in a di-
rect ratio of their distance ;
but at the same time that
there must be a constant
angular space, correspond-
ing probably to the zone,
a few minutes of a de-
gree wide, around the
sun's disk, which is a limit Fie- 1L
to the occurrence of the appearance. This would explain
how the real extent which it occupies on the earth's surface
varies with the relative distance of the spot from the eye of
the observer, and accounts also for the phenomenon being
O
Fig. I!
never seen in the low country, where I have often looked for
it in vain. Now that you are acquainted with the circum-
stances of the fact, I have 110 doubt you will easily observe
it in some part or other of your Scotch hills ; it may be
182 THE LADDEK CONDEMNED. [1858.
some long heather or furze will play the part of our
Alpine forests, and I would advise you to try and place a
bee-hive in the required position, and it would perfectly
represent our swallows, sparks, and stars."
Our porters, with one exception, reached the Pierre a
1'Echelle as soon as ourselves ; and here having refreshed
themselves, and the due exchange of loads having been
made, we advanced upon the glacier, which we crossed,
until we came nearly opposite to the base of the Grands
Mulets. The existence of one wide crevasse, which was
deemed impassable, had this year introduced the practice
of assailing the rocks at their base, and climbing them to
the cabin, an operation which Balmat wished to avoid.
At Chamouni, therefore, he had made inquiries regarding
the width of the chasm, and acting on his advice I had
had a ladder constructed in two pieces, which, united toge-
ther by iron attachments, was supposed to be of sufficient
length to span the fissure. On reaching the latter, the
pieces were united, and the ladder thrown across, but the
bridge was so frail and shaky at the place of junction, and
the chasm so deep, that Balmat pronounced the passage
impracticable.
The porters were all grouped beside the crevasse when
this announcement was made, and, like hounds in search of
the scent, the group instantly broke up, seeking in all
directions for a means of passage. The talk was incessant
and animating ; attention was now called in one direction,
anon in another, the men meanwhile throwing themselves
into the most picturesque groups and attitudes. All eyes
at length were directed upon a fissure which was spanned
at one point by an arch of snow, certainly under two feet
deep at the crown. A stout rope was tied round the waist
of one of our porters, and he was sent forward to test the
bridge. He approached it cautiously, treading down the
snow to give it compactness, and thus make his footing
1858.] CROSSING CREVASSES. 183
sure as lie advanced ; bringing regelation into play, he
gave the mass the necessary continuity, and crossed in
safety. The rope was subsequently stretched over the
pont, and each of us causing his right hand to slide along it,
followed withont accident. Soon afterwards, however, we
met with a second and very formidable crevasse, to cross
which we had but half of our ladder, which was applied as
follows : — The side of the fissure on which we stood was
lower than the opposite one ; over the edge of the latter
projected a cornice of snow, and a ledge of the same
material jutted from the wall of the crevasse, a little below
us. The ladder was placed from ledge to cornice, both of
its ends being supported by snow. I could hardly believe
that so frail a bearing could possibly support a man's
weight ; but a porter was tied as before, and sent up the
ladder, while we followed protected by the rope. We
were afterwards tied together, and thus advanced in an
orderly line to the Grands Mulets.
The cabin was wet and disagreeable, but the sunbeams
fell upon the brown rocks outside, and thither Mr. Wills
and myself repaired to watch the changes of the atmo-
sphere. I took possession of the flat summit of a prism of
rock, where, lying upon my back, I watched the clouds
forming, and melting, and massing themselves together,
and tearing themselves like wool asunder in the air above.
It was nature's language addressed to the intellect;
these clouds were visible symbols which enabled us to
understand what was going on in the invisible air. Here
unseen currents met, possessing different temperatures,
mixing their contents both of humidity and motion, pro-
ducing a mean temperature unable to hold their moisture
in a state of vapour. The water-particles, obeying their
mutual attractions, closed up, and a visible cloud suddenly
•shook itself out, where a moment before we had the pure
blue of heaven. Some of the clouds were wafted by the
184 GOKGEOUS SUNSET. [1858.
air towards atmospheric regions already saturated with
moisture, and along their frontal borders new cloudlets
ever piled themselves, while the hinder portions, invaded
by a drier or a warmer air, were dissipated ; thus the
cloud advanced, with gain in front and loss behind, its per-
manence depending on the balance between them. The
day waned, and the sunbeams began to assume the colour-
ing due to their passage through the horizontal air. The
glorious light, ever deepening in colour, was poured boun-
teously over crags, and snows, and clouds, and suffused
with gold and crimson the atmosphere itself. I had never
seen anything grander than the sunset on that day.
Clouds with their central portions densely black, denying
all passage to the beams which smote them, floated
westward, while the fiery fringes which bordered them
were rendered doubly vivid by contrast with the adjacent
gloom. The smaller and more attenuated clouds were
intensely illuminated throughout. Across other inky
masses were drawn zigzag bars of radiance which re-
sembled streaks of lightning. The firmament between
the clouds faded from a blood-red through orange and
daffodil into an exquisite green, which spread like a
sea of glory through which those .magnificent argosies
slowly sailed. Some of the clouds were drawn in straight
chords across the arch of heaven, these being doubtless
the sections of layers of cloud whose horizontal dimen-
sions were hidden from us. The cumuli around and near
the sun himself could not be gazed upon, until, as the
day declined, they gradually lost their effulgence and
became tolerable to the eyes. All was calm — but there
was a wildness in the sky like that of anger, which boded
evil passions on the part of the atmosphere. The sun
at length sank behind the hills, but for some time after-
wards carmine clouds swung themselves on high, and cast
their ruddy hues upon the mountain snows. Duskier and
1858.] STORM ON THE GRANDS MULETS. 185
colder waxed the west, colder and sharper the breeze
of evening upon the Grands Mulets, and as twilight
deepened towards night, and the stars commenced to
twinkle through the chilled air, we retired from the
scene.
The anticipated storm at length gave notice of its
coming. The sea-waves, as observed by Aristotle, some-
times reach the shore before the wind which produces them
is felt ; and here the tempest sent out its precursors,
which broke in detached shocks upon the cabin before the
real storm arrived. Billows of air, in ever quicker succes-
sion, rolled over us with a long surging sound, rising and
falling as crest succeeded trough and trough succeeded
crest. And as the pulses of a vibrating body, when
their succession is quick enough, blend to a continuous
note, so these fitful gusts linked themselves finally to a
storm which made its own wild music among the crags.
Grandly it swelled, carrying the imagination out of doors,
to the clouds and darkness, to the loosened avalanches and
whirling snow upon the mountain heads. Moored to the rock
on two sides, the cabin stood firm, and its manifest security
allowed the mind the undisturbed enjoyment of the atmo-
spheric war. We were powerfully shaken, but had no
fear of being uprooted ; and a certain grandeur of the
heart rose responsive to the grandeur of the storm.
Mounting higher and higher, it at length reached its
maximum strength, from which it lowered fitfully, until
at length, with a melancholy wail, it bade our rock fare-
well.
A little before half-past one we issued from the cabin.
The night being without a moon, we carried three lanterns.
The heavens were crowded with stars, among which, how-
ever, angry masses of cloud here and there still wandered.
The storm, too, had left a rear-guard behind it ; and strong
gusts rolled down upon us at intervals, at one time, indeed,
186 A COMET DISCOVERED. [1858.
so violent as to cause Balmat to express doubts of our
being able to reach the summit. With a thick handkerchief
bound around my hat and ears I enjoyed the onset of the
wind. Once, turning my head to the left, I saw what ap-
peared to me to be a huge mass of stratus cloud, at a
great distance, with the stars shining over it. In another
instant a precipice of neve loomed upon us ; we were close
to its base, and along its front the annual layers were sepa-
rated from each other by broad dark bands. Through the
gloom it appeared like a cloud, the lines of bedding giving
to it the stratus character.
Immediately before lying down on the previous evening
I had opened the little window of the cabin to admit some
air. In the sky in front of me shone a curious nodule of misty
light with a pale train attached to it. In 1853, on the
side of the Brocken, I had observed, without previous
notice, a comet discovered a few days previously by a
former fellow student, and here was another " discovery "
of the same kind. I inspected the stranger with my
telescope, and assured myself that it was a comet. Mr.
Wills chanced to be outside at the time, and made the same
observation independently. As we now advanced up the
mountain its ominous light gleamed behind us, while high
up in heaven to our left the planet Jupiter burned like
a lamp of intense brightness. The Petit Plateau forms
a kind of reservoir for the avalanches of the Dome du
Gouter, and this year the accumulation of frozen debris
upon it.was enormous. We could see nothing but the ice-
blocks on which the light of the lanterns immediately fell ;
we only knew that they had been discharged from the
semes, and that similar masses now rose threatening to our
right, and might at any moment leap down upon us. Bal-
mat commanded silence, and urged us to move across the
plateau with all possible celerity. The warning of our
guide, the wild and rakish appearance of the sky, the spent
1858.] DAWN ON THE GKAND PLATEAU. 187
projectiles at our feet, and the comet with its " horrid
hair " behind, formed a combination eminently calculated
to excite the imagination.
And now the sky began to brighten towards dawn, with
that deep and cairn beauty which suggests the thought of
adoration to the human mind. Helped by the contem-
plation of the brightening east, which seemed to lend
lightness to our muscles, we cheerily breasted the steep
slope up to the Grand Plateau. The snow here was
deep, and each of our porters took the lead in turn.
We paused upon the Grand Plateau and had breakfast ;
digging, while we halted, our feet deeply into the snow.
Thence up to the corridor, by a totally different route from
that pursued by Mr. Hirst and myself the year previously ;
the slope was steep, but it had not a precipice for its boun-
dary. Deep steps were necessary for a time, but when we
reached the summit our ascent became more gentle. The
eastern sky continued to brighten, and by its illumination
the Grand Plateau and its bounding heights were lovely
beyond conception. The snow was of the purest white, and
the glacier, as it pushed itself on all sides into the basin, was
riven by fissures filled with a coerulean light, which deep-
ened to inky gloom as the vision descended into them. The
edges were overhung with fretted cornices, from which
depended long clear icicles, tapering from their abutments
like spears of crystal. The distant fissures, across which
the vision ranged obliquely without descending into them,
emitted that magical firmamental shimmer which, contrasted
with the pure white of the snow, was inexpressibly lovely.
Near to us also grand castles of ice reared themselves, some
erect, some overturned, with clear cut sides, striped by
the courses of the annual snows, while high above the
semes of the plateau rose their still grander brothers of
the Dome du Gouter. There was a nobility in this glacier
scene which I think I have never seen surpassed ;— -a
188 BALMAT IN DANGER [1858.
strength of nature, and yet a tenderness, which at once
raised and purified the soul. The gush of the direct
sunlight could add nothing to this heavenly beauty ; in-
deed I thought its yellow beams a profanation as they
crept down from the humps of the Dromedary, and invaded
more and more the solemn purity of the realm below.
Our way lay for a time amid fine fissures with blue
walls, until at length we reached the edge of one which
elicited other sentiments than those of admiration. It
must be crossed. At the opposite side was a high and
steep bank of ice which prolonged itself downwards, and
ended in a dependent eave of snow which quite over-
hung the chasm, and reached to within about a yard of
our edge of the crevasse. Balmat came forward with his
axe, and tried to get a footing on the eave : he beat it
gently, but the axe went through the snow, forming an
aperture through which the darkness of the chasm was
rendered visible. Our guide was quite free, without rope
or any other means of security ; he beat down the snow so
as to form a kind of stirrup, and upon this he stepped.
The stirrup gave way, it was right over the centre of the
chasm, but with wonderful tact and coolness he contrived
to get sufficient purchase from the yielding mass to toss
himself back to the side of the chasm. The rope was
now brought forward and tied round the waist of one
of the porters ; another step was cautiously made in the
eave of snow, the man was helped across, and lessened
his own weight by means of his hatchet. He gra-
dually got footing on the face of the steep, which he
mounted by escaliers ; and on reaching a sufficient height
he cut two large steps in which his feet might rest
securely. Here he laid his breast against the sloping wall,
and another person was sent forward, who drew himself
up by the rope which was attached to the leader. Thus
we all passed, each of us in turn bearing the strain of his
1858.] STOEM ON MONT BLANC. 189
successor upon the rope; it was our last difficulty, and
we afterwards slowly plodded through the snow of the
corridor towards the base of the Mur de la Cote.
Climbing zigzag, we soon reached the summit of
the Mur, and immediately afterwards found ourselves
in the midst of cold drifting clouds, which obscured
everything. They dissolved for a moment and re-
vealed to us the sunny valley of Chamouni ; but they
soon swept down again and completely enveloped us.
Upon the Calotte, or last slope, I felt no trace of the ex-
haustion which I had experienced last year, but enjoyed free
lungs and a quiet heart. The clouds now whirled wildly
round us, and the fine snow, which was caught by
the wind and spit bitterly against us, cut off all visible
communication between us and the lower world. As
we approached the summit the air thickened more and
more, and the cold, resulting from the withdrawal of the
sunbeams, became intense. We reached the top, how-
ever, in good condition, and found the new snow piled up
into a sharp ar6te, and the summit of a form quite dif-
ferent from that of the Dos d'un Ane, which it had presented
the previous year. Leaving Balmat to make a hole for the
thermometer, I collected a number of batons, drove them
into the snow, and, drawing my plaid round them, formed
a kind of extempore tent to shelter my boiling- water
apparatus. The covering was tightly held, but the snow
was as fine and dry as dust, and penetrated everywhere :
my lamp could not be secured from it, and half a box of
matches was consumed in the effort to ignite it. At length
it did flame up, and carried on a sputtering combustion.
The cold of the snow-filled boiler condensing the vapour
from the lamp gradually produced a drop, which, when
heavy enough to detach itself from the vessel, fell upon
the flame and put it out. It required much patience and
the expenditure of many matches to relight it. Meanwhile
190 THERMOMETER BURIED. [1858.
the absence of muscular action caused the cold to affect
our men severely. My beard and1 whiskers were a mass
of clotted ice. The batons were coated with ice, and even
the stem of my thermometer, the bulb of which was in hot
water, was covered by a frozen enamel. The clouds whirled,
and the little snow granules hit spitefully against the skin
wherever it was exposed. The temperature of the air was
20° Fahr. below the freezing point. I was too intent upon
my work to heed the cold much, but I was numbed ; one of
my fingers had lost sensation, and my right heel was in
pain : still I had no thought of forsaking my observation
until Mr. Wills came to me and said that we must return
speedily, for Balmat's hands were gelees. I did not com-
prehend the full significance of the word ; but, looking at
the porters, they presented such an aspect of suffering that
I feared to detain them longer. They looked like worn
old men, their hair and clothing white with snow, and
their faces blue, withered, and anxious-looking. The hole
being ready, I asked Balmat for the magnet to arrange
the index of the thermometer : his hands seemed power-
less. I struck my tent, deposited the instrument, and, as I
watched the covering of it up, some of the party, among
whom were Mr. Wills and Balmat, commenced the
descent.*
I followed them speedily. Midway down the Calotte
I saw Balmat, who was about a hundred yards in ad-
vance of me, suddenly pause and thrust his hands into
the snow, and commence rubbing them vigorously. The
suddenness of the act surprised me, but I had no idea
at the time of its real significance : I soon came up to him ;
he seemed frightened, and continued to beat and rub his
hands, plunging them, at quick intervals, into the snow. Still
* In August, 1859, I found the temperature of water, boiling in an
open vessel at the summit of Mont Blanc, to be 184-95° Fahr. On that
occasion also, though a laborious search was made for the thermometer, it
could not be found.
1858.] BALMAT FROSTBITTEN. 191
I thought the thing would speedily pass away, for I had too
much faith in the man's experience to suppose that he would
permit himself to be seriously injured. But it did not pass
as I hoped it would, and the terrible possibility of his losing
his hands presented itself to me. He at length became
exhausted by his own efforts, staggered like a drunken
man, and fell upon the snow. Mr. Wills and myself took
each a hand, and continued the process of beating and
rubbing. I feared that we should injure him by our blows,
but he continued to exclaim, " N'ayez pas peur, frappez tau-
jours, frappez fortement ! " We did so, until Mr. Wills
became exhausted, and a porter had to take his place.
Meanwhile Balmat pinched and bit his fingers at inter-
vals, to test their condition ; but there was no sensation.
He was evidently hopeless himself; and, seeing him thus,
produced an effect upon me that I had not experienced
since my boyhood — my heart swelled, and I could have
wept like a child. The idea that I should be in some mea-
sure the cause of his losing his hands was horrible to me ;
schemes for his support rushed through my mind with the
usual swiftness of such speculations, but no scheme could
restore to him his lost hands. At length returning sensation
in one hand announced itself by excruciating pain. " Je
souffre ! " he exclaimed at intervals — words which, from a
man of his iron endurance, had a more than ordinary signifi-
cance. But pain was better than death, and, under the
circumstances, a sign of improvement. We resumed our
descent, while he continued to rub his hands with snow and
brandy, thrusting them at every few paces into the mass
through which we marched. At Chamouni he had skilful
medical advice, by adhering to which he escaped with the
loss of six of his nails — his hands were saved.
I cannot close this recital without expressing my ad-
miration of the dauntless bearing of our porters, and of
the cheerful and efficient manner in which they did their
192 PROOFS-VERBAL. [1858.
duty throughout the whole expedition. Their names are
Edouard Bellin, Joseph Favret, Michel Payot, Joseph
Folliguet, and Alexandre Balmat.
(26.)
The hostility of the chief guide to the expedition was
not diminished by the letter of the Intendant ; and he at
once entered a proces-verlml against Balmat and his com-
panions on their return to Chamouni. I felt that the
power thus vested in an unlettered man to arrest the pro-
gress of scientific observations was so anomalous, that the
enlightened and liberal Government of Sardinia would
never tolerate such a state of things if properly represented
to it. The British Association met at Leeds that year, and
to it, as a guardian of science, my thoughts turned. I
accordingly laid the case before the Association, and ob-
tained its support : a resolution was unanimously passed
" that application be made to the Sardinian authorities for
increased facilities for making scientific observations in
the Alps."
Considering the arduous work which Balmat had per-
formed in former years in connexion with the glaciers, and
especially his zeal in determining, under the direction of
Professor Forbes, their winter motion — for which, as in the
case above recorded, he refused all personal remuneration
—I thought such services worthy of some recognition on
the part of the Royal Society. I suggested this to the
Council, and was met by the same cordial spirit of co-
operation which I had previously experienced at Leeds.
A sum of five-and-twenty guineas was at once voted for
the purchase of a suitable testimonial ; and a committee,
consisting of Sir Roderick Murchison, Professor Forbes,
1858.] BRITISH ASSOCIATION. 193
and myself, was appointed to carry the thing out. Balmat
was consulted, and he chose a photographic apparatus,
which, with a suitable inscription, was duly presented to
him.
Thus fortified, I drew up an account of what had occurred
at Chamouni during my last visit, accompanied by a brief
statement of the changes which seemed desirable. This
was placed in the hands of the President of the British
Association, to whose prompt and powerful co-operation in
this matter every Alpine explorer who aspires to higher
ground than ordinary is deeply indebted. The following
letter assured me that the facility applied for by the British
Association would be granted by the Sardinian Govern-
ment, and that future men of science would find in the
Alps a less embarrassed field of operations than had fallen
to my lot in the summer of 1858.
" 12, Hertford-street, Mayfair, W.,
" My dear Sir,— "February 18th, 1859.
" Having, as I informed you in my last note,
communicated with the Sardinian Minister Plenipotentiary
the day after receiving your statement relative to the
guides at Chamouni, I have been favoured by replies from
the Minister, of the 4th and 17th February. In the first
the Marquis d'Azeglio assures me that he will bring the
subject before the competent authorities at Turin, accom-
panying the transmission 'd'une recomraandation. toute
speciale.' In the second letter the Marquis informs me
that ' the preparation of new regulations for the guides at
Chamouni had for some time occupied the attention of the
Minister of the Interior, and that these regulations will be
in rigorous operation, in all probability, at the commence-
'ment of the approaching summer.' The Marquis adds
that, ' as the regulations will be based upon a principle of
much greater liberty, he has every reason to believe that
0
194 THE PKESIDENT'S LETTER. [1858.
they will satisfy all the desires of travellers in the interests
of science.'
" With much pleasure at the opportunity of having been
in any degree able to bring about the fulfilment of your
wishes on the subject,
" I remain, my dear Sir,
" Faithfully yours,
" RICHARD OWEN.
" Pres. Brit. Association.
" Prof. Tyndall, F.R.S."
It ought to be stated that, previous to my arrival at
Chamouni in 1858, an extremely cogent memorial drawn
up by Mr. John Ball had been presented to the Marquis
d'Azeglio by a deputation from the Alpine Club. It was
probably this memorial which first directed the attention
of the Sardinian Minister of the Interior to the subject.
1859.] FIKST DEFEAT, AND FRESH ATTEMPT. 195
WINTER EXPEDITION TO THE
MER DE GLACE, 1859.
(27.)
HAVING ten days at my disposal last Christmas, I was
anxious to employ them in making myself acquainted with
the winter aspects and phenomena of the Mer de Glace.
On Wednesday, the 21st of December, I accordingly took
my place to Paris, but on arriving at Folkestone found
the sea so tempestuous that no boat would venture out.
The loss of a single day was more than I could afford,
and this failure really involved the loss of two. Seeing,
therefore, the prospect of any practical success so small,
I returned to London, purposing to give the expedition
up. On the following day, however, the weather lightened,
and I started again, reaching Paris on Friday morning.
On that day it was not possible to proceed beyond Macon,
where, accordingly, I spent the night, and on the following
day reached Geneva.
Much snow had fallen ; at Paris it still cumbered the
streets, and round about Macon it lay thick, as if a more
than usually heavy cloud had discharged itself on that
portion of the country. Between Macon and Eoussilloii
it was lighter, but from the latter station onwards the
quantity upon the ground gradually increased.
On Christmas morning, at 8 o'clock, I left Geneva by
}he diligence for Sallenches. The dawn was dull, but the
jky cleared as the day advanced, and finally a dome of
cloudless blue stretched overhead. The mountains were
*rand ; their sunward portions of dazzling whiteness, while
;he shaded sides, in contrast with the blue sky behind them,
presented a ruddy, subjective tint. The brightness of the
o 2
196 GENEVA TO CHAMOUNI. [1859.
day reached its maximum towards one o'clock, after which
a milkiness slowly stole over the heavens, and increased
in density until finally a drowsy turbidity filled the entire
air. The distant peaks gradually blended with the white
atmosphere above them and lost their definition. The black
pine forests on the slopes of the mountains stood out in
strong contrast to the snow ; and, when looked at through
the spaces enclosed by the tree branches at either side of
the road, they appeared of a decided indigo-blue. It was
only when thus detached by a vista in front that the blue
colour was well seen, the air itself between the eye and
the distant pines being the seat of the colour. Goethe
would have regarded it as an excellent illustration of his
' Farbenlehre.'
We reached Sallenches a little after 4 P.M., where I
endeavoured to obtain a sledge to continue my journey. A
fit one was not to be found, and a carriage was therefore
the only resort. We started at five ; it was very dark, but
the feeble reflex of the snow on each side of the road was
preferred by the postilion to the light of lamps. Unlike
the enviable ostrich, I cannot shut my eyes to danger when
it is near : and as the carriage swayed towards the pre-
cipitous road side, I could not fold myself up, as it was
intended I should, but, quitting the interior and divesting
my limbs of every encumbrance, I took my seat beside the
driver, and kept myself in readiness for the spring, which
in some cases appeared imminent. My companion how-
ever was young, strong, and keen-eyed ; and though we
often had occasion for the exercise of the quality last
mentioned, we reached Servoz without accident.
Here we baited, and our progress afterwards was slow
and difficult. The snow on the road was deep and
hummocky, and the strain upon the horses very great.
Having crossed the Arve at the Pont-Pelissier, we both
alighted, and I went on in advance. The air was
1859.] DESOLATION. 197
warm, and not a whisper disturbed its perfect repose.
There was no moon, and the heavy clouds, which now
quite overspread the heavens, cut off even the feeble
light of the stars. The sound of the Arve, as it rushed
through the deep valley to my left, came up to me
through crags and trees with a sad murmur. Some-
times on passing an obstacle, the sound was entirely cut
off, and the consequent silence was solemn in the extreme.
It was a churchyard stillness, and the tall black pines,
which at intervals cast their superadded gloom upon the
road, seemed like the hearse-plumes of a dead world. I
reached a wooden hut, where a lame man offers batons,
minerals, and eau de vie, to travellers in summer. It was
forsaken, and half buried in the snow. I leaned against
the door, and enjoyed for a time the sternness of the
surrounding scene. My conveyance was far behind, and
the intermittent tinkle of the horses' bells, which aug-
mented instead of diminishing the sense of solitude, in-
formed me of the progress and the pauses of the vehicle.
At the summit of the road I halted until my companion
reached me ; we then both remounted, and proceeded slowly
towards Les Ouches. We passed some houses, the aspect
of which was even more dismal than that of Nature ; their
roofs were loaded with snow, and white buttresses were
reared against the walls. There was no sound, no light, '
no voice of joy to indicate that it was the pleasant Christmas
time. We once met the pioneer of a party of four drunken
peasants : he came right against us, and the coachman had
to pull up. Planting his feet in the snow and propping
himself against the leader's shoulder, the bacchanal
exhorted the postilion to drive on ; the latter took him
at his word, and overturned him in the snow. After
this we encountered no living thing. The horses seemed
seized by a kind of torpor, and leaned listlessly against
each other; vainly the postilion endeavoured to rouse
198 A HOESE IN THE SNOW. [1859.
them by word and whip ; they sometimes essayed to
trot down the slopes, but immediately subsided to their
former monotonous crawl. As we ascended the valley,
the stillness of the air was broken at intervals by wild
storm-gusts, sent down against us from Mont Blanc
himself. These chilled me, so I quitted the carriage,
and walked on. Not far from Chamouni, the road, for
some distance, had been exposed to the full action of the
wind, and the snow had practically erased it. Its left wall
was completely covered, while a few detached stones,
rising here and there above the surface, were the only
indications of the presence and direction of the right-hand
wall. I could not see the state of the surface, but I
learned by other means that the snow had been heaped
in oblique ridges across my path. I staggered over four
or five of these in succession, sinking knee-deep, and
finally found myself immersed to the waist. This made
me pause ; I thought I must have lost the road, and vainly
endeavoured to check myself by the positions of surround-
ing objects. I turned back and met the carriage : it had
stuck in one of the ridges ; one horse was down, his hind
legs buried to the haunches, his left fore leg plunged to
the shoulder in snow, and the right one thrown forward
upon the surface. C'est lien la route ? demanded my com-
•panion. I went back exploring, and assured myself that
we were over the road ; but I recommended him to release
the horses and leave the carriage to its fate. He, however,
succeeding in extricating the leader, and while I went on
in advance seeking out the firmer portions of the road, he
followed, holding his horses by their heads ; and half an
hour's struggle of this kind brought us to Chamouni.
It also was a little " city of the dead." There was no
living thing in the streets, and neither sound nor light in
the houses. The fountain made a melancholy gurgle, one or
two loosened window-shutters creaked harshly in the wind,
1859.] CHAMOUNI ON CHEISTMAS NIGHT. 199
and banged against the objects which limited their oscilla-
tions. The Hotel de 1'Union, so bright and gay in summer,
was nailed up and forsaken ; and the cross in front of it,
stretching its snow-laden arms into the dim air, was the type
of desolation. We rang the bell at the Hotel Royal, but
the bay of a watch-dog resounding through the house was
long our only reply. The bell appeared powerless to wake
the sleepers, and its sound mingled dismally with that of
the wind howling through the deserted passages. The
noise of my boot-heel, exerted long on the front door, was
at length effective ; it was unbarred, and the physical
heat of a good stove soon added itself to the warmth of
the welcome with which my hostess greeted me.
December 26th. — The snow fell heavily, at frequent in-
tervals, throughout the entire day. Dense clouds draped
all the mountains, and there was not the least prospect
of my being able to see across the Mer de Glace. I
walked out alone in the dim light, and afterwards traversed
the streets before going to bed. They were quite forsaken.
Cold and sullen the Arve rolled under its wooden bridge,
while the snow fell at intervals with heavy shock from the
roofs of the houses, the partial echoes from the surfaces
of the granules combining to render the sound loud and
hollow. Thus were the concerns of this little hamlet
changed and fashioned by the obliquity of the earth's axis,
the chain of dependence which runs throughout creation,
linking the roll of a planet alike with the interests of
marmots and of men.
Tuesday, 27th December. — I rose at six o'clock, having
arranged with my men to start at seven, if the weather at
all permitted. Edonard Simond, my old assistant of 1857,
and Joseph Tairraz were the guides of the party ; the
porters were Edouard Balmat, Joseph Simond (fils d'Au-
guste), Francois Eavanal, and another. They came at the
time appointed ; it was snowing heavily, and we agreed to
200 ASCENT OF THE MOUNTAIN. [1359.
wait till eight o'clock and then decide. They returned at
eight, and finding them disposed to try the ascent to the
Montanvert, it was not my place to baulk them. Through
the valley the work was easy, as the snow had been par-
tially beaten down, but we soon passed the habitable limits,
and had to break ground for ourselves. Three of my men
had tried to reach the Montanvert by la Filia on the previous
Thursday, but their experience of the route had been such
as to deter them from trying it again. We now chose the
ordinary route, breasting the slope until we reached the
cluster of chalets, under the projecting eave of one of
which the men halted and applied " pattens " to their
feet. These consisted of planks about sixteen inches
long and ten wide, which were firmly strapped to the feet.
My first impression was that they were worse than useless,
for though they sank less deeply than the unarmed feet,
on being raised they carried with them a larger amount of
snow, which, with the leverage of the leg, appeared to
necessitate an enormous waste of force. I stated this em-
phatically, but the men adhered to their pattens, and
before I reached the Montanvert I had reason to commend
their practice as preferable to my theory. I was however
guided by the latter, and wore no pattens. The general
depth of the snow along the track was over three feet ; the
footmarks of the men were usually rigid enough to bear
my weight, but in many cases I went through the crust
which their pressure had produced, and sank suddenly
in the mass. The snow became softer as we ascended,
and my immersions more frequent, but the work was
pure enjoyment, and the scene one of extreme beauty.
The previous night's snow had descended through a per-
fectly still atmosphere, and had loaded all the branches
of the pines ; the long arms of the trees drooped under
the weight, and presented at their extremities the ap-
pearance of enormous talons turned downwards, Some
1859.] SNOW ON THE PINES, 201
of the smaller and thicker trees were almost entirely
covered, and assumed grotesque and beautiful forms ; the
upper part of one in particular resembled a huge white
parrot with folded wings and drooping head, the slumber
of the bird harmonizing with the torpor of surrounding
nature. I have given a sketch of it in Fig. 13.
Fig. 13.
Previous to reaching the half-way spring, where the
peasant girls offer strawberries to travellers in summer,
we crossed two large couloirs filled with the debris of
avalanches which had fallen the night before. Between
these was a ridge forty or fifty yards wide on which the
snow was very deep, the slope of the mountain also adding
a component to the fair thickness of the snow. My
' shoulder grazed the top of the embankment to my right as
I crossed the ridge, and once or twice I found myself waist
deep in a vertical shaft from which it required a consider-
202 SOUND OF BREAKING SNOW. [1859.
able effort to escape. Suddenly we heard a deep sound
resembling the dull report of a distant gun, and at the same
moment the snow above us broke across, forming a fissure
parallel to our line of march. The layer of snow had been
in a state of strain, which our crossing brought to a crisis :
it gave way, but having thus relieved itself it did not
descend. Several times during the ascent the same phe-
nomenon occurred. Once, while engaged upon a very steep
slope, one of the men cried out to the leader, " Arretez ! "
Immediately in front of the latter the snow had given way,
forming a zigzag fissure across the slope. We all paused,
expecting to see an avalanche descend. Tairraz was in
front ; he struck the snow with his baton to loosen it, but
seeing it indisposed to descend he advanced cautiously
across it, and was followed by the others. I brought up
the rear. The steepness of the mountain side at this
place, and the absence of any object to which one might
cling, would have rendered a descent with the snow in the
last degree perilous, and we all felt more at ease when a
safe footing was secured at the further side of the incline.
At the spring, which showed a little water, the men
paused to have a morsel of bread. The wind had changed,
the air was clearing, and our hopes brightening. As we
ascended the atmosphere went through some extraordinary
mutations. Clouds at first gathered round the Aiguille
and Dome du Gouter, casting the lower slopes of the
mountain into intense gloom. After a little time all this
cleared away, and the beams of the sun striking detached
pieces of the slopes and summits produced an extra-
ordinary effect. The Aiguille and Dome were most sin-
gularly illumined, and to the extreme left rose the white
conical hump of the Dromedary, from which a long
streamer of snow-dust was carried southward by the wind.
The Aiguille du Dru, which had been completely mantled
during the earlier part of the day, now threw off its cloak
18.59.] COLOUR OF SNOW. 203
of vapour and rose in most solemn majesty before us ;
half of its granite cone was warmly illuminated, and
half in shadow. The wind was high in the upper regions,
and, catching the dry snow which rested on the asperities
and ledges of the Aiguille, shook it out like a vast banner
in the air. The changes of the atmosphere, and the
grandeur which they by turns revealed and concealed,
deprived the ascent of all weariness. We were usually
flanked right and left by pines, but once between the
fountain and the Montanvert we had to cross a wide un-
sheltered portion of the mountain which was quite covered
with the snow of recent avalanches. This was lumpy and
far more coherent than the undisturbed snow.. We took
advantage of this, and climbed zigzag over the avalanches
for three-quarters of an hour, thus reaching the opposite
pines at a point considerably higher than the path. This,
though not the least dangerous, was the least fatiguing
part of the ascent.
I frequently examined the colour of the snow : though
fresh, its blue tint was by no means so pronounced as I
have seen it on other occasions ; still it was beautiful. The
colour is, no doubt, due to the optical reverberations
which occur within a fissure or cavity formed in the
snow. The light is sent from side to side, each time
plunging a little way into the mass ; and being ejected
from it by reflection, it thus undergoes a sifting process,
and finally reaches the eye as blue light. The pre-
sence of any object which cuts off this cross-fire of the
light destroys the colour. I made conical apertures in the
snow, in some cases three feet deep, a foot wide at the
mouth, and tapering down to the width of my baton.
When the latter was placed along the axis of such a cone,
the blue light which had previously filled the cavity disap-
peared ; on the withdrawal of the baton it was followed
by the light, and thus by moving the staff up and down
204 THE MONTANVERT IN WINTER, [1859.
its motions were followed by the alternate appearance and
extinction of the light. I have said that the holes made
in the snow seemed filled with a blue light, and it certainly
appeared as if the air contained in the cavities had
itself been coloured, and thereby rendered visible, the
vision plunging into it as into a blue medium. Another
fact is perhaps worth notice : snow rarely lies so smooth as
not to present little asperities at its surface ; little ridges
or hillocks, with little hollows between them. Such small
hollows resemble, in some degree, the cavities which I made
in the snow, and from them, in the present instance, a
delicate light was sent to the eye, faintly tinted with
the pure blue of the snow-crystals. In comparison
with the spots thus illuminated, the little protuberances
were gray. The portions most exposed to the light seemed
least illuminated, and their defect in this respect made
them appear as if a light-brown dust had been strewn over
them.
After five hours and a half of hard work we reached the
Montanvert. I had often seen it with pleasure. Often,
having spent the day alone amid the seracs of the Col du
Geant, on turning the promontory of Trelaporte on my way
home, the sight of the little mansion has gladdened me, and
given me vigour to scamper down the glacier, knowing
that pleasant faces and wholesome fare were awaiting
me. This day, also, the sight of it was most welcome,
despite its desolation. The wind had swept round the
auberge, and carried away its snow-buttresses, piling the
mass thus displaced against the adjacent sheds, to the roofs
of which one might step from the surface of the snow. The
floor of the little chateau in which I lodged in 1857 was
covered with snow, and on it were the fresh footmarks
of a little animal — a marmot might have made such
marks, had not the marmots been all asleep — what the
creature was I do not know,
1859.] CRYSTAL CURTAIN. 205
In the application of her own principles, Nature often
transcends the human imagination ; her acts are bolder than
our predictions. It is thus with the motion of glaciers; it was
thus at the Montanvert on the day now referred to. The
floors, even where the windows appeared well closed, were
covered with a thin layer of fine snow ; and some of the
mattresses in the bedrooms were coated to the depth of
half an inch with this fine powder. Given a chink through
which the finest dust can pass, dry snow appears com-
petent to make its way through the same fissure. It had
also been beaten against the windows, and clung there
like a ribbed drapery. In one case an effect so singular
was exhibited, that I doubted my eyes when I first saw it.
In front of a large pane of glass, and quite detached
from it, save at its upper edge, was a festooned curtain
formed entirely of minute ice-crystals. It appeared to be
as fine as muslin ; the ease of its curves and the depth
of its folds being such as could not be excelled by the
intentional arrangement of ordinary gauze. The frost-
figures on some of the window-panes were also of the most
extraordinary character : in some cases they extended
over large spaces, and presented the appearance which we
often observe in London ; but on other panes they oc-
curred in detached clusters, or in single flowers, these
grouping themselves together to form miniature bouquets
of inimitable beauty. I placed my warm hand against
a pane which was covered by the crystallization, and
melted the frostwork which clung to it. I then withdrew
my hand and looked at the film of liquid through a pocket-
lens. The glass cooled by contact with the air, and after
a time the film commenced to move at one of its edges ;
atom closed with atom, and the motion ran in living lines
through the pellicle, until finally the entire film presented
the beauty and delicacy of an organism. The connexion
between such objects and what we are accustomed to
206 THE MER DE GLACE IN WINTER. [1859.
call the feelings may not be manifest, but it is nevertheless
true that, besides appealing to the pure intellect of man,
these exquisite productions can also gladden his heart and
moisten his eyes.
The glacier excited the admiration of us all : not as in
summer, shrunk and sullied like a spent reptile, steaming
under the influence of the sun ; its frozen muscles were
compact, strength and beauty were associated in its
aspect. At some places it was pure and smooth; at
others frozen fins arose from it, high, steep, and sharply
crested. Down the opposite mountain side arrested streams
set themselves erect in successive terraces, the fronts of
which were fluted pillars of ice. There was no sound of
water ; even the Nant Blanc, which gushes from a spring,
and which some describe as permanent throughout the
winter, showed no trace of existence. From the Montanvert
to Trelaporte the Mer de Glace was all in shadow ; but the
sunbeams pouring down the corridor of the Geant ruled
a beam of light across the glacier at its upper portion,
smote the base of the Aiguille du Moine, and flooded
the mountain with glory to its crest. At the opposite side
of the valley was the Aiguille du Dru, with a banneret
of snow streaming from its mighty cone. The Grande
Jorasse, and the range of summits between it and the
Aiguille du Geant, were all in view, and the Charmoz
raised its precipitous cliffs to the right, and pierced with
its splinter-like pinnacles the clear cold air. As the night
drew on, the mountains seemed to close in upon us ; and
on looking out before retiring to rest, a scene so solemn
had never before presented itself to my eyes or affected
my imagination.
My men occupied the afternoon of the day of our
arrival in making a preliminary essay upon the glacier
while I prepared my instruments. To the person whom
I intended to fix my stations, three others were at-
1859.] THE FIEST NIGHT. 207
tached by sound ropes of considerable length. Hidden
crevasses we knew were to be encountered, and we had
made due preparation for them. Throughout the afternoon
the weather remained fine, and at night the .stars shone
out, but still with a feeble lustre. I could notice a tur-
bidity gathering in the air over the range of the Brevent,
which seemed disposed to extend itself towards us. At
night I placed a chair in the middle of the snow, at some
distance from the house, and laid on it a registering
thermometer. A bountiful fire of pine logs was made in
the salle d manger ; a mattress was placed with its foot
towards the fire, its middle line bisecting the right angle
in which the fireplace stood ; this being found by experi-
ment to be the position in which the draughts from the door
and from the windows most effectually neutralized each
other. In this region of calms I lay down, and covering
myself with blankets and duvets, listened to the crack-
ling of the logs, and watched their ruddy flicker upon the
walls, until I fell asleep.
The wind rose during the night, and shook the windows :
one pane in particular seemed set in unison to the gusts,
and responded to them by a loud and melodious vibration.
I rose and wedged it round with sous and penny pieces,
and thus quenched its untimely music.
December 28th. — We were up before the dawn.
Tairraz put my fire in order, and I then rose. The tem-
perature of the room at a distance of eight feet from
the fire was two degrees of Centigrade below zero ; the
lowest temperature outside was eleven degrees of Centi-
grade below zero, — not at all an excessive cold. The
clouds indeed had, during the night, thrown vast diaphragms
across the sky, and thus prevented the escape of the earth's
heat into space.
While my assistants were preparing breakfast I had
time to inspect the glacier and its bounding heights. On
208 A "ROSE OF DAWN." [1859.
looking up the Mer de Glace, the Grande Jorasse meets
the view, rising in steep outline from the wall of cliffs
which terminates the Glacier de Lechaud. Behind this
steep ascending ridge, which is shown on the frontis-
piece, and upon it, a series of clouds had ranged them-
selves, stretching lightly along the ridge at some places,
and at others collecting into ganglia. A string of
rosettes was thus formed which were connected together
by gauzy filaments. The portion of the heavens behind
the Bridge was near the domain of the rising sun, and
when he cleared the horizon his red light fell upon
the clouds, and ignited them to ruddy flames. Some
of the lighter clouds doubled round the summit of the
mountain, and swathed its black crags with a vestment of
transparent red. The adjacent sky wore a strange and
supernatural air ; indeed there was something in the whole
scene which baffled analysis, and the words of Tennyson
rose to my lips as I gazed upon it :—
" God made Himself an awful rose of dawn."
I have spoken several times of the cloud-flag which
the wind wafted from the summit of the Aiguille du Dru.
On the present occasion this grand banner reached ex-
traordinary dimensions. It was brindled in some places
as if whipped into curds by the wind ; but through these
continuous streamers were drawn, which were bent into
sinuosities resembling a waving flag at a mast-head.
All this was now illuminated with the sun's red rays,
which also fringed with fire the exposed edges and
pinnacles both of the Aiguille du Dru and the Aiguille
Verte. Thus rising out of the shade of the valley the
mountains burned like a pair of torches, the flames of
which were blown half a mile through the air. Soon after-
wards the summits of the Aiguilles Rouges were illuminated,
and day declared itself openly among the mountains.
1859.] THE STAKES FIXED. 209
But these red clouds of the morning, magnificent
though they were, suggested thoughts which tended to
qualify the pleasure which they gave : they did not indi-
cate good weather. Sometimes, indeed, they had to fight
with denser masses, which often prevailed, swathing the
mountains in deep neutral tint, but which, again yielding,
left the glory of the sunrise augmented by contrast with
their gloom. Between eight and nine A.M. we commenced
the setting out of our first line, one of whose termini was a
point about a hundred yards higher up than the Montanvert
hotel ; a withered pine on the opposite mountain side mark-
ing the other terminus. The stakes made use of were four
feet long. With the selfsame baton which I had employed
upon the Mer de Glace in 1857, and which Simond had pre-
served, the worthy fellow now took up the line. At some
places the snow was very deep, but its lower portions were
sufficiently compact to allow of a stake being firmly fixed in
it. At those places where the wind had removed the snow
or rendered it thin, the ice was pierced with an auger
and the stake driven into it. The greatest caution was
of course necessary on the part of the men ; they were in
the midst of concealed crevasses, and sounding was essen-
tial at every step. By degrees they withdrew from me,
and approached the eastern boundary of the glacier, where
the ice was greatly dislocated, and the labour of wading
through the snow enormous. Long detours were some-
times necessary to reach a required point ; but they were all
accomplished, and we at length succeeded in fixing eleven
stakes along this line, the most distant of which was within
about eighty yards of the opposite side of the glacier.
The men returned, and I consulted them as to the pos-
sibility of getting a line across at the Fonts ; but this was
' judged to be impossible in the time. We thought, however,
that a second line might be staked out at some distance
below the Montanvert. I took the theodolite down the
210 STORM ON THE GLACIER. [1859.
mountain -slope, wading at times breast-deep in snow, and
having selected a line, the men tied themselves together
as before, and commenced the staking out. The work
was slowly but steadily and steadfastly done. The air
darkened ; angry clouds gathered around the moun-
tains, and at times the glacier was swept by wild
squalls. The men were sometimes hidden from me by
the clouds of snow which enveloped them, but between
those intermittent gusts there were intervals of repose,
which enabled us to prosecute our work. This line
was more difficult than the first one; the glacier was
broken into sharp-edged chasms ; the ridges to be climbed
were steep, and the snow which filled the depressions pro-
found. The oblique arrangement of the crevasses also
magnified the labour by increasing the circuits. I saw the
leader of the party often shoulder-deep in snow, treading the
soft mass as a swimmer walks in water, and I felt a wish
to be at his side to cheer him and to share his toil. Each
man there, however, knew my willingness to do this if
occasion required it, and wrought contented. At length
the last stake being fixed, the faces of the men were
turned homeward. The evening became wilder, and the
storm rose at times to a hurricane. On the more level
portions of the glacier the snow lay deep and unshel-
tered ; among its frozen waves and upon its more dislo-
cated portions it had been partially engulfed, and the
residue was more or less in shelter. Over the former
spaces dense clouds of snow rose, whirling in the air and
cutting off all view of the glacier. The whole length of
the Mer de Glace was thus divided into clear and cloudy
segments, and presented an aspect of wild and wonderful
turmoil. A large pine stood near me, with its lowest
branch spread out upon the surface of the snow ; on t his
branch I seated myself, and, sheltered by the trunk, waited
until I saw my men in safety. The wind caught the
1859.] HEAVY SNOW. 211
branches of the trees, shook down their loads of snow,
and tossed it wildly in the air. Every mountain gave
a quota to the storm. The scene was one of most im-
pressive grandeur, and the moan of the adjacent pines
chimed in noble harmony with the picture which addressed
the eyes.
At length we all found ourselves in safety within
doors. The windows shook violently. The tempest was
however intermittent throughout, as if at each effort it
had exhausted itself, and required time to recover its
strength. As I heard its heralding roar in the gullies of
the mountains, and its subsequent onset against our habi-
tation, I thought wistfully of my stations, not knowing
whether they would be able to retain their positions in
the face of such a blast. That night however, as if the
storm had sung our lullaby, we all slept profoundly,
having arranged to commence our measurements as early
as light permitted on the following day.
Thursday, 29th December. — "Snow, heavy snow: it must
have descended throughout the entire night ; the quantity
freshly fallen is so great ; the atmosphere at seven o'clock
is thick with the descending flakes." At eight o'clock it
cleared up a little, and I proceeded to my station, while
the men advanced upon the glacier ; but I had scarcely
fixed my theodolite when the storm recommenced. I
had a man to clear away the snow and otherwise assist me ;
he procured an old door from the hotel, and by rearing
it upon its end sheltered the object-glass of the in-
strument. Added to the flakes descending from the clouds
was the spitting snow- dust raised by the wind, which
for a time so blinded me that I was unable to see the
glacier. The measurement of the first stake was very
tedious, but practice afterwards enabled me to take advan-
tage of the brief lulls and periods of partial clearness
with which the storm was interfused,
P 2
212 A MAN IN A CREVASSE. [1859.
At nine o'clock my telescope happened to be directed
upon the men as they struggled through the snow ; all
evidence of the deep track which they had formed yester-
day having been swept away. I saw the leader sink
and suddenly disappear. He had stood over a concealed
fissure, the roof of which had given way and he had dropped
in. I observed a rapid movement on the part of the re-
maining three men : they grouped themselves beside the
fissure, and in a moment the missing man was drawn from
between its jaws. His disappearance and reappearance
were both extraordinary. We had, as I have stated, pro-
vided for contingencies of this kind, and the man's rescue
was almost immediate.
My attendant brought two poles from the hotel which
we thrust obliquely into the snow, causing the free ends
to cross each other ; over these a blanket was thrown, be-
hind which I sheltered myself from the storm as the men
proceeded from stake to stake. At 9.30 the storm was so
thick that I was unable to see the men at the stake
which they had reached at the time ; the flakes sped
wildly in their oblique course across the field of the tele-
scope. Some time afterwards the air became quite still,
and the snow underwent a wonderful change. Frozen
flowers similar to those I had observed on Monte Rosa
fell in myriads. For a long time the flakes were wholly
composed of these exquisite blossoms entangled together.
On the surface of my woollen dress they were soft as
down ; the snow itself on which they fell seemed covered
by a layer of down ; while my coat was completely
spangled with six-rayed stars. And thus prodigal Nature
rained down beauty, and had done so here for ages unseen
by man. And yet some flatter themselves with the idea that
this world was planned with strict reference to human use ;
that the lilies of the field exist simply to appeal to the sense
of the beautiful in man. True, this result is secured, but it
18.59.] SIX-RAYED CRYSTALS. 213
is one of a thousand all equally important in the eyes of
Nature. Whence those frozen blossoms ? Why for aeons
wasted ? The question reminds one of the poet's answer
when asked whence was the Rhodora : —
" Why wert thou there, 0 rival of the rose ?
I never thought to ask, I never knew ;
But in my simple ignorance suppose
The selfsame power that brought me there brought you ! " *
I sketched some of the crystals, but, instead of repro-
ducing these sketches, which were rough and hasty, I have
annexed two of the forms drawn with so much skill and
patience by Mr. Glaisher.
We completed the measurement of the first line before
eleven o'clock, and I felt great satisfaction in the thought
that I possessed something of which the weather could not
deprive me. As I closed my note-book and shifted the
instrument to the second station, I felt that my expedi-
tion was already a success.
At a quarter past eleven I had my theodolite again fixed,
and ranging the telescope along the line of pickets, I saw
them all standing. Crossing the ice wilderness, and sug-
gesting the operation of intelligence amid that scene of
desolation, their appearance was pleasant to me. Just
before I commenced, a solitary jay perched upon the sum-
mit of an adjacent pine and watched me. The air was
still at the time, and the snow fell heavily. The flowers
moreover were magnificent, varying from about the twen-
tieth of an inch to two lines in diameter, while, falling
through the quiet air, their forms were perfect. Adjacent
to my theodolite was a stump of pine, from which I had
the snow removed, in order to have something to kick my
toes against when they became cold ; and on the stump
was placed a blanket to be used as a screen in case of need.
While I remained at the station a layer of snow an inch
* Emerson.
Fig. 14.
Fig. 15.
1859.] SOUND THROUGH THE SNOWSTORM. 215
thick fell upon this blanket, the whole layer being com-
posed of these exquisite flowers. The atmosphere also was
filled with them. From the clouds to the earth Nature was
busy marshalling her atoms, and putting to shame by the
beauty of her structures the comparative barbarities of Art.
My men at length reached the first station, and the
measurement commenced. The storm drifted up the val-
ley, thickening all the air as it approached. Denser and
denser the flakes fell ; but still, with care and tact I was
able to follow my party to a distance of 800 yards. I had
not thought it possible to see so far through so dense a storm.
At this distance also my voice could be heard, and my
instructions understood ; for once, as the man who took
up the line stood behind his baton and prevented its pro-
jection against the white snow, I called out to him to stand
aside, and he promptly did so. Throughout the entire
measurement the ' snow never ceased falling, and some of
the illusions which it produced were extremely singular.
The distant boundary of the glacier appeared to rise to an
extraordinary height, and the men wading through the snow
appeared as if climbing up a wall. The labour along this
line was still greater than on the former ; on the steeper
slopes especially the toil was great ; for here the effort of
the leader to lift his own body added itself to that of cut-
ting his way through the snow. His footing I could see
often yielded, and he slid back, checking his recession,
however, by still plunging forward ; thus, though the
limbs were incessantly exerted, it was, for a time, a mere
motion of vibration without any sensible translation. At
the last stake the men shouted, " Nous avons finis ! " and
I distinctly heard them through the falling snow. By this
time I was quite covered with the crystals which clung to
my wrapper. They also formed a heap upon my theodo-
lite, rising over the spirit-levels and embracing the lower
portion of the vertical arc. The work was done ; I struck
216 SWIFT DESCENT. [1859.
my theodolite and ascended to the hotel ; the greatest
depth of snow through which I waded reaching, when I
stood erect, to within three inches of my breast.
The men returned ; dinner was prepared and consumed ;
the disorder which we had created made good ; the rooms
were swept, the mattresses replaced, and the shutters fast-
ened, where this was possible. We locked up the house,
and with light hearts and lithe limbs commenced the de-
scent. My aim now was to reach the source of the Arvei-
ron, to examine the water and inspect the vault. With
this view we went straight down the mountain. The inclina-
tions were often extremely steep, and down these we swept
with an avalanche-velocity ; indeed usually accompanied
by an avalanche of our own creation. On one occasion
Balmat was for a moment overwhelmed by the descending
mass : the guides were startled, but he emerged instantly.
Tairraz followed him, and I followed Tairraz, all of us roll-
ing in the snow at the bottom of the slope as if it were so
much flour. My practice on the Finsteraarhom rendered
me at home here. One of the porters could by no means
be induced to try this flying mode of descent. Simond
carried my theodolite box, tied upon a crotchet on his
back ; and once, while shooting down a slope, he incau-
tiously allowed a foot to get entangled ; his momentum
rolled him over and over down the incline, the theodolite
emerging periodically from the snow during his successive
revolutions. A succession of qlissades brought us with
*/ O
amazing celerity to the bottom of the mountain, whence
we picked our way amid the covered boulders and over the
concealed arms of the stream to the source of the Arveiron.
The quantity of water issuing from the vault was consider-
able, and its character that of true glacier water. It was turbid
with suspended matter, though not so turbid as in summer ;
but the difference in force and quantity would, I think, be
sufficient to account for the greater summer turbidity. This
1859.] VAULT OF THE ARVEIRON. 217
character of the water could only be due to the grinding mo-
tion of the glacier upon its bed ; a motion which seems not
to be suspended even in the depth of winter. The tempe-
rature of the water was the tenth of a degree Centigrade
above zero ; that of the ice was half a degree below zero :
this was also the temperature of the air, while that of the
snow, which in some places covered the ice-blocks, was
a degree and a quarter below zero.
The entrance to the vault was formed by an arch of ice
which had detached itself from the general mass of the
glacier behind : between them was a space through which
we could look to the sky above. Beyond this the cave nar-
rowed, and we found ourselves steeped in the blue light of
the ice. The roof of the inner arch was perforated at one
place by a shaft about a yard wide, which ran vertically to
the surface of the glacier. Water had run down the sides
of this shaft, and, being re-frozen below, formed a compo-
site pillar of icicles at least twenty feet high and a yard
thick, stretching quite from roof to floor. They were all
united to a common surface at one side, but at the
other they formed a series of flutiiigs of exceeding beauty.
This group of columns was bent at its base as if it had
yielded to the forward motion of the glacier, or to the
weight of the arch overhead. Passing over a number of
large ice-blocks which partially filled the interior of the
vault, we reached its extremity, and here found a sloping
passage with a perfect arch of crystal overhead, and lead-
ing by a steep gradient to the air above. This singular gal-
lery was about seventy feet long, -and was floored with
snow. We crept up it, and from the summit descended by
a glissade to the frontal portion of the cavern. To me this
crystal cave, with the blue light glistening from its walls,
presented an aspect of magical beauty. My delight, how-
ever, was tame compared with that of my companions.
Looking from the blue arch westwards, the heavens were
218 MAJESTIC SCENE. [1859.
seen filled by crimson clouds, with fiery outliers reaching
up to the zenith. On quitting the vault I turned to
have a last look at those noble sentinels of the Mer de
Glace, the Aiguille du Dru, and the Aiguille Verte. The
glacier below the mountains was in shadow, and its frozen
precipices of a deep cold blue. From this, as from a
basis, the mountain cones sprang steeply heavenward,
meeting halfway down the .fiery light of the sinking sun.
The right-hand slopes and edges of both pyramids burned
in this light, while detached protuberant masses also caught
the blaze, and mottled the mountains with effulgent spaces.
A range of minor peaks ran slanting downwards from
the summit of the Aiguille Verte ; some of these were
covered with snow, and shone as if illuminated with
the deep crimson of a strontian flame. I was absolutely
struck dumb by the extraordinary majesty of this scene,
and watched it silently till the red light faded from the
highest summits. Thus ended my winter expedition to
the Mer de Glace.
Next morning, starting at three o'clock, I was driven
by my two guides in an open sledge to Sallenches. The
rain was pitiless and the road abominable. The distance,
I believe, is only six leagues, but it took us five hours to
accomplish it. The leading mule was beyond the reach of
Simond's whip, and proved a mere obstructive ; during
part of the way it was unloosed, tied to the sledge, and
dragged after it. Simond afterwards mounted the hind-
most beast and brought his whip to bear upon the leader ;
the jerking he endured for an hour and a half seemed
almost sufficient to dislocate his bones. We reached
Sallenches half an hour late, but the diligence was behind
its time by this exact interval. We met it on the Pont St.
Martin, and I transferred myself from the sledge to the
interior. This was the morning of the 30th of December,
and on the evening of the 1st of January I was in London.
1859.] MY ASSISTANTS. . 219
I cannot finish this recital without saying one word about
my men. Their behaviour was admirable throughout. The
labour was enormous, but it was manfully and cheerfully
done. I know Simond well ; he is intelligent, truthful,
and affectionate, and there is no guide of my acquaint-
ance for whom I have a stronger regard. Joseph Tairraz
is an extremely intelligent and able guide, and on this
trying occasion proved himself worthy of my highest praise
and commendation. Their two companions upon the gla-
cier, Edouard Balmat (le Petit Balmat) and Joseph Si-
mond (fils d'Auguste), acquitted themselves admirably ;
and it also gives me pleasure to bear testimony to the will-
ing and efficient service of Franpois Ravanal, who attended
upon me during the observations.
PART II.
CHIEFLY SCIENTIFIC,
Aber im stillen Gemach entwirft bedeutende Zirkel
Sinnend der Weise, beschleicht forschend den schaffenden Geist,
Priift der Stoffe Gewalt, der Magnete Hassen und Lieben,
Folgt durch die Liifte dem Klang, folgt durch den Aether dem Strahl,
Sucht das^vertraute Gesetz in des Zufalls grausenden Wundern,
Sucht den ruhenden Pol in der Erscheinungen Flucht.
SCHILLER.
THEORIES OF LIGHT. 223
ON LIGHT AND HEAT.
WHAT is Light ? The ancients supposed it to be some-
thing emitted by the eyes, and for ages no notion was
entertained that it required time to pass through space.
In the year 1676 Homer first proved that the light from
Jupiter's satellites required a certain time to cross the
earth's orbit. Bradley afterwards found that, owing to
the velocity with which the earth flies through space,
the rays of the stars are slightly inclined, just as rain-
drops which descend vertically appear to meet us when
we move swiftly through the shower. In Kew Gardens
there is a sun-dial commemorative of this discovery, which
is called the aberration of light. Knowing the velocity of
the earth, and the inclination of the stellar rays, Bradley
was able to calculate the velocity of light ; and his result
agrees closely with that of Romer. Celestial distances
were here involved, but a few years ago M. Fizeau, by
an extremely ingenious contrivance, determined the time
required by light to pass over a distance of about 9000
yards ; and his experiment is quite in accordance with the
results of his predecessors.
But what is it which thus moves ? Some, and among
the number Newton, imagined light to consist of particles
darted out from luminous bodies. This is the so-called
Emission-Theory, which was held by some of the greatest
men : Laplace, for example, accepted it ; and M. Biot
has developed it with a lucidity and power peculiar to
himself. It was first opposed by the astronomer Huyghens,
and afterwards by Euler, both of whom supposed light to
be a kind of undulatory motion ; but they were borne
224 NATURE OF SOUND.
down by their great antagonists, and the emission-theory
held its ground until the commencement of the present
century, when Thomas Young, Professor of Natural Phi-
losophy in the Royal Institution, reversed the scientific
creed by placing the Theory of Undulation on firm founda-
tions. He was followed by a young Frenchman of extra-
ordinary genius, who, by the force of his logic and the
conclusiveness of his experiments, left the Wave-Theory
without a competitor. The name of this young French-
man was Augustin Fresnel.
Since his time some of the ablest minds in Europe have
been applied to the investigation of this subject ; and thus
a mastery, almost miraculous, has been attained over the
grandest and most subtle of natural phenomena. True
knowledge is always fruitful, and a clear conception
regarding any one natural agent leads infallibly to better
notions regarding others. Thus it is that our knowledge
of light has corrected and expanded our knowledge of
heat, while the latter, in its turn, will assuredly lead us to
clearer conceptions regarding the other forces of Nature.
I think it will not be a useless labour if I here endeavour
to state, in a Simple manner, our present views of light
and heat. Such knowledge is essential to the explanation
of many of the phenomena referred to in the foregoing
pages ; and even to the full comprehension of the origin
of the glaciers themselves. A few remarks on the nature
of sound will form a fit introduction.
It is known that sound is conveyed to our organs of
hearing by the air : a bell struck in a vacuum emits no
sound, and even when the air is thin the sound is enfeebled.
Hawksbee proved this by the air-pump ; De Saussure fired
a pistol at the top of Mont Blanc, — I have repeated the
experiment myself, and found, with him, that the sound is
feebler than at the sea level. Sound is not produced by
anything projected through the air. The explosion of a
CAUSE OF MUSIC. 225
gun, for example, is sent forward by a motion of a totally
different kind from that which animates the bullet pro-
jected from the gun : the latter is a motion of translation;
the former, one of vibration. To use a rough comparison,
sound is projected through the air as a push is through a
crowd ; it is the propagation of a wave or pulse, each par-
ticle taking up the motion of its neighbour, and delivering
it on to the next. These aerial waves enter the external
ear, meet a membrane, the so-called tympanic membrane,
which is drawn across the passage at a certain place, and
break upon it as sea-waves do upon the shore. The mem-
brane is shaken, its tremors are communicated to the
auditory nerve, and transmitted by it to the brain, where
they produce the impression to which we give the name
of sound.
In the tumult of a city, pulses of different kinds strike
irregularly upon the tympanum, and we call the effect
noise ; but when a succession of impulses reach the ear at
regular intervals we feel the effect as music. Thus, a
vibrating string imparts a series of shocks to the air around
it, which are transmitted with perfect regularity to the ear,
and produce a musical note. When we hear the song of a
soaring lark we may be sure that the entire atmosphere
between us and the bird is filled with pulses, or undula-
tions, or waves, as they are often called, produced by the
little songster's organ of voice. This organ is a vibrating
instrument, resembling, in principle, the reed of a clarionet.
Let us suppose that we hear the song of a lark, ele-
vated to a height of 500 feet in the air. Before this is
possible, the bird must have agitated a sphere of air 1000
feet in diameter ; that is to say, it must have communi-
cated to 17,888 tons of air a motion sufficiently intense
to be appreciated by our organs of hearing.
Musical sounds differ in pitch : some notes are high and
shrill, others low and deep. Boys are chosen as choristers
Q
226 CAUSE OF PITCH.
to produce the shrill notes ; men are chosen to produce
the bass notes. Now, the sole difference here is, that the
boy's organ vibrates more rapidly than the man's — it sends
a greater number of impulses per second to the ear.
In like manner, a short string emits a higher note than a
long one, because it vibrates more quickly. The greater
the number of vibrations which any instrument performs
in a given time, the higher will be the pitch of the note
produced. The reason why the hum of a gnat is shriller
than that of a beetle is that 'the wings of the small
insect vibrate more quickly than those of the larger one.
We can, with suitable arrangements, make those sonorous
vibrations visible to the eye ; * and we also possess instru-
ments which enable us to tell, with the utmost exacti-
tude, the number of vibrations due to any particular note.
By such instruments we learn that a gnat can execute
many thousand flaps of its little wings in a second of time.
In the study of nature the coarser phenomena, which
come under the cognizance of the senses, often suggest to
us the finer phenomena which come under the cognizance
of the mind ; and thus the vibrations which produce sound,
and which, as has been stated, can be rendered visible to
the eye by proper means, first suggested that light might
be due to a somewhat similar action. This is now the
universal belief. A luminous body is supposed to have its
atoms, or molecules, in a state of intense vibration. The
* The vibrations of the air of a room in which a musical instrument is
sounded may be made manifest by the way in which fine sand arranges
itself upon a thin stretched membrane over which it is strewn ; and indeed
Savart has thus rendered visible the vibrations of the tympanum itself.
Every trace of sand was swept from a paper drum held in the clock-tower
of Westminster when the Great Bell was sounded. Another way of showing
the propagation of aerial pulses is to insert a small gas jet into a vertical
glass tube about a foot in length, in which the flame may be caused to
burn tranquilly. On pitching the voice to tlie note of an open tube a
foot long, the little flame quivers, stretches itself, and responds by pro-
ducing a clear melodious note of the same pitch as that which excited
it. The flame will continue its song for hours without intermission.
NATUEE OF LIGHT. 227
motions of the atoms are supposed to be communicated to
a medium suited to their transmission, as air is to the trans-
mission of sound. This medium is called the luminiferous
ether, and the little billows excited in it speed through it
with amazing celerity, enter the pupil of the eye, pass
through the humours, and break upon the retina or optic
nerve, which is spread out at the back of the eye. Hence
the tremors they produce are transmitted along the nerve
to the brain, where they announce themselves as light. The
swiftness with which the waves of light are propagated
through the ether, is however enormously greater than
that with which the waves of sound pass through the air.
An aerial wave of sound travels at about the rate of 1100
feet in a second: a wave of light leaves 192,000 miles
behind it in the same time.
Thus, then, in the case of sound, we have the sonorous
body, the air, and the auditory nerve, concerned in the
phenomenon ; in the case of light, we have the luminous
body, the ether, and the optic nerve. The fundamental
analogy of sound and light is thus before us, and it is
easily remembered. But we must push the analogy
further. We know that the white light which comes to
us from the sun is made up of an infinite number of
coloured rays. By refraction with a prism we can separate
those rays from each other, and arrange them in the series
of colours which constitute the solar spectrum. The
rainbow is an imperfect or impure spectrum, produced by
the drops of falling rain, but by prisms we can unravel the
white light into pure red, orange, yellow, green, blue,
indigo, and violet. Now, this spectrum is to the eye what
the gamut is to the ear; each colour represents a note,
and the different colours represent notes of different pitch.
The vibrations which produce the impression of red are
slower, and the waves which they produce are longer, than
those to which we owe the sensation of violet ; while the
Q 2
228 CAUSE OF COLOUE.
vibrations which excite the other colours are intermediate
between these two extremes. This, then, is the second
grand analogy between light and sound : Colour answers to
Pitch. There is therefore truth in the figure when we say
that the gentian of the Alps sings a shriller note than the
wild rhododendron, and that the red glow of the mountains
at sunset is of a lower pitch than the blue of the firmament
at noon.
These are not fanciful analogies. To the mind of the
philosopher these waves of ether are almost as palpable
and certain as the waves of the sea, or the ripples on the
surface of a lake. The length of the waves, both of sound
and light, and the number of shocks which they respec-
tively impart to the ear and eye, have been the subjects of
the strictest measurement. Let us here go through a
simple calculation. It has been found that 39,000 waves
of red light placed end to end would make up an inch.
How many inches are there in 192,000 miles ? My
youngest reader can make the calculation for himself,
and find the answer to be 12,165,120,000 inches. It is
evident that, if we multiply this number by 39,000, we
shall obtain the number of waves of red light in 192,000
miles; this number is 474,439,680,000,000. All these
waves enter the eye in one second ; thus the expression
"I see red colour," strictly means, " My eye is now in
receipt of four hundred and seventy-four millions of
millions of impulses per second." To produce the im-
pression of violet light a still greater number of impulses
is necessary; the wave-length of violet is the 57500"^
part of an inch, and the number of shocks imparted in a
second by waves of this length is, in round numbers, six
hundred and ninety-nine millions of millions. The other
colours of the spectrum, as already stated, rise gradually
in pitch from the red to the violet.
A very curious analogy between the eye and ear may
LENGTH OF ETHEREAL WAVES. 229
here be noticed. The range of seeing is different in dif-
ferent persons — some see a longer spectrum than others ;
that is to say, rays which are obscure to some are luminous
to others. Dr. Wollaston pointed out a similar fact as regards
hearing ; the range of which differs in different individuals.
Savart has shown that a good ear can hear a musical note
produced by 8 shocks in a second ; it can also hear a note
produced by 24,000 shocks in a second ; but there are ears
in which the range is much more limited. It is possible
indeed to produce a sound which shall be painfully shrill to
one person, while it is quite unheard by another. I once
crossed a Swiss mountain in company with a friend ; a
donkey was in advance of us, and the dull tramp of the
animal was plainly heard by my companion ; but to me
this sound was almost masked by the shrill chirruping of
innumerable insects which thronged the adjacent grass ;
my friend heard nothing of this, it lay quite beyond his
range of hearing.
A third and most important analogy between sound and
light is now to be noted ; and it will be best understood •
by reference to something more tangible than either.
When a stone is thrown into calm water a series of rings
spread themselves around the centre of disturbance. If a
second stone be thrown in at some distance from the first,
the rings emanating from both centres will cross each other,
and at those points where the ridge of one wave coincides
with the ridge of another the water will be lifted to a
greater height. At those points, on the contrary, where
the ridge of one wave crosses the furrow of another, we
have both obliterated, and the water restored to its ordinary
level. Where two ridges or two" furrows unite, we have a
case of coincidence ; but where a ridge and a furrow unite
we have what is called interference. It is quite possible
to send two systems of waves into the same channel, and
to hold back one system a little, so that its ridges shall
230 LIGHT ADDED TO LIGHT MAKES DARKNESS.
coincide with the furrows of the other system. The
" interference " would be here complete, and the waves
thus circumstanced would mutually destroy each other,
smooth water being the result. In this way, by the
addition of motion to motion, rest may be produced.
In a precisely similar manner two systems of sonorous
waves can be caused to interfere and mutually to destroy
each other : thus, by adding sound to sound, silence may
be produced. Two beams of light also may be caused to
interfere and effect their mutual extinction: thus, by
adding light to light, we can produce darkness. Here
indeed we have a critical analogy between sound and
light — the one, in fact, which compels the most profound
thinkers of the present day to assume that light, like sound,
is a case of undulatory motion.
We see here the vision of the intellect prolonged
beyond the boundaries of sense into the region of what
might be considered mere imagination. But, unlike other
imaginations, we can bring ours to the test of experiment ;
indeed, so great a mastery have we obtained over these
waves, which eye has not seen, nor ear heard, that we
can with mathematical certainty cause them to coin-
cide or to interfere, to help each other or to destroy
each other, at pleasure. It is perhaps possible to be a
little more precise here. Let two stones — with a small
distance between them — be dropped into water at the
same moment ; a system of circular waves will be formed
round each stone. Let the distance from one little crest
to the next following one be called the length of the
wave, and now let us inquire what will take place at
a point equally distant from the places where the two
stones were dropped in. Fixing our attention upon the
ridge of the first wave in each case, it is manifest that,
as the water propagates both systems with the same velo-
city, the two foremost ridges will reach the point in
COINCIDENCE AND INTERFEEENCE. 231
question at the same moment ; the ridge of one would
therefore coincide with the ridge of the other, and the
water at this point would be lifted to a height greater
than that of either of the previous ridges.
Again, supposing that by any means we had it in our
power to retard one system of waves so as to cause the first
ridge of the one to be exactly one wave length behind the
first ridge of the other, when they arrive at the point
referred to. It is plain that the first ridge of the retarded
system now falls in with the second ridge of the unre-
tarded system, and we have another case of coincidence.
A little reflection will show the same to be true when one
system is retarded any number of whole wave-lengths ;
the first ridge of the retarded system will always, at the
point referred to, coincide with a ridge of the unretarded
system.
But now suppose the one system to be retarded only
half a wave-length ; it is perfectly clear that in this case
the first ridge of the retarded system would fall in with
the first furrow of the unretarded system, and instead of
coincidence we should have interference. One system, in
fact, would tend to make a hollow at the point referred to,
the other would tend to make a hill, and thus the two
systems would oppose and neutralise each other, so that
neither the hollow nor the hill would be produced ; the
water would maintain its ordinary level. What is here said
of a single half-wave-length of retardation, is also true if
the retardation amount to any odd number of half-wave-
lengths. In all such cases we should have the ridge of
the one system falling in with the furrow of the other ; a
mutual destruction of the waves of both systems being the
consequence. The same remarks apply when the point,
instead of being equally distant from both stones, is an even
or an odd number of semi-undulations farther from the
one than from the other. In the former case we should
232 LIQUID WAVES.
have coincidence, and in the latter case interference, at
the point in question.
To the eye of a person who understands these things,
nothing can be more interesting than the rippling of water
under certain circumstances. By the action of interference
its surface is sometimes shivered into the most beautiful
mosaic, shifting and trembling as if with a kind of visible
music. When the tide advances over a sea-beach on a
calm and sunny day, and its tiny ripples enter, at various
points, the clear shallow pools which the preceding tide
had left behind, the little wavelets run and climb and cross
each other, and thus form a lovely chasing, which has its
counterpart in the lines of light converged by the ripples
upon the sand underneath. When waves are skilfully
generated in a vessel of mercury, and a strong light reflected
from the surface of the metal is received upon a screen, the
most beautiful effects may be observed. The shape of the
vessel determines, in part, the character of the figures
produced ; in a circular dish of mercury, for example, a dis-
turbance at the centre propagates itself in circular waves,
which after reflection again encircle the centre. If the
point of disturbance be a little removed from the centre,
the intersections of the direct and reflected waves produce
the magnificent chasing shown in the annexed figure (16),
which I have borrowed from the excellent work on Waves
by the Messrs. Weber. The luminous figure reflected from
such a surface is exceedingly beautiful. When the mer-
cury is. lightly struck by a glass point, in a direction con-
centric with the circumference of the vessel, the lines of
light run round the vessel in mazy coils, interlacing and
unravelling themselves in the most wonderful manner. If
the vessel be square, a splendid mosaic is produced by the
crossing of the direct and reflected waves. Description,
however, can give but a feeble idea of these exquisite
effects ;—
CHASING PEODUCED BY WAVES. 233
" Thou canst not wave thy staff in the air,
Or dip thy paddle in the lake,
But it carves the brow of beauty there,
And the ripples in rhymes the oar forsake."
Now, all that we have said regarding the retardation of
the waves of water, by a whole undulation and a semi-
Fig. 16.
undulation, is perfectly applicable to the case of light.
Two luminous points may be placed near to each other
so as to resemble the two stones dropped into the water ; and
when the light of these is properly received upon a screen,
or directly upon the retina, we find that at some places the
action of the rays upon each other produces darkness, and at
others augmented light. The former places are those where
the rays emitted from one point are an odd number of semi-
undulations in advance of the rays sent from the other ;
the latter places are those where the difference of path
described by the rays is either nothing, or an even number of
234
EFFECT OF EETAEDATION.
semi-undulations. Supposing a and b (Fig. 17) to be two such
sources of light, and s R a screen on which the light falls ;
at a point Z, equally distant from a and 6, we have -light ;
at a point eZ, where a d is half an undulation longer than
b dj we have darkness ; at Z', where a I' is a whole wave-
length, or two semi-undulations, longer than b Z', we again
have light ; and at a point dr, where the difference is three
semi- undulations, we have darkness ; and thus we obtain a
Fig. 17.
series of bright and dark spaces as we recede laterally
from the central point I.
Let a bit of tin foil be closely pasted upon a piece of glass,
and the edge of a penknife drawn across the foil so as to
produce a slit. Looking through this slit at a small and
distant light, we find the light spread out in a direction at
right angles to the slit, and if the light looked at be mono-
chromatic, that is, composed of a single colour, we shall
have a series of bright and dark bars corresponding to the
points at which the rays from the different points of the
slit alternately coincide and interfere upon the retina.
• c— i c±)baoaDac:ioDDCiDacnaDcnaaq3aDDQDnc3OQaDOOC3 a
I \\X
IMTEBFEBENCE SPECTRA, PEODUCED BY DIFFBACTION.
FIG. 18.
To face p. 235.
CHEOMATIC EFFECTS. 235
By properly drawing a knife across a sheet of letter-paper
a suitable slit may also be obtained ; and those practised in
such things can obtain the effect by looking through their
fingers or their eyelashes.
But if the light looked at be white, the light of a candle
for example, or of a jet of gas, instead of having a series of
bright and dark bars, we have the bars coloured. And see
how beautifully this harmonizes with what has been already
said regarding the different lengths of the waves which
produce different colours. Looking again at Fig. 17 we see
that a certain obliquity is necessary to cause one ray to be
a whole undulation in advance of the other at the point /' ;
but it is perfectly manifest that the obliquity must depend
upon the length of the undulation ; a long undulation
would require a greater obliquity than a short one ; red
light, for example, requires a greater obliquity than blue
light ; so that if the point V represents the place where the
first bar of red light would be at its maximum strength,
the maximum for blue would lie a little to the left of I' ;
the different colours are in this way separated from each
other, and exhibit themselves as distinct fringes when a dis-
tant source of white light is regarded through a narrow slit.
By varying the shape of the aperture we alter the form
of the chromatic image. A circular aperture, for example,
placed in front of a telescope through which a point
of white light is regarded, is seen surrounded by a con-
centric system of coloured rings. If we multiply our slits
or apertures the phenomena augment in complexity and
splendour. To give some notion of this I have copied
from the excellent work of M. Schwerd the annexed figure
(Fig. 18) which represents the gorgeous effect observed
when a distant point of light is looked at through two
gratings with slits of different widths.* A bird's feather
* I am not aware whether in his own country, or in any other, a re-
cognition at all commensurate with the value of the performance has
236 COLOURS OF THIN FILMS.
represents a peculiar system of slits, and the effect observed
on properly looking through it is extremely interesting.
There are many ways by which the retardation necessary
to the production of interference is effected. The splendid
colours of a soap-bubble are entirely due to interference ;
the beam falling upon the transparent film is partially
reflected at its outer surface, but a portion of it enters
the film and is reflected at its inner surface. The latter
portion having crossed the film and returned, is retarded,
in comparison with the former, and, if the film be of
suitable thickness, these two beams will clash and extin-
guish each other, while another thickness will cause the
beams to coincide and illuminate the film with a light of
greater intensity. From what has been said it must be
manifest that to make two red beams thus coincide a
thicker film would be required than would be necessary for
two blue or green beams ; thus, when the thickness of the
bubble is suitable for the development of red, it is not
suitable for the development of green, blue, &c. ; the
consequence is that we have different Colours at different
parts of the bubble. Owing to its compactness and to
its being shaded by a covering of debris from the direct
heat of the sun, the ice underneath the moraines of
glaciers appears sometimes of a pitchy blackness. While
cutting such ice with my axe I have often been surprised
and delighted by sudden flashes of coloured light which
broke like fire from the mass. These flashes were due
to internal rupture, by which fissures were produced as
thin as the film of a soap-bubble ; the colours being due
to the interference of the light reflected from the opposite
sides of the fissures.
If spirit of turpentine, or olive oil, be thrown upon
water, it speedily spreads in a thin film over the surface,
followed Schwerd's admirable essay entitled ' The Phenomena of Dif-
fraction deduced from the Theory of Undulation.'
DIFFKACTION. 237
and the most gorgeous 'chromatic phenomena may be thus
produced. Oil of lemons is also peculiarly suited to this
experiment. If water be placed in a tea-tray, and light
of sufficient intensity be suffered to fall upon it, this light
will be reflected from the upper and under surfaces of
the film of oil, and the colours thus produced may be
received upon a screen, and seen at once by many hundred
persons. If the oil of cinnamon be used, fine colours are also
obtained, and the breaking up of this film exhibits a most
interesting case of molecular action. By using a kind of
varnish, instead of oil, Mr. Delarue has imparted such
tenacity to these films that they may be removed from
the water on which they rest and preserved for any length
of time. By such films the colours of certain beetles, and
of the wings of certain insects, may be accurately imi-
tated ; and a rook's feather may be made to shine with
magnificent iridescences. The colours of tempered metals,
and the beautiful metallochrome of Nobili are also due to
a similar cause.
These colours are called the colours of thin plates, and
are distinguished in treatises on optics from the coloured
bars and fringes above referred to, which are produced
by diffraction, or the bending of the waves round the edge
of an object. One result of this bending, which is of
interest to us, was obtained by the celebrated Thomas
Young. Permitting a beam of sunlight to enter a dark
room through an aperture made with a fine needle, and
placing in the path of the beam a bit of card one-thirtieth
of an inch wide, he found the shadow of this card, or rather
the line on which its shadow might be supposed to fall,
always bright ; and he proved the effect to be due to the
bending of the waves of ether round the two edges of the
card, and their coincidence at the other side. It has,
indeed, been shown by M. Poisson, that the centre of the
shadow of a small circular opaque disk which stands in
238 CLOUD IRIDESCENCES, ETC., EXPLAINED.
the way of a beam diverging from a point is exactly as
much illuminated as if the disk were absent. The sin-
gular effects described by M. Necker in the letter quoted
at page 178 at once suggest themselves here ; and we see
how possible it is for the solar rays, in grazing a distant
tree, so to bend round it as to produce upon the retina,
where shadow might be expected, the impression of a tree
of light.* Another effect of diffraction is especially in-
teresting to us at present. Let the seed of lycopodium
be scattered over a glass plate, or even like a cloud in
the air, and let a distant point of light be regarded through
it ; the luminous point will appear surrounded by a series
of coloured rings, and when the light is intense, like the
electric or the Drummond light, the effect is exceedingly
fine.
And now for the application of these experiments. I
have already mentioned a series of coloured rings observed
around the sun by Mr. Huxley and myself from the Rhone
glacier ; I have also referred to the cloud iridescences on
the Aletschhorn ; and to the colours observed during my
second ascent of Monte Rosa, the magnificence of which
is neither to be rendered by pigments nor described in
words. All these splendid phenomena are, I believe, pro-
duced by diffraction, the vesicles or spherules of water in the
case of the cloud acting the part of the sporules in the case of
the lycopodium. The coloured fringe which surrounds the
Spirit of the Brocken, and the spectra which I have spoken
of as surrounding the sun, are also produced by diffraction.
By the interference of their rays in the earth's atmo-
sphere the stars can momentarily quench themselves ; and
probably to an intermittent action of this kind their twink-
ling, and the swift chromatic changes already mentioned,
are due. Does not all this sound more like a fairy
* I think, however, that the strong irradiation from the glistening sides
of the twigs and branches must also contribute to the result.
EADIANT HEAT. 239
tale than the sober conclusions of science ? What effort of
the imagination could transcend the realities here pre-
sented to us ? The ancients had their spheral melodies,
but have not we ours, which only want a sense sufficiently
refined to hear them? Immensity is filled with this
music ; wherever a star sheds its light its notes are heard.
Our sun, for example, thrills concentric waves through
space, and every luminous point that gems our skies is
surrounded by a similar system. I have spoken of the
rising, climbing and crossing of the tiny ripples of a calm
tide upon a smooth strand ; but what are they to those
intersecting ripples of the " uncontinented deep " by which
Infinity is engine-turned ! Crossing solar and stellar dis-
tances, they bring us the light of sun and stars ; thrilled
back from our atmosphere, they give us the blue radiance
of the sky ; rounding liquid spherules, they clash at the
other side, and the survivors of the tumult bear to our
vision the wondrous cloud-dyes of Monte Rosa.
Thus, then, we have been led from Sound to Light, and
light now in its turn will lead us to Radiant Heat ; for
in the order in which they are here mentioned the
conviction arose that they are all three different kinds of
motion. It has been said that the beams of the sun con-
sist of rays of different colours, bub this is not a complete
statement of the case. The sun emits a multitude of rays
which are perfectly non-luminous ; and the same is true, in a
still greater degree, of our artificial sources of illumination.
Measured by the quantity of heat which they produce, 90
per cent, of the rays emanating from a flame of oil are
240 OBSCUEE KAYS.
obscure; while 99 out of every 100 of those which ema-
nate from an alcohol flame are of the same description.*
In fact, the visible solar spectrum simply embraces an
interval of rays of which the eye is formed tn take cog-
nizance, but it by no means marks the limits of solar
action. Beyond the violet end of the spectrum we have
obscure rays capable of producing chemical changes, and
beyond the red we have rays possessing a high heating
power, but incapable of exciting the impression of light.
This latter fact was first established by Sir William Her-
schel, and it has been amply corroborated since.
The belief now universally prevalent is, that the rays of
heat differ from the rays of light simply as one colour
differs from another. As the waves which produce red
are longer than those which produce yellow, so the waves
which produce this obscure heat are longer than those
which produce red. In fact, it may be shown that the
longest waves never reach the retina at all ; they are com-
pletely absorbed by the humours of the eye.
What is true of the sun's obscure rays is also true of
calorific rays emanating from any obscure source, — from
our own bodies, for example, or from the surface of a
vessel containing boiling water. We must, in fact, figure
a warm body also as having its particles in a state of vibra-
tion. When these motions are communicated from particle
to particle of the body the heat is said to be conducted ;
when, on the contrary, the particles transmit their vibra-
tions through the surrounding ether, the heat is said to
be radiant. This radiant heat, though obscure, exhibits a
deportment exactly similar to light. It may be refracted
and reflected, and collected in the focus of a mirror or of a
suitable lens. The principle of interference also applies
to it, so that by adding heat to heat we can produce cold.
The identity indeed is complete throughout, and, recurring
* Melloni.
HEAT A KIND OF MOTION. 241
to the analogy of sound, we might define this radiant heat
to be light of too low a pitch to be visible.
I have thus far spoken of obscure heat only ; but the
selfsame ray may excite both light and heat. The red rays
of the spectrum possess a very high heating power. It was
once supposed that the heat of the spectrum was an
essence totally distinct from its light ; but a profounder
knowledge dispels this supposition, and leads us to infer
that the selfsame ray, falling upon the nerves of feeling,
excites heat, and falling upon the nerves of seeing, excites
light. As the same electric current, if sent round a mag-
netic needle, along a wire, and across a conducting liquid,
produces different physical effects, so also the same agent
acting upon different organs of the body affects our con-
sciousness differently.
(3.)
Heat has been defined in the foregoing section as a
motion of the molecules or atoms of a body ; but though
the evidence in favour of this view is at present over-
whelming, I do not ask the reader to accept it as a cer-
tainty, if he feels sceptically disposed. In this case, I would
only ask him to accept it as a symbol. Regarded as a mere
physical image, a kind of paper-currency of the mind,
convertible, in due time, into the gold of truth, the hypo-
thesis will be found exceedingly useful.
All known bodies possess more or less of this molecular
motion, and all bodies are communicating it to the ether
in which they are immersed. Ice possesses it. Ice before
it melts attains a temperature of 32° Fahr., but the sub-
stance in winter often possesses a temperature far below
32°, so that in rising to 32° it is luarmed. In experimenting
R
242 QUALITIES OF HEAT.
with ice I have often had occasion to cool it to 100° and
more below the freezing point, and to warm it afterwards
up to 32°.
If then we stand before a wall of ice, the wall radiates
heat to us, and we also radiate heat to it ; but the quan-
tity which we radiate being greater than that which the
ice radiates, we lose more than we gain, and are conse-
quently chilled. If, on the contrary, we stand before a
warm stove, a system of exchanges also takes place ; but
here the quantity we. receive is in excess of the quantity
lost, and we are warmed by the difference.
In like manner the earth radiates heat by day and by
night into space, and against the sun, moon, and stars.
By day, however, the quantity received is greater than
the quantity lost, and the earth is warmed ; by night the
conditions are reversed ; the earth radiates more heat
than is sent to her by the moon and stars, and she is con-
sequently cooled.
But here an important point is to be noted : — the earth
receives the heat of the sun, moon, and stars, in great part
as luminous heat, but she gives it out as obscure heat. I do
not now speak of the heat reflected by the earth into
space, as the light of the moon is to us ; but of the heat
which, after it has been absorbed by the earth, and has con-
tributed to warm it, is radiated into space, as if the earth
itself were its independent source. Thus we may properly
say that the heat radiated from the earth is different in
quality from that which the earth has received from the sun.
In one particular especially does this difference of qua-
lity show itself; besides being non-luminous, the heat
radiated from the earth is more easily intercepted anc
absorbed by almost all transparent substances. A
portion of the sun's rays, for example, can pass instan-
taneously through a thick sheet of water; gunpowdei
could easily be fired by the heat of the sun's rays cop-
THE ATMOSPHEKE LIKE A RATCHET. 243
verged by passing through a thick water lens ; the drops
upon leaves in greenhouses often act as lenses, and cause
the sun to burn the leaves upon which they rest. But
with regard to the rays of heat emanating from an ob-
scure source, they are all absorbed by a layer of water
less than the 20th of an inch in thickness : water is
opaque to such rays, and cuts them off almost as effectually
as a metallic screen. The same is true of other liquids,
and also of many transparent solids.
Assuming the same to be true of gaseous bodies, that
they also intercept the obscure rays much more readily
than the luminous ones, it would follow that while the
sun's rays penetrate our atmosphere with freedom, the
change which they undergo in warming the earth deprives
them in a measure of this penetrating power. They can
reach the earth, but they cannot get lack ; thus the atmo-
sphere acts the part of a ratchet-wheel in mechanics ; it
allows of motion in one direction, but prevents it in the
other.
De Saussure, Fourier, M. Pouillet, and Mr. Hopkins have
developed this speculation, and drawn from it consequences
of the utmost importance ; bat it nevertheless rested
upon a basis of conjecture. Indeed some of the eminent
men above-named deemed its truth beyond the possibility
of experimental verification. Melloni showed that for a dis-
tance of 18 or 20 feet the absorption of obscure rays by
the atmosphere was absolutely inappreciable. Hence, the
total absorption being so small as to elude even Melloni's
delicate tests, it was reasonable to infer that differences of
absorption, if such existed at all, must be far beyond the
reach of the finest means which we could apply to detect
them.
This exclusion of one of the three states of material
aggregation from the region of experiment was, however,
by no means satisfactory ; for our right to infer, from the
244 DIFFEEENCES OF ABSORPTION BY GASES.
deportment of a solid or a liquid towards radiant heat, the
deportment of a gas, is by no means evident. In both
liquids and solids we have the molecules closely packed,
and more or less chained by the force of cohesion ; in
gases, on the contrary, they are perfectly free, and widely
separated. How do we know that the interception of
radiant heat by liquids and solids may not be due to
an arrangement and comparative rigidity of their parts,
which gases do not at all share ? The assumption which
took no note of such a possibility seemed very insecure,
and called for verification.
My interest in this question was augmented by the
fact, that the assumption referred to lies, as will be seen, at
the root of the glacier question. I therefore endeavoured
to fill the gap, and to do for gases and vapours what had
been already so ably done for liquids and solids by Mel-
loni. I tried the methods heretofore pursued, and found
them unavailing ; oxygen, hydrogen, nitrogen, and atmo-
spheric air, examined by such methods, showed no action
upon radiant heat. Nature was dumb, but the question
occurred, " Had she been addressed in the proper lan-
guage ? " If the experimentalist is convinced of this, he
will rest content even with a negative ; but the absence
of this conviction is always a source of discomfort, and a
stimulus to try again.
The principle of the method finally applied is all that
can here be referred to; and it, I hope, will be quite
intelligible. Two beams of heat, from two distinct sources,
were allowed to fall upon the same instrument,* and to
contend there for mastery. When both beams were per-
fectly equal, they completely neutralized each other's
action ; but when one of them was in any sensible degree
stronger than the other, the predominance of the former
was shown by the instrument. It was so arranged that
* The opposite faces of a thermo-electric pile.
SELECTED HEAT. 245
one of the conflicting beams passed through a tube which
could be exhausted of air, or filled with any gas; thus
varying at pleasure the medium through which it passed.
The question then was, supposing the two beams to be
equal when the tube was filled with air, will the ex-
hausting of the tube disturb the equality ? The answer
was affirmative; the instrument at once showed that a
greater quantity of heat passed through the vacuum than
through the air.
The experiment was so arranged that the effect thus
produced was very large as measured by the indications of
the instrument. But the action of the simple gases, oxygen,
hydrogen, and nitrogen, was incomparably less than that
produced by some of the compound gases, while these
latter again differed widely from each other. Vapours ex-
hibited differences of equal magnitude. The experiments
indeed proved that gaseous bodies varied among them-
selves, as to their power of transmitting radiant heat, just
as much as liquids and solids. It was in the highest degree
interesting to observe how a gas or vapour of perfect trans-
parency, as regards light, acted like an opaque screen upon
the heat. To the eye, the gas within the tube might be
as invisible as the air itself, while to the radiant heat it
behaved like a cloud which it was almost impossible to
penetrate.
Applying the same method, I have found that from the
sun, from the electric light, or from the lime-light, a
large amount of heat can be selected, which is un-
affected not only by air, but by the most energetic gases
that experiment has revealed to me; while this same
heat, when it has its quality changed by being rendered
, obscure, is powerfully intercepted. Thus the bold and
beautiful speculation above referred to has been made an
experimental fact ; the radiant heat of the sun does cer-
tainly pass through the atmosphere to the earth with
246 POSSIBLE HEAT OF NEPTUNE,
greater facility than the radiant heat of the earth can
escape into space.
It is probable that, were the earth unfurnished with this
atmospheric swathing, its conditions of temperature would
be such as to render it uninhabitable by man ; and it is
also probable that a suitable atmosphere enveloping the
most distant planet might render it, as regards tempera-
ture, perfectly habitable. ' If the planet Neptune, for
example, be surrounded by an atmosphere which permits
the solar and stellar rays to pass towards the planet, but
cuts off the escape of the warmth which they excite, it is
easy to see that such an accumulation of heat may at
length take place as to render the planet a comfortable
habitation for beings constituted like ourselves.*
But let us not wander too far from our own concerns.
Where radiant heat is allowed to fall upon an absorbing
substance, a certain thickness of the latter is always
necessary for the absorption. Supposing we place a thin
film of glass before a source of heat, a certain percentage of
the heat will pass through the glass, and the remainder
will be absorbed. Let the transmitted portion fall upon a
second film similar to the first, a smaller percentage than
before will be absorbed. A third plate would absorb still
less, a fourth still less ; and, after having passed through a
sufficient number of layers, the heat would be so sifted that
all the rays capable of being absorbed by glass would be
abstracted from it. Suppose all these films to be placed
together so as to form a single thick plate of glass, it is
evident that the plate must act upon the heat which
falls upon it, in such a manner that the major portion is
absorbed near the surface at which the heat enters. This
has been completely verified by experiment.
Applying this to the heat radiated from the earth, it is
* See a most interesting paper on this subject by Mr. Hopkins in the
Cambridge ' Transactions,' May, 1856.
COLD OF UPPER ATMOSPHERE. 247
manifest that the greatest quantity of this heat will be
absorbed by the lowest atmospheric strata. And here we
find ourselves brought, by considerations apparently re-
mote, face to face with the fact upon which the existence
of all glaciers depends, namely, the comparative coldness
of the upper regions of the atmosphere. The sun's rays
can pass in a great measure through these regions without
heating them; and the earth's rays, which they might
absorb, hardly reach them at all, but are intercepted by
the lower portions of the atmosphere.*
Another cause of the greater coldness of the higher
atmosphere is the expansion of the denser air of the lower
strata when it ascends. The dense air makes room for
itself by pushing back the lighter and less elastic air which
surrounds it : it does work, and, to perform this work, a
certain amount of heat must be consumed. It is the con-
sumption of this heat — its absolute annihilation as heat —
that chills the expanded air, and to this action a share of
the coldness of the higher atmosphere must undoubtedly
be ascribed. A third cause of the difference of tempera-
ture is the large amount of heat communicated, by way
of contact, to the air of the earth's surface ; and a fourth
and final cause is the loss endured by the highest strata
through radiation into space.
* See M. Pouillet's important Memoir on Solar Radiation. Taylor's
Scientific Memoirs, vol. iv. p. 44.
248 THE SNOW-LINE.
ORIGIN OF GLACIERS.
(4)
HAVING thus accounted for the greater cold of the
higher atmospheric regions, its consequences are next to
be considered. One of these is, that clouds formed in
the lower portions of the atmosphere, in warm and tem-
perate latitudes, usually discharge themselves upon the
earth as rain ; while those formed in the higher regions
discharge themselves upon the mountains as snow. The
snow of the higher atmosphere is often melted to rain in
passing through the warmer lower strata : nothing indeed is
more common than to pass, in descending a mountain,
from snow to rain ; and I have already referred to a case
of this kind. The appearance of the grassy and pine-
clad alps, as seen from the valleys after a wet night, is
often strikingly beautiful; the level at which the snow
turned to rain being distinctly marked upon the slopes.
Above this level the mountains are white, while below it
they are green. The eye follows this snow-line with ease
along the mountains, and when a sufficient extent of
country is commanded its regularity is surprising.
The term " snow-line," however, which has been here
applied to a local and temporary phenomenon, is commonly
understood to mean something else. In the case just
referred to it marked the place where the supply of solid
matter from the upper atmospheric regions, during a
single fall, was exactly equal to its consumption; but
the term is usually understood to mean the line along
which the quantity of snow which falls annually is melted,
and no more. Below this line each year's snow is com-
MOUNTAINS UNLOADED BY GLACIERS. 249
pletely cleared away by the summer heat ; above it a
residual layer abides, which gradually augments in thick-
ness from the snow-line upwards.
Here then we have a fresh layer laid on every year ;
and it is evident that, if this process continued without
interruption, every mountain which rises above the
snow-line must augment annually in height ; the waters
of the sea thus piled, in a solid form, upon the summits
of the hills, would raise the latter to an indefinite
elevation. But, as might be expected, the snow upon steep
mountain-sides frequently slips and rolls down in avalanches
into warmer regions, where it is reduced to water. A
comparatively small quantity of the snow is, however, thus
got rid of, and the great agent which Nature employs
to relieve her overladen mountains is the glaciers.
Let us here avoid an error which may readily arise out
of the foregoing reflections. The principal region of clouds
and rain and snow extends only to a limited distance
upwards in the atmosphere ; the highest regions contain
very little moisture, and were our mountains sufficiently
lofty to penetrate those regions, the quantity of snow
falling upon their summits would be too trifling to resist
the direct action of the solar rays. These would annually
clear the summits to a certain level, and hence, were
our mountains high enough, we should have a superior,
as well as an inferior, snow-line ; the region of perpetual
snow would form a belt, below which, in summer, snowless
valleys and plains would extend, and above which snowless
summits would rise.
(5.)
At its origin then a glacier is snow — at its lower ex-
tremity it is ice. The blue blocks that arch the source of
250 WHITE AND BLUE ICE.
the Arveiron were once powdery snow upon the slopes of the
Col du Geant. Could our vision penetrate into the body
of the glacier, we should find that the change from white
to blue essentially consists in the gradual expulsion of the
air which was originally entangled in the meshes of the
fallen snow. Whiteness always results from the intimate
and irregular mixture of air and a transparent solid ; a
crushed diamond would resemble snow ; if we pound
the most transparent rock-salt into powder we have a
substance as white as the whitest culinary salt ; and the
colourless glass vessel which holds the salt would also, if
pounded, give a powder as white as the salt itself. It is a
law of light that in passing from one substance to another
possessing a different power of refraction, a portion of it is
always reflected. Hence when light falls upon a transparent
solid mixed with air, at each passage of the light from the air
to the solid and from the solid to the air a portion of it is
reflected ; and, in the case of a powder, this reflection
occurs so frequently that the passage of the light is prac-
tically cut off. Thus, from the mixture of two perfectly
transparent substances, we obtain an opaque one ; from the
intimate mixture of air and water we obtain foam ; clouds
owe their opacity to the same principle ; and the condensed
steam of a locomotive casts a shadow upon the fields
adjacent to the line, because the sunlight is wasted in
echoes at the innumerable limiting surfaces of water and
air.
The snow which falls upon high mountain-eminences
has often a temperature far below the freezing point
of water. Such snow is dry, and if it always con-
tinued so the formation of a glacier from it would be
impossible. The first action of the summer's sun is to
raise the temperature of the superficial snow to 32°, and
afterwards to melt it. The water thus formed percolates
through the colder mass underneath, and this I take to be
AIK-BUBBLES IN ICE. 251
the first active agency in expelling the air entangled in
the snow. But as the liquid trickles over the surfaces of
granules colder than itself it is partially deposited in a
solid form on these surfaces, thus augmenting the size of
the granules, and cementing them together. When the
mass thus formed is examined, the air within it is found as
round bubbles. Now it is manifest that the air caught in the
irregular interstices of the snow can have no tendency to
assume this form so long as the snow remains solid ;
but the process to which I have referred — the saturation
of the lower portions of the snow by the water produced
by the melting of the superficial portions — enables the
air to form itself into globules, and to give the ice of
the neve its peculiar character. Thus we see that, though
the sun cannot get directly at the deeper portions of the
snow, by liquefying the upper layer he charges it with
heat, and makes it his messenger to the cold subjacent
mass.
The frost of the succeeding winter may, I think, or may
not, according to circumstances, penetrate through this
layer, and solidify the water which it still retains in its
interstices. If the winter set in with clear frosty wea-
ther, the penetration will probably take place ; but if
heavy snow occur at the commencement of winter, thus
throwing a protective covering over the neve, freezing to
any great depth may be prevented. Mr. Huxley's idea
seems to be quite within the range of possibility, that
water-cells may be transmitted from the origin of the
glacier to its end, retaining their contents always liquid.
It was formerly supposed, and is perhaps still supposed
by many, that the snow of the mountains is converted into
the ice of the glacier by the process of saturation and
freezing just indicated. But the frozen layer would not yet
resemble glacier ice ; it is only at the deeper portions of
the neve that we find an approximation to the true ice of
252 SNOW PKESSED TO ICE.
the glacier. This brings us to the second great agent in
the process of glacification, namely, pressure. The ice of the
neve at 32° may be squeezed or crushed with extreme fa-
cility ; and if the force be applied slowly and with caution,
the yielding of the mass may be made to resemble the
yielding of a plastic body. In the depths of the neve,
where each portion of the ice is surrounded by a resistant
mass, rude crushing is of course out of the question.
The layers underneath yield with extreme slowness to
the pressure of the mass above them ; they are squeezed,
but not rudely fractured ; and even should rude fracture
occur, the ice, as shall subsequently be shown, possesses
the power of restoring its own continuity. Thus, then,
the lower portions of the neve are removed by pressure
more and more from the condition of snow, the air-bubbles
which give to the neve-icQ its whiteness are more and
more expelled, and this process, continued throughout the
entire glacier, finally brings the ice to that state of mag-
nificent transparency which we find at the termination
of the glacier of Eosenlaui and elsewhere. This is all
capable of experimental proof. The Messrs. Schlagint-
weit compressed the snow of the neve to compact ice ; and
I have myself frequently obtained slabs of ice from snow
in London.
LONG WAVES MOST ABSORBED. 253
COLOUR OF WATER AND ICE.
(6.)
THE sun is continually sending forth waves of different
lengths, all of which travel with the same velocity through
the ether. When these waves enter a prism of glass they
are retarded, but in different degrees. The shorter waves
suffer the greatest retardation, and in consequence of this
are most deflected from their straight course. It is this
property which enables us to separate one from the other
in the solar spectrum, and this separation proves that the
waves are by no means inextricably entangled with each
other, but that they travel independently through space.
In consequence of this independence, the same body
may intercept one system of waves while it allows another
to pass : on this quality, indeed, depend all the phenomena
of colour. A red glass, for example, is red because it
is so constituted that it destroys the shorter waves which
produce the other colours, and transmits only the waves
which produce red. I may remark, however, that scarcely
any glass is of a pure colour ; along with the predominant
waves, some of the other waves are permitted to pass.
The colours of flowers are also very impure ; in fact, to
get pure colours we must resort to a delicate prismatic
analysis of white light.
It has already been stated that a layer of water less than
the twentieth of an inch in thickness suffices to stop and
destroy all waves of radiant heat emanating from an obscure
source. The longer waves of the obscure heat cannot get
through water, and I find that all transparent com-
pounds which contain hydrogen are peculiarly hostile
to the longer undulations. It is, I think, the presence of
254 FINAL COLOUR OF ICE AND WATER BLUE.
this element in the humours of the eye which prevents the
extra red rays of the solar spectrum from reaching the
retina. It is interesting to observe that while bisulphide
of carbon, chloride of phosphorus, and other liquids which
contain no hydrogen, permit a large portion of the rays
emanating from an iron or copper ball, at a heat below
redness, to pass through them with facility, the same
thickness of substances equally transparent, but which con-
tain hydrogen, such as ether, alcohol, water, or the vitreous
humour of the eye of an ox, completely intercepts these
obscure rays. The same is true of solid bodies ; a very
slight thickness of those which contain hydrogen offers an
impassable barrier to all rays emanating from a non-
luminous source.* But the heat thus intercepted is by no
means lost ; its radiant form merely is destroyed. Its waves
are shivered upon the particles of the body, but they
impart warmth to it, while the heat which retains its
radiant form contributes in no way to the warmth of the
body through which it passes.
Water then absorbs all the extra red rays of the sun,
and if the layer be thick enough it invades the red rays
themselves. Thus the greater the distance the solar beams
travel through pure water the more are they deprived
of those components which lie at the red end of the
spectrum. The consequence is, that the light finally
transmitted by the water, and which gives to it its colour,
is blue.
I find the following mode of examining the colour of
water both satisfactory and convenient : — A tin tube,
fifteen feet long and three inches in diameter, has its two
ends stopped securely by pieces of colourless plate glass. It
* What is here stated regarding hydrogen is true of all the liquids and
solids which have hitherto been examined,— but whether any exceptions
occur, future experience must determine. It is only when in combination
that it exhibits this impermeability to the obscure rays.
EXPEKIMENT. 255
is placed in a horizontal position, and pure water is poured
into it through a small lateral pipe, until the liquid reaches
half way up the glasses at the ends ; the tube then holds
a semi-cylinder of water and a semi-cylinder of air. A
white plate, or a sheet of white paper, well illuminated, is
then placed at a little distance from one end of the tube,
and is looked at through the tube. Two semicircular
spaces are then seen, one by the light which has passed
through the air, the other by the light which has passed
through the water ; and their proximity furnishes a means of
comparison, which is absolutely necessary in experiments
of this kind. It is always found that, while the former
semicircle remains white, the latter one is vividly coloured.*
When the beam from an electric lamp is sent through this
tube, and a convex lens is placed at a suitable distance from
its most distant end, a magnified image of the coloured
and uncoloured semicircles may be projected upon a
screen. Tested thus, I have sometimes found, after rain,
the ordinary pipe-water of the Royal Institution quite
opaque ; while, under other circumstances, I have found
the water of a clear green. The pump- water of the Insti-
tution thus examined exhibits a rich sherry colour, while
distilled water is blue-green.
The blueness of the Grotto of Capri is due to the fact
that the light which enters it has previously traversed a
great depth of clear water. According to Bunsen's account,
the laugs, or cisterns of hot water, in Iceland must be
extremely beautiful. The water contains silica in solution,
which, as the walls of the cistern arose, was deposited
upon them in fantastic incrustations. These, though white,
when looked at through the water appear of a lovely blue,
which deepens in tint as the vision plunges deeper into the
liquid.
* In my own experiments I have never yet been able to obtain a pure
blue, the nearest approach to it being a blue-green.
256 ICE OPAQUE TO EADIANT HEAT.
Ice is a crystal formed from this blue liquid, the
colour of which it retains. Ice is the most opaque of
transparent solids to radiant heat, as water is the most
opaque of liquids. According to Melloni, a plate of ice one
twenty-fifth of an inch thick, which permits the rays of
light to pass without sensible absorption, cuts off 94 per
cent, of the rays of heat issuing from a powerful oil lamp,
99J per cent, of the rays issuing from incandescent pla-
tinum, and the whole of the rays issuing from an obscure
source. The above numbers indicate how large a portion
of the rays emitted by our artificial sources of light is
obscure.
When the rays of light pass through a sufficient thickness
of ice the longer waves are, as in the case of water, more and
more absorbed, and the final colour of the substance is there-
fore blue. But when the ice is filled with minute air-bubbles,
though we should loosely call it white, it may exhibit, even
in small pieces, a delicate blue tint. This, I think, is
due to the frequent interior reflection which takes place
at the surfaces of the air-cells ; so that the light which
reaches the eye from the interior may, in consequence of
its having been reflected hither and thither, really have
passed through a considerable thickness of ice. The same
remark, as we have already seen, applies to the delicate
colour of newly fallen snow.
NEWTON'S HYPOTHESIS. 257
COLOURS OF THE SKY.
IN treating of the Colours of Thin Plates we found that a
certain thickness was necessary to produce blue, while
a greater thickness was necessary for red. With that
wonderful power of generalization which belonged to him,
Newton thus applies this apparently remote fact to the
blue of the sky : — " The blue of the first order, though
very faint and little, may possibly be the colour of some
substances, and particularly the azure colour of the skies
seems to be of this order. For all vapours, when they
begin to condense and coalesce into small parcels, become
first of that bigness whereby such an azure is reflected,
before they can constitute clouds of other colours. And
so, this being the first colour which vapours begin to
reflect, it ought to be the colour of the finest and rnosfc
transparent skies, in which vapours are not arrived at that
grossness requisite to reflect other colours, as we find it is
by experience."
M. Clausius has written a most interesting paper,
which he endeavours to show that the minute particles of
water which are supposed by Newton to reflect the light,
cannot be little globes entirely composed of water, but
bladders or hollow spheres ; the vapour must be in what
is generally termed the vesicular state. He was followed
by M. Briicke, whose experiments prove that the sus-
pended particles may be so small that the reasoning of
M. Clausius may not apply to them.
But why need we assume the existence of such particles
at all ? — why not assume that the colour of the air is blue,
and renders the light of the sun blue, after the fashion of a
s
258 GOETHE'S HYPOTHESIS.
blue glass or a solution of the sulphate of copper ? I have
already referred to the great variation which the colour
of the firmament undergoes in the Alps, and have re-
marked that this seems to indicate that the blue depends
upon some variable constituent of the atmosphere. Fur-
ther, we find that the blue light of the sky is reflected
light ; and there must be something in the atmosphere
capable of producing this reflection ; but this thing, what-
ever it is, produces another effect which the blue glass or
liquid is unable to produce. These transmit blue light,
whereas, when the solar beams have traversed a great
length of air, as in the morning or the evening, they are
yellow, or orange, or even blood-red, according to the
state of the atmosphere : — the transmitted light and the
reflected light of the atmosphere are then totally different
in colour.
Goethe, in his celebrated ' Farbenlehre,' gives a theory
of the colour of the sky, and has illustrated it by a series
of striking facts. He assumed two principles in the uni-
verse— Light and Darkness — and an intermediate stage of
Turbidity. When the darkness is seen through a turbid
medium on which the light falls, the medium appears
blue ; when the light itself is viewed through such a
medium, it is yellow, or orange, or ruby-red. This he
applies to the atmosphere, which sends us blue light, or
red, according as the darkness of infinite space, or the
bright surface of the sun, is regarded through it.
As a theory of colours Goethe's work is of no value, but
the facts which he has brought forward in illustration of the
action of turbid media are in the highest degree interest-
ing. He refers to the blueness of distant mountains, of
smoke, of the lower part of the flame of a candle (which if
looked at with a white surface behind it completely dis-
appears), of soapy water, and of the precipitates of various
resins in water. One of his anecdotes in connexion with
SUSPENDED PARTICLES. 259
this subject is extremely curious and instructive. The
portrait of a very dignified theologian having suffered
from dirt, it was given to a painter to be cleaned. The
clergyman was drawn in a dress of black velvet, over
which the painter, in the first place, passed his sponge. To
his astonishment the black velvet changed to the colour of
blue plush, and completely altered the aspect of its
wearer. Goethe was informed of the fact; the experi-
ment was repeated in his presence, and he at once solved
it by reference to his theory. The varnish of the picture
when mixed with the water formed a turbid medium, and
the black coat seen through it appeared blue ; when the
water evaporated the coat resumed its original aspect.
With regard to the real explanation of these effects, it
may be shown, that, if a beam of white light be sent
through a liquid which contains extremely minute parti-
cles in a state of suspension, the short waves are more
copiously reflected by such particles than the long ones ;
blue, for example, is more copiously reflected than red.
This may be shown by various fine precipitates, but the
best is that of Briicke. We know that mastic and various
resins are soluble in alcohol, and are precipitated when
the solution is poured into water : Eau de Cologne, for ex-
ample, produces a white precipitate when poured into
water. If however this precipitate be sufficiently diluted,
it gives the liquid a bluish colour by reflected light.
Even when the precipitate is very thick and gross, and
floats upon the liquid like a kind of curd, its under por-
tions often exhibit a fine blue. To obtain particles of a
proper size, Briicke recommends 1 gramme of colourless
mastic to be dissolved in 87 grammes of alcohol, and
dropped into a beaker of water, which is kept in a state
of agitation. In this way a blue resembling that of the
firmament may be produced. It is best seen when a black
cloth is placed behind the glass ; but in certain positions
s 2
260 THE SUN THROUGH LONDON SMOKE.
this blue liquid appears yellow ; and these are the positions
when the transmitted light reaches the eye. It is evident
that this change of colour must necessarily exist ; for the
blue being partially withdrawn by more copious reflec-
tion, the transmitted light must partake more or less of
the character of the complementary colour ; though it does
not follow that they should be exactly complementary to
each other.
When a long tube is filled with clear water, the colour
of the liquid, as before stated, shows itself by transmitted
light. The effect is very interesting when a solution of
mastic is permitted to drop into such a tube, and the fine
precipitate to diffuse itself in the water. The blue-green
of the liquid is first neutralized, and a yellow colour
shows itself; on adding more of the solution the colour
passes from yellow to orange, and from orange to blood-
red. With a cell an inch and a half in width, containing
water, into which the solution of mastic is suffered to drop,
the same effect may be obtained. If the light of an
electric lamp be caused to form a clear sunlike disk upon
a white screen, the gradual change of this light by aug-
mented precipitation into deep glowing red, resembling
the colour of the sun when seen through fine London
smoke, is exceedingly striking. Indeed the smoke acts, in
some measure, the part of our finely-suspended matter.
By such means it is possible to imitate the phenomena
of the firmament ; we can produce its pure blue, and cause
it to vary as in nature. The milkiness which steals over
the heavens, and enables us to distinguish one cloudless
day from another, can be produced with the greatest ease.
The yellow, orange, and red light of the morning and
evening can also be obtained : indeed the effects are so
strikingly alike as to suggest a common origin — that the
colours of the sky are due to minute particles diffused
through the atmosphere. These particles are doubtless
MORNING AND EVENING RED. 261
the condensed vapour of water, and its variation in quality
and amount enables us to understand the variability of the
firmamental blue, and of the morning and the evening red.
Professor Forbes, moreover, has made the interesting ob-
servation that the steam of a locomotive, at a certain stage
of its condensation, is blue or red according as it is viewed
by reflected or transmitted light.
These considerations enable us to account for a number
of facts of common occurrence. Thin milk, when poured
upon a black surface, appears bluish. The milk is colour-
less ; that is, its blueness is not due to absorption, but to a
separation of the light by the particles suspended in the
liquid. The juices of various plants owe their blueness to
the same cause ; but perhaps the most curious illustration
is that presented by a blue eye. Here we have no true
colouring matter, no proper absorption ; but we look
through a muddy medium at the black chproid coat within
the eye, and the medium appears blue.*
Is it not probable that this action of finely-divided
matter may have some influence on the colour of some of
the Swiss lakes — as that of Geneva for example ? This
lake is simply an expansion of the river Rhone, which
rushes from the end of the Rhone glacier, as the Arveiron
does from the end of the Mer de Glace. Numerous other
streams join the Rhone right and left during its down-
ward course ; and these feeders, being almost wholly de-
rived from glaciers, join the Rhone charged with the
finer matter which these in their motion have ground
from the rocks over which they have passed. But the
glaciers must grind the mass beneath them to particles
of all sizes, and I cannot help thinking that the finest of
them must remain suspended in the lake throughout its
entire length. Faraday has shown that a precipitate of
gold may require months to sink to the bottom of a
* Helmholtz, ' Das Sehen des Menschen.'
262 COLOUR OF SWISS LAKES.
bottle not more than five inches high, and in all probability
it would require ages of calm subsidence to bring all
the particles which the Lake of Geneva contains to its
bottom. It seems certainly worthy of examination whether
such particles suspended in the water contribute to the
production of that magnificent blue which has excited
the admiration of all who have seen it under favourable
circumstances.
LATERAL MORAINES. 263
THE MORAINES.
' (8.)
THE surface of the glacier does not long retain the shining
whiteness of the snow from which it is derived. It is
flanked by mountains which are washed by rain, dislocated ^
by frost, riven by lightning, traversed by avalanches, and
swept by storms. The lighter de*bris is scattered by the
winds far and wide over the glacier, sullying the purity of
its surface. Loose shingle rattles at intervals down the
sides of the mountains, and falls upon the ice where it
touches the rocks. Large rocks are continually let loose,
which come jumping from ledge to ledge, the cohesion of
some being proof against the shocks which they experience ;
while others, when they hit the rocks, burst like bomb-
shells, and shower their fragments upon the ice.
Thus the glacier is incessantly loaded along its borders
with the ruins of the mountains which limit it ; and it is
evident that the quantity of rock and rubbish thus cast
upon the glacier depends upon the character of the ad-
jacent mountains. Where the summits are bare and
friable, we may expect copious showers ; where they are
resistant, and particularly where they are protected by a
covering of ice and snow, the quantity will be small. As
the glacier moves downward, it carries with it the load
deposited upon it. Long ridges of debris thus flank the
glacier, and these ridges are called lateral moraines.
Where two tributary glaciers join to form a trunk-glacier,
their adjacent lateral moraines are laid side by side
at the place of confluence, thus constituting a ridge
which runs along the middle of the trunk-glacier, and
264 MEDIAL AND TERMINAL MORAINES.
which is called a medial moraine. The rocks and debris
carried down by the glacier are finally deposited at its
lower extremity, forming there a terminal moraine.
It need hardly be stated that the number of medial
moraines is only limited by the number of branch glaciers.
If a glacier have but two branches, it will have only one
medial moraine ; if it have three branches, it will have two
medial moraines ; if n branches, it will have n — 1 medial
moraines. The number of medial moraines, in short, is
always one less than the number of branches. A glance at
the annexed figure will reveal the manner in which the
lateral moraines of the Mer de Glace unite to form medial
ones. (See Fig. 19.)
When a glacier diminishes in size it leaves its lateral
moraines stranded on the flanks of the valleys. Successive
shrinkings may thus occur, and have occurred at intervals
of centuries ; and a succession of old lateral moraines, such
as many glacier-valleys exhibit, is the consequence. The
Mer de Glace, for example, has its old lateral moraines,
which run parallel with its present ones. The glacier may
also dimmish in length at distant intervals ; the result being
a succession of more .or less concentric terminal moraines.
In front of the Rhone-glacier we have six or seven such
moraines, and the Mer de Glace also possesses a series of
them.
Let us now consider the effect produced by a block of
stone upon the surface of a glacier. The ice around it
receives the direct rays of the sun, and is acted on by the
warm air ; it is therefore constantly melting. The stone
also receives the solar beams, is warmed, and transmits
its heat, by conduction, to the ice beneath it. If the heat
thus transmitted to the ice through the stone be less than
an equal space of the surrounding ice receives, it is
manifest that the ice around the stone will waste more
quickly than that beneath it, and the consequence is, that,
MORAINES OF THE MER DE GLACE.
FIG. 19.
To face p. 264 .
GLACIER TABLES ACCOUNTED FOE, 265
as the surface sinks, it leaves behind it a pillar of ice, on
which the block is elevated. If the stone be wide and flat,
it may rise to a considerable height, and in this position it
constitutes what is called a glacier-table. (See Fig. 6.)
Almost all glaciers present examples of such tables ; but
no glacier with which I am acquainted exhibits them in
greater number and perfection than the Unteraar glacier,
near the Grimsel. Vast masses of granite are thus poised
aloft on icy pedestals ; but a limit is placed to their exalta-
tion by the following circumstance. The sun plays
obliquely upon the table all day ; its southern extremity
receives more heat than its northern, and the conse-
quence is, that it dips towards the south. Strictly
speaking, the plane of the dip rotates a little during
the day, being a little inclined towards the east in the
morning, north and south a little after noon, and in-
clined towards the west in the evening ; so that, theore-
tically speaking, the block is a sun-dial, showing by
its position the hour of the day. This rotation is,
however, too small to be sensible, and hence the dip of the
stones upon a glacier sufficiently exposed to the sunlight,
enables us at any time to draw the meridian line along its
surface. The inclination finally becomes so great that the
block slips off its pedestal, and begins to form another,
while the one which it originally occupied speedily dis-
appears, under the influence of sun and air. Fig. 20 repre-
sents a typical section of a glacier-table, the sun's rays
being supposed to fall in the direction of the shading lines.
Stones of a certain size are always lifted in the way
described. A considerable portion of the heat which a
large block receives is wasted by radiation, and by com-
munication to the air, so that the quantity which reaches
the ice beneath is trifling. Such a mass is, of course, a
protector of the ice beneath it. But if the stone be small,
and dark in colour, it absorbs the heat with avidity, com-
266
TYPE "TABLE."
municates it quickly to the ice with which it is in contact,
and consequently sinks in the ice. This is also the case
with bits of dirt and the finer fragments of debris ; they sink
in the glacier. Sometimes, however, a pretty thick layer
Fig. 20.
of sand is washed over the ice from the moraines, or from
the mountain-sides ; and such sand-layers give birth to
ice-cones, which .grow to peculiarly grand dimensions on
the Lower Aar glacier. I say " grow," but the truth, of
course, is, that the surroundiug ice wastes, while the por-
tion underneath the sand is so protected that it remains
as an eminence behind. At first sight, these sand-covered
cones appear huge heaps of dirt, but on examination they
are found to be cones of ice, and that the dirt constitutes
merely a superficial covering.
Turn we now to the moraines. Protecting, as they do, the
ice from waste, they rise, as might be expected, in vast ridges
above the general surface of the glacier. In some cases the
surrounding mass has been so wasted as to leave the spines
of ice which support the moraines forty or fifty feet above
the general level of the glacier. I should think the moraines
MOKAINES ENGULFED AND DISGOKGED. 267
of the Mer de Glace about the Tacul rise to this height.
But lower down, in the neighbourhood of the Echelets,
these high ridges disappear, and nought remains to mark
the huge moraine but a strip of dirt, and perhaps a slight
longitudinal protuberance on the surface of the glacier.
How have the blocks vanished that once loaded the
moraines near the Tacul ? They have been swallowed in
the crevasses which intersect the moraines lower down ;
and if we could examine the ice at the Echelets we
should find the engulfed rocks in the body of the glacier.
Oases occur, wherein moraines, after having been
engulfed, and hidden for a time, are again entirely
disgorged by the glacier. Two moraines run along the
basin of the Talefre, one from the Jardin, the other from
an adjacent promontory, proceeding parallel to each other
towards the summit of the great ice-fall. Here the ice is
riven, and profound chasms are formed, in which the
blocks and shingle of the moraines disappear. Through-
out the entire ice-fall the only trace of the moraines is a
broad dirt-streak, which the eye may follow along the centre
of the fall, with perhaps here and there a stone which has
managed to rise from its frozen sepulchre. But the ice
wastes, and at the base of the fall large masses of stone
begin to reappear; these become more numerous as we
descend; the smaller debris also appears, and finally, at
some distance below the fall, the moraine is completely
restored, and begins to exercise its protecting influence ;
it rises upon its ridge of ice, and dominates as before over
the surface of the glacier.
The ice under the moraines and sand-cones is of a
different appearance from that of the surrounding glacier,
and the principles we have laid down enable us to explain
the difference. The sun's rays, striking upon the unpro-
tected surface of the glacier, enter the ice to a considerable
depth; and the consequence is, that the ice near the
268 TRANSPARENCY OF ICE UNDER THE MORAINES.
surface of the glacier is always disintegrated, being cut up
with minute fissures and cavities, filled with water and air,
which, for reasons already assigned, cause the glacier,
when it is clean, to appear white and opaque. The ice
under the moraines, on the contrary, is usually dark and
transparent ; I have sometimes seen it as black as pitch,
the blackness being a proof of its great transparency,
which prevents the reflection of light from its interior.
The ice under the moraines cannot be assailed in its
depths by the solar heat, because this heat becomes
obscure before it reaches the ice, and as such it lacks
the power of penetrating the substance. It is also com-
municated in great part by way of contact instead of by
radiation. A thin film at the surface of the moraine-ice
engages all the heat that acts upon it, its deeper portions
remaining intact and transparent.
NEVE AND GLACIER. 269
GLACIER MOTION.
PRELIMINAEY.
(9-)
THOUGH a glacier is really composed of two portions, one
above and the other below the snow-line, the term glacier
is usually restricted to the latter, while the French term
neve is applied to the former. It is manifest that the snow
which falls upon the glacier proper can contribute nothing
to its growth or permanence ; for every summer is not only
competent to abolish the accumulations of the foregoing
winter, but to do a great deal more. During each summer
indeed a considerable quantity of the ice below the snow-
line is reduced to water ; so that, if the waste were not in
some way supplied, it is manifest that in a few years the
lower portion of the glacier must entirely disappear. The
end of the Mer de Glace, for example, could never year
after year thrust itself into the valley of Chamouni, were
there not some agency by which its manifest waste is
made good. This agency is the motion of the glacier.
To those unacquainted with the fact of their motion, but
who have stood upon these vast accumulations of ice, and
noticed their apparent fixity and rigidity, the assertion
that a glacier moves must appear in the highest degree
startling and incredible. They would naturally share the
doubts of a certain professor of Tubingen, who, after a visit
to the glaciers of Switzerland, went home and wrote a
book flatly denying the possibility of their motion. But
reflection comes to the aid of sense, and qualifies first
impressions. We ask ourselves how is the permanence
of the glacier secured? How are the moraines to be
270 HUGI'S MEASUREMENTS.
accounted for ? Whence come the blocks which we often
find at the terminus of a glacier, and which we know
belong to distant mountains ? The necessity of motion to
produce these results becomes more and more apparent,
until at length we resort to actual experiment. We take
two fixed points at opposite sides of the glacier, so that a
block of stone which rests upon the ice may be in the
straight line which unites the points ; and we soon find
that the block quits the line, and is borne downwards by
the glacier. We may well realize the interest of the man
who first engaged in this experiment, and the pleasure
which he felt on finding that the block moved ; for
even now, after hundreds of observations on the motion
of glaciers have been made, the actual observance of this
motion for the first time is always accompanied by a thrill
of delight. Such pleasure the direct perception of natural
truth always imparts. Like Antasus we touch our mother,
and are refreshed by the contact.
The fact of glacier-motion has been known for an inde-
finite time to the inhabitants of the mountains ; but the
first who made quantitative observations of the motion was
Hugi. He found that from 1827 to 1830 his cabin upon
the glacier of the Aar had moved 100 metres, or about 110
yards, downwards ; in 1836 it had moved 714 metres ; and
in 1841 M. Agassiz found it at a distance of 1,428 metres
from its first position. This is equivalent in round num-
bers to an average velocity of 100 metres a year. In
1840 M. Agassiz fixed the position of the rock known as
the Hotel des Neufchatelois ; and on the 5th of September,
1841, he found that it had moved 213 feet downward.
Between this date and September, 1842, the rock moved
273 feet, thus accomplishing a distance of 486 feet in two
years.
But much uncertainty prevailed regarding the motion
of the boulders, for they sometimes rolled upon the glacier,
AGASSIZ'S MEASUREMENTS. 271
and hence it was resolved to use stakes of wood driven into
the ice. In the month of July, 1841, M. Escher de la
Linth fixed a system of stakes, every two of which were
separated from each other by a distance of 100 metres,
across the great Aletsch glacier. A considerable number
of other stakes were fixed along the glacier, the longitu-
dinal separation being also 100 metres. On the 8th of
July the stakes stood at a depth of about three feet in
the ice. On the 16th of August he returned to the glacier.
Almost all the stakes had fallen, and no trace, even of the
holes in which they had been sunk, remained. M. Agassiz
was equally unsuccessful on the glacier of the Aar. It
must therefore be borne in mind, that, previous to the
introduction of the facile modes of measurement which we
now employ, severe labour and frequent disappointment
had taught observers the true conditions of success.
After his defeat upon the Aletsch, M. Escher joined
MM. Agassiz and Desor on the Aar glacier, where, between
the 31st of August and the 5th of September, they fixed
in concert the positions of a series of blocks upon the ice,
with the view of measuring their displacements the follow-
ing year.
Another observation of great importance was also com-
menced in 1841. Warned by previous failures, M. Agassiz
had iron boring-rods carried up the glacier, with which he
pierced the ice at six places to a depth of ten feet, and
at each place drove a wooden pile into the ice. These six
stations were in the same straight line across the glacier ;
three of them standing upon the Finsteraar and three on
the Lauteraar tributary. About this time also M. Agassiz
conceived the idea of having the displacements measured
the year following with precise instruments, and also of
having constructed, by a professional engineer, a map of
the entire glacier, on which all its visible "accidents"
should be drawn according to scale. This excellent work
272 PROF. J. D. FORBES INVITED.
was afterwards executed by M. Wild, now Professor of
Geodesy and Topography in the Polytechnic School of
Zurich, and it is published as a separate atlas in connexion
with M. Agassiz's ' Systeme Glaciaire.'
M. Agassiz is a naturalist, and he appears to have de-
voted but little attention to the study of physics. At all
events, the physical portions of his writings appear to me
to be very often defective. It was probably his own con-
sciousness of this deficiency that led him to invoke the
advice of Arago and others previous to setting out upon his
excursions. It was also his desire " to see a philosopher so
justly celebrated occupy himself with the subject," which
induced him to invite Prof. J. D. Forbes of Edinburgh to
be his guest upon the Aar glacier in 1841. On the 8th
of August they met at the Grimsel Hospice, and for
three weeks afterwards they were engaged together daily
upon the ice, sharing at night the shelter of the same
rude roof. It is in reference to this visit that Prof. Forbes
writes thus at page 38 of the ' Travels in the Alps ' : — " Far
from being ready to admit, as my sanguine companions
wished me to do in 1841, that the theory of glaciers was
complete, and the cause of their motion certain, after pa-
tiently hearing all they had to say and reserving my opinion,
I drew the conclusion that no theory which I had then
heard of could account for the few facts admitted on all
hands." In 1842 Prof. Forbes repaired, as early as the
state of the snow permitted, to the Mer de Glace ; he worked
there, in the first instance, for a week, and afterwards
crossed over to Courmayeur to witness a solar eclipse. The
result of his week's observations was immediately commu-
nicated to Prof. Jameson, then editor of the ' Edinburgh
New Philosophical Journal.'
In that letter he announces the fact, but gives no details
of the measurement, that " the central part of the glacier
moves faster than the edges in a very considerable proper-
CENTRE MOVES QUICKEST. 273
tion ; quite contrary to the opinion generally entertained."
He also announced at the same time the continuous
hourly advance of the glacier. This letter bears the date,
" Courmayeur, Piedmont, 4th July," but it was not pub-
lished until the month of October following.
Meanwhile M. Agassiz, in company with M. Wild, re-
turned to complete his experiment upon the glacier of the
Aar. On the 20th of July, 1842, the displacements of the
six piles which he had planted the year before were de-
termined by means of a theodolite. Of the three upon
the Finsteraar affluent, that nearest the side had moved
160 feet, the next 225 feet, while that nearest to the centre
had moved 269 feet. Of those on the Lauteraar, that
nearest the side had moved 125 feet, the next 210 feet,
and that nearest the centre 246 feet. These observations
were perfectly conclusive as to the quicker motion of the
centre : they embrace a year's motion ; and the magnitude
of the displacements, causing errors of inches, which might
seriously affect small displacements, to vanish, justifies us
in ranking this experiment with the most satisfactory of
the kind that have ever been made. The results were
communicated to Arago in a letter dated from the glacier
of the Aar, on the 1st of August, 1842 ; they were laid
before the Academy of Sciences on the 29th of August,
1842, and are published in the * Comptes Kendus' of
the same date.
The facts, then, so far as I have been able to collect
them, are as follows : — M. Agassiz commenced his ex-
periment about ten months before Professor Forbes, and
the results of his measurements, with quantities stated,
were communicated to the French Academy about two
months prior to the publication of the letter of Professor
* Forbes in the ' Edinburgh Philosophical Journal.' But
the latter communication, announcing in general terms
the fact of the speedier central motion, was dated from
T
274 STATE OF THE QUESTION.
Courmayeur twenty-seven days before the date of M.
Agassiz's letter from the glacier of the Aar.
The speedier motion of the central portion of a glacier
has been justly regarded as one of cardinal importance,
and no other observation has been the subject of such
frequent reference ; but the general impression in Eng-
land is that M. Agassiz had neither part nor lot in the
establishment of the above fact ; and in no English work
with which I am acquainted can I find any reference to
the above measurements. Relying indeed upon such
sources for my information, I remained ignorant of the
existence of the paper in the ' Comptes Rendus ' until my
attention was directed to it by Professor Wheatstone. In
the next following chapters I shall have to state the results
of some of my own measurements, and shall afterwards
devote a little time to the consideration of the cause of
glacier-motion. In treating a question on which so much
has been written, it is of course impossible, as it would be
undesirable, to avoid subjecting both my own views and
those of others to a critical examination. But in so doing
I hope that no expression shall escape me inconsistent with
the courtesy which ought to be habitual among philoso-
phers or with the frank recognition of the just claims of
my predecessors.
MY FIRST OBSERVATION. 275
MOTION OF THE MER DE GLACE.
(10.)
ON Tuesday, the 14th of July, 1857, I made my first
observation on the motion of the Mer de Glace. Accom-
panied by Mr. Hirst I selected on the steep slope of the
Glacier des Bois a straight pinnacle of ice, the front edge
of which was perfectly vertical. In coincidence with this
edge I fixed the vertical fibre of the theodolite, and per-
mitted the instrument to stand for three hours. On
looking through it at the end of this interval, the cross
hairs were found projected against the white side of the
pyramid ; the whole mass having moved several inches
downwards.
The instrument here mentioned, which had long been
in use among engineers and surveyors, was first applied
to measure glacier-motion in 1842; by Prof. Forbes on
the Mer de Glace, and by M. Agassiz on the glacier of
the Aar. The portion of the theodolite made use of
is easily understood. The instrument is furnished with
a telescope capable of turning up and down upon a
pivot, without the slightest deviation right or left ; and
also capable of turning right or left without the slight-
est deviation up or down. Within the telescope two
pieces of spider's thread, so fine as to be scarcely visible
to the naked eye, are drawn across the tube and across
each other. When we look through the telescope we
see these fibres, their point of intersection being exactly
in the centre of the tube; and the instrument is fur-
nished with screws by means of which this point can
be fixed upon any desired object with the utmost preci-
sion.
T 2
276 MODE OF MEASUREMENT.
In setting a straight row of stakes across the glacier,
our mode of proceeding was in all cases this : — The theo-
dolite was placed on the mountain-side flanking the
glacier, quite dear of the ice; and having determined
the direction of a line perpendicular to the axis of the
glacier, a well-defined object was sought at the opposite
side of the valley as close as possible to this direction ;
the object being, in some cases, the sharp edge of a cliff;
in others, a projecting corner of rock ; and, in others, a
well-defined mark on the face of the rock. This object
and those around it^ were carefully sketched, so that on
returning to the place it could be instantly recognized.
On commencing a line the point of intersection of the
two spiders' threads within the telescope was first fixed
accurately upon the point thus chosen, and an assistant
carrying a straight baton was sent upon the ice. By rough
signalling he first stood near the place where the first
stake was to be driven in ; and the object end of the tele-
scope was then lowered until he came within the field of
view. He held his staff upright upon the ice, and, in
obedience to signals, moved upwards or downwards until
the point of intersection of the spiders' threads exactly
hit the bottom of the baton ; a concerted signal was
then made, the ice was pierced with an auger to a depth
of about sixteen inches, and a stake about two feet long
was firmly driven into it. The assistant then advanced
for some distance across the glacier; the end of the
telescope was now gently raised until he and his upright
staff again appeared in the field of view. He then moved
as before until the bottom of his staff was struck by the
point of intersection, and here a second stake was fixed
in the ice. In this way the process was continued until
the line of stakes was completed.
Before quitting the station, a plummet was suspended
from a hook directly underneath the centre of the theo-
THE FIRST LINE. 277
dolite, and the place where the point touched the ground
was distinctly marked. To measure the motion of the
line of stakes, we returned to the place a day or two
afterwards, and by means of the plummet were able to
make the theodolite occupy the exact position which it
occupied when the line was set out. The telescope being
directed upon the point at the opposite side of the valley,
and gradually lowered, it was found that no single stake
along the line preserved its first position : they had all
shifted downwards. The assistant was sent to the first
stake ; the point which it had first occupied was again
determined, and its present distance from that point
accurately measured. The same thing was done in the
case of each stake, and thus the displacement of the
whole row of stakes was ascertained.* The time at which
the stake was fixed, and at which its displacement was
measured, being carefully noted, a simple calculation de-
termined the daily motion of the stake.
Thus, on the 17th of July, 1857, we set out our first
line across the Mer de Glace, at some distance below the
Montanvert ; on the day following we measured the pro-
gress of the stakes. The observed displacements are set
down in the following table : —
FIRST LINE. — DAILY MOTION.
No. of stake. Inches.
WEST 1 moved 12£
2 „ 16f
3 „ 221
4
No. of stake. Inches.
6 moved
7 „ 26£
8
9 „ 28f
5 „ 24| 10 „ 35£ EAST.
* Great care is necessary on the part of the man who measures the dis-
placements. The staff ought to be placed along the original line, and the
assistant ought to walk along it until the foot of a perpendicular from the
stake is attained. When several days' motion is to be measured, this pre-
caution is absolutely necessary ; the eye being liable to be grossly deceived
in guessing the direction of a perpendicular.
278 THE CENTRE-POINT NOT THE QUICKEST.
The theodolite in this case stood on the Montanvert side
of the valley, and the stakes are numbered from this side.
We see that the motion gradually augments from the 1st
stake onward — the 1st stake being held back by the
friction of the ice against the flanking mountain-side.
The stakes 4, 6, and 8 have no motion attached to them,
as an accident rendered the measurement of their displace-
ments uncertain. But one remarkable fact is exhibited
by this line ; the 7th stake stood upon the middle of the
glacier, and we see that its motion is by no means the
quickest ; it is exceeded in this respect by the stakes 9
and 10.
The portion of the glacier on which the 10th stake stood
was very much cut up by crevasses, and, while the assistant
was boring it with his auger, the ice beneath him was
observed, through the telescope, to slide suddenly forward
for about 4 inches. The other stakes retained their posi-
tions, so that the movement was purely local. Deducting
the 4 inches thus irregularly obtained, we should have a
daily motion of 31-J inches for stake No. 10, The place was
watched for some time, but the slipping was not repeated ;
and a second measurement on the succeeding day made
the motion of the 10th stake 32 inches, whilst that of the
centre of the glacier was only 27.
Here, then, was a fact which needed explanation ; but,
before attempting this, I resolved, by repeated measure-
ments in the same locality, to place the existence of the
fact beyond doubt. We therefore ascended to a point
upon the old and now motionless moraine, a little above
the Montanvert Hotel ; and choosing, as before, a well-
defined object at the opposite side of the valley, we set
between it and the theodolite a row of twenty stakes
across the glacier. Their motions, measured on a sub-
sequent day, and reduced to their daily rate, gave the
results set down in the following table : —
CORROBORATIVE MEASUREMENTS. 279
SECOND LINE. — DAILY MOTION.
No. of stake. Inches.
WEST 1 moved 7i
2 „ 10f
3 „ _12J
4 „ 14|
5 „ 16
6 „ 16f
7 „ 17*
8 „ 19
9 „ 19±
10 21
No. of stake. Inches.
11 moved 21
12 „ 22|
13 „ 21
14 „ 22|
15 „ 20i
16 „ 21f
17 „ 22£
18 „ 25£
19
20 „ 25f EAST.
As regards the retardation of the side, we observe here
the same fact as that revealed by our first line — the
motion gradually augments from the first stake to the last.
The stake No. 20 stood upon the dirty portion of the ice,
which was derived from the Talefre tributary of the Mer
de Glace, and far beyond the middle of the glacier.
These measurements, therefore, corroborate that made
lower down, as regards the non-coincidence of the point
of swiftest motion with the centre of the glacier.
But it will be observed that the measurements do not
show any retardation of the ice at the eastern extremity of
the line of stakes — the motion goes on augmenting from the
first stake to the last. The reason of this is, that in neither
of the cases recorded were we able to get the line quite
across the glacier ; the crevasses and broken ice-ridges,
which intercepted the vision, compelled us to halt before
we came sufficiently close to the eastern side to make its
retardation sensible. But on the 20th of July my friend
Hirst sought out an elevated station on the Chapeau, or
eastern side of the valley, whence he could command a
view from side to side over all the humps and inequalities
of the ice, the fixed point at the opposite side, upon
which the telescope was directed, being the corner of a
window of the Montaiivert Hotel. Along this line were
280 A NEW PECULIARITY OF GLACIEK MOTION.
placed twelve stakes, the daily motions of which were
found to be as follows : —
THIRD LINE. — DAILY MOTION.
No. of stake.
EAST 1 moved
2
3
4
5
6
Inches.
22f
28f
33f
No. of stake.
7 moved
8
9
10
11
12
Inches.
24|
25
25
18
8 1 WEST.
The numbering of the stakes along this line commenced
from the Chapeau-side of the glacier, and the retardation
of that side is now manifest enough ; the motion gradually
augmenting from 19^ to 33^ inches. But, comparing the
velocity of the two extreme stakes, we find that the retarda-
tion of stake 12 is much greater than that of stake 1.
Stake 5, moreover, which moved with the maximum velo-
city, was not upon the centre of the glacier, but much
nearer to the eastern than to the western side.
It was thus placed beyond doubt that the point of maxi-
mum motion of the Mer de Glace, at the place referred to,
is not the centre of the glacier. But, to make assurance
doubly sure, I examined the comparative motion along
three other lines, and found in all the same undeviating
result.
This result is not only unexpected, but is quite at
variance with the opinions hitherto held regarding the
motion of the Mer de Glace. The reader knows that the
trunk-stream is composed of three great tributaries from
the Geant, the Lechaud, and the Taldfre. The Glacier du
Geant fills more than half of the trunk-valley, and the
junction between it and its neighbours is plainly marked
by the dirt upon the surface of the latter. In fact four
medial moraines are crowded together on the eastern side
LAW OF MOTION SOUGHT. 281
of the glacier, and before reaching the Montanvert they
have strewn their debris quite over the adjacent ice.
A distinct limit is thus formed between the clean Glacier
du Geant and the other dirty tributaries of the trunk-
stream.
Now the eastern side of the Mer de Glace is observed
on the whole to be much more fiercely torn than the
western side, and this excessive crevassing has been re-
ferred to the swifter motion of the Glacier du Geant. It
has been thought that, like a powerful river, this glacier
drags its more sluggish neighbours after it, and thus tears
them in the manner observed. But the measurement of
the foregoing three lines shows that this cannot be the true
cause of the crevassing. In each case the stakes which
moved quickest lay upon the dirty portion of the inuiik-
stream, far to the east of the line of junction of the Glacier
du Geant, which in fact moved slowest of all.
The general view of the glacier, and of the shape of the
valley which it filled, suggested to me that the analogy
with a river might perhaps make itself good beyond the
limits hitherto contemplated. The valley was not straight,
but sinuous. At the Montanvert the convex side of the
glacier was turned eastward ; at some distance higher up,
near the passages called Les Fonts, it was turned west-
ward; and higher up again it was turned once more,
for a long stretch, eastward. Thus between Trelaporte and
the Fonts we had what is called a point of contrary flex-
ure, and between the Fonts and the Montanvert a second
point of the same kind."
Supposing a river, instead of the glacier, to sweep
through this valley ; its point of maximum motion would
not always remain central, but would deviate towards that
side of the valley to which the river turned its convex
boundary. Indeed the positions of towns along the banks
of a navigable river are mainly determined by this circum-
282 CONJECTURE REGARDING CHANGE OF FLEXURE.
stance. They are, in most cases, situate on the convex
sides of the bends, where the rush of the water prevents
silting up. Can it be then that the ice exhibits a simi-
lar deportment ? that the same principle which regulates
the distribution of people along the banks of the Thames
is also acting with silent energy amid the glaciers of the
Alps ? If this be the case, the position of the point of
maximum motion ought, of course, to shift with the
bending of the glacier. Opposite the Fonts, for example,
the point ought to be on the Glacier du Geant, and west-
ward of the centre of the trunk-stream ; while, higher up,
we ought to have another change to the eastern side, in
accordance with the change of flexure.
On the 25th of July a line was set out across the glacier,
one of its fixed termini being a mark upon the first of the
three Fonts. The motion of this line, measured on a sub-
sequent day, and reduced to its daily rate, was found to
be as follows :—
FOURTH LINE. — DAILY MOTION.
No. of stake.
EAST 1 moved
2
3
4
5
6
7
8
9
Inches.
18
18f
No. of stake.
Inches.
10
moved
21
11
»
20^
12
,,
23J
13
„
23^
14
M
21
15
J5
22^
16
,,
17i
17
»
15 V
This line, like the third, was set out and numbered from
the eastern side of the glacier, the theodolite occupying a
position on the heights of the Echelets. A moment's
inspection of the table reveals a fact different from that
observed on the third line ; there the most easterly stake
moved with more than twice the velocity of the most
CONJECTURE TESTED. 288
westerly one ; here, on the contrary, the most westerly
stake moves with more than twice the velocity of the most
easterly one.
To enable me to compare the motion of the eastern and
western halves of the glacier with greater strictness, my
able and laborious companion undertook the task of mea-
suring with a surveyor's chain the line just referred to ;
noting the pickets which had been fixed along the line, and
the other remarkable objects which it intersected. The
difficulty of thus directing a chain over crevasses and
ridges can hardly be appreciated except by those who
have tried it. Nevertheless, the task was accomplished, and
the width of the Mer de Glace, at this portion of its course,
was found to be 863 yards, or almost exactly half a mile.
Referring to the last table, it will be seen that the
two stakes numbered 12 and 13 moved with a common
velocity of 23 J inches per day, and that their motion is
swifter than that of any of the others. The point of
swiftest motion may be taken midway between them, and
this point was found by measurement to lie 233 yards west
of the dirt which marked the junction of the Glacier du
Geant with its fellow tributaries : whereas, in the former
cases, it lay a considerable distance east of this limit.
Its distance from the eastern side of the glacier was
601 yards, and from the western side 262 yards, being
170 yards west of the centre of the glacier.
But the measurements enabled me to take the stakes in
pairs, and to compare the velocity of a number of them
which stood at certain distances from the eastern side of
the valley, with an equal number which stood at the same
distances from the western side. By thus arranging the
points two by two, I was able to compare the motion of
the entire body of the ice at the one side of the central
line with that of the ice at the other side. Stake 17
stood about as far from the western side of the glacier as
284
WESTERN HALF MOVES QUICKEST.
stake 3 did from its eastern side; 16 occupied the same
relation to 4 ; 15, to 5 ; 13, to 7 ; and 12, to 9.
Calling each pair of points which thus stand at equal
distances from the opposite sides corresponding points, the
following little table exhibits their comparative motions : —
NUMBERS AND VELOCITIES OF CORRESPONDING POINTS
ON THE FOURTH LINE.
No. Vel. No. Vel. No. Vel. No. Vel. No. Vel.
West... 17 15 16 17 J 15 22J 13 23| 12 23£
East... 3 12£ 4 15£ 5 15f 7 18J 9 19£
The table explains itself. We see that while stake 17,
which stands west of the centre, moves 15 inches, stake 3,
which stands an equal distance east of the centre, moves
only 12J inches. Comparing every pair of the other points,
we find the same to hold good ; the western stake moves
in each case faster than the corresponding eastern one.
Hence, the entire western half of the Her de Glace, at the
place crossed by our fourth line, moves more quickly than the
eastern half of the glacier.
We next proceeded farther up, and tested the contrary
curvature of the glacier, opposite to Trelaporte. The
station chosen for this purpose was on a grassy platform
of the promontory, whence, on the 28th of July, a row of
stakes was fixed at right angles to the axis of the glacier.
Their motions, measured on the 31st, gave the following
results :—
FIFTH LINE.*— DAILY MOTION.
No. of stake.
WEST 1 moved
2
3
4
5
6
7
8
* The details of the measurement of the fourth and fifth lines are
published in the 'Philosophical Transactions,' vol. cxlix., p. 261.
nches.
No. of stake.
Inches.
n?
9 moved
19f
134
10
19
12f
H
19|
15
12
17!
15*
13
16
16
14
14f
17|
15
10 E
EASTERN HALF MOVES QUICKEST.
285
This line was set out and numbered from the Trelaporte
side of the valley, and was also measured by Mr. Hirst,
over boulders, ice-ridges, chasms, and moraines. The entire
width of the glacier here was found to be 893 yards, or
somewhat wider than it is at the Fonts. It will also be
observed that its motion is somewhat slower.
An inspection of the notes of this line showed me that
stakes 3 and 14, 4 and 12, 7 and 10, were "correspond-
ing points " ; the first of each pair standing as far from the
western side, as the second stood from the eastern. In
the following table these points and their velocities are
arranged exactly as in the case of the fourth line.
NUMBERS AND VELOCITIES OF THE CORRESPONDING POINTS
ON THE FIFTH LINE.
No. Vel. No. Vel. No. Vel.
West ... 3 12f 4 15 7 17£
East ... 14 14f 12 m 10 19
In each case we find that the stake on the eastern side
moves more quickly than the corresponding one upon the
western side : so that where the fifth line crosses the glacier
the eastern half of the Mer de Glace moves more quickly than
the western half. This is the reverse of the result obtained
at our fourth line, but it agrees with that obtained on our
first three lines, where the curvature of the valley is
similar. The analogy between a river and a glacier
moving through a sinuous valley is therefore complete.
Supposing the points of maximum motion to be deter-
mined for a great number of lines across the glacier, the
line uniting all these points is what mathematicians would
call the locus of the point of maximum motion. At Trela-
porte this line would lie east of the centre ; at the Fonts
it would lie west of the centre ; hence, in passing from
Trelaporte to the Fonts, it must cross the axis of the
glacier. Again, at the Montanvert, it would lie east of the
286
LOCUS OF POINT OF SWIFTEST MOTION.
centre, and between the Fonts and the Montanvert the
axis of the glacier would be crossed a second time. Sup-
posing the dotted line in Fig. 21 to represent the middle
Fig. 21.
line of the glacier, then the defined line would represent
the locus of the point of maximum motion. It is a curve
more deeply sinuous than tlie valley itself, and it crosses the
axis of the glacier at each point of contrary flexure.
To complete our knowledge of the motion of the Mer
de Glace, we afterwards determined the velocity of its two
accessible tributaries — the Glacier du Geant, and the
Glacier de Lechaud. On the 29th of July, a line of stakes
was set out across the former, a little above the Tacul,
and their motion was subsequently found to be as follows :
SIXTH LINE. — DAILY MOTION.
No. of stake. Inches.
1 moved 11
2 „ 10
3 „ 12
4 „ 13
5 12
No. of stake. Inches.
6 moved . 12|
7 „ 10|
8 „ 10
9 » 9
10 5
The width of the glacier at this place we found to be 1 134
yards, and its maximum velocity, as shown by the fore-
going table, 13 inches a day.
On the 1st of August a line was set out across the
Glacier de Lechaud, above its junction with the Talefre :
it commenced beneath the block of stone known as the
Pierre de Beranger. The displacements of the stakes,
measured on the 3rd of August, gave the following
results : —
SQUEEZING AT TEELAPORTE. 287
SEVENTH LINE. — DAILY MOTION.
No. of stake. Inches. No. of stake. Inches.
1 moved 4|
2 „ 8|
3 „ 94
4 „ 9
5 8i
6 moved
10
The width of the Glacier de Lechaud at this place was
found to be 825 yards ; its maximum motion, as shown by
the table, being 9J inches a day. This is the slowest rate
which we observed upon either the Mer de Glace or its
tributaries. The width of the Talefre-branch, as it descends
the cascade, or, in other words, before it is influenced by
the pressure of the Lechaud, was found approximately to
be 638 yards.
The widths of the tributaries were determined for the
purpose of ascertaining the amount of lateral compres-
sion endured by the ice in its passage through the neck
of the valley at Trelaporte. Adding all together we
have —
Geant 1134 yards.
Lechaud 825 „
Talefre* 638
Total 2597 yards.
These three branches, as shown by the actual measurement
of our 5th line, are forced at Trelaporte through a channel
893 yards wide ; the width of the trunk stream is a little
better than one-third of that of its tributaries, and it passes
through this gorge at a velocity of nearly 20 inches a day.
Limiting our view to one of the tributaries only, the
result is still more impressive. Previous to its junction
with the Talefre, the Glacier de Lechaud stretches before
the observer as a broad river of ice, measuring 825 yards
across : at Trelaporte it is squeezed, in a frozen vice,
between the Talefre on one side and the Geant on the
288 THE LECHAUD A DEIBLET.
other, to a driblet, measuring 85 yards in width, or about
one-tenth of its former transverse dimension. It will of
course be understood that it is the form and not the volume
of the glacier that is affected to this enormous extent
by the pressure.
Supposing no waste took place, the Glacier de Lechaud
would force precisely the same amount of ice through the
"narrows" at Trelaporte, in one day, as it sends past the
Pierre de Beranger. At the latter place its velocity is
about half of what it is at the former, but its width is more
than nine times as great. Hence, if no waste took place,
its depth, at Trelaporte, would be at least 4^ times its depth
opposite the Pierre de Beranger. Superficial and sub-
glacial melting greatly modify this result. Still I think it
extremely probable that observations directed to this end
would prove the comparative shallowness of the upper
portions of the Glacier de Lechaud.
FIEST ATTEMPT AT MEASUREMENT. 289
ICE-WALL AT THE TACUL.
VELOCITIES OF TOP AND BOTTOM.
(11.)
As regards the motion of the surface of a glacier, two laws
are to be borne in mind : 1st, that regarding the quicker
movement of the centre ; 2nd, that regarding the locus
of the point of maximum motion. Our next care must
be to compare the motion of the surface of a glacier
with the motion of those parts which lie near its bed.
Rendu first surmised that the bottom of the glacier was
retarded by friction, and both Professor Forbes * and M.
Martins f have confirmed the conjecture. Theirs are the
only observations which we possess upon the subject ; and
I was particularly desirous to instruct myself upon this
important head by measurements of my own.
During the summer of 1857 the eastern side of the
Glacier du Geant, near the Tacul, exposed a nearly ver-
tical precipice of ice, measuring 140 feet from top to
bottom. I requested Mr. Hirst to fix two stakes in the
same vertical plane, one at the top of the precipice
and one near the bottom. This he did upon the 3rd of
August, and on the 5th I accompanied him to measure
the progress of the stakes. On the summit of the pre-
cipice, and running along it, was the lateral moraine of
the glacier. The day was warm and the ice liquefying
rapidly, so that the boulders and debris, deprived inces-
santly of their support, came in frequent leaps and rushes
• down the precipice. Into this peril my guide was about
* ' Edinb. Phil. Journ.,' Oct. 1846, p. 417.
t Agassiz, ' Syst^me Glaciaire,' p. 522.
U
290 STAKES FIXED AT TOP, BOTTOM, AND CENTRE.
to enter, to measure the displacement of the lower
stake, while I was to watch, and call out the direction in
which he was to run when a stone gave way. But I soon
found that the initial motion was no sure index of the final
motion. By striking the precipice, the stones were often
deflected, and carried wide of their original direction. I
therefore stopped the man, and sent him to the summit ot
the precipice to remove all the more dangerous blocks.
This accomplished, he descended, and while I stood beside
him, executed the required measurement. From the 3rd
to the 5th of August the upper stake had moved twelve
inches, and the lower one six.
Unfortunately some uncertainty attached itself to this
result, due to the difficulty of fixing the lower stake.
The guide's attention had been divided between his work
and his safety, and he had to retreat more than a dozen
times from the falling boulders and debris. I, on the other
hand, was unwilling to accept an observation of such im-
portance with a shade of doubt attached to it. Hence arose
the desire to measure the motion myself. On the llth of
August I therefore reascended to the Tacul, and fixed a
stake at the top of the precipice, and another at the
bottom. While sitting on the old moraine looking at the
two pickets, the importance of determining the motion
of a point midway between the top and bottom forcibly
occurred to me, but, on mentioning it to my guide, he
promptly pronounced any attempt of the kind absurd.
On scanning the place carefully, however, the value of
the observation appeared to me to outweigh the amount of
danger. I therefore took my axe, placed a stake and an
auger against my breast, buttoned my coat upon them,
and cut an oblique staircase up the wall of ice, until I
reached a height of forty feet from the bottom. Here the
position of the stake being determined by Mr. Hirst, who
was at the theodolite, I pierced the ice with the auger,
THROUGH GLOOM TO THE TACUL. 291
drove in the stake, and descended without injury. During
the whole operation however my guide growled audibly.
On the following morning we commenced the ascent of
Mont Blanc, a narrative of which is given in Part I.
We calculated on an absence of three days, and estimated
that the stakes which had just been fixed would be ready
for measurement on our return ; but we did not reach
Chamouni until the afternoon of Friday, the 14th. Heavy
clouds settled, during our descent, upon the summits
behind us, and a thunder-peal from the Aiguilles soon
heralded a fall of rain, which continued without inter-
mission till the afternoon of the 16th, when the atmo-
sphere cleared, and showed the mountains clothed to their
girdles with snow. The Montanvert was thickly covered,
and on our way to it we met the servants in charge of
the cattle, which had been driven below the snow-line to
obtain food.
On Monday morning, the 17th, a dense fog filled the
valley of the Mer de Glace. I watched it anxiously. The
stakes which we had set at the Tacul had been often
in my thoughts, and I wished to make some effort to
save the labour and peril incurred in setting them
from being lost. I therefore set out, in one of the clear
intervals, accompanied by my friend and Simond, deter-
mined to measure the motion of the stakes, if possible,
or to fix them more firmly, if they still stood. As we
passed, however, from 1'Angle to the glacier, the fog
became so dense and blinding that we halted. At my re-
quest Mr. Hirst returned to the Montanvert ; and Simond,
leaving the theodolite in the shelter of a rock, accom-
panied me through the obscurity to the Tacul. We found
the topmost stake still stuck by its point in the ice ; but
'the two others had disappeared, and we afterwards dis-
covered their fragments in a snow-buttress, which reared
itself against the base of the precipice. They had been
u 2
292 DESCENT OF BOULDERS.
hit by the falling stones, and crushed to pieces. Having
thus learned the worst, we descended to the Montanvert
amid drenching rain.
On the morning of the 18th there was no cloud to
be seen anywhere, and the sunlight glistened brightly on
the surface of the ice. We ascended to the Tacul. The
spontaneous falling of the stones appeared more frequent
this morning than I had ever seen it. The sun shone
with unmitigated power upon the ice, producing copious
liquefaction. The rustle of falling debris was incessant,
and at frequent intervals the boulders leaped down the
precipice, and rattled with startling energy amid the rocks
at its base. I sent Simond to the top to remove the looser
stones ; he soon appeared, and urged the moraine -shingle
in showers down the precipice, upon a bevelled slope of
which some blocks long continued to rest. They were
out of the reach of the guide's baton, and he sought to
dislodge them by sending other stones down upon them.
Some of them soon gave way, drawing a train of smaller
shingle after them ; others required to be hit many times
before they yielded, and others refused to be dislodged
at all. I then cut my way up the precipice in the manner
already described, fixed the stake, and descended as
speedily as possible. We afterwards fixed the bottom
stake, and on the 20th the displacements of all three were
measured.* The spaces passed over by the respective
stakes in 24 hours were found to be as follows :—
Inches.
Top stake 6-00
Middle stake 4-50
Bottom stake 2-56
The height of the precipice was 140-8 feet, but it sloped
off at its upper portion. The height of the middle
* On this latter occasion my guide volunteered to cut the steps for me
up to the pickets ; and I permitted him to do so. In fact, he was at last
as anxious as myself to see the measurement carried out.
MOTION OF STAKES. 293
stake above the ground was 35 feet, and of the bottom
one 4 feet. It is therefore proved by these measurements
that the bottom of the ice-wall at the Tacul moves with
less than half the velocity of the top ; while the displace-
ment of the intermediate stake shows how the velocity
gradually increases from the bottom upwards.
294 HALF OF SUMMER MOTION.
WINTER MOTION OF THE MER DE GLACE.
(12.)
THE winter measurements were executed in the manner
already described, on the 28th and 29th of December,
1859. The theodolite was placed on the mountain's
side flanking the glacier, and a well-defined object was
chosen at the opposite side of the valley, so that a
straight line between this object and the theodolite was
approximately perpendicular to the axis of the glacier.
Fixing the telescope in the first instance with its cross hairs
upon the object, its end was lowered until it struck the
point upon the glacier at which a stake was to be fixed.
Thanks to the intelligence of my assistants, after the fixing
of the first stake they speedily took up the line at all
other points, requiring very little correction to make their
positions perfectly accurate. On the day following that
on which the stakes were driven in, the theodolite was
placed in the same position, and the distances to which the
stakes had moved from their original positions were accu-
rately determined. As already stated, the first line crossed
the glacier about 80 yards above the Montanvert Hotel.
LINE No. I. — WINTER MOTION IN TWENTY-FOUR HOURS.
No. of stake.
Inches.
No. of stake.
Inches.
WEST 1
7i
7
15f
2
11
8
15f
3
13!
9
12*
4
13
10
12
5
13f
11
6| EAST.
6
14*
The maximum here is fifteen and three-quarters inches ;
the maximum summer motion of the same portion of the
THE SAME LAW IN SUMMER AND WTNTEK. 295
glacier is about thirty inches. These measurements also
show that in winter, as well as in summer, the side of the
glacier opposite to the Montanvert moves quicker than
that adjacent to it. The stake which moved with the maxi-
mum velocity was beyond the moraine of La Noire. The
second line crossed the glacier about 130 yards below the
Montanvert.
LINE No. II. — WINTER MOTION IN TWENTY-FOUR HOURS.
No. of stake.
Inches.
No. of stake.
Inches.
1
7f
6
15f
2
9*
7
3
13f
8
ief
4
16
9
5
16
10
143
The maximum here is an inch and three-quarters greater
than that of line No. 1. The summer maximum at this
portion of the glacier also exceeds that of the part inter-
sected by line No. 1. The surface of the glacier between
the two lines is in a state of tension which relieves itself
by a system of transverse fissures, and thus permits of the
quicker advance of the forward portion.
My desire, in making these measurements, was, in the
first place, to raise the winter observations of the motion to
the same degree of accuracy as that already possessed by
the summer ones. Auguste Balmat had already made a
series of winter observations on the Mer de Glace ; but
they were made in the way employed before the intro-
duction of the theodolite by Agassiz and Forbes, and
shared the unavoidable roughness of such a mode of mea-
surement. They moreover gave us no information as to
the motion of the different parts of the glacier along the
same transverse line, and this, for reasons which will
appear subsequently, was the point of chief interest to me.
296 THE GLACIER SLIDES.
CAUSE OF GLACIER-MOTIOK
DE SAUSSURE'S THEORY.
(13.)
PERHAPS the first attempt at forming a glacier-theory is
that of Scheuchzer in 1705. He supposed the motion to
be caused by the conversion of water into ice within the
glacier ; the known and almost irresistible expansion which
takes place on freezing, furnishing the force which pushed
the glacier downward. This idea was illustrated and deve-
loped with so much skill by M. de Charpentier, that his
name has been associated with it ; and it is commonly
known as the Theory of Charpentier, or the Dilatation-
Theory. M. Agassiz supported this theory for a time, but
his own thermometric experiments show us that the body
of the glacier is at a temperature of 32° Fahr. ; that conse-
quently there is no interior magazine of cold to freeze the
water with which the glacier is supposed to be incessantly
saturated. So that these experiments alone, if no other
grounds existed, would prove the insufficiency of the theory
of dilatation. I may however add, that the arguments most
frequently urged against this theory deal with an assump-
tion, which I do not think its author ever intended to
make.
Another early surmise was that of Altmann and Gruner
(1760), both of whom conjectured that the glacier slid
along its bed. This theory received distinct expression
from De Saussure in 1799 ; and has since been associated
with the name of that great alpine traveller, being usually
called the ' Theory of Saussure,' and sometimes the ' Slid-
ing Theory.' It is briefly stated in these words :—
STRAINED INTERPRETATION. 297
" Almost every glacier reposes upon an inclined bed,
and those of any considerable size have beneath them,
even in winter, currents of water which flow between the
ice and the bed which supports it. It may therefore be
understood that these frozen masses, drawn down the slope
on which they repose, disengaged by the water from all
adhesion to the bottom, sometimes even raised by this
water, must glide by little and little, and descend, follow-
ing the inclinations of the valleys, or of the slopes which
they cover. It is this slow but continual sliding of the
ice on its inclined base which carries it into the lower
valleys." *
De Saussure devoted but little time to the subject of
glacier-motion ; and the absence of completeness in the
statement of his views, arising no doubt from this cause,
has given subsequent writers occasion to affix what I cannot
help thinking a strained interpretation to the sliding theory.
It is alleged that he regarded a glacier as a perfectly rigid
body; that he considered it to be " a mass of ice of small
depth, and considerable but uniform breadth, sliding down
a uniform valley, or pouring from a narrow valley into a
wider one." f The introduction " of the smallest flexi-
bility or plasticity" is moreover emphatically denied to
him. J
It is by no means probable that the great author of the
' Voyages ' would have subscribed to this "rigid" annota-
tion. His theory, be it remembered, is to some extent
true : the glacier moves over its bed in the manner sup-
posed, and the rocks of Britain bear to this day the traces
of these mighty sliders. De Saussure probably contented
himself with a general statement of what he believed to
* 'Voyages,' §535.
f James D. Forbes, ' Occasional Papers on the Theory of Glaciers,'
1859, p. 100.
t "I adhere to the definition as excluding the introduction of the
smallest flexibility or plasticity." ' Occ. Pap.,' p. 96.
298 GLACIER OF MONT DOLENT.
be the substantial cause of the motion. He visited the
Jardin, and saw the tributaries of the Mer de Glace turning
round corners, welding themselves together, and after-
wards moving through a sinuous trunk- valley ; and it is
scarcely credible that in the presence of such facts he
would have denied all flexibility to the glacier.
The statement that he regarded a glacier to be a mass
of ice of uniform width, is moreover plainly inconsistent
with the following description of the glacier of Mont Dolent :
" Its most elevated plateau is a great circus, surrounded
by high cliffs of granite, of pyramidal forms ; thence the
glacier descends through a gorge, in which it is narrowed ;
but after having passed the gorge, it enlarges again,
spreading out like a fan. Thus it has on the whole the
form of a sheaf tied in the middle and dilated at its two
extremities." *
Curiously enough this very glacier, and these very
words, are selected by M. Rendu as illustrative of the
plasticity of glaciers. " Nothing," he says, " shows better
the extent to which a glacier moulds itself to its locality
than the form of the glacier of Mont Dolent in the Valley
of Ferret ; " and he adds, in connexion with the same
passage, these remarkable words : — " There is a multitude
of facts which would seem to necessitate the belief that
the substance of glaciers enjoys a kind of ductility which
permits it to mould itself to the locality which it occupies,
to grow thin, to swell, and to narrow itself like a soft
paste." f
* ' Voyages,' tome ii. p. 290.
f In connexion with this brief sketch of the ' Sliding Theory,' it ought
to be stated, that Mr. Hopkins has proved experimentally, that ice may
descend an incline at a sensibly uniform rate, and that the velocity is
augmented by increasing the weight. In this remarkable experiment the
motion was due to the slow disintegration of the lower surface of the ice.
See ' Phil. Mag.,' 1845, vol. 26.
EENDU'S CHAEACTER. 299
RENDU'S THEORY.
(14.)
M..RENDU, Bishop of Annecy, to whose writings I have
just referred, died last autumn.* He was a man of great
repute in his diocese, and we owe to him one of the most
remarkable essays upon glaciers that have ever appeared.
His knowledge was extensive, his reasoning close and
accurate, and his faculty of observation extraordinary.
With these were associated that intuitive power, that
presentiment concerning things as yet untouched by ex-
periment, which belong only to the higher class of minds.
Throughout his essay a constant effort after quantitative
accuracy reveals itself. He collects observations, makes
experiments, and tries to obtain numerical results ; always
taking care, however, so to state his premises and qualify
his conclusions that nobody shall be led to ascribe to his
numbers a greater accuracy than they merit. It is im-
possible to read his work, and not feel that he was a man
of essentially truthful mind, and that science missed an
ornament when he was appropriated by the Church.
The essay above referred to is printed in the tenth
volume of the Memoirs of the Royal Academy of Sciences
of Savoy, published in 1841, and is entitled, c Theorie des
Glaciers de la Savoie, par M. le Ghanoine Rendu, Chevalier
du Merite Civil el Secretaire perpetueV The paper had
been written for nearly two years, and might have re-
mained unprinted, had not another publication on the
same subject called it forth.
I will place a few of the leading points of this remark-
* [Expressions such as " last summer," " last autumn," " recently,"
will be taken throughout in the sense which they had in the early half
of 1860, when this book was first published.— L. C. T.]
300 "THEORIE DES GLACIERS DE LA SAVOIE."
able production before the reader ; commencing with a
generalization which is highly suggestive of the character
of the author's mind.
He reflects on the accumulation of the mountain-snows,
each year adding fifty-eight inches of ice to a glacier.
This would make Mont Blanc four hundred feefc higher in
a century, and four thousand feet higher in a thousand
years. " It is evident," he says, " that nothing like this
occurs in nature." The escape of the ice then leads him
to make some general remarks on what he calls the " law
of circulation." " The conserving will of the Creator has.
employed for the permanence of His work the great law
of circulation, which, strictly examined, is found to repro-
duce itself in all parts of nature. The waters circulate
from the ocean to the air, from the air to the earth,
and from the earth to the ocean. . . . The elements of
organic substances circulate, passing from the solid to
the liquid or aeriform condition, and thence again to
the state of solidity or of organisation. That universal
agent which we designate by the names of fire, light,
electricity, and magnetism, has probably also a circula-
tion as wide as the universe." The italics here are
Eendu's own. This was published in 1841, but written,
we are informed, nearly two years before. In 1842
Mr. Grove wrote thus : — " Light, heat, magnetism, motion,
and chemical affinity, are all convertible material affec-
tions." More recently Helmholtz, speaking of the " cir-
cuit " formed by " heat, light, electricity, magnetism, and
chemical affinity," writes thus : — " Starting from each of
these different manifestations of natural forces, we can
set every other in action." I quote these passages be-
cause they refer to the same agents as those named by
M. Rendu, and to which he ascribes " circulation." Can it
be doubted that this Savoyard priest had a premonition
of the Conservation of Force ? I do not want to lay more
GLACISES EIGHTLY DIVIDED. 301
stress than it deserves upon a conjecture of this kind ; but its
harmony with an essay remarkable for its originality gives
it a significance which, if isolated, it might not possess.
With regard to the glaciers, Rendu commences by dividing
them into two kinds, or rather the selfsame glacier into
two parts, one of which he calls the " glacier reservoir"
the other the " glacier d'ecoulement" — two terms highly
suggestive of the physical relationship of the neve and
the glacier proper. He feeds the reservoirs from three
sources, the principal one of which is the snow, to which he
adds the rain, and the vapours which are condensed upon
the heights without passing into the state of either rain or
snow. The conversion of the snow into ice he supposes
to be effected by four different causes, the most efficacious
of which is pressure* It is needless to remark that this
quite agrees with the views now generally entertained.
In page 60 of the volume referred to there is a passage
which shows that the " veined structure " of the glacier
had not escaped him, though it would seem that he as-
cribed it to stratification. " When," he writes, " we per-
ceive the profile of a glacier on the walls of a crevasse, we
see different layers distinct in colour, but more particularly
in density ; some seem to have the hardness, as they
have the greenish colour, of glass; others preserve the
whiteness and porosity of the snow." There is also a very
close resemblance between his views of the influence of
" time and cohesion " and those of Prof. Forbes. " We may
conclude," he writes, " that time, favouring the action of
affinity, and the pressure of the layers one upon the other,
causes the little crystals of which snow is composed to
approach each other, bring them into contact, and convert
them into ice." f Regelation also appears to have attracted
his notice.! " When we fill an ice-house," he writes, " we
break the ice into very small fragments ; afterwards we wet
* « Memoir,' p. 77. t P- 75. J P. 71.
302 OBSERVATIONS AND HYPOTHESES.
it with water 8 or 10 degrees above zero (Cent.) in tempera-
ture; but, notwithstanding this, the whole is converted into
a compact mass of ice." He moreover maintains, in almost
the same language as Prof. Forbes,* the opinion, that ice
has always an inner temperature lower than zero (Cent. ).
He believed this to be a property "inherent to ice."
" Never," he says, " can a calorific ray pass the first surface
of ice to raise the temperature of the interior." f
He notices the direction bf the glacier as influencing
the wasting of its ridges by the sun's heat ; ascribing to it
the effect to which I have referred in explaining the wave-
like forms upon the surface of the Mer de Glace. His
explanation of the Moulins, too, though insufficient, assigns
a true cause, and is an excellent specimen of physical
reasoning.
With regard to the diminution of the glaciers reservoirs,
or, in other words, to the manner in which the ice dis-
appears, notwithstanding the continual additions made
to it, we have the following remarkable passage : — " In
seeking the cause of the diminution of glaciers, it has
occurred to my mind that the ice, notwithstanding its hard-
ness and its rigidity, can only support a given pressure
without breaking or being squeezed out. According to this
supposition, whenever the pressure exceeds that force, there
will be rupture of the ice, and a flow in consequence. Let
us take, at the summit of Mont Blanc, a column of ice
reposing on a horizontal base. The ice which forms the
first layer of that column is compressed by the weight of
all the layers above it ; but if the solidity of the said first
layer can only support a weight equal to 100, when the
weight exceeds this amount there will be rupture and
spreading out of the ice of the base. Now, something very
similar occurs in the immense crust of ice which covers the
summits of Mont Blanc. This crust appears to augment at
* Philosophical Magazine ' 1859 f ' Memoir,' p. 69.
MEASUEEMENT OF MOTION. 303
the upper surface and to diminish by the sides. To assure
oneself that the movement is due to the force of pressure,
it would be necessary to make a series of experiments upon
the solidity of ice, such as have not yet been attempted." *
I may remark that such experiments substantially verify
M. Eendu's notion.
But it is his observations and reasoning upon the glaciers
d'ecoulement that chiefly interest us. The passages in
his writings where he insists upon the power of the
glaciers to mould themselves to their localities, and com-
pares them to a soft paste, to lava at once ductile and
liquid, are well known from the frequent and nattering
references of Professor Forbes ; but there are others of
much greater importance, which have hitherto remained
unknown in this country. Regarding the motion of the
Mer de Glace, Rendu writes as follows : —
" I sought to appreciate the quantity of its motion ; but
I could only collect rather vague data. I questioned my
guides regarding the position of an enormous rock at the
edge of the glacier, but still upon the ice, and conse-
quently partaking of its motion. The guides showed
me the place where it stood the preceding year, and
where it had stood two, three, four, and five years pre-
viously ; they showed me the place where it would be
found in a year, in two years, &c. ; so certain are they
of the regularity of the motion. Their reports, however,
did not always agree precisely with each other, and their
indications of time and distance lack the precision without
which we proceed obscurely in the physical sciences. In
reducing these different indications to a mean, I found
the total advance of the glacier to be about 40 feet
a year. During my last journey I obtained more certain
data, which I have stated in the preceding chapter. The
enormous difference between the two results arises from the
* Page 80.
304 THE SIDES OF THE GLACIER RETARDED.
fact that the latter observations were made at the centre of
the glacier, WHICH MOVES MORE RAPIDLY, while the former
were made at the side, where the ice is RETAINED BY THE
FRICTION AGAINST ITS ROCKY WALLS." *
An opinion, founded on a grave misapprehension which
Eendu enables us to correct, is now prevalent in this
country, not only among the general public, but also
among those of the first rank in science. The nature of
the mistake will be immediately apparent. At page 128 of
the i Travels in the Alps ' its distinguished author gives a
sketch of the state of our knowledge of glacier-motion pre-
vious to the commencement of his inquiries. He cites
Ebel, Hugi, Agassiz, Bakewell, De la Beche, Shirwell,
Rendu, and places them in open contradiction to each
other. Kendu, he says, gives the motion of the Mer de
Glace to be " 242 feet per annum ; 442 feet per annum ; a
foot a day ; 400 feet per annum, and 40 feet per annum,
or one-tenth of the last !".... and he adds, " I was not
therefore wrong in supposing that the actual progress of a
glacier was yet a new problem when I commenced my ob-
servations on the Mer de Glace in 1842. "f
In the 'North British Review' for August, 1859, a
writer equally celebrated for the brilliancy of his dis-
coveries and the vigour of his pen, collected the data
furnished by the above paragraph into a table, which
he introduced to his readers in the following words : —
" It is to Professor Forbes alone that we owe the first and
most correct researches respecting the motion of glaciers ;
and in proof of this, we have only to give the following
list of observations which had been previously made.
* Page 95.
f At page 38 of the ' Travels ' the following passage also occurs :— " I
believe that I may safely affirm that not one observation of the rate of
motion of a glacier, either on the average or at any particular season of
the year, existed when I commenced my experiments in 1842."
DISCREPANCIES EXPLAINED. 305
Observers. Name of glacier. Annual rate of motion.
Ebel Chamouni 14 feet
Ebel Grindelwald 25 „
Hugi Aar 240 „
Agassiz Aar 200 „
Bakewell Mer de Glace 540 „
DelaBeche Mer de Glace 600 „
Shirwell Mer de Glace 300 „
M. Kendu Mer de Glace 365 „
Saussure's Ladder ... Mer de Glace :.. ... ... 375 „
. . . Such was the state of our knowledge when Professor
Forbes undertook the investigation of the subject."
I am persuaded that the writer of this article will be
the first to applaud any attempt to remove an error which,
advanced on his great authority, must necessarily be
widely disseminated. The numbers in the above table
certainly differ widely, and it is perhaps natural to con-
clude that such discordant results can be of no value ; but
the fact really is that every one of them may be perfectly
correct. This fact, though overlooked by Professor Forbes,
was clearly seen by Rendu, who pointed out with perfect
distinctness the sources from which the discrepancies were
derived.
" It is easy," he says, " to comprehend that it is impos-
sible to obtain a general measure, — that there ought to be
one for each particular glacier. The nature of the slope,
the number of changes to which it is subjected, the depth
of the ice, the width of the couloir, the form of its sides, and
a thousand other circumstances, must produce variations
in the velocity of the glacier, and these circumstances
cannot be everywhere absolutely the same. Much more, it
is not easy to obtain this velocity for a single glacier, and
for this reason. In those portions where the inclination is
steep, the layer of ice is thin, and its velocity is great ; in
those where the slope is almost nothing, the glacier swells
and accumulates ; the mass in motion being double, triple,
&c., the motion is only the half, the third, &c.
x
806 LIQUID MOTION ASCEIBED TO GLACIER.
" But this is not all," adds M. Rendu : " Between the Her
de Glace and a river, there is a resemblance so complete that
it is impossible to find in the latter a circumstance which does
not exist in the former. In currents of water the motion is
not uniform, neither throughout their width nor throughout
their depth; the friction of the bottom, that of the sides,
the action of obstacles, cause the motion to vary, and only
towards the middle of the surface is this entire . . . ." *
In 1845 Professor Forbes appears to have come to the
same conclusion as M. Rendu ; for after it had been proved
that the centre of the Aar glacier moved quicker than the
side in the ratio of fourteen to one, he accepted the result
in these words : — " The movement of the centre of the gla-
cier is to that of a point five metres from the edge as
FOURTEEN to ONE : such is the effect of plasticity ! " f In-
deed, if the differences exhibited in the table were a proof
of error, the observations of Professor Forbes himself would
fare very ill. The measurements of glacier-motion made
with his own hands vary from less than 42 feet a year to
848 feet a year, the minimum being less than one-twentieth
of the maximum ; and if we include the observations made
by Balmat, the, fidelity of which has been certified by
Professor Forbes, the minimum is only one-thirty-seventh of
the maximum.
There is another point connected with Rendu's theory
which needs clearing up : — " The idea," writes the eminent
reviewer, "that a glacier is a semifluid body is no doubt
startling, especially to those who have seen the apparently
rigid ice of which it is composed. M. Rendu himself
shrank from the idea, and did not scruple to say that
' the rigidity of a mass of ice was in direct opposition to
it;' and we think that Professor Forbes himself must have
stood aghast when his fancy first associated the notion of
imperfect fluidity with the solid or even the fissured ice of
* ' Theorie,' p. 96 f ' Occ. Pap.,' p. 74.
NORTH BRITISH REVIEW. 307
the glacier, and when he saw in his mind's eye the glaciers
of the Alps flowing like a river along their rugged bed.
A truth like this was above the comprehension and beyond
the sympathy of the age ; and it required a moral power of
no common intensity to submit it to the ordeal of a shallow
philosophy, and the sneers of a presumptuous criticism."
These are strong words ; but the fact is that, so far
from " shrinking " from the idea, Eendu affirmed, with a
clearness and an emphasis which have not been ex-
ceeded since, that all the phenomena of a river were
reproduced upon the Mer de Glace ; its deeps, its shal-
lows, its widenings, its narrowings, its rapids, its places
of slow motion, and the quicker flow of its centre than
of its sides. He did not shrink from accepting a differ-
ence between the central and lateral motion amounting to
a ratio of ten to one — a ratio so large that Professor Forbes
at one time regarded the acceptance of it as a simple
absurdity. In this he was perhaps justified ; for his own
first observations, which, however valuable, were hasty and
incomplete, gave him a maximum ratio of about one and a
half to one, while the ratio in some cases was nearly one
of equality. The observations of Agassiz however show
that the ratio, instead of being ten to one, may be
infinity to one ; for the lateral ice may be so held back by
a local obstacle that in the course of a year it shall make
no sensible advance at all.
From one thing only did M. Rendu shrink ; and it is the
thing regarding which we are still disunited. He shrank
from stating the physical quality of the ice in virtue of
which a glacier moved like a river. He demands experi-
ments upon snow and ice to elucidate this subject. The
very observations which Professor Forbes regards as proofs
* are those of which we require the physical explanation. It
is not the viscous flow, if you please to call it such, of
the glacier as a whole that here concerns us ; but it
x 2
308 THE ICE AND THE GLACIER.
is the quality of the ice in virtue of which this kind
of motion is accomplished. Professor Forbes sees this dif-
ference clearly enough : he speaks of " fissured ice " being
" flexible " in hand specimens ; he compares the glacier
to a mixture of ice and sand ; and finally, in a more ma-
tured paper, falls back for an explanation upon the obser-
vations of Agassiz regarding the capillaries of the glacier.*
(15.)
The measurements of Agassiz and Forbes completely
verify the anticipations of Rendu ; but no writer with
whom I am acquainted has added anything essential to
the Bishop's statements as to the identity of glacier and
liquid motion. He laid down the conditions of the pro-
blem with perfect clearness, and, as regards the distribu-
tion of merit, the point to be decided is the relative
importance of his idea, and of the measurements which
were subsequently made.
The observations on which Professor Forbes based the
analogy between a glacier and a river are the following : —
In 1842 he fixed four marks upon the Mer de Glace a little
below the Montanvert, the first of which was 100 yards
distant from the side of the glacier, while the last was at
* In all that has been written upon glaciers in this country the above
passages from the writings of Rendu are unquoted ; and many who mingled
very warmly in the discussions of the subject were, until quite recently,
ignorant of their existence. I was long in this condition myself, for I
never supposed that passages which bear so directly upon a point so much
discussed, and of such cardinal import, could have been overlooked ; or
that the task of calling attention to them should devolve upon myself
nearly twenty years after their publication. Now that they are discovered,
I conceive no difference of opinion can exist as to the propriety of placing
them in their true position.
OBSERVATIONS OF FOEBES. 309
the centre a or a little beyond it." The relative velocity
of these four points was found to be
1-000 1-332 1-356 1-367.
The first observations were made upon two of these points,
two others being subsequently added. Professor Forbes
also determined the velocity of two points on the Glacier
du Geant, and found the ratio of motion, in the first
instance, to be as 14 to 32. Subsequent measurements,
however, showed the ratio to be as 14 to 18, the larger
motion belonging to the station nearest to the centre of
the glacier. These are the only measurements which I
can find in his large work that establish the swifter motion
of the centre of the glacier ; and in these cases the velocity
of the centre is compared with that of one side only. In
no instance that I am aware of, either in 1842 or subse-
quent years, did Professor Forbes extend his measure-
ments quite across a glacier ; and as regards completeness
in this respect, no observations hitherto made can at all
compare with those executed at the instance of Agassiz
upon the glacier of the Aar.
In 1844 Professor Forbes made a series of interesting
experiments on a portion of the Mer de Glace near
1' Angle. He divided a length of 90 feet into 45 equal
spaces, and fixed pins at the end of each. His theodolite
was placed upon the ice, and in seventeen days he found
that the ice 90 feet nearer the centre than the theodolite
had moved 26 inches past the latter. These measurements
were undertaken for a special object, and completely
answered the end for which they were intended.
In 1846 Professor Forbes made another important
observation. Fixing three stakes at the heights of 8, 54,
and 143 feet above the bed of the glacier, he found that
in five days they moved respectively 2-87, 4*18, and
4*66 feet. The stake nearest the bed moved most slowly,
310 MEASUREMENTS OF AG-ASSIZ.
thus showing that the ice is retarded by friction. This
result was subsequently verified by the measurements of
M. Martins, and by my own.
If we add to the above an observation made during
a short visit to the Aletsch glacier in 1844, which
showed its lateral retardation, I believe we have before us
the whole of the measurements executed by Professor
Forbes, which show the analogy between the motion of a
glacier and that of a viscous body.
Illustrative of the same point, we have the elaborate and
extensive series of measurements executed by M. Wild
under the direction of M. Agassiz upon the glacier of the
Aarin 1842, 1843, 1844, and 1845, which exhibit on a
grand scale, and in the most conclusive manner, the charac-
ter of the motion of this glacier ; and also show, on close
examination, an analogy with fluid motion which neither
M. Agassiz nor Professor Forbes suspected. The former
philosopher publishes a section in his ' Systeme Glaciaire,'
entitled ' Migrations of the Centre ; ' in which he shows
that the middle of the glacier is not always the point of
swiftest motion. The detection of this fact demonstrates
the attention devoted by M. Agassiz to the discussion of his
observations, but he gives no clue to the cause of the
variation. On inspecting the shape of the valley through
which the Aar glacier moves, I find that these " migra-
tions" follow the law established in 1857 upon the Mer de
Glace, and enunciated at page 286.
To sum up this part of the question : — The idea of semi-
fluid motion belongs entirely to Eendu ; the proof of the
quicker central flow belongs in part to Kendu, but almost
wholly to Agassiz and Forbes ; the proof of the retardation
of the bed belongs to Forbes alone ; while the discovery
of the locus of the point of maximum motion belongs, I
suppose, to me.
"FACTS AND PRINCIPLES." 811
FORBES'S THEORY.
(16.)
THE formal statement of this theory is given in the follow-
ing words: — t( A glacier is an imperfect fluid, or viscous
body, which is urged down slopes of a certain inclination
by the mutual pressure of its parts." The consistency of
the glacier is illustrated by reference to treacle, honey,
and tar, and the theory thus enunciated and exemplified is
called the i Viscous Theory.'
It has been the subject of much discussion, and great
differences of opinion are still entertained regarding it.
Able and sincere men take opposite sides ; and the extra-
ordinary number of Reviews which have appeared upon the
subject during the last two years show the interest which
the intellectual public of England take in the question.
The chief differences of opinion turn upon the inquiry as
to what Professor Forbes really meant when he propounded
the viscous theory ; some affirm one thing, some another,
and, singularly enough, these differences continue, though
the author of the theory has at various times published
expositions of his views.
The differences referred to arise from the circumstances
that a sufficient distinction has not been observed between
facts and principles, and that the viscous theory has assumed
various forms since its first promulgation. It has been
stated to me that the theory of Professor Forbes is " the
congeries of facts" which he has discovered. But it is
quite evident that no recognition, however ample, of these
facts would be altogether satisfactory to Professor Forbes
himself. He claims recognition of his theory,* and no writer
* " Mr. Hopkins," writes Professor Forbes, "has done me the honour,
in the memoirs before alluded to, to mention with approbation my observa-
312 VISCOUS THEOEY; — WHAT IS IT?
with whom I am acquainted makes such frequent use of
the term. "What then can the viscous theory mean apart
from the facts ? I interpret it as furnishing the principle
from which the facts follow as physical consequences — that
the glacier moves as a river because the ice is viscous. In
this sense only can Professor Forbes's views be called a
theory ; in any other, his experiments are mere illustrations
of the facts of glacier motion, which do not carry us a hair's
breadth towards their physical cause.
What then is the meaning of viscosity or viscidity ? I
have heard it defined by men of high culture as " gluey
tenacity; " and such tenacity they once supposed a glacier to
possess. If we dip a spoon into treacle, honey, or tar, we can
draw the substance out into filaments, and the same may be
done with melted caoutchouc or lava. All these substances
are viscous, and all of them have been chosen to illustrate
the physical property in virtue of which a glacier moves.
Viscosity then consists in the power of being drawn out
when subjected to a force of tension, the substance, after
stretching, being in a state of molecular equilibrium, or, in
other words, devoid of that elasticity which would restore it
to its original form. This certainly was the idea attached
to Professor Forbes's words by some of his most strenuous
supporters, and also by eminent men who have never
taken part in any controversy on the subject. Mr. Darwin,
for example, speaks of fel spathic rocks being " stretched "
while flowing slowly onwards in a pasty condition, in pre-
cisely the same manner as Professor Forbes believes that
the ice of moving glaciers is stretched and fissured ; and
Professor Forbes himself quotes these words of Mr. Darwin
as illustrative of his theory.*
tions and experiments on the subject of glaciers. He has been more
sparing either in praise or criticism of the theory which I have founded
upon them. Had Mr. Hopkins," &c.— Eighth Letter; ' Occ. Papers,'?. 66.
* ' Occ. Papers,' p. 92.
THEOKY TESTED. 313
The question now before us is, — Does a glacier exhibit
that power of yielding to a force of tension which would
entitle its ice to be regarded as a viscous substance ?
With a view to the solution of this question Mr. Hirst
took for me the inclinations of the Mer de Glace and
all its tributaries in 1857 ; the effect of a change of incli-
nation being always noted. I will select from those mea-
surements a few which bear more specially upon the
subject now under consideration, commencing with the
Glacier des Bois, down which the ice moves in that state
of wild dislocation already described. The inclination of
the glacier above this cascade is 5° 10', and that of the
cascade itself is 22° 20', the change of inclination being
therefore 17° 10'.
In Fig. 221 have protracted the inclination of the cascade
and of the glacier above it ; the line A B representing the
Pig. 22.
former and B C the latter. Now a stream of molten lava,
of treacle, or tar, would, in virtue of its viscosity, be able
to flow over the brow at B without breaking across ; but
this is not the case with the glacier ; it is so smashed and
riven in crossing this brow, that, to use the words of Pro-
fessor Forbes himself, a it pours into the valley beneath in
a cascade of icy fragments."
But this reasoning will appear much stronger when we
revert to other slopes upon the Mer de Glace. For ex-
ample, its inclination above FAngle is 4°, and it afterwards
descends a slope of 9° 25', the change of inclination being
5° 25'. If we protract these inclinations to scale, we have
314 INCLINATIONS OF THE MER BE GLACE.
the line A B, Fig. 23, representing the steeper slope, and
B C that of the glacier above it. One would surely think
Fig. 23.
that a viscous body could cross the brow B without trans-
verse fracture, but this the glacier cannot do, and Professor
Forbes himself pronounces this portion of the Mer de
Glace impassable. Indeed it was the profound crevasses
here formed which placed me in a difficulty already
referred to. Higher up again, the glacier is broken
on passing from a slope of 3° 10' to one of 5°. Such
observations show how differently constituted a glacier is
from a stream of lava in a " pasty condition," or of treacle,
honey, tar, or melted caoutchouc, to all which it has been
compared. In the next section I shall endeavour to
explain the origin of the crevasses, and shall afterwards
make a few additional remarks on the alleged viscosity of
ice.
CKEVASSES CAUSED BY THE MOTION. 315
THE CREVASSES.
(17.)
HAVING made ourselves acquainted with the motion of
the glacier, we are prepared to examine those rents,
fissures, chasms, or, as they are most usually called,
Crevasses, by which all glaciers are more or less intersected.
They result from the motion of the glacier, and the
laws of their formation are deduced immediately from
those of the motion. The crevasses are sometimes very
deep and numerous, and apparently without law or order
in their distribution. They cut the ice into long ridges,
and break these ridges transversely into prisms ; these
prisms gradually waste away, assuming, according to
the accidents of their melting, the most fantastic forms.
I have seen them like the mutilated statuary of an ancient
temple, like the crescent moon, like huge birds with out-
stretched wings, like the claws of lobsters, and like antlered
deer. Such fantastic sculpture is often to be found on
the ice cascades, where the riven glacier has piled vast
blocks on vaster pedestals, and presented them to the
wasting action of sun and air. In Fig. 24 I have given
a sketch of a mass of ice of this character, which stood
in 1859 on the dislocated slope of the Glacier des Bois.
It is usual for visitors to the Montanvert to descend to
the glacier, and to be led by their guides to the edges of
the crevasses, where, being firmly held, they look down into
them ; but those who have only made their acquaintance
in this way know but little of their magnitude and beauty
in the more disturbed portions of glaciers. As might be
expected, they have been the graves of many a moun-
taineer ; and the skeletons found upon the glacier prove
that even the chamois itself, with its elastic muscles and
316 FANTASTIC ICE-MASSES.
admirable sureness of foot, is not always safe among the
crevasses. They are grandest in the higher ice-regions,
where the snow hangs like a coping over their edges, and
the water trickling from these into the gloom forms splendid
icicles. The Gorner Glacier, as we ascend it towards the
old Weissthor, presents many fine examples of such cre-
vasses ; the ice being often torn in a most curious and
irregular manner. You enter a porch, pillared by icicles,
and look into a cavern in the very body of the glacier,
encumbered with vast frozen bosses which are fringed all
round by dependent icicles. At the peril of your life from
slipping, or from the yielding of the stalactites, you may
enter these caverns, and find yourself steeped in the blue
illumination of the place. Their beauty is beyond descrip-
tion ; but you cannot deliver yourself up, heart and soul, to
its enjoyment. There is a strangeness about the place which
repels you, and not without anxiety do you look from your
BIRTH OF A CREVASSE. 317
ledge into the darkness below, through which the sound of
subglacial water sometimes rises like the tolling of dis-
tant bells. You feel that, however the cold splendours
of the place might suit a purely spiritual essence, they
are not congenial to flesh and blood, and you gladly
escape from its magnificence to the sunshine of the world
above.
From their numbers it might be inferred that the
formation of crevasses is a thing of frequent occurrence
and easy to observe ; but in reality it is very rarely ob-
served. Simond was a man of considerable experience upon
the ice, but the first crevasse he ever saw formed was during
the setting out of one of our lines, when a narrow rent
opened beneath his feet, and propagated itself through the
ice with loud cracking for a distance of 50 or 60 yards. Cre-
vasses always commence in this way as mere narrow cracks,
which open very slowly afterwards. I will here describe
the only case of crevasse-forming which has come under
my direct observation.
On the 31st of July, 1857, Mr. Hirst and myself, having
completed our day's work, were standing together upon
the Glacier du Geant, when a loud dull sound, like that
produced by a heavy blow, seemed to issue from the body
of the ice underneath the spot on which we stood. This
was succeeded by a series of sharp reports, which were
heard sometimes above us, sometimes below us, sometimes
apparently close under our feet, the intervals between the
louder reports being filled by a low singing noise. We
turned hither and thither as the direction of the sounds
varied ; for the glacier was evidently breaking beneath
our feet, though we could discern no trace of rupture.
For an hour the sounds continued without our being able
to discover their source ; this at length revealed itself
by a rush of air-bubbles from one of the little pools upon
the surface of the glacier, which was intersected by
318 MECHANICAL ORIGIN.
the newly-formed crevasse. We then traced it for some
distance up and down, but hardly at any place was it
sufficiently wide to permit the blade of my penknife
to enter it. M. Agassiz has given an animated descrip-
tion of the terror of his guides upon a similar occasion,
and there was an element of awe in our own feelings
as we heard the evening stillness of the glacier thus
disturbed.
With regard to the mechanical origin of the crevasses
the most vague and untenable notions had been entertained
until Mr. Hopkins published his extremely valuable
papers. To him, indeed, we are almost wholly indebted
for our present knowledge of the subject, my own experi-
ments upon this portion of the glacier-question being for
the most part illustrations of the truth of his reasoning.
To understand the fissures in their more complex aspects
it is necessary that we should commence with their
elements. I shall deal with the question in my own
way, adhering, however, to the mechanical principles upon
which Mr. Hopkins has based his exposition.
Let A B, C D, be the bounding sides of a glacier moving
in the direction of the arrow ; let m, n be two points upon
the ice, one, m, close to the retarding side of the valley,
and the other, n, at some distance from it. After a
certain time, the point m will have moved downwards to
m', but in consequence of the swifter movement of the
LINE OF GREATEST STRAIN. 319
parts at a distance from the sides, n will have moved in
the same time to nr. Thus the line m n, instead of being
at right angles to the glacier, takes up the oblique position
m' n' ; but to reach from m' to n' the line m n would
have to stretch itself considerably ; every other line that
we can draw upon the ice parallel to m' nf is in a similar
state of tension ; or, in other words, the sides of the glacier
are acted upon by an oblique pull towards the centre.
Now, Mr. Hopkins has shown that the direction in which
this oblique pull is strongest encloses an angle of 45° with
the side of the glacier.
What is the consequence of this ? Let A B, c D, Fig. 26.
Fig. 26.
represent, as before, the sides of the glacier, moving
in the direction of the arrow ; let the shading lines
enclose an angle of 45° with the sides. Along these lines
the marginal ice suffers the greatest strain, and, conse-
quently across these lines and at right angles to them, the
ice tends to break and to form marginal crevasses. The
lines, o p, o p, mark the direction of these crevasses ; they
are at right angles to the line of greatest strain, and
hence also enclose an angle of 45° with the side of the
valley, being obliquely pointed upwards.
This latter result is noteworthy; it follows from the
mechanical data that the swifter motion of the centre
tends to produce marginal crevasses which are inclined
from the side of the glacier towards its source, and not
320 MARGINAL AND TRANSVERSE CREVASSES.
towards its lower extremity. But when we look down
upon a glacier thus crevassed, the first impression is that
the sides have been dragged down, and have left the
central portions behind them ; indeed, it was this very
appearance that led M. de Charpentier and M. Agassiz
into the error of supposing that the sides of a glacier
moved more quickly than its middle portions ; and it was
also the delusive aspect of the crevasses which led Pro-
fessor Forbes to infer the slower motion of the eastern
side of the Mer de Glace.
The retardation of the ice is most evident near the
sides ; in most cases, the ice for a considerable distance
right and left of the central line moves with a sensibly
uniform velocity; there is no dragging of the particles
asunder by a difference of motion, and, consequently, a
compact centre is perfectly compatible with fissured
sides. Nothing is more common than to see a glacier
with its sides deeply cut, and its central portions com-
pact; this, indeed, is always the case where the glacier
moves down a bed of uniform inclination.
But supposing that the bed is not uniform — that the
valley through which the glacier moves changes its incli-
nation abruptly, so as to compel the ice to pass over a
brow ; the glacier is then circumstanced like a stick
which we try to break by holding its two ends and pressing
it against the knee. The brow, where the bed changes
its inclination, represents the knee in the case of the
stick, while the weight of the glacier itself is the force
that tends to break it. It breaks ; and fissures are
formed across the glacier, which are hence called transverse
crevasses.
No glacier with which I am acquainted illustrates the
mechanical laws just developed more clearly and fully
than the Lower glacier of Grindelwald. Proceeding along
the ordinary track beside the glacier, at about an hour's
GRIKDELWALD GLACIER, 321
distance from the village the traveller reaches a point
whence a view of the glacier is obtained from the
heights above it. The marginal fissures are very cleanly
cut, and point nearly in the direction already indicated ;
the glacier also changes its inclination several times
along the distance within the observer's view. On crossing
each brow the glacier is broken across, and a series of
transverse crevasses is formed, which follow each other
down the slope. At the bottom of the slope tension
gives place to pressure, the walls of the crevasses are
squeezed together, and the chasms closed up. They
remain closed along the comparatively level space which
stretches between the base of one slope and the brow of
the next; but here the glacier is again transversely broken,
and continues so until the base of the second slope is
reached, where longitudinal pressure instead of longitu-
dinal strain begins to act, and the fissures are closed
as before. In Fig. 27A I have given a sketchy section of
a portion of the glacier, illustrating the formation of the
crevasses at the top of a slope, and their subsequent
obliteration at its base.
Another effect is here beautifully shown, namely, the
union of the transverse and marginal crevasses to form con-
tinuous fissures which stretch quite across the glacier. Fig.
2?B will illustrate my meaning, though very imperfectly;
it represents a plan of a portion of the Lower Grindelwald
glacier, with both marginal and transverse fissures drawn
upon it. I have placed it under the section so that each
part of it may show in plan the portion of the glacier which
is shown in section immediately above it. It shows
how the marginal crevasses remain after the compres-
sion of the centre has obliterated the transverse ones ;
and how the latter join on to the former, so as to
form continuous fissures, which sweep across the glacier
in vast curves, with their convexities turned upwards.
y
322
COMPKESSION AND TENSION.
The illusion before referred to is here strengthened ; the
crevasses turn, so to say, against the direction of motion,
instead of forming loops, with their convexities pointing
downwards, and thus would impress a person unacquainted
with the mechanical data with the idea that the glacier
margins moved more quickly than the centre. The figures
are intended to convey the idea merely ; on the actual
slopes of the glacier between twenty and thirty chasms
may be counted : also the word " compression " ought to
have been limited to the level portions of the sketch.
Besides the two classes of fissures mentioned we often
find others, which are neither marginal nor transverse.
The terminal portions of many glaciers, for example, are
in a state of compression ; the snout of the glacier abuts
against the ground, and having to bear the thrust of the
mass behind it, if it have room to expand laterally, the ice
LONGITUDINAL CKEVASSES. 323
will yield, and longitudinal crevasses will be formed. They
are of very common occurrence, but the finest example
of the kind is perhaps exhibited by the glacier of the
Rhone. After escaping from the steep gorge which holds
the cascade, this glacier encounters the bottom of a com-
paratively wide and level valley ; the resistance to its for-
ward motion is augmented, while its ability to expand
laterally is increased ; it has to bear a longitudinal thrust,
and it splits at right angles to the pressure [strain ?]. A
series of fissures is thus formed, the central ones of which
are truly longitudinal ; but on each side of the central line
the crevasses diverge, and exhibit a fan-like arrangement.
This disposition of the fissures is beautifully seen from the
summit of the Mayenwand 011 the Grimsel Pass.
Here then we have the elements, so to speak, of glacier-
crevassing, and through their separate or combined action
the most fantastic cutting up of a glacier may be effected.
And see how beautifully these simple principles enable
us to account for the remarkable crevassing of the
eastern side of the Mer
de Glace. Let A B, c D, c,
be the opposite sides of a
portion of the glacier, near
theMontanvert; c D being
east, and A B west, the
glacier moving in the di- A Montanvert
rection of the arrow ; let Fi°- 28-
the points m n represent the extremities of our line of
stakes, and let us suppose an elastic string stretched across
the glacier from one to the other. We have proved that
the point of maximum motion here lies much nearer to
the side c D than to A B. Let o be this point, and, seizing
the string at o, let it be drawn in the direction of motion
until it assumes the position, m, o', n. It is quite evident
that o' n is in a state of greater tension than o' m, and the
324 CKEVASSING- OF CONVEX SIDE.
ice at the eastern side of the Mer de Glace is in a precisely
similar mechanical condition. It suffers a greater strain
than the ice at the opposite side of the valley, and hence is
more fissured and broken. Thus we see that the crevassing
of the eastern side of the glacier is a simple consequence
of the quicker motion of that side, and does not, as hitherto
supposed, demonstrate its slower motion. The reason why
the eastern side of the glacier, as a whole, is much more
fissured than the western side is, that there are two long
segments which turn their convex curvature eastward, and
only one segment of the glacier which turns its convexity
westward.
The lower portion of the Rhone glacier sweeps round
the side of the valley next the Furca, and turns through-
out a convex curve to this side : the crevasses here are
wide and frequent, while they are almost totally absent at
the opposite side of the glacier. The lower Grindelwald
glacier turns at one place a convex curve towards the
Eiger, and is much more fissured at that side than at
the opposite one ; indeed, the fantastic ice - splinters,
columns, and minarets, which are so finely exhibited upon
this glacier, are mainly due to the deep crevassing of the
convex side. Numerous other illustrations of the law might,
I doubt not, be discovered, and it would be a pleasant and
useful occupation to one who takes an interest in the sub-
ject, to determine, by strict measurements upon other gla-
ciers, the locus of the point of maximum motion, and
to observe the associated mechanical effects.
The appearance of crevasses is often determined by cir-
cumstances more local and limited than those above indi-
cated ; a boss of rock, a protuberance on the side of the
flanking mountain, anything, in short, which checks the
motion of one part of the ice and permits an adjacent
portion to be pushed away from it, produces crevasses.
Some valleys are terminated by a kind of mountain-circus
BEEGSCHRUNDS. 325
with steep sides, against which the snow rises to a con-
siderable height. As the mass is urged downwards, the
lower portion of the snow-slope is often torn away from its
higher portion, and a chasm is formed, which usually
extends round the head of the valley. To such a crevasse
the specific name Bergschrund is applied in the Bernese
Alps ; I have referred to one of them in the account of
the " Passage of the Strahleck."
(18.)
The phenomena described and accounted for in the last
chapter have a direct bearing upon the question of visco-
sity. In virtue of the quicker central flow the lateral ice
is subject to an oblique strain ; but, instead of stretching,
it breaks, and marginal crevasses are formed. We also see
that a slight curvature in the valley, by throwing an addi-
tional strain upon one half of the glacier, produces an
augmented crevassing of that side.
But it is known that a substance confessedly viscous may
be broken by a sudden shock or strain. Professor Forbes
justly observes that sealing-wax at moderate temperatures
will mould itself (with time) to the most delicate inequa-
lities of the surface on which it rests, but may at the same
time be shivered to atoms by the blow of a hammer.
Hence, in order to estimate the weight of the objection
that a glacier breaks when subjected to strain, we must
know the conditions under which the force is applied.
The Mer de Glace has been shown (p. 287) to move
through the neck of the valley at Trelaporte at the rate of
twenty inches a day. Let the sides of this page represent
the boundaries of the glacier at Trelaporte, and any one of
its lines of print a transverse slice of ice. Supposing the line
326 NUMEEICAL TEST OF VISCOSITY.
to move down the page as the slice of ice moves down the
valley, then the bending of the ice in twenty-four hours,
shown on such a scale, would only be sufficient to push
forward the centre in advance of the sides by a very small
fraction of the width of the line of print. To such an
extremely gradual strain the ice is unable to accommodate
itself without fracture.
Or, referring to actual numbers : — the stake No. 15 on
our 5th line, page 284, stood on the lateral moraine of the
Mer de Glace ; and between it and No. 14 a distance of
190 feet intervened. Let A B, Fig. 29, be the side of the
glacier, moving in the direction of the arrow,
and let a ~b c d be a square upon the glacier
with a side of 190 feet. The whole square
moves with the ice, but the side b d moves
quickest ; the point a moving 10 inches,
while b moves 14-75 inches in 24 hours ; the
differential motion therefore amounts to an
inch in five hours. Let a br d' c be the
shape of the figure after five hours' motion ;
then the line a b would be extended to a br
Fig. 29. and c d to cdr.
The extension of these lines does not however express the
maximum strain to which the ice is subjected. Mr. Hop-
kins has shown that this takes place along the line ad; in
five hours then this line, if capable of stretching, would be
stretched to ad'. From the data given every boy who has
mastered the 47th Proposition of the First Book of Euclid
can find the length both of a d and a d' ; the former is
3224-4 inches, and the latter is 3225-1, the difference be-
tween them being seven-tenths of an inch.
This is the amount of yielding required from the ice
in five hours, but it cannot grant this ; the glacier breaks,
and numerous marginal crevasses are formed. It must
not be forgotten that the evidence here adduced merely
STRETCHING OF ICE NOT PROVED. 327
shows what ice cannot do ; what it can do in the way of
viscous yielding we do not know : there exists as yet no
single experiment on great masses or small to show that
ice possesses in any sensible degree that power of being
drawn out which seems to be the very essence of viscosity.
I have already stated that the crevasses, on their first
formation, are exceedingly narrow rents, which widen very
slowly. The new crevasse observed by our guide required
several days to attain a width of three inches ; while that
observed by Mr. Hirst and myself did not widen a single
inch in three days. This, I believe, is the general cha-
racter of the crevasses ; they form suddenly and open
slowly. Both facts are at variance with the idea that ice
is viscous ; for were this substance capable of stretching at
the slow rate at which the fissures widen, there would be
no necessity for their formation.
It cannot be too clearly and emphatically stated that
the proved fact of a glacier conforming to the law of semi-
fluid motion is a thing totally different from the alleged
fact of its being viscous. Nobody since its first enuncia-
tion disputed the former. I had no doubt of it when I
repaired to the glaciers in 1856 ; and none of the eminent
men who have discussed this question with Professor
Forbes have thrown any doubt upon his measurements.
It is the assertion that small pieces of ice are proved to
be viscous * by the experiments made upon glaciers, and
fhe consequent impression left upon the public mind —
that ice possesses the " gluey tenacity " which the term
viscous suggests — to which these observations are meant
to apply.
* " The viscosity, though it cannot be traced in the parts if very minute
nevertheless exists there, as unequivocally proved by experiments on the
large scale."— Forbes in ' Phil. Mag.,' vol. x., p. 301.
328 CONNEXION OF NATURAL FORCES.
HEAT AND WORK.
(19.) /'.; .
GREAT scientific principles, though usually announced by
individuals, are often merely the distinct expression of
thoughts and convictions which had long been entertained
by all advanced investigators. Thus the more profound
philosophic thinkers had long suspected a certain equiva-
lence and connexion between the various forces of nature ;
experiment had shown the direct connexion and mutual
convertibility of many of them, and the spiritual insight,
which, in the case of the true experimenter, always sur-
rounds and often precedes the work of his hands, revealed
more or less plainly that natural forces either had a
common root, or that they formed a circle, whose links
were so connected that by starting from any one of them
we could go through the circuit, and arrive at the point
from which we set out. For the last eighteen years
this subject has occupied the attention of some of the
ablest natural philosophers, both in this country and on
the Continent. The connexion, however, which has most
occupied their minds is that between heat and work ; the
absolute numerical equivalence of the two having, I
believe, been first announced by a German physician
named Mayer, and experimentally proved in this country
by Mr. Joule.
A lead bullet may be made hot enough to burn the
hand, by striking it with a hammer, or by rubbing it against
a board ; a clever blacksmith can make a nail red-hot by
hammering it ; Count Rumford boiled water by the heat
developed in the boring of cannon, and inferred from the
experiment that heat was not what it was generally
MECHANICAL EQUIVALENT OF HEAT. 329
supposed to be, an imponderable fluid, but a kind of
motion generated by the friction. Now Mr. Joule's
experiments enable us to state the exact amount of heat
which a definite expenditure of mechanical force can ori-
ginate. I say originate, not drag from any hiding-place in
which it had concealed itself, but actually bring into exist-
ence, so that the total amount of heat in the universe is
thereby augmented. If a mass of iron fall from a tower
770 feet in height, we can state the precise amount of heat
developed by its collision with the earth. Supposing all
the heat thus generated to be concentrated in the iron
itself, its temperature would thereby be raised nearly 10°
Fahr. Gravity in this case has expended a certain amount
of force in pulling the iron to the earth, and this force is
the mechanical equivalent of the heat generated. Further-
more, if we had a machine so perfect as to enable us to
apply all the heat thus produced to the raising of a weight,
we should be able, by it, to lift the mass of iron to the
precise point from which it fell.
But the heat cannot lift the weight and still continue
heat; this is the peculiarity of the modern view of the
matter. The heat is consumed, used up, it is no longer
heat ; but instead of it we have a certain amount of gravi-
tating force stored up, which is ready to act again, and to
regenerate the heat when the weight is let loose. In fact,
when the falling weight is stopped by the earth, the motion
of its mass is converted into a motion of its molepules ;
when the weight is lifted by heat, molecular motion is con-
verted into ordinary mechanical motion, but for every
portion of either of them brought into existence an equiva-
lent portion of the other must be consumed.
What is true for masses is also true for atoms. As the
' earth and the piece of iron mutually attract each other,
and produce heat by their collision, so the carbon of a
burning candle and the oxygen of the surrounding air
330 HEAT PEODUCED IF THE EAETH STRUCK THE SUN.
mutually attract each other ; they rush together, and on
collision the arrested motion becomes heat. In the former
case we have the conversion of gravity into heat, in the
latter the conversion of chemical affinity into heat ;
but in each case the process consists in the generation
of motion by attraction, and the subsequent change of
that motion into motion of another kind. Mechanically
considered, the attraction of the atoms and its results is
precisely the same as the attraction of the earth and
weight and its results.
But what is true for an atom is also true for a planet or a
sun. Supposing our earth to be brought to rest in her orbit
by a sudden shock, we are able to state the exact amount of
heat which would be thereby generated. The consequence
of the earth's being thus brought to rest would be that it
would fall into the sun, and the amount of heat which
would be generated by this second collision is also calcul-
able. Helmholtz has calculated that in the former case
the heat generated would be equal to that produced by
the combustion of fourteen earths of solid coal, and in
the latter case the amount would be 400 times greater.
Whenever a weight is lifted by a steam-engine in oppo-
sition to the force of gravity an amount of heat is consumed
equivalent to the work done ; and whenever the molecules
of a body are shifted in opposition to their mutual attractions
work is also performed, and an equivalent amount of heat
is consumed. Indeed the amount of work done in the
shifting of the molecules of a body by heat, when expressed
in ordinary mechanical work, is perfectly enormous. The
lifting of a heavy weight to the height of 1000 feet maybe
as nothing compared with the shifting of the atoms of a body
by an amount so small that our finest means of measure-
ment hardly enable us to determine it. Different bodies
give heat different degrees of trouble, if I may use the term,
in shifting their atoms and putting them in new places.
SHIFTING OF ATOMS. 331
Iron gives more trouble than lead ; and water gives far more
trouble than either. The heat expended in this molecular
work is lost as heat ; it does not show itself as temperature.
Suppose the heat produced by the combustion of an ounce
of candle to be concentrated in a pound of iron, a certain
portion of that heat would go to perform the molecular
work to which I have referred, and the remainder would be
expended in raising the temperature of the body ; and if
the same amount of heat were communicated to a pound
of iron and to a pound of lead, the balance in favour of
temperature would be greater in the latter case than in the
former, because the heat would have less molecular work
to do ; the lead would become more heated than the iron.
To raise a pound of iron a certain number of degrees in
temperature would, in fact, require more than three times
the absolute quantity of heat which would be required to
raise a pound of lead the same number of degrees. Con-
versely, if we place the pound of iron and the pound of lead,
heated to the same temperature, into ice, we shall find that
the quantity of ice melted by the iron will be more than
three times that melted by the lead. In fact, the greater
amount of molecular work invested in the iron now comes
into play, the atoms again obey their own powerful forces,
and an amount of heat corresponding to the energy of
these forces is generated.
This molecular work is that which has usually been called
specific heat, or capacity for heat. According to the mate-
rialistic view of heat, bodies are figured as sponges, and heat
as a kind of fluid absorbed by them, different bodies pos-
sessing different powers of absorption. According to the
dynamic view, as already explained, heat is regarded as a
motion, and capacity for heat indicates the quantity of that
motion consumed in internal changes.
The greatest of these changes occurs when a body passes
from one state of aggregation to another, from the solid
332 HEAT CONSUMED IN MOLECULAR WORK.
to the liquid, or from the liquid to the aeriform state ; and
the quantity of heat required for such changes is often
enormous. To convert a pound of ice at 32° Fahr. into
water at the same temperature would require an amount
of heat competent, if applied as mechanical force, to
lift the same pound of ice to a height of 110,000 feet;
it would raise a ton of ice nearly 50 feet, or it would
lift between 49 and 50 tons to a height of one foot
above the earth's surface. To convert a pound of water at
212° into a pound of steam at the same temperature would
require an amount of heat which would perform nearly
seven times the amount of mechanical work just mentioned.
This heat is entirely expended in interior work* and does
nothing towards augmenting the temperature ; the water
is at the temperature of the ice which produced it, both
are 32° ; and the steam is at the temperature of the water
which produced it, both are 212°. The whole of the heat
is consumed in producing the change of aggregation ; I
say " consumed" not hidden or "latent" in either the water
or the steam, but absolutely non-existent as heat. The
molecular forces, however, which the heat has sacrificed
itself to overcome are able to reproduce it ; the water in
freezing and the steam in condensing give out the exact
amount of heat which they consumed when the change of
aggregation was in the opposite direction.
At a temperature of several degrees below its freezing
point ice is much harder than at 32°. I have more than
once cooled a sphere of the substance in a bath of solid
carbonic acid and ether to a temperature of 100° below the
freezing point. During the time of cooling the ice crackled
audibly from its contraction, and afterwards it quite resisted
the edge of a knife ; while at 32° it may be cut or crushed
with extreme facility. The cold sphere was subjected to
* I borrow this term from Professor Clausius's excellent papers on the
Dynamical Theory of Heat.
ICE NEAR THE MELTING POINT. 333
pressure ; it broke with the detonation of a vitreous body,
and was taken from the press a white opaque powder ; which,
on being subsequently raised to 32° and again compressed,
was converted into a pellucid slab of ice.
But before the temperature of 32° is quite attained, ice
gives evidence of a loosening of its crystalline texture.
Indeed the unsoundness of ice at and near its melting
point has been long known. Sir John Leslie, for example,
states that ice at 32° is friable ; and every skater knows how
rotten ice becomes before it thaws. M. Person has further
shown that the latent heat of ice, that is to say, the quantity
of heat necessary for its liquefaction, is not quite expressed
by the quantity consumed in reducing ice at 32° to the liquid
state. The heat begins to be rendered latent, or in other
words the change of aggregation commences, a little before
the substance reaches 32°, — a conclusion which is illus-
trated and confirmed by the deportment of melting ice
under pressure.
In reference to the above result Professor Forbes
writes as follows : — " I have now to refer to a fact ....
established by a French experimenter, M. Person, who
appears not to have had even remotely in his mind the
theory of glaciers, when he announced the following facts,
viz. — * That ice does not pass abruptly from the solid to the
fluid state ; that it begins to soften at a temperature of
2° Centigrade below its thawing point ; that, consequently,
between 28° 4' and 32° of Fahr. ice is actually passing
through various degrees of plasticity within narrower limits,
but in the same manner that wax, for example, softens be-
fore it melts.' " The " softening " here referred to is the
"friability," of Sir J. Leslie, and what I have called a
" loosening of the texture." Let us suppose the Serpentine
covered by a sheet of pitch so smooth and hard as to
enable a skater to glide over it ; and which is afterwards
gradually warmed until it begins to bend under his weight,
334 ROTTEN ICE AND SOFTENED WAX.
and finally lets him through. A comparison of this
deportment with that of a sheet of ice under the same
circumstances enables us to decide whether ice "passes
through various degrees of plasticity in the same manner
as wax softens before it melts." M. Person concerned
himself solely with the heat absorbed, and no doubt
in both wax and ice that heat is expended in " interior
work." In the one case, however, the body is so consti-
tuted that the absorbed heat' is expended in rendering the
substance viscous ; and the question simply is, whether the
heat absorbed by the ice gives its molecules a freedom of
play which would entitle it also to be called viscous ;
whether, in short, "rotten ice" and softened wax present
the same physical qualities ?
(20.)
There is one other point in connexion with the viscous
theory which claims our attention. The announcement of
that theory startled scientific men, and for two or three
years after its first publication it formed the subject of
keen discussion. This finally subsided, and afterwards
Professor Forbes drew up an elaborate paper, which was
presented in three parts to the Royal Society in 1845
and 1846, and subsequently published in the c Philosophical
Transactions.'
In the concluding portion of Part III. Professor Forbes
states and answers the question, " How far a glacier is to
be regarded as a plastic mass ? " in these words : — " Were
a glacier composed of a solid crystalline cake of ice, fitted
or moulded to the mountain bed which it occupies,
like a lake tranquilly frozen, it would seem impossible
to admit such a flexibility or yielding of parts as should
CAPILLARY HYPOTHESIS. 335
permit any comparison to a fluid or semifluid body, trans-
mitting pressure horizontally, and whose parts might
change their mutual positions so that one part should be
pushed out whilst another remained behind. But we
know, in point of fact, that a glacier is a body very dif-
ferently constituted. It is clearly proved by the experi-
ments of Agassiz and others that the glacier is not a mass
of ice, but of ice and water, the latter percolating freely
through the crevices of the former to all depths of the gla-
cier ; and it is a matter of ocular demonstration that these
crevices, though very minute, communicate freely with
one another to great distances ; the water with which they
are filled communicates force also to great distances, and
exercises a tremendous hydrostatic pressure to move on-
wards in the direction in which gravity urges it, the vast
porous mass of seemingly rigid ice in which it is as it
were bound up."
" Now the water in the crevices," continues Professor
Forbes, " does not constitute the glacier, but only the
principal vehicle of the force which acts on it, and the slow
irresistible energy with which the icy mass moves onwards
from hour to hour with a continuous march, bespeaks of
itself the presence of a fluid pressure. But if the ice were
not in some degree ductile or plastic, this pressure could
never produce any the least forward motion of the mass.
The pressure in the capillaries of the glacier can only tend
to separate one particle from another, and thus produce
tensions and compressions within the body of the glacier
itself j which yields, owing to its slightly ductile nature, in
the direction of least resistance, retaining its continuity,
or recovering it by reattachment after its parts have suffered
a bruise, according to the violence of the action to which it
has been exposed."
I will not pretend to say that I fully understand this
passage, but, taking it and the former one together, I think
336 TEMPEEATUEE AT CHAMOUNI ; WINTEE 1859.
it is clear that the water which is. supposed to gorge
the capillaries of the glacier is assumed to be essential
to its motion. Indeed, an extreme degree of sensitiveness
has been ascribed to the glacier as regards the changes of
temperature by which the capillaries are affected. In
three succeeding days, for example, Professor Forbes
found the diurnal summer motion of a point upon the
Mer de Glace to increase from 15*2 to 17 '5 inches a
day; a result which he says he is "persuaded" to be
due to the increasing heat of the weather at the time.
If, then, the glacier capillaries can be gorged so quickly
as this experiment would indicate, it is fair to assume that
they are emptied with corresponding speed when the
supply is cut away.
The extraordinary coldness of the weather previous to
the Christmas of 1859 is in the recollection of everybody :
this lowness of temperature also extended to the Mer de
Glace and its environs. I had last summer left with
Auguste Balmat and the Abbe Vueillet thermometers
with which observations were made daily during the cold
weather referred to. I take the following from Balmat's
register.
Date.
December 16
17
18
19
20
21
22
Minimum
temperature
Centigrade.
- 15°
Da
Decei
•
te.
nber 23 ...
24 ...
25 ...
27 ...
28
Minimur
temperati
Centigrac
... ~— 4;
... — 61
... - 2'
... + 2
... - 3
- 10
- 20
-16*
- 9
- 13
- 4f
29
- 6
The temperature at the Montanvert during the above
period may be assumed as generally some degrees lower, so
that for a considerable period, previous to my winter observa-
tions, the portion of the Mer de Glace near the Montanvert
had been exposed to a very low temperature. I reached
BALMAT'S MEASUREMENTS. 337
the place after the weather had become warm, but during
my stay there the maximum temperature did not exceed
— 41° 0. Considering therefore the long drain to which the
glacier had been subjected previous to the 29th of Decem-
ber, it is not unreasonable to infer that the capillary supply
assumed by Professor Forbes must by that time have been
exhausted. Notwithstanding this, the motion of the glacier
at the Montanvert amounted at the end of December to
half its maximum summer motion.
The observations of Balmat which have been published
by Professor Forbes * also militate, as far as they go,
against the idea of proportionality between the capillary
supply and the motion. If the temperatures recorded
apply to the Mer de Glace during the periods of observa-
tion, it would follow that from the 19th of December 1846
to the 12th of April 1847 the temperature of the air was
constantly under zero Centigrade, and hence, during this
time, the gorging of the capillaries, which is due to super-
ficial melting, must have ceased. Still, throughout this
entire period of depletion the motion of the glacier steadily
increased from twenty-four inches to thirty-four and a half
inches a day. What has been here said of the Montan-
vert, and of the points lower down where Balmat's measure-
ments were made, of course applies with greater force to
the higher portions of the glacier, which are withdrawn
from the operation of superficial melting for a longer
period, and which, nevertheless, if I understand Professor
Forbes aright, have their motion least affected in winter.
He records, for example, an observation of Mr. Bakewell's,
by which the Glacier des Bossons is shown to be stationary
at its end, while its upper portions are moving at the rate
of a foot a day. This surely indicates that, at those places
* where the glacier is longest cut off from superficial supply,
the motion is least reduced, which would be a most strange
* ' Occ. Pap.,' p. 224.
338 BAKEWELL'S OBSERVATIONS.
result if the motion depended, as affirmed, upon the gorging
of the capillaries.
The perusal of the conclusion of Professor Forbes's last
volume shows me that a thought similar to that expressed
above occurred to Mr. Bakewell also. Speaking of a
shallow glacier which moved when the alleged tempera-
ture was so enormously below the freezing point that Pro-
fessor Forbes regards the observation as open to question
(in which I agree with him), Mr. Bakewell asks, " Is it
possible that infiltrated water can have any action what-
ever under such circumstances?" The reply of Professor
Forbes contains these words : — " I have nowhere affirmed
the presence of liquid water to be a sine qua non to the
plastic motion of glaciers." This statement, I confess,
took me by surprise, which was not diminished by further
reading. Speaking of the influence of temperature on the
motion of the Mer de Glace, Professor Forbes says, the
glacier u took no real start until the frost had given way,
and the tumultuous course of the Arveiron showed that
its veins were again filled with the circulating medium to
which the glacier, like the organic frame, owes its moving
energy." * And again : — " It is this fragility precisely
which, yielding to the hydrostatic pressure of the unfrozen
water contained in the countless capillaries of the glacier,
produces the crushing action which shoves the ice over its
neighbour particles." f
After the perusal of the foregoing paragraphs the reader
will probably be less interested in the question as to
whether the assumed capillaries exist at all in the glacier.
According to Mr. Huxley's observations, they do not 4
During the summer of 1857 he carefully experimented
with coloured liquids on the Mer de Glace and its tribu-
taries, and in no case was he able to discover these fissures
* ' Phil. Trans.,' 1846, p. 137, and ' Occ. Pap.,' p. 138.
t ' Occ. Pap.,' p. 47. 1 ' Phil. Mag.,' 1857, vol. xiv., p. 241.
HUXLEY'S OBSEEVATIONS. 339
in the sound unweathered ice. I have myself seen the red
liquid resting in an auger-hole, where it had lain for an
hour without diffusing itself in any sensible degree. This
cavity intersected both the white ice and the blue veins
of the glacier ; and Mr. Huxley, in my presence, cut away
the ice until the walls of the cavity became extremely thin,
still no trace of liquid passed through them. Experiments
were also made upon the higher portions of the Mer de
Glace, and also on the Glacier du Geant, with the same
result. Thus the very existence of these capillaries is
rendered so questionable, that no theory of glacier-motion
which invokes their aid could be considered satisfactory.
z 2
340 STATEMENT OF THEOEY.
THOMPSON'S THEORY.
(21.)
IN the * Transactions ' of the Royal Society of Edinburgh for
1849 is published a very interesting paper by Prof. James
Thomson of Queen's College, Belfast, wherein he deduces,
as a consequence of a principle announced by the French
philosopher Carnot, that water, when subjected to pressure,
requires a greater cold to freeze it than when the pressure is
removed. He inferred that the lowering of the freezing
point for every atmosphere of pressure amounted to '0075
of a degree Centigrade. This deduction was afterwards
submitted to the test of experiment by his distinguished
brother Prof. Wm. Thomson, and proved correct. On the
fact thus established is founded Mr. James Thomson's theory
of the " Plasticity of Ice as manifested in Glaciers."
The theory is this : — Certain portions of the glacier are
supposed first to be subjected to pressure. This pressure
liquefies the ice, the water thus produced being squeezed
through the glacier in the direction in which it can most
easily escape. But cold has been evolved by the act of
liquefaction, and, when the water has been relieved from
the pressure, it freezes in a new position. The pressure
being thus abolished at the place where it was first applied,
new portions of the ice are subjected to the force ; these
in their turn liquefy, the water is dispersed as before,
and re-frozen in some other place. To the succession .of
processes here assumed Mr. Thomson ascribes the changes
of form observed in glaciers.
This theory was first communicated to the Royal Society
through the author's brother, Prof. William Thomson, and
is printed in the ' Proceedings ' of the Society for May, 1857.
It was afterwards communicated to the British Association
DIFFICULTIES OF THEORY. 341
in Dublin, in whose ( Reports ' it is further published ; and
again it was communicated to the Belfast Literary and
Philosophical Society, in whose ' Proceedings ' it also finds
a place.
On the 24th of November, 1859, Mr. James Thomson
communicated to the Royal Society, through his brother,
a second paper, in which he again draws attention to his
theory. He offers it in substitution for my views as the
best argument that he can adduce against them ; he also
controverts the explanations of regelation propounded by
Prof. James D. Forbes and Prof. Faraday, believing that
his own theory explains all the facts so well as to leave
room for no other.
But the passage in this paper which demands my chief
attention is the following : — " Prof. Tyndall (writes Mr.
Thomson), in papers and lectures subsequent to the publi-
cation of this theory, appears to adopt it to some extent,
and to endeavour to make its principles co-operate with
the views he had previously founded on Mr. Faraday's fact
of regelation." I may say that Mr. Thomson's main
thought was familiar to me long before his first communi-
cation on the plasticity of ice appeared ; but it had little
influence upon my convictions. Were the above passage
correct, I should deserve censure for neglecting to express
my obligations far more explicitly than I have hitherto
done ; but I confess that even now I do not understand
the essential point of Mr. Thomson's theory, — that is to
say, its application to the phenomena of glacier motion.
Indeed, it was the obscurity in my mind in connexion with
this point, and the hope that time might enable me to
seize more clearly upon his meaning, which prevented me
from giving that prominence to the theory of Mr. Thomson
which, for aught I know, it may well deserve. I will
here briefly state one or two of my difficulties, and shall
feel very grateful to have them removed.
342 IMPKOBABLE DEDUCTION.
Let us fix our attention on a vertical slice of ice trans-
verse to the glacier, and to which the pressure is applied
perpendicular to its surfaces. The ice liquefies, and, sup-
posing the means of escape offered to the compressed water
to be equal all round, it is plain that there will be as great
a tendency to squeeze the water upwards as downwards;
for the mere tendency to flow down by its own gravity
becomes, in comparison to the forces here acting on the
water, a vanishing quantity. But the fact is, that the ice
above the slice is more permeable than that below it ; for,
as we descend a glacier, the ice becomes more compact.
Hence the greater part of the dispersed water will be re-
frozen on that side of the slice which is turned towards
the origin of the glacier; and the consequence is, that,
according to Mr. Thomson's principle, the glacier ought
to move up hill instead of down.
I would invite Mr. Thomson to imagine himself and me
together upon the ice, desirous of examining this question
in a philosophic spirit ; and that we have taken our places
beside a stake driven into the ice, and descending with the
glacier. We watch the ice surrounding the stake, and find
that every speck of dirt upon it retains its position ; there
is no liquefaction of the ice that bears the dirt, and con-
sequently it rests on the glacier undisturbed. After twelve
hours we find the stake fifteen inches distant from its first
position : I would ask Mr. Thomson how did it get there ?
Or let us fix our attention on those six stakes which M.
Agassiz drove into the glacier of the Aar in 1841, and
found erect in 1842 at some hundreds of feet from their
first position : — how did they get there ? How, in fine,
does the end of a glacier become its end ? Has it been
liquefied and re-frozen ? If not, it must have been pushed
down by the very forces which Mr. Thomson invokes to
produce his liquefaction. Both the liquefaction, as far as
it exists, and the motion, are products of the same cause.
REQUISITE PRESSURE CALCULATED. 343
In short, this theory, as it presents itself to my mind,
is so powerless to account for the simplest fact of glacier-
motion, that I feel disposed to continue to doubt my own
competence to understand it rather than ascribe to Mr.
Thomson an hypothesis apparently so irrelevant to the
facts which it professes to explain.
Another difficulty is the following : — Mr. Thomson will
have seen that I have recorded certain winter measure-
ments made on the Mer de Glace, and that these mea-
surements show not only that the ice moves at that period
of the year, but that it exhibits those characteristics
of motion from which its plasticity has been inferred ;
the velocity of the central portions of the glacier being in
round numbers double the velocity of those near the sides.
Had there been any necessity for it, this ratio might have
been augmented by placing the side-stakes closer to the
walls of the glacier. Considering the extreme coldness of
the weather which preceded these measurements, it is a
moderate estimate to set down the temperature of the
ice in which my stakes were fixed at 5° Cent, below zero.
Let us now endeavour to estimate the pressure existing
at the portion of the glacier where these measurements
were made. The height of the Montanvert above the sea-
level is, according to Prof. Forbes, 6300 feet ; that of the
Col du Geant, which is the summit of the principal tribu-
tary of the Mer de Glace, is 11,146 feet : deducting the
former from the latter, we find the height of the Col du
Geant above the Montanvert to be 4846 feet.
Now, according to Mr. Thomson's theory and his bro-
ther's experiments, the melting point of ice is lowered
'0075° Centigrade for every atmosphere of pressure ; and
one atmosphere being equivalent to the pressure of about
9 thirty-three feet of water, we shall not be over the truth if
we take the height of an equivalent column of glacier-ice,
of a compactness the mean of those which it exhibits upon
344 ACTUAL PRESSUEE INSUFFICIENT.
the Col du Geant and at the Montanvert respectively, at
forty feet. The compactness of glacier ice is, of course,
affected by the air-bubbles contained within it.
If, then, the pressure of forty feet of ice lower the melting
point "0075° Centigrade, it follows that the pressure of a
column 4846 feet high will lower it nine-tenths of a degree
Centigrade. Supposing, then, the unimpeded thrust of the
whole glacier, from the Col- du Oeant doiunwards, to be
exerted on the ice at the Montanvert ; or, in other words,
supposing the bed of the glacier to be absolutely smooth
and every trace of friction abolished, the utmost the
pressure thus obtained could perform would be to lower
the melting point of the Montanvert ice by the quantity
above mentioned. Taking into account the actual state
of things, the friction of the glacier against its sides
and bed, the opposition which the three tributaries en-
counter in the neck of the valley at Trelaporte, the
resistance encountered in the sinuous valley through
which it passes; and finally, bearing in mind the com-
paratively short length of the glacier, which has to
bear the thrust, and oppose the latter by its own friction
merely ; — I think it will appear evident that the ice at
the Montanvert cannot possibly have its melting point
lowered by pressure more than a small fraction of a de-
gree,
The ice in which my stakes were fixed being — 5° Centi-
grade, according to Mr. Thomson's calculation and his
brother's experiments, it would require 667 atmospheres of
pressure to liquefy it ; in other words, it would require the
unimpeded pressure of a column of glacier-ice 26,680 feet
high. Did Mont Blanc rise to two and a half times its
present height above the Montanvert, and were the latter
place connected with the summit of the mountain by a
continuous glacier with its bed absolutely smooth, the pres-
sure at the Montanvert would be rather under that neces-
MEASUREMENTS APPLY TO SURFACE. 345
sary to liquefy the ice on which my winter observations
were made.
If it be urged that, though the temperature near the
surface may be several degrees below the freezing point,
the great body of the glacier does not share this tempera-
ture, but is, in all probability, near to 32°, my reply
is simple. I did not measure the motion of the ice in the
body of the glacier ; nobody ever did ; my measurements
refer to the ice at and near the surface, and it is this ice
which showed the plastic deportment which the measure-
ments reveal.
Such, then, are some of the considerations which prevent
me from accepting the theory of Mr. Thomson, and I trust
they will acquit me of all desire to make his theory co-
operate with my views. I am, however, far from con-
sidering his deduction the less important because of its
failing to account for the phenomena of glacier motion.
346
POSSIBLE MOULDING OF ICE.
THE PRESSURE-THEORY OF GLACIER-MOTION.
(22.)
BROADLY considered, two classes of facts are presented to
the glacier-observer ; the one suggestive of viscosity, and
the other of the reverse. The former are seen where pres-
sure comes into play, the latter where tension is operative.
By pressure ice can be moulded to any shape, while the
same ice snaps sharply asunder if subjected to tension.
Were the result worth the labour, ice might be moulded
into vases or statuettes, bent into spiral bars, and, I doubt
not, by the proper application of pressure, a rope of ice
might be formed and coiled into a knot. But not one of
these experiments, though they might be a thousandfold
more striking than any ever made upon a glacier, would
in the least demonstrate that ice is really a viscous body.
I have here stated what I believe to be feasible. Let
me now refer to the experiments which have been actually
A B
Fig. 30.
made in illustration of this point. Two pieces of seasoned
box-wood had corresponding cavities hollowed in them, so
that, when one was placed upon the other, a lenticular
ACTUAL MOULDING OF ICE.
347
space was enclosed. A and B, Fig. 30, represent the
pieces of box-wood with the cavities in plan : c represents
their section when they are placed upon each other.
A sphere of ice rather more than sufficient to fill the
lenticular space was placed between the pieces of wood
and subjected to the action of a small hydraulic press.
The ice was crushed, but the crushed fragments soon re-
attached themselves, and, in a few seconds, a lens of com-
pact ice was taken from the mould.
This lens was placed in a cylindrical cavity hollowed out
in another piece of box-wood, and represented at c, Fig. 31 ;
and a flat piece of the wood was placed
over the lens as a cover, as at D. On sub-
jecting the whole to pressure, the lens broke,
as the sphere had done, but the crushed mass
soon re-established its continuity, and in less
than half a minute a compact cake of ice
was taken from the mould.
In the following experiment the ice was
subjected to a still severer test : — A hemi-
spherical cavity was formed in one block of
box- wood, and upon a second block a hemi- Fig 3L
spherical protuberance was turned, smaller than the cavity,
so that, when the latter was placed in the former, a space
of a quarter of an inch existed between the two. Fig. 32
represents a section of the two G
pieces of box-wood ; the brass pins
a, 6, fixed in the slab G H, and #< r^F"""
entering suitable apertures in the ];.
mould I K, being intended to
keep the two surfaces concentric, i w-<(<mr <*
A lump of ice being placed in pig. 32.
the cavity, the protuberance was brought down upon it,
and the mould subjected to hydraulic pressure : after a
short interval the ice was taken from the mould as a
348
ICE MOULDED TO CUPS AND RINGS.
smooth compact cup, its crushed particles having reunited,
and established their continuity.
To make these results more applicable to the bending of
glacier-ice, the following experiments were made : — A block
of box-wood, M, Fig. 33, 4 inches long, 3 wide, and 3 deep,
had its upper surface slightly curved,
and a groove an inch wide, and about
an inch deep, worked into it. A corre-
sponding plate was prepared, having
its under surface part of a convex cy-
linder, of the same curvature as the
concave surface of the former piece.
When the one slab was placed upon
the other, they presented the appear-
ance represented in section at N. A
straight prism of ice 4 inches long, an
inch wide, and a little more than an
inch in depth, was placed in the groove ; the upper slab
was placed upon it, and the whole was subjected to the
hydraulic press. The prism broke, but, the quantity of ice
being rather more than sufficient to fill the groove, the
pressure soon brought the fragments together and re-esta-
blished the continuity of the ice. After a few seconds it
was taken from the mould a bent bar of ice. This bar
was afterwards passed through three other moulds of
gradually augmenting curvature, and was taken from
the last of them a semi-ring of compact ice.
The ice, in changing its form from that of one mould to
that of another, was in every instance broken and crushed
by the pressure ; but suppose that instead of three moulds
three thousand had been used ; or, better still, suppose the
curvature of a single mould to change by extremely slow
degrees ; the ice would then so gradually change its form
that no rude rupture would be apparent. Practically the
ice would behave as a plastic substance; and indeed
SOFTNESS OF ICE DEFINED. 349
this plasticity has been contended for by M. Agassiz, in
opposition to the idea of viscosity. As already stated, the
ice, bruised, and flattened, and bent in the above experi-
ments, was incapable of being sensibly stretched ; it was
plastic to pressure but not to tension.
A quantity of water was always squeezed out of the
crushed ice in the above experiments, and the bruised
fragments were intermixed with this and with air. Minute
quantities of both remained in the moulded ice, and thus
rendered it in some degree turbid. Its character, how-
ever, as to continuity may be inferred from the fact that
the ice-cup, moulded as described, held water without the
slightest visible leakage.
Ice at 32° may, as already stated, be crushed with
extreme facility, and glacier-ice with still more readiness
than lake-ice : it may also be scraped with a knife with
even greater facility than some kinds of chalk. In com-
parison with ice at 100° below the freezing point, it might
be popularly called soft. But its softness is not that of
paste, or wax, or treacle, or lava, or honey, or tar. It is the
softness of calcareous spar in comparison with that of rock-
crystal; and although the latter is incomparably harder
than the former, I think it will be conceded that the term
viscous would be equally inapplicable to both. My object
here is clearly to define terms, and not permit physical
error to lurk beneath them, How far this ice, with a soft-
ness thus defined, when subjected to the gradual pressures
exerted in a glacier, is bruised and broken, and how far the
motion of its parts may approach to that of a truly viscous
body under pressure, I do not know. The critical point
here is that the ice changes its form, and preserves its
continuity, during its motion, in virtue of external force.
It remains continuous whilst it moves, because its par-
ticles are kept in juxtaposition by pressure, and when
this external prop is removed, and the ice, subjected to
350 PRESSUEE AND TENSION.
tension, has to depend solely upon the mobility of its
own particles to preserve its continuity, the analogy with
a viscous body instantly breaks down.*
* " Imagine," writes Professor Forbe-s, " a long narrow trough or canal,
stopped at both ends and filled to a considerable depth with treacle, honey,
tar, or any such viscid fluid. Imagine one end of the trough to give way,
the bottom still remaining horizontal : if the friction of the fluid against the
bottom be greater than the friction against its own particles, the upper
strata will roll over the lower ones, and protrude in a convex slope, which
will be propagated backwards towards the other or closed end of the
trough. Had the matter been quite fluid the whole would have run out,
and spread itself on a level : as it is, it assumes precisely the conditions
which we suppose to exist in a glacier." This is perfectly definite, and
my equally definite opinion is that no glacier ever exhibited the me-
chanical effects implied by this experiment.
FARADAY'S FIEST EXPERIMENT. 351
REGELATION.
(23.)
I WAS led to the foregoing results by reflecting on an
experiment performed by Mr. Faraday, at a Friday
evening meeting of the Royal Institution, on the 7th
of June, 1850, and described in the 'Athenaeum' and
c Literary Gazette ' for the same month. Mr. Faraday
then showed that when two pieces of ice, with moistened
surfaces, were placed in contact, they became cemented
together by the freezing of the film of water between
them, while, when the ice was below 32° Fahr., and
therefore dry, no effect of the kind could be produced.
The freezing was also found to take place under water ;
and indeed it occurs even when the water in which the
ice is plunged is as hot as the hand can bear.
A generalisation from this interesting fact led me to
conclude that a bruised mass of ice, if closely confined,
must re-cement itself when its particles are brought into
contact by pressure; in fact, the whole of the experi-
ments above recorded immediately suggested themselves
to my mind as natural deductions from the principle esta-
blished by Faraday. A rough preliminary experiment
assured me that the deductions would stand testing ; and
the construction of the box-wood moulds was the conse-
quence. We could doubtless mould many solid substances
to any extent by suitable pressure, breaking the attach-
ment of their particles, and re-establishing a certain con-
tinuity by the mere force of cohesion. With such sub-
stances, to which we should never think of applying the
term viscous, we might also imitate the changes of form to
which glaciers are subject : but, superadded to the mere
cohesion which here comes into play, we have, in the case of
352 RECENT EXPERIMENTS OF FARADAY.
ice, the actual regelation of the severed surfaces, and conse-
quently a more perfect solid. In the Introduction to this
book I have referred to the production of slaty cleavage by
pressure ; and at a future page I hope to show that the
lamination of the ice of glaciers is due to the same cause ;
but, as justly observed by Mr. John Ball, there is no ten-
dency to cleave in the sound ice of glaciers ; in fact, this
tendency is obliterated by the perfect regelation of the
severed surfaces.
Mr. Faraday has recently placed pieces of ice, in water,
under the strain of forces tending to pull them apart.
When two such pieces touch at a single point they adhere
and move together as a rigid piece ; but a little lateral
force carefully applied breaks up this union with a crack-
ling noise, and a new adhesion occurs which holds the
pieces together in opposition to the force which tends to
divide them. Mr. James Thomson had referred regelation
to the cold produced by the liquefaction of the pressed ice ;
but in the above experiment all pressure is not only taken
away, but is replaced by tension. Mr. Thomson also con-
ceives that, when pieces of ice are simply placed together
without intentional pressure, the capillary attraction brings
the pressure of the atmosphere into play ; but Mr. Faraday
finds that regelation takes place in vacuo. A true viscidity
on the part of ice Mr. Faraday never has observed, and he
considers that his recent experiments support the view
originally propounded by himself, namely, that a particle
of water on a surface of ice becomes solid when placed
between two surfaces, because of the increased influence
due to their joint action.
HOW CRYSTALS ARE "NURSED." 353
CRYSTALLIZATION AND INTERNAL
LIQUEFACTION
(24.)
IN the Introduction to this book I have briefly referred to
the force of crystallization. To permit this force to exer-
cise its full influence, it must have free and unimpeded
action ; a crystal, for instance, to be properly built, ought
to be suspended in the middle of the crystallizing solu-
tion, so that the little architects can work all round it ;
or if placed upon the bottom of a vessel, it ought to be
frequently turned, so that all its facets may be succes-
sively subjected to the building process. In this way
crystals can be nursed to an enormous size. But where
other forces mingle with that of crystallization, this har-
mony of action is destroyed ; the figures, for example,
that we see upon a glass window, on a frosty morning,
are due to an action compounded of the pure crystalline
force and the cohesion of the liquid to the window-pane.
A more regular effect is obtained when the freezing par-
ticles are suspended in still air, and here they build them-
selves into those wonderful figures which Dr. Scoresbyhas
observed in the Polar Regions, Mr. Glaisher at Greenwich,
and I myself on the summit of Monte Rosa and elsewhere.
Not only however in air, but in water also, figures of
great beauty are sometimes formed. Harrison's excellent
machine for the production of artificial ice is, I suppose,
now well known ; the freezing being effected by carrying
brine, which had been cooled by the evaporation of ether,
round a series of flat tin vessels containing water. The
latter gradually freezes, and, on watching those vessels
while the action was proceeding very slowly, I have seen
little six-rayed stars of thin ice forming, and rising to the
A A
354 DISSECTION OF ICE BY SUNBEAM.
surface of the liquid. I believe the fact was never before
observed, but it would be interesting to follow it up, and
to develop experimentally this most interesting case of
crystallization.
The surface of a freezing lake presents to the eye of the
observer nothing which could lead him to suppose that
a similar molecular architecture is going on there. Still
the particles are undoubtedly related to each other in this
way ; they are arranged together on this starry type. And
not only is this the case at the surface, but the largest
blocks of ice which reach us from Norway and the Wen-
ham Lake are wholly built up in this way. We can re-
veal the internal constitution of these masses by a reverse
process to that which formed them ; we can send an agent
into the interior of a mass of ice which shall take down
the atoms which the crystallizing forces had set up.
This agent is a solar beam ; with which it first occurred
to me to make this simple experiment in the autumn of
1857. I placed a large converging lens in the sunbeams
passing through a room, and observed the place where the
rays were brought to a focus behind the lens ; then shad-
ing the lens, I placed a clear cube of ice so that the point
of convergence of the rays might fall within it. On re-
moving the screen from the lens, a cone of sunlight went
through the cube, and along the course of the cone the
ice became studded with lustrous spots, evidently formed
by the beam, as if minute reflectors had been sud-
denly, established within the mass, from which the light
flashed when it met them. On examining the cube after-
wards I found that each of these spots was surrounded by a
liquid flower of six petals ; such flowers were distributed in
hundreds through the ice, being usually clear and detached
from each other, but sometimes crowded together into
liquid bouquets, through which, however, the six-starred
element could be plainly traced. At first the edges of the
LIQUID FLOWEES IN ICE. 355
leaves were unbroken curves, but when the flowers expanded
under a long-continued action, the edges became serrated.
When the ice was held at a suitable angle to the solar
beams, these liquid blossoms, with their central spots
shining more intensely than burnished silver, presented
an exhibition of beauty not easily described. I have given
a sketch of their appearance in Fig. 34.
Fig. 34.
I have here to direct attention to an extremely curious
fact. On sending the sunbeam through the transparent
ice, I often noticed that the appearance of the lustrous
spots was accompanied by an audible clink, as if the ice
were ruptured inwardly. But there is no ground for
assuming such rupture, and on the closest examination
no flaw is exhibited by the ice. What then can be the
cause of the noise ? I believe the following considerations
will answer the question : —
Water always holds a quantity of air in solution, the
diffusion of which through the liquid, as proved by M.
Donny, has an immense effect in weakening the cohesion
of its particles ; recent experiments of my own show that
this is also the case in an eminent degree with many
volatile liquids. M. Donny has proved that, if water be
thoroughly purged of its air, a long glass tube filled with
A A 2
356 WATER DEPRIVED OF AIR SNAPS ASUNDER.
this liquid may be inverted, while the tenacity with which
the water clings to the tube, and with which its particles
cling to each other, is so great that it will remain securely
suspended, though no external hindrance be offered to
its descent. Owing to the same cause, water deprived of its
air will not boil at 212° Fahr., and may be raised to a tem-
perature of nearly 300° without boiling ; but when this
occurs the particles break .their cohesion suddenly, and
ebullition is converted into explosion.
Now, when ice is formed, every trace of the air which
the water contained is squeezed out of it ; the particles in
crystallizing reject all extraneous matter, so that in ice we
have a substance quite free from the air, which is never
absent in the case of water ; it therefore follows that if we
could preserve the water derived from the melting of ice
from contact with the atmosphere, we should have a liquid
eminently calculated to show the effects described by M.
Donny. Mr. Faraday has proved by actual experiment
that this is the case.
Let us apply these facts to the explanation of the clink
heard in my experiments. On sending a sunbeam through
ice, liquid cavities are suddenly formed at various points
within the mass, and these cavities are completely cut off
from atmospheric contact. But the water formed by the
melting ice is less in volume than the ice which produces
it; the water of a cavity is not able to fill it, hence a
vacuous space must be formed in the cell. I have 110
doubt that, for a time, the strong cohesion between the
walls of the cell and the drop within it augments the
volume of the latter a little, so as to compel it to fill the
cell; but as the quantity of liquid becomes greater the
shrinking force augments, until finally the particles snap
asunder like a broken spring. At the same moment a
lustrous spot appears, which is a vacuum, and simul-
taneously with the appearance of this vacuum the clink
FIGURES IN ICE; VACUOUS SPOTS. 357
was always heard. Multitudes of such little explosions
must be heard upon a glacier when the strong summer
sun shines upon it, the aggregate of which must, I think,
contribute to produce the "crepitation" noticed by M.
Agassiz, and to which I have already referred.
In Plate VI. of the Atlas which accompanies the ' Sys-
teme Glaciaire ' of M. Agassiz, I notice drawings of figures
like those I have described, which he has observed in glacier-
ice, and which were doubtless produced by direct solar radia-
tion. I have often myself observed figures of exquisite
beauty formed in the ice on the surface of glacier-pools by
the morning sun. In some cases the spaces between the
leaves of the liquid flowers melt partially away, and leave
the central spot surrounded by a crimped border ; sometimes
these spaces wholly disappear, and the entire space bounded
by the lines drawn from point to point of the leaves be-
comes liquid, thus forming perfect hexagons. The crimped
borders exhibit different degrees of serration, from the
full leaves themselves to a gentle undulating line, which
latter sometimes merges into a perfect circle. In the ice
of glaciers, I have seen the internal liquefaction ramify
itself like sprigs of myrtle ; in the same ice, and par-
ticularly towards the extremities of the glacier, disks innu-
merable are also formed, consisting of flat round liquid
spaces, a bright spot being usually associated with each.
These spots have been hitherto mistaken for air-bubbles ;
but both they and the lustrous disks at the centres of the
flowers are vacuous. I proved them to be so by plunging
the ice containing them into hot water, and watching
what occurred when the walls of the cells were dissolved,
and a liquid connexion established between them and the
atmosphere. In all cases they totally collapsed, and no
trace of air rose to the surface of the warm water.
No matter in what direction a solar beam is sent through
lake-ice, the liquid flowers are all formed parallel to the
358 CONSTITUTION OF GKLACIEK-ICE.
surface of freezing. The beam may be sent parallel, per-
pendicular, or oblique to this surface; the flowers are
always formed in the same planes. Every line perpendi-
cular to the surface of a frozen lake is in fact an axis of
symmetry, round which the molecules so arrange them-
selves, that, when taken down by the delicate fingers of the
sunbeam, the six-leaved liquid flowers are the result.
In the ice of glaciers we have no definite planes of
freezing. It is first snow, which has been disturbed by
winds while falling, and whirled, and tossed about by the
same agency after it has fallen, being often melted, satur-
ated with its own water, and refrozen : it is cast in shattered
fragments down cascades, and reconsolidated by pressure
at the bottom. In ice so formed and subjected to such
mutations, definite planes of freezing are, of course, out of
the question.
The flat round disks and vacuous spots to which I have
referred come here to our aid, and furnish us with an entirely
new means of analysing the internal constitution of a glacier.
When we examine a mass of glacier-ice which contains these
disks, we find them lying in all imaginable planes ; not
confusedly, however — closer examination shows us that the
disks are arranged in groups, the members of each group
being parallel to a common plane, but the parallelism
ceases when different groups are compared. The effect is
exactly what would be observed, supposing ordinary lake-
ice to be broken up, shaken together, and the confused
fragments regelated to a compact continuous mass. In
such a jumble the original planes of freezing would lie in
various directions ; but no matter how compact or how
transparent ice thus constituted might appear, a solar
beam would at once reveal its internal constitution by
developing the flowers parallel to the planes of freezing of
the respective fragments. A sunbeam sent through glacier-
ice always reveals the flowers in the planes of the disks, so
VACUOUS CELLS MISTAKEN FOR AIR-CELLS. 359
that the latter alone at once informs us of its crystalline
constitution.
Hitherto, as I have said, these disks have been mistaken
for bubbles containing air, and their flattening has been
ascribed to the pressure to which they have been subjected.
M. Agassiz thus refers to them : — " The air-bubbles un-
dergo no less curious modifications. In the neighbourhood of
the neve, where they are most numerous, those which one
sees on the surface are all spherical or ovoid, but by
degrees they begin to be flattened, and near the end of the
glacier there are some that are so flat that they might be
taken for fissures when seen in profile. The drawing
represents a piece of ice detached from the gallery of infil-
tration. All the bubbles are greatly flattened. But what
is most extraordinary is, that, far from being uniform, the
flattening is different in each fragment ; so that the bubbles,
according to the face which they offer, appear either very
broad or very thin." This description of glacier-ice is
correct : it agrees with the statements of all other obser-
vers. But there are two assumptions in the description
which must henceforth be given up ; first, the bubbles
seen like fissures in profile are not air-bubbles at all, but
vacuous spots, which the very constitution of ice renders
a necessary concomitant of its inward melting; secondly,
the assumption that the bubbles have been flattened by
pressure must be abandoned; for they are found, and
may be developed at will, in lake-ice on which no pres-
sure has been exerted.
But these remarks dispose only of a certain class of cells
contained in glacier-ice. Besides the liquid disks and
vacuous spots, there are innumerable true bubbles en-
tangled in the mass. These have also been observed and
described by M. Agassiz ; and Mr. Huxley has also given
us an accurate account of them. M. Agassiz frequently
found air and water associated in the same cell. Mr.
360 CELLS OF AIR AND WATER.
Huxley found no exception to the rule : in each case the
bubble of air was enclosed in a cell which was also partially
filled with water. He supposes that the water may be that
of the originally-melted snow which has been carried down
from the neve unfrozen. This hypothesis is worthy of a
great deal more consideration than I have had time to give
to it, and I state it here in the hope that it will be duly
examined.
My own experience of these associated air and water
cells is derived almost exclusively from lake-ice, in which I
have often observed them in considerable numbers. In
examining whether the liquid contents had ever been
frozen or not, I was guided by the following considerations.
If the air be that originally entangled in the solid, it will
have the ordinary atmospheric density at least ; but if it be
due to the melting of the walls of the cell, then the water-
so formed being only eight-ninths of that of the ice which
produced it, the air of the bubble must be rarefied. I
suppose I have made a hundred different experiments upon
these bubbles to determine whether the air was rarefied or
not, and in every case found it so. Ice containing the
bubbles was immersed in warm water, and always, when
the rigid envelope surrounding a bubble was melted away,
the air suddenly collapsed to a fraction of its original
dimensions. I think I may safely affirm that, in some
cases, the collapse reduced the bubbles to the thousandth
part of their original volume. From these experiments I
should undoubtedly infer, that in lake-ice at least, the
liquid of the cells is produced by the melting of the ice
surrounding the bubbles of air.
But I have not subjected the bubbles of glacier-ice to
the same searching examination. I have tried whether
the insertion of a pin would produce the collapse of the
bubbles, but it did not appear to do so. I also made a few
experiments at Rosenlaui, with warm water, but the result
"LIQUID LIBERTY." 361
was not satisfactory. That ice melts internally at the
surfaces of the bubbles is, I think, rendered certain by my
experiments, but whether the water-cells of glacier-ice
are entirely due to such melting, subsequent observers
will no doubt determine.
I have found these composite bubbles at all parts of
glaciers ; in the ice of the moraines, over which a protective
covering had been thrown ; in the ice of sand-cones, after
the removal of the superincumbent debris ; also in ice
taken from the roofs of caverns formed in the glacier, and
which the direct sunlight could hardly by any possibility
attain. That ice should liquefy at the surface of a cavity
is, I think, in conformity with all we know concerning the
physical nature of heat. Regarding it as a motion of the
particles, it is easy to see that this motion is less restrained
at the surface of a cavity than in the solid itself, where
the oscillation of each atom is controlled by the particles
which surround it ; hence liquid liberty, if I may use the
term, is first attained at the surface. Indeed I have proved
by experiment that ice may be melted internally by heat
which has been conducted through its external portions
without melting them. These facts are the exact com-
plements of those of " regelation ; " for here, two moist sur-
faces of ice being brought into close contact, their liquid
liberty is destroyed and the surfaces freeze together.
362 MOULIN ON GKINDELWALD GLACIER
THE MOULINS.
(25.)
THE first time I had an opportunity of seeing these
remarkable glacier-chimneys, was in the summer of 1856,
upon the lower glacier of Grindelwald. Mr. Huxley was
my companion at the time, and on crossing the so-called
Eismeer we heard a sound resembling the rumble of distant
thunder, which proceeded from a perpendicular shaft
formed in the ice, and into which a resounding cataract
discharged itself. The tube in fact resembled a vast organ-
pipe, whose thunder-notes were awakened by the concussion
of the falling water, instead of by the gentle flow of a
current of air. Beside the shaft our guide hewed steps, on
which we stood in succession, and looked into the tre-
mendous hole. Near the first shaft was a second and
smaller one, the significance of which I did not then
understand ; it was not more than 20 feet deep, but
seemed filled with a liquid of exquisite blue, the colour
being really due to the magical shimmer from the walls
of the moulin, which was quite empty. As far as we
could see, the large shaft was vertical, but on dropping a
stone into it a shock was soon heard, and after a succession
of bumps, which occupied in all seven seconds, we heard the
stone no more. The depth of the moulin could not be thus
ascertained, but we soon found a second and still larger one
which gave us better data. A stone dropped into this de-
scended without interruption for four seconds, when a con-
cussion was heard ; and three seconds afterwards the final
shock was audible : there was thus but a single interruption
in the descent. Supposing all the acquired velocity to have
been destroyed by the shock, by adding the space passed
DEPTH OF SHAFT. 363
over by the stone in four and in three seconds respectively,
and making allowance for the time required by the sound
to ascend from the bottom, we find the depth of the shaft
to be about 345 feet. There is, however, no reason to
suppose that this measures the depth of the glacier at
the place referred to. These shafts are to be found in
almost all great glaciers ; they are very numerous in the
Unteraar Glacier, numbers of them however being empty.
On the Mer de Glace they are always to be found in the
region of Trelaporte, one of the shafts there being, par
excellence, called the Grand Moulin. Many of them also
occur on the Glacier de Lechaud.
As truly observed by M. Agassiz, these moulins occur
only at those parts of the glacier which are not much rent
by fissures, for only at such portions can the little rills
produced by superficial melting collect to form streams
of any magnitude. The valley of unbroken ice formed in
the Mer de Glace near Trelaporte is peculiarly favourable
for the collection of such streams ; we see the little rills
commencing, and enlarging by the contributions of others,
the trunk-rill pouring its contents into a little stream
which stretches out a hundred similar arms over the sur-
face of the glacier. Several such streams join, and finally
a considerable brook, which receives the superficial drainage
of a large area, cuts its way through the ice.
But although this portion of the glacier is free from
those long-continued and permanent strains which, having
once rent the ice, tend subsequently to widen the rent and
produce yawning crevasses, it is not free from local strains
sufficient to produce cracks which penetrate the glacier to
a great depth. Imagine such a crack intersecting such
a glacier-rivulet as we have described. The water rushes
down it, and soon scoops a funnel large enough to engulf
the entire stream. The moulin is thus formed, and, as the
ice moves downward, the sides of the crack are squeezed
364 MOULINS EXPLAINED.
together and regelated, the seam which marks the line
of junction being in most cases distinctly visible. But
as the motion continues, other portions of the glacier come
into the same state of strain as that which produced the
first crack; a second one is formed across the stream,
the old shaft is forsaken, and a new one is hollowed out,
in which for a season the cataract plays the thunderer. I
have in some cases counted the forsaken shafts of six
old moulins in advance of an active one. Not far from
the Grand Moulin of the Mer de Glace in 1857 there was
a second empty shaft, which evidently communicated by
a subglacial duct with that into which the torrent was
precipitated. Out of the old orifice issued a strong cold
blast, the air being manifestly impelled through the duct
by the falling water of the adjacent moulin.
These shafts are always found in the same locality ; the
portion of the Mer de Glace to which I have referred is
never without them. Some of the guides affirm that they
are motionless; and a statement of Prof. Forbes has led
to the belief that this was also his opinion.* M. Agassiz,
however, observed the motion of some of these shafts
upon the glacier of the Aar ; and when on the spot in
1857, I was anxious to decide the point by accurate
measurements with the theodolite.
My friend Mr. Hirst took charge of the instrument, and
on the 28th of July I fixed a single stake beside the Grand
Moulin, in a straight line between a station at Trelaporte
and a well-defined mark on the rock at the opposite side
of the valley. On the 31st, the displacement of the stake
amounted to 50 inches, and on the 1st of August it had
moved 74^ inches — the moulin, to all appearance, occupy-
ing throughout the same position with regard to the stake.
* " Every year, and year after year, the watercourses follow the same
lines of direction— their streams are precipitated into the heart of the
glacier by vertical funnels, called ' moulins,' at the very same points."—
Forbes's Fourth Letter upon Glaciers : ' Occ. Pap.,' p. 29.
MOTION OF THE MOULINS. 365
To render this certain, moreover we subsequently drove two
additional stakes into the ice, thus enclosing the mouth
of the shaft in a triangle. On the 8th of August the
displacements were measured and gave the following
results :—
Total Motion.
First (old) stake 198 inches.
Second (new) do 123
Third 124 „
The old stake had been fixed for 11 days, and its daily
motion — which ivas also that of the moulin — averaged
18 inches a day. Hence the moulins share the general
motion of the glacier, and their apparent permanence is
not, as has been alleged, a proof of the semi-fluidity of the
glacier, but is due to the breaking of the ice as it passes
the place of local strain.
Wishing to obtain some estimate as to the depth of
the ice, Mr. Hirst undertook the sounding of some of the
moulins upon the Glacier de Lechaud, making use of a
tin vessel filled with lumps of lead and iron as a weight.
The cord gave way and he lost his plummet. To measure
the depth of the Grand Moulin, we obtained fresh cord
from Chamouni, to which we attached a four-pound weight.
Into a cavity at the bottom of the weight we stuffed a quan-
tity of butter, to indicate the nature of the bottom against
which the weight might strike. The weight was dropped
into the shaft, and the cord paid out until its slackening
informed us that the weight had come to rest ; by shaking
the string, however, and walking round the edge of the
shaft, the weight was liberated, and sank some distance fur-
ther. The cord partially slackened a second time, but the
strain still remaining was sufficient to render it doubtful
whether it was the weight or the action of the falling water
which produced it. We accordingly paid out the cord to
the end, but, on withdrawing it, found that the greater part
of it had been coiled and knotted up by the falling water.
366 DEPTH OF "GRAND MOULIN" SOUGHT.
We uncoiled, and sounded again. At a depth of 132 feet
the weight reached a ledge or protuberance of ice, and by
shaking and lifting it, it was caused to descend 31 feet more.
A depth of 163 feet was the utmost we could attain to.
We sounded the old moulin to a depth of 90 feet ; while a
third little shaft, beside the large one, measured only
18 feet in depth. We could see the water escape from it
through a lateral canal at its bottom, and doubtless the
water of the Grand Moulin found a similar exit. There
was no trace of dirt upon the butter, which might have
indicated that we had reached the bed of the glacier.
DIRT-BANDS OF THE MER DE GLACE, AS SEEN FROM A POINT
NEAR THE FLEGERE.
FIG. 35.
To face p. 367.
DIET-BANDS FROM THE FLEG-ERE. 367
DIRT-BANDS OF THE MER, DE GLACE.
(26.)
THESE bands were first noticed by Prof. Forbes on the 24th
of July, 1842, and were described by him in the following
words : — {C My eye was caught by a very peculiar appear-
ance of the surface of the ice, which I was certain that I
now saw for the first time. It consisted of nearly hyper-
bolic brownish bands on the glacier, the curves pointing
downwards, and the two branches mingling indiscriminately
with the moraines, presenting an appearance of a succession
of waves some hundred feet apart." * From no single point
of view hitherto attained can all the Dirt-Bands of the
Mer de Glace be seen at once. To see those on the
terminal portion of the glacier, a station ought to be chosen
on the opposite range of the Brevent, a few hundred yards
beyond the Croix de la Flegere, where we stand exactly
in front of the glacier as it issues into the valley of Cha-
mouni. The appearance of the bands upon the portion
here seen is represented in Fig. 35.
It will be seen that the bands are confined to one side
of the glacier, and either do not exist, or are obliterated by
the debris, upon the other side. The cause of the accumu-
lation of dirt on the right side of the glacier is, that no less
than five moraines are crowded together at this side. In
the upper portions of the Mer de Glace these moraines are
distinct from each other ; but in descending, the successive
engulfments and disgorgings of the blocks and dirt have
broken up the moraines ; and at the place now before us the
materials which composed them are strewn confusedly on
' the right side of the glacier. The portion of the ice on
which the dirt-bands appear is derived from the Col du
* ' Travels,' page 162.
368 DIET-BANDS FKOM LES CHAKMOZ.
Geant. They do not quite extend to the end of the glacier,
being obliterated by the dislocation of the ice upon the
frozen cascade of Des Bois.
Let us now proceed across the valley of Chamouni to
the Montanvert ; where, climbing the adjacent heights to
an elevation of six or eight hundred feet above the hotel,
we command a view of the Mer de Glace, from Trelaporte
almost to the commencement of the Glacier des Bois. It
was from this position that Professor Forbes first observed
the bands. Fifteen, sixteen, and seventeen years later I
observed them from the same position. The number of
bands which Professor Forbes counted from this position was
eighteen, with which my observations agree. The entire
series of bands which I observed, with the exception of
one or two, must have been the successors of those observed
by Professor Forbes ; and my finding the same number
after an interval of so many years proves that the bands
must be due to some regularly recurrent cause. Fig. 36
represents the bands as seen from the heights adjacent to
the Montanvert.
I would here direct attention to an analogy between a
glacier and a river, which may be observed from the
heights above the Montanvert, but to which no reference,
as far as I know, has hitherto been made. When a river
meets the buttress of a bridge, the water rises against it,
and, on sweeping round it, forms an elevated ridge, be-
tween which and the pier a depression occurs which varies
in depth with the force of the current. This effect is
shown by the Mer de Glace on an exaggerated scale.
Sweeping round Trelaporte, the ice pushes itself beyond
the promontory in an elevated ridge, from which it drops
by a gradual slope to the adjacent wall of the valley,
thus forming a depression typified by that already alluded
to. A similar effect is observed at the opposite side of the
glacier on turning round the Echelets ; and both combine
DIRT-BANDS OP THE MEK DE GLACE, AS SEEN FROM
LES CHARMOZ.
FIG. 3(i.
To fate p. 368.
DIRT-BANDS OF THE HER DE GLACE, AS SEEN FROM THE
CLEFT STATION, TRELAPORTE.
FIG. 37.
To face p. 369.
FEOM THE CLEFT-STATION.
369
to form a kind of skew surface. A careful inspection of
the frontispiece will detect this peculiarity in the shape of
the glacier.
From neither of the stations referred to do we obtain
any clue to the origin of the dirt-bands. A stiff but
pleasant climb will place us in that singular cleft in the
cliffy mountain-ridge which is seen to the right of the
frontispiece ; and from it we easily attain the high plat-
form of rock immediately to the left of it. We stand here
high above the promontory of Trelaporte, and occupy the
finest station from which the Mer de Glace and its tribu-
taries can be viewed. From this station we trace the dirt-
bands over most of the ice that we have already scanned,
and have the further advantage of being able to follow
them to their very source.
This source is the grand ice-cascade which descends in a
succession of precipices from the plateau of the Col du
Geant into the valley which the Glacier du Geant fills.
We see from our present point of view that the bands
are confined to the portion of the glacier ivhich has descended
the cascade. Fig. 37 represents the bands as seen from
the Cleft-station above Trelaporte.
We are now however at such a height above the glacier
and at such a distance from the base of the cascade, that we
can form but an imperfect notion of the true contour of the
surface. Let us therefore descend, and walk up the Glacier
du Geant towards the cascade. At first our road is level,
but we gradually find that at certain intervals we have to
ascend slopes which follow each other in succession, each
being separated from its neighbour by a space of compara-
tively level ice. The slopes increase in steepness as we
ascend ; they are steepest, moreover, on the right-hand
*ide of the glacier, where it is bounded by that from the
Periades, and at length we are unable to climb them without
the aid of an axe. Soon afterwards the dislocation of the
B B
370 SNOW-BANDS ON THE GLACIER DU GEANT.
glacier becomes considerable ; we are lost in the clefts and
depressions of the ice, and are unable to obtain a view
sufficiently commanding to subdue these local appearances
and convey to us the general aspect. We have at all events
satisfied ourselves as to the existence, on the upper portion
of the glacier, of a succession of undulations which sweep
transversely across it. The term " wrinkles," applied to
them by Prof. Forbes, is highly suggestive of the appear-
ance which they present.
From the Cleft-station bands of snow may also be seen
partially crossing the glacier in correspondence with the
undulations upon its surface. If the quantity deposited
the winter previous be large, and the heat of summer not
too great, these bands extend quite across the glacier.
They were first observed by Professor Forbes in 1843. In
his Fifth Letter is given an illustrative diagram, which,
though erroneous as regards the position of the veined
structure, is quite correct in limiting the snow-bands to
the Glacier du Geant proper.
At the place where the three welded tributaries of the Mer
de Glace squeeze themselves through the strait of Trela-
porte, the bands undergo a considerable modification in
shape. Near their origin they sweep across the Glacier
du Geant in gentle curves, with their convexities directed
downwards ; but at Trelaporte these curves, the chords
of which a short time previous measured a thousand yards
in length, have to squeeze themselves through a space of
four hundred and ninety-five yards wide ; and as might be
expected, they are here suddenly sharpened. The apex of
each being thrust forward, they take the form of sharp
hyperbolas, and preserve this character throughout the
entire length of the Mer de Glace.
I would now conduct the reader to a point from which a
good general view of the ice cascade of the Geant is
attainable. From the old moraine near the lake of the
FOKBES'S EXPLANATION. 371
Tacul we observe the ice, as it descends the fall, to be
broken into a succession of precipices. It would appear as
if the glacier had its back periodically broken at the sum-
mit of the fall, and formed a series of vast chasms separated
from each other by cliffy ridges of corresponding size.
These, as they approach the bottom of the fall, become
more and more toned down by the action of sun and air,
and at some distance below the base of the cascade
they are subdued so as to form the transverse undula-
tions already described. These undulations are more and
more reduced as the glacier descends; and long before
the Tacul is attained, every sensible trace of them has
disappeared. The terraces of the ice-fall are referred to by
Professor Forbes in his Thirteenth Letter, where he thus
describes them : — " The ice-falls succeed one another at
regulated intervals, which appear to correspond to the
renewal of each summer's activity in those realms of almost
perpetual frost, when a swifter motion occasions a more rapid
and wholesale projection of the mass over the steep, thus
forming curvilinear terraces like vast stairs, which appear
afterwards by consolidation to form the remarkable pro-
tuberant wrinkles on the surface of the Glacier du Geant."
With regard to the cause of the distribution of the dirt in
bands, Professor Forbes writes thus in his Third Letter :—
" I at length assured myself that it was entirely owing to
the structure of the ice, which retains the dirt diffused by
avalanches and the weather on those parts which are most
porous, whilst the compacter portion is washed clean by
the rain, so that those bands are nothing more than visible
traces of the direction of the internal icy structure." Pro-
fessor Forbes's theory, at that time, was that the glacier is
composed throughout of a series of alternate segments of
hard and porous ice, in the latter of which the dirt found a
lodgment. I do not know whether he now retains his
first opinion ; but in his Fifteenth Letter he speaks of
B B 2
372 TRANSVERSE UNDULATIONS.
accounting for " the less compact structure of the ice
beneath the dirt-band."
It appears to me that in the above explanation cause has
been mistaken for effect. The ice on which the dirt-bands
rest certainly appears to be of a spongier character than
the cleaner intermediate ice ; but instead of this being
the cause of the dirt-bands, the latter, I imagine, by
their more copious absorption of the sun's rays and the
consequent greater disintegration of the ice, are the cause
of the apparent porosity. I have not been able to detect
any relative porosity in the " internal icy structure," nor am
I able to find in the writings of Professor Forbes a de-
scription of the experiments whereby he satisfied himself
that this assumed difference exists.
Several days of the summer of 1857 were devoted by
me to the examination of these bands. I then found the
bases and the frontal slopes of the undulations to which I
have referred covered with a fine brown mud. These
slopes were also, in some cases, covered with snow which
the great heat of the weather had not been able entirely
to remove. At places where the residue of snow was small
its surface was exceedingly dirty — so dirty indeed that it
appeared as if peat-mould had been strewn over it ; its edges
particularly were of a black brown. It was perfectly mani-
fest that this snow formed a receptacle for the fine dirt
transported by the innumerable little rills which trickled
over the glacier. The snow gradually wasted, but it left
its sediment behind, and thus each of the snowy bands ob-
served by Professor Forbes in 1843, contributed to produce
an appearance perfectly antithetical to its own. I have
said that the frontal slopes of the undulations were thus
covered ; and it was on these, and not in the depressions,
that the snow principally rested. The reason of this is to
be found in the bearing of the Glacier du Geant, which,
looking downwards, is about fourteen degrees east of the
INFLUENCE OF DIRECTION OF GLACIEK. 373
meridian.* Hence the frontal slopes of the undulations
have a northern aspect, and it is this circumstance which,
in my opinion, causes the retention of the snow upon them.
Irrespective of the snow, the mere tendency of the dirt to
accumulate at the bases of the undulations would also
produce bands, and indeed does so on many glaciers ;
but the precision and beauty of the dirt-bands of the Mer
de Glace are, I think, to be mainly referred to the inter-
ception by the snow of the fine dark mud before referred
to on the northern slopes of its undulations.
Were the statements of some writers upon this subject
well founded, or were the dirt-bands as drawn upon the
map of Professor Forbes correctly shown, this explanation
could not stand a moment. It has been urged that the dirt-
bands cannot thus belong to a single tributary of the Mer
de Glace ; for if they did, they would be confined to that
tributary upon the trunk-glacier ; whereas the fact is that
they extend quite across the trunk, and intersect the
moraines which divide the Glacier du Geant from its
fellow-tributaries. From my first acquaintance with the
Mer de Glace I had reason to believe that this statement
was incorrect ; but last year I climbed a third time to the
Cleft-station for the purpose of once more inspecting the
bands from this fine position. I was accompanied by
Dr. Frankland and Auguste Balmat, and I drew the at-
tention of both particularly to this point. Neither of them
could discern, nor could I, the slightest trace of a dirt-
band crossing any one of the moraines. Upon the trunk-
stream they were just as much confined to the Glacier
du Geant as ever. If the bands even existed east of the
* In the large map of Professor Forbes the bearing of the valley is
nearly sixty degrees west of the meridian ; but this is caused by the true
north being drawn on the wrong side of the magnetic north ; thus making
the declination easterly instead of westerly. In the map in Johnson's
' Physical Atlas ' this mistake is corrected.
374 BANDS DO NOT CROSS MORAINES.
moraines, they could not be seen, the dirt on this part of
the glacier being sufficient to mask them.
The following interesting fact may perhaps have contri-
buted to the production of the error referred to. Opposite
to Trelaporte the eastern arms of the dirt-bands run so
obliquely into the moraine of La Noire that the latter
appears to be a tangent to them. But this moraine runs
along the Mer de Glace, not far from its centre, and con-
sequently the point of contact of each dirt-band with the
moraine moves more quickly than the point of contact of
the western arm of the same band with the side of the
valley. Hence there is a tendency to straighten the bands ;
and at some distance down the glacier the effect of this is
seen in the bands abutting against the moraine of La Noire
at a larger angle than before. The branches thus abutting
have, I believe, been ideally prolonged across the moraines.
On the map published by Prof. Forbes in 1843 the
bands are shown crossing the medial moraines of the Mer de
Glace; and they are also thus drawn on the
map in Johnson's ' Physical Atlas ' pub-
lished in 1849. The text is also in ac-
cordance with the map : — " Opposite to
the Montanvert, and beyond les Echelets,
the curved loops (dirt-bands) extend
across the entire glacier. They are single,
and therefore cut the medial moraine,
though at a very slight angle." — ' Travels,'
p. 166. The italics here belong to Prof.
Forbes. In order to help future observers
to place this point beyond doubt, I annex,
in Fig. 38, a portion of the map of the
Mer de Glace taken from the Atlas re-
ferred to. If it be compared with Fig. 35 the difference
between Prof. Forbes and myself will be clearly seen. The
portion of the glacier represented in both diagrams may
ANNUAL "KINGS." 375
be viewed from the point near the Flegere already re-
ferred to.
The explanation which I have given involves three con-
siderations : — The transverse breaking of the glacier on the
cascade, and the gradual accumulation of the dirt in the
hollows between the ridges ; the subsequent toning down
of the ridges to gentle protuberances which sweep across
the glacier ; and the collection of the dirt upon the slopes
and at the bases of these protuberances. Whether the
periods of transverse fracture are annual or not — whether
the " wrinkles " correspond to a yearly gush — and whether,
consequently, the dirt-bands mark the growth of a glacier
as the " annual rings " mark the growth of a tree, I do not
know. It is a conjecture well worthy of consideration ; but
it is only a conjecture, which future observation may either
ratify or refute.
376 GENERAL APPEARANCE,
THE VEINED STRUCTURE OF GLACIERS.
THE general appearance of the veined structure may be
thus briefly described : — The ice of glaciers, especially mid-
way between their mountain-sources and their inferior ex-
tremities, is of a whitish hue, caused by the number of
small air-bubbles which it contains, and which, no doubt,
constitute the residue of the air originally entrapped in the
interstices of the snow from which it has been derived.
Through the general whitish mass, at some places, innumer-
able parallel veins of clearer ice are drawn, which usually
present a beautiful blue colour, and give the ice a laminated
appearance. The cause of the blueness is, that the air-
bubbles, distributed so plentifully through the general
mass, do not exist in the veins, or only in comparatively
small numbers.
In different glaciers, and in different parts of the same
glacier, these veins display various degrees of perfection.
On the clean unweathered walls of some crevasses, and in
the channels worn in the ice by glacier-streams, they are
most distinctly seen, and are often exquisitely beautiful.
They are not to be regarded as a partial phenomenon, or as
affecting the constitution of glaciers to a small extent merely.
A large portion of the ice of some glaciers is thus affected.
The greater part, for example, of the Mer de Glace con-
sists of this laminated ice ; and the whole of the Glacier of
the Rhone, from the base of the ice-cascade downwards, is
composed of ice of the same description.
Those who have ascended Snowdon, or wandered among
the hills of Cumberland, or even walked in the environs of
Leeds, Blackburn, and other towns in Yorkshire and Lan-
cashire, where the stratified sandstone of the district is
GROOVES ON THE SURFACE OF GLACIERS. 377
used for building purposes, may have observed the
weathered edges of the slate rocks or of the building-stone
to be grooved and furrowed. Some laminae of such rocks
withstand the action of the atmosphere better than others,
and the more resistant ones stand out in ridges after
the softer parts between them have been eaten away. An
effect exactly similar is observed where the laminated ice
of glaciers is exposed to the action of the sun and air.
Little grooves and ridges are formed upon its surface, the
more resistant plates protruding after the softer material
between them has been melted away.
One consequence of this furrowing is, that the light dirt
scattered by the winds over the surface of the glacier is
gradually washed into the little grooves, thus forming fine
lines resembling those produced by the passage of a rake
over a sanded walk. These lines are a valuable index to
some of the phenomena of motion. From a position on
the ice of the Glacier du Geant a little higher up than Tre-
laporte a fine view of these superficial groovings is obtained ;
but the dirt-lines are not always straight. A slight power
of independent motion is enjoyed by the separate parts into
which a glacier is divided by its crevasses and dislocations,
and hence it is, that, at the place alluded to, the dirt-lines
are bent hither and thither, though the ruptures of conti-
nuity are too small to affect materially the general direction
of the structure. On the glacier of the Talefre I found
these groovings useful as indicating the character of the
forces to which the ice near the summit of the fall is sub-
jected. The ridges between the chasms are in many cases
violently bent and twisted, while the adjacent groovings
enable us to see the normal position of the mass.
The veined structure has been observed by different
travellers; but it was probably first referred to by Sir
David Brewster, who noticed the veins of the Mer
de Glace on the 10th of September, 1814. I was also
378 GUYOT'S OBSEKVATIONS.
observed by General Sabine,* by Rendu, by Agassiz, and
no doubt by many others ; but the first clear description
of it was given by M. Guyot, in a communication pre-
sented to the Geological Society of France in 1838. I quote
the following passage from this paper : — " I saw under my
feet the surface of the entire glacier covered with regular
furrows from one to two inches wide, hollowed out in a half
snowy mass, and separated by protruding plates of harder
and more transparent ice. It was evident that the mass
of the glacier here was composed of two sorts of ice, one
that of the furrows, snowy and more easily melted ; the
other that of the plates, more perfect, crystalline, glassy,
and resistant ; and that the unequal resistance which the
two kinds of ice presented to the atmosphere was the cause
of the furrows and ridges. After having followed them for
several hundreds of yards, I reached a fissure twenty or thirty
feet wide, which, as it cut the plates and furrows at right
angles, exposed the interior of the glacier to a depth of
* In reply to a question in connexion with this subject, General Sabine
has favoured me with the following note : —
" MY DEAR TYNDALL,
" It was in the summer of 1841, at the Lower Grinclelwald Glacier,
that I first saw, and was greatly impressed and interested by examining
and endeavouring to understand (in which I did not succeed), the veined
structure of the ice. I do not remember when I mentioned it to Forbes,
but it must be before 1843, because it is noticed in his book, p. 29. I had
never observed it in the glaciers of Spitzbergen or Baffin's Bay, or in the
icebergs of the shores and straits of Davis or Barrow. I feel the more
confident of this, because, when I first saw the veined structure in Switzer-
land, my Arctic experience was more fresh in my recollection, and I recol-
lected nothing like it.
" Veins are indeed not uncommon in icebergs, but they quite resemble
veins in rocks, and are formed by water filling fissures and freezing into
blue ice, finely contrasted with the white granular substance of the berg.
" The ice of the Grindelwald Glacier (where I examined the veined
structure) was broken up into very large masses, which by pressure had
been upturned, so that a very poor judgment would be formed of the direc-
tion of the veins as they existed in the glacier before it had broken up.
" Sincerely yours,
" Feb. 20, 1860." « EDWAKD SABINE.
FORBES'S KESEARCHES. 379
thirty or forty feet, and gave a beautiful transverse section
of the structure. As far as my vision could reach I saw
the mass of the glacier composed of layers of snowy ice,
each two of which were separated by one of the plates of
which I have spoken, the whole forming a regularly lami-
nated mass, which resembled certain calcareous slates."
Previous observers had mistaken the lamination for
stratification ; but M. Guyot not only clearly saw that they
were different, but in the comparison which he makes he
touches, I believe, on the true cause of the glacier-structure.
He did not hazard an explanation of the phenomenon, and
I believe his memoir remained unprinted. In 1841 the
structure was noticed by Professor Forbes during his visit
to M. Agassiz on the lower Aar Glacier, and described in
a communication presented by him to the Koyal Society
of Edinburgh. He subsequently devoted much time to the
subject, and his great merit in connexion with it consists
in the significance which he ascribed to the phenomenon
when he first observed it, and in the fact of his having
proved it to be a constitutional feature of glaciers in general.
The first explanation given of those veins by Professor
Forbes was, that they were small fissures formed in the ice
by its motion ; that these were filled with the water of the
melted ice in summer, which froze in winter so as to form
the blue veins. This is the explanation given in his
' Travels,' page 377 ; and in a letter published in the
1 Edinburgh New Philosophical Journal,' October, 1844, it is
re-affirmed in these words : — " With the abundance of blue
bands before us in the direction in which the differential
motion must take place (in this case sensibly parallel to the
sides of the glacier), it is impossible to doubt that these
infiltrated crevices (for such they undoubtedly are) have
this origin." This theory was examined by Mr. Huxley
and myself in our joint paper ; but it has been since alleged
that ours was unnecessary labour, Prof. Forbes himself
380 FORBES'S THEOEY.
having in his Thirteenth Letter renounced the theory,
and substituted another in its place. The latter theory
differs, so far as I can understand it, from the former in
this particular, that the freezing of the water in the fissures
is discarded, their sides being now supposed to be united
" by the simple effects of time and cohesion." * For a
statement of the change which his opinions have undergone,
I would refer to the Prefatory Note which precedes the
volume of ' Occasional Papers ' recently published by Prof.
Forbes ; but it would have diminished my difficulty had
the author given, in connexion with his new volume, a
more distinct statement of his present views regarding
the veined structure. With many of his observations
and remarks I should agree ; with many others I cannot
say whether I agree or not ; and there are others still
with which I do not think I should agree : but in hardly
any case am I certain of his precise views, excepting,
indeed, the cardinal one, wherein he and others agree in
ascribing to the structure a different origin from stratifi-
cation. Thus circumstanced, my proper course, I think,
will be to state what I believe to be the cause of the
structure, and leave it to the reader to decide how far
our views harmonize ; or to what extent either of them is
a true interpretation of nature.
Most of the earlier observers considered the structure to
be due to the stratification of the mountain-snows — a view
which has received later development at the hands of Mr.
John Ball ; and the practical difficulty of distinguishing
the undoubted effects of stratification from the phenomena
* In a letter to myself, published in the 17th volume of the ' Philoso-
phical Magazine,' Professor Forbes writes as follows : — " In 1846, then, I
abandoned no part of the theory of the veined structure, on which as you
say so much labour had been expended, except the admission, always
yielded with reluctance, and got rid of with satisfaction, that the conge-
lation of water in the crevices of the glacier may extend in winter to a
great depth."
USUAL ASPECT OF BLUE VEINS.
381
presented by structure, entitles this view to the fullest
consideration. The blue veins of glaciers are, however,
not always, nor even generally, such as we should expect
to result from stratification. The latter would furnish us
with distinct planes extending parallel to each other for
considerable distances through the glacier ; but this,
though sometimes the case, is by no means the general
character of the structure. We observe blue streaks, from
a few inches to several feet in length, upon the walls of
the same crevasse, and varying from the fraction of an
inch to several inches in thickness. In some cases the
streaks are definitely bounded, giving rise to an appear-
ance resembling the section of a lens, and hence called
the " lenticular structure" by Mr. Huxley and myself ; but
more usually they fade away in pale washy streaks through
the general mass of the whitish ice. In Fig. 39 I have
given a representation of the
structure as it is very com-
monly exhibited on the walls
of crevasses. Its aspect is not
that which we should expect
from the consolidation of suc-
cessive beds of mountain snow.
Further, at the bases of ice-
cascades the structural lami-
nae are usually vertical : below
the cascade of the Talefre,
of the Noire, of the Strah-
leck branch of the Lower
Grindelwald Glacier, of the
Rhone, and other ice-falls,
this is the case ; and it seems extremely difficult to
conceive that a mass horizontally stratified at the summit
of the fall, should, in its descent, contrive to turn its strata
perfectly on end.
Fig. 39.
382 ILLUSTRATIVE EXPERIMENTS.
Again, we often find a very feebly-developed structure
at the central portions of a glacier, while the lateral por-
tions are very decidedly laminated. This is the case where
the inclination of the glacier is nearly uniform through-
out ; and where no medial moraines occur to complicate
the phenomenon. But if the veins mark the bedding,
there seems to be no sufficient reason for their appearance
at the lateral portions of the glacier, and their absence
from the centre.
This leads me to the point at which what I consider
to be the true cause of the structure may be referred to.
The theoretic researches of Mr. Hopkins have taught
us a good deal regarding the pressures and tensions
consequent upon glacier-motion. Aided by this know-
ledge, and also by a mode of experiment first introduced
by Professor Forbes, I will now endeavour to explain the
significance of the fact referred to in the last paragraph.
If a plastic substance, such as mud, flow down a sloping
canal, the lateral portions, being held back by friction, will
be outstripped by the central ones. When the flow is so
regulated that the velocity of a point at the centre shall
not vary throughout the entire length of the canal, a
coloured circle stamped upon the centre of the mud
stream, near its origin, will move along with the mud,
and still retain its circular form ; for, inasmuch as the
velocity of all points along the centre is the same, there
can be no elongation of the circle longitudinally or
transversely by either strain or pressure. A similar ab-
sence of longitudinal pressure may exist in a glacier, and,
where it exists throughout, no central structure can, in my
opinion, be developed.
But let a circle be stamped upon the mud-stream near
its side, then, when the mud flows, this circle will be
distorted to an oval, with its major axis oblique to the
direction of motion ; the cause of this is that the portion
MAKGINAL STRUCTURE. 883
of the circle farthest from the side of the canal moves
more freely than that adjacent to the side. The mecha-
nical effect of the slower lateral motion is to squeeze the
circle in one direction, and. draw it out in the perpendicular
one.
A glance at Fig. 40 will render all that I have said in-
telligible. The three cir-
cles are first stamped on
the mud in the same
transverse line ; but
after they have moved
downwards they will be Elg> 40'
in the same straight line no longer. The central one
will be the foremost ; while the lateral ones have their
forms changed from circles to ovals. In a glacier of
the shape of this canal exactly similar effects are pro-
duced. Now the shorter axis m n of each oval is a
line of squeezing or pressure ; the longer axis is a line
of strain or tension ; and the associated glacier-pheno-
mena are as follows : — Across the line m n, or perpen-
dicular to the pressure, we have the veined structure
developed, while across the line of tension the glacier
usually breaks and forms marginal crevasses. Mr. Hopkins
has shown that the lines of greatest pressure and of greatest
strain are at right angles to each other, and that in valleys of
a uniform width they enclose an angle of forty-five degrees
with the side of the glacier. To the structure thus formed
I have applied the term marginal structure. Here, then,
we see that there are mechanical agencies at work near the
side of such a glacier which are absent from the centre,
and we have effects developed — I believe by the pressure —
in the lateral ice, which are not produced in the central.
I have used the term " uniform inclination " in con-
nexion with the marginal structure, and my reason for
doing so will now appear. In many glaciers the structure,
384 STEUCTUEE OF GEINDELWALD GLACIEE,
instead of being confined to the margins, sweeps quite
across them. This is the case, for example, on the Glacier
du Geant, the structure of which is prolonged into the
Mer de Glace. In passing the strait at Trelaporte, how-
ever, the curves are squeezed and their apices bruised,
so that the structure is thrown into a state of confusion ;
and thus upon the Mer de Glace we encounter difficulty
in tracing it fairly from side to side. Now the key to this
transverse structure I believe to be the following : Where
the inclination of the glacier suddenly changes from a
steep slope to a gentler, as at the bases of the " cas-
cades,"— the ice to a certain depth must be thrown into
a state of violent longitudinal compression; and along
with this we have the resistance which the gentler slope
throws athwart the ice descending from the steep one.
At such places a structure is developed transverse to
the axis of the glacier, and likewise transverse to the
pressure. The quicker flow of the centre causes this struc-
ture to bend more and more, and after a time it sweeps in
vast curves across the entire glacier.
In illustration of this point I will refer, in the first place,
to that tributary of the Lower Glacier of Grindelwald
which descends from the Strahleck. Walking up this tri-
butary we come at length to the base of an ice-fall. Let
the observer here leave the ice, and betake himself to
either side of the flanking mountain. On attaining a point
which commands a view both of the fall and of the glacier
below it, an inspection of the glacier will, I imagine, solve
to his satisfaction the case of structure now under consi-
deration.
It is indeed a grand experiment which Nature here
submits to our inspection. The glacier descending from
its neve reaches the summit of the cascade, and is broken
transversely as it crosses the brow ; it afterwards descends
the fall in a succession of cliffy ice-ridges with transverse
BASE OF CASCADE A " STRUCTURE-MILL." 385
hollows between them. In these latter the broken ice and
debris collect, thus partially choking the fissures formed in
the first instance. Carrying the eye downwards along the
fall, we see, as we approach the base, these sharp ridges
toned down; and a little below the base they dwindle
into rounded protuberances which sweep in curves quite
across the glacier. At the base of the fall the structure
begins to appear, feebly at first, but becoming gradually
more pronounced, until, at a short distance below the base
of the fall, the eye can follow the fine superficial groovings
from side to side ; while at the same time the ice under-
neath the surface has become laminated in the most
beautiful manner.
It is difficult to convey by writing the force of the evi-
dence which the actual observation of this natural experi-
ment places before the mind. The ice at the base of the
fall, retarded by the gentler inclination of the valley, has
to bear the thrust of the descending mass, the sudden
change of inclination producing powerful longitudinal
compression. The protuberances are squeezed more
closely together, the hollows between them appear to
wrinkle up in submission to the pressure — in short, the
entire aspect of the glacier suggests the powerful opera-
tions of the latter force. At the place where it is exerted
the veined structure makes its appearance ; and being once
formed, it moves downwards, and gives a character to other
portions of the glacier which had no share in its for-
mation.
An illustration almost as good, and equally accessi-
ble, is furnished by the Glacier of the Rhone. I have
examined the grand cascade of this glacier from both
, sides; and an ordinary mountaineer will find little diffi-
culty in reaching a point from which the fall and the
terminal portion of the glacier are both distinctly visible.
Here also he will find the cliffy ridges separated from
C C
386
STRUCTURE OF RHONE GLACIER.
each other by transverse chasms, becoming more and
more subdued at the bottom of the fall, and disappearing
entirely lower down the glacier. As in the case of the
Grindelwald Glacier, the squeezing of the protuberances
and of the spaces between them is quite apparent, and
where this squeezing commences the transverse structure
makes its appearance. All the ice that forms the lower
portion of this glacier has to pass through the structure-
mill at the bottom of the fall, and the consequence is that
it is all laminated.
Fig. 41.
This case of structural development will be better appre-
ciated on reference to Figs. 41 and 42, the former of which
Fig. 42.
TRANSVERSE STRUCTURE. 387
is a plan, and the latter a section, of a part of the
ice-fall and of the glacier below it ; a b e f is the gorge
of the fall, / b being the base. The transverse cliffy
ice-ridges are shown crossing the cascade, being subdued
at the base to protuberances which gradually disappear as
they advance downwards. The structure sweeps over the
glacier in the direction of the fine curved lines ; and I have
also endeavoured to show the direction of the radial cre-
vasses, which, in the centre at least,, are at right angles to
the veins. To the manifestation of structure here consi-
dered I have, for the sake of convenient reference, applied
the term transverse structure.
A third exhibition of the structure is now to be
noticed. We sometimes find it in the middle of a glacier
and running parallel to its length. On the centre of the
ice-fall of the Talefre, for example, we have a structure of
this kind which preserves itself parallel to the axis of the
fall from top to bottom. But we discover its origin higher
up. The structure here has been produced at the extremity
of the Jardin, where the divided ice meets, and not only
brings into partial parallelism the veins previously exist-
ing along the sides of the Jardin, but develops them still
further by the mutual pressure of the portions of newly
welded ice. Where two tributary glaciers unite, this is
perhaps without exception the case. Underneath the
moraine formed by the junction of the Talefre and Lechaud
the structure is finely developed, and the veins run in the
direction of the moraine. The same is true of the ice
under the moraine formed by the junction of the Lechaud
and Geant. These afterwards form the great medial mo-
raines of the Mer de Glace, and hence the structure of the
trunk-stream underneath these moraines is parallel to the
direction of the glacier. This is also true of the system of
moraines formed by the glaciers of Monte Rosa. It is
true in an especial manner of the lower glacier of the Aar,
c c 2
888
LONGITUDINAL STKUCTUKE.
whose medial moraine perhaps attains grander proportions
than any other in the Alps, and underneath which the
structure is finely developed.
The manner in which I have illustrated the production
of this structure will be understood from Fig. 43. B B
are two wooden boxes,
communicating by
sluice-fronts with two
branch canals, which
unite to a common
trunk atG. They are
intended to. represent
respectively the trunk
and tributaries of the
Unteraar Glacier, the
part G being the Ab-
schwung, where the
Lauteraar and Fin-
steraar glaciers unite
to form the Unteraar.
The mud is first per-
Fig- 43> mitted to flow beneath
the two sluices until it has covered the bottom of the
trough for some distance, when it is arrested. The end of
a glass tube is then dipped into a mixture of rouge and
water, and small circles are stamped upon the mud. The
two branches are thickly covered with these circles. The
sluices being again raised, the mud in the branches moves
downwards, carrying with it the circles stamped upon it ;
and the manner in which these circles are distorted enables
us to infer the strains and pressures to which the mud is
subjected during its descent. The figure represents approxi-
mately what takes place. The side-circles, as might be ex-
pected, are squeezed to oblique ovals, but it is at the
junction of the branches that the chief eifect of pressure is
EFFOETS TO SOLVE QUESTION. 389
produced. Here, by the mutual thrust of the branches, the
circles are not only changed to elongated ellipses, but even
squeezed to straight lines. In the case of the glacier this
is the region at which the structure receives its main
development. To this manifestation of the veins I have
applied the term longitudinal structure.
The three main sources of the blue veins are, I think,
here noted ; but besides these there are many local causes
which influence their production. I have seen them well
formed where a glacier is opposed by the sudden bend of
a valley, or by a local promontory which presents an ob-
stacle sufficient to bring the requisite pressure into play.
In the glaciers of the Tyrol and of the Oberland I have
seen examples of this kind ; but the three principal
sources of the veins are, I think, those stated above.
It was long before I cleared my mind of doubt regard-
ing the origin of the lamination. When on the Mer de
Glace in 1857 I spared neither risk nor labour to instruct
myself regarding it. I explored the Talefre basin, its cas-
cade, and the ice beneath it. Several days were spent
amid the ice humps and cliffs at the lower portion of
the fall. I suppose I traversed the Glacier du Geant
twenty times, and passed eight or ten days amid the con-
fusion of its great cascade. I visited those places where,
it had been affirmed, the veins were produced. I endea-
voured to satisfy myself of the mutability which had been
ascribed to them ; but a close examination reduced the
value of each particular case so much that I quitted the
glacier that year with nothing more than an opinion that
the structure and the stratification were two different
things. I, however, drew up a statement of the facts
, observed, with the view of presenting it to the Eoyal
Society ; but I afterwards felt that in thus acting I should
merely swell the literature of the subject without adding
anything certain. I therefore withheld the paper, and
390 EXPEDITION FOE THIS PURPOSE.
resolved to devote another year to a search among the chiet
glaciers of the Oberland, of the Canton Valais, and of Savoy,
for proofs which should relieve my mind of all doubt upon
the subject.
Accordingly in 1858 I visited the glaciers of Rosenlaui,
Schwartzwald, Grindelwald, the Aar, the Ehone, and the
Aletsch, to the examination of which latter I devoted more
than a week. I afterwards went to Zermatt, and, taking up
my quarters at the Riffelberg, devoted eleven days to the
examination of the great system of glaciers of Monte Rosa.
I explored the Gorner Glacier up almost to the Cima de
Jazzi ; and believed that in it I could trace the structure
from portions of the glacier where it vanished, through
various stages of perfection, up to its full development. I
believe this still ; but yet it is nothing but a belief, which
the utmost labour that I could bestow did not raise
to a certainty. The Western glacier of Monte Rosa, the
Schwartze Glacier, the Trifti Glacier, the glacier of the
little Mont Cervin, and of St. Theodule, were all examined
in connexion with the great trunk-stream of the Gorner,
to which they weld themselves ; and though the more I
pursued the subject the stronger my conviction became
that pressure was the cause of the structure, a crucial case
was still wanting.
In the phenomena of slaty cleavage, it is often, if not
usually, found that the true cleavage cuts the planes of
stratification — sometimes at a very high angle. Had this
not been proved by the observations of Sedgwick and
others, geologists would not have been able to conclude that
cleavage and bedding were two different things, and
needed wholly different explanations. My aim, throughout
the expedition of 1858, was to discover in the ice a parallel
case to the above ; to find a clear and undoubted instance
where the veins and the stratification were simultaneously
exhibited, cutting each other at an unmistakable angle.
CASE OF STKUCTUEE ON THE ALETSCH. 391
On the 6th of August, while engaged with Professor
Kamsay upon the Great Aletsch Glacier, not far from
its junction with the Middle Aletsch , I observed what
appeared to me to be the lines of bedding running nearly
horizontal along the wall of a great crevasse, while cut-
ting them at a large angle was the true veined structure.
I drew my friend's attention to the fact, and to him it
appeared perfectly conclusive. It is from a sketch made
by him at the place that Fig. 44 has been taken.
Fig. 44.
This was the only case of the kind which I observed
upon the Aletsch Glacier ; and as I afterwards spent day
after day upon the Monte Kosa glaciers, vainly seek-
ing a similar instance, the thought again haunted me
that we might have been mistaken upon the Aletsch.
In this state of mind I remained until the 18th of August,
a day devoted to the examination of the Furgge Glacier,
which lies at the base of the Mont Cervin.
Crossing the valley of the Gorner Glacier, and taking a
plunge as I passed into the Schwarze See, I reached, in
good time, the object of my day's excursion. Walking up
the glacier, I at length found myself opposed by a frozen
cascade composed of four high terraces of ice. The
highest of these was chiefly composed of ice-cliffs and
j many of which had fallen, and now stood like
392 STKUCTUKE OF THE FURGGE GLACIER.
rocking-stones upon the edge of the second terrace. The
glacier at the base of the cascade was strewn with
broken ice, and some blocks two hundred cubic feet in
volume had been cast to a considerable distance down
the glacier.
Upon the faces of the terraces the stratification of the
neve was most beautifully shown, running in parallel and
horizontal lines along the weathered surface. The snow-
field above the cascade is a frozen plain, smooth almost as
a sheltered lake. The successive snow-falls deposit them-
selves with great regularity, and at the summit of the
cascade the sections of the neve are for the first time
exposed. Hence their peculiar beauty and definition.
Indeed the figure of a lake pouring itself over a rocky
barrier which curves convexly upwards, thus causing the
water to fall down it, not only longitudinally over the
vertex of the curve, but laterally over its two arms, will
convey a tolerably correct conception of the shape of the
fall. Towards the centre the ice was powerfully squeezed
laterally, the beds were bent, and their continuity often
broken by faults. On inspecting the ice from a distance
with my opera glass, I thought I saw structural groovings
cutting the strata at almost a right angle. Had the ques-
tion been an undisputed one, I should perhaps have felt
so sure of this as not to incur the danger of pushing the
inquiry further; but, under the circumstances, danger
was a secondary point. Eesigning, therefore, my glass
to my guide, who was to watch the tottering blocks over-
head, and give me warning should they move, I advanced
to the base of the fall, removed with my hatchet the
weathered surface of the ice, and found underneath it the
true veined structure, cutting, at nearly a right angle, the
planes of stratification. The superficial groovings were not
uniformly distributed over the fall, but appeared most
decided at those places where the ice appeared to have
ICE TERRACE EXAMINED. 393
been most squeezed. I examined three or four of these
places, and in each case found the true veins nearly ver-
tical, while the bedding was horizontal. Having perfectly
satisfied myself of these facts, I made a speedy retreat,
for the ice-blocks seemed most threatening, and the sunny
hour was that at which they fall most frequently.
I next tried the ascent of the glacier up a dislocated
declivity to the right. The ice was much riven, but
still practicable. My way for a time lay amid fissures
which exposed magnificent sections, and every step I
took added further demonstration to what I had observed
below. The strata were perfectly distinct, the structure
equally so, and one crossed the other at an angle 01
seventy or eighty degrees. Mr. Sorby has adduced a case
of the crumpling of a bed of sandstone through which
the cleavage passes : here on the glacier I had parallel
cases ; the beds were bent and crumpled, but the struc-
ture ran through the ice in sharp straight lines. This
perhaps was the most pleasant day I ever spent upon
the glaciers : my mind was relieved of a long brooding
doubt, and the intellectual freedom thus obtained added
a subjective grandeur to the noble scene before me.
Climbing the cliffs near the base of the Matterhorn, I
walked along the rocky spine which extends to the Hornli,
and afterwards descended by the valley of Zmutt to Zer-
matt.
A year after my return to England a remark contained
in Professor Mousson's interesting little work 'Die Gletscher
der Jetzzeit ' caused me to refer to the atlas of M.
Agassiz's c Systeme Glaciaire,' from which I learned that
this indefatigable observer had figured a case of stratifi-
cation and structure cutting each other. If, however, I
had seen this figure beforehand, it would not have changed
my movements ; for the case, as sketched, would not have
convinced me. I have now no doubt that M. Agassiz has
394
LAMINATION AND STRATIFICATION.
preceded me in this observation, and hence my results are
to be taken as mere confirmations of his.
Fig. 45 represents a
crumpled portion of the ice
with the lines of lamination
passing through the strata.
Fig. 46 represents a case
where a fault had oc-
curred, the veins at both
sides of the line of dislocation being inclined towards each
other.
[Figs. 45 and 46 are from sketches made on the Furgge Glacier.— L. C. T.]
DIFFERENTIAL MOTION GREATEST AT EDGES. 395
THE VEINED STRUCTURE AND THE
DIFFERENTIAL MOTION.
(28.)
I HAVE now to examine briefly the explanation of the
structure which refers it to differential motion — to a sliding
of the particles of ice past each other, which leaves the
traces of its existence in the blue veins. The fact is em-
phatically dwelt upon by those who hold this view, that
the structure is best developed nearest to the sides of the
glacier, where the differential motion is greatest. Why
the differential motion is at its maximum near to the
sides is easily understood. Let A B, A ... c<
c D, Fig. 47, represent the two sides
of a glacier, moving in the direction of
the arrow, and let m a b c n be a
straight line of stakes set out across
the glacier to-day. Six months hence
this line, by the motion of the ice
downwards, will be bent to the form
m a' I' c' n: this curve will not be cir-
cular, it will be flattened in the middle ;
the points a and c, at some distance
on each side of the centre 6, move in rig. 47.
fact with nearly the same velocity as the centre itself.
Not so with the sides : — a' and c' have moved considerably
in advance of m and n, and hence we say that the differ-
ence of motion, or the differential motion, of the particles
of ice near to the side is a maximum.
During all this time the points m a' V cr n have been
moving straight down the glacier ; and hence it will be
understood that the sliding of the parts past each other,
396 STKUCTUEE OBLIQUE TO SIDES.
or in other words, the differential motion, is parallel to the
sides of the glacier. This, indeed, is the only differential
motion that experiment has ever established ; and conse-
quently, when we find the best blue veins referred to
the sides of the glacier because the differential motion
is there greatest, we naturally infer that the motion meant
is parallel to the sides.
But the fact is, that this motion would not at all account
for the blue veins, for they are not parallel to the sides,
but oblique to them. This difficulty revealed itself after a
time to those who first propounded the theory of differen-
tial motion, and caused them to modify their explanation
of the structure. Differential motion is still assumed to be
the cause of the veins, but now a motion is meant oblique to
the sides, and it is supposed to be obtained in the following
way : — Through the quicker motion of the point c' the
ice between it and n becomes distended ; that is to
say, the line c' n is in a state of strain — there is a drag,
it is said, oblique to the sides of the glacier ; and it
is therefore in this direction that the particles will be
caused to slide past each other. Dr. Whew ell, who ad-
vocates this view, thus expounds it. He supposes the case
of an alpine valley filled with india-rubber which has been
warmed until it has partially melted, or become viscous, and
then asks, " What will now be the condition of the mass ?
The sides and bottom will still be held back by the fric-
tion ; the middle and upper part will slide forwards, but not
freely. This want of freedom in the motion (arising from
the viscosity) will produce a drag towards the middle of
the valley, where the motion is freest; hence the direction
in which the filaments slide past each other will be ob-
liquely directed towards the middle. The sliding will
separate the mass according to such lines ; and though new
attachments will take place, the mass may be expected to
retain the results of this separation in the traces of parallel
STRUCTURE CROSSES LINES OF SLIDING 397
fissures." * Nothing can be clearer than the image of the
process thus placed before the mind's eye.
One fact of especial importance is to be borne in mind : the
sliding of filaments which is thus supposed to take place
oblique to the glacier has never been proved ; it is wholly
assumed. A moraine, it is admitted, will run parallel to
the side of a glacier, or a block will move in the same
direction from beginning to end, without being sensibly
drawn towards the centre, but still it is supposed that the
sliding of parts exists, though of a character so small as
to render it insensible to measurement.
My chief difficulty as regards this theory may be ex-
pressed in a very few words. If the structure be produced
by differential motion, why is the large and real differential
motion which experiments have established incompetent
to produce it ? And how can the veins run, as they are
admitted to do, across the lines of maximum sliding from
their origin throughout the glacier to its end ?
That a drag towards the centre of the glacier exists is
undeniable, but that in consequence of the drag there is a
sliding of filaments in this direction, is quite another thing.
I have in another place f endeavoured to show experi-
mentally that no such sliding takes place, that the drag
on any point towards the centre expresses only half the
conditions of the problem ; being exactly neutralized by
the thrust towards the sides. It has been, moreover,
shown by Mr. Hopkins that the lines of maximum strain
and of maximum sliding cannot coincide ; indeed, if all the
particles be urged by the same force, no matter how
strong the pull may be, there will be no tendency of one
to slide past the other.
* 'Philosophical Magazine,' Ser. III., vol. xxvi.
t ' Proceedings of the Royal Institution,' vol. ii. p. 324.
398 THEORY STATED.
THE RIPPLE-THEORY OF THE VEINED
STRUCTURE.
(29.) '' .
THE assamption of oblique sliding, and the production
thereby of the marginal structure, have, however, been
fortified by considerations of an ingenious and very inte-
resting kind. " How," I have asked, " can the oblique
structure persist across the lines of greatest differential
motion throughout the length of the glacier ? " But here I
am met by another question which at first sight might
seem equally unanswerable — " How do ripple-marks on
the surface of a flowing river, which are nothing else
than lines of differential motion of a low order, cross the
river from the sides obliquely, while the direction of greatest
differential motion is parallel to the sides ? " If I under-
stand aright, this is the main argument of Professor Forbes
in favour of his theory of the oblique marginal structure.
It is first introduced in a note at page 378 of his c Travels ; '
he alludes to it in a letter written the following year ; in his
paper in the ' Philosophical Transactions ' he develops the
theory. He there gives drawings of ripple-marks observed
in smooth gutters after rain, arid which he finds to be in-
clined to the course of the stream, exactly as the marginal
structure is inclined to the side of the glacier. The explana-
tion also embraces the case of an obstacle placed in the centre
of a river. " A case," writes Professor Forbes, " parallel
to the last mentioned, where a fixed obstacle cleaves a de-
scending stream, and leaves its trace in a fan-shaped tail,
is well known in several glaciers, as in that at Ferpecle,
and the Glacier de Lys on the south side of Monte Rosa ;
particularly the last, where the veined structure follows
the law just mentioned." In his Twelfth Letter he
THEORY EXAMINED. 399
also refers to the ripples " as exactly corresponding to
the position of the icy bands." In his letter to Dr.
Whewell, published in the ' Occasional Papers,' page 58,
he writes as follows : — " The same is remarkably shown
in the case of a stream of water, for instance a mill-
race. Although the movement of the water, as shown
by floating bodies, is exceedingly nearly (for small velo-
cities sensibly) parallel to the sides, yet the variation
of the speed from the side to the centre of the stream
occasions a ripple, or molecular discontinuity, which
inclines forwards from the sides to the centre of the
stream at an angle with the axis depending on the
ratio of the central and lateral velocity. The veined
structure of the ice corresponds to the ripple of the water,
a molecular discontinuit}T whose measure is not com-
parable to the actual velocity of the ice ; and therefore
the general movement of the glacier, as indicated by the
moraines, remains sensibly parallel to the sides." This
theory opens up to us a series of interesting and novel
considerations which I think will repay the reader's atten-
tion. If the ripples in the water and the veins in the
ice be due to the same mechanical cause, when we develop
clearly the origin of the former we are led directly to the
explanation of the latter. I shall now endeavour to re-
duce the ripples to their mechanical elements.
The Messrs. Weber have described in their ' Wellen-
lehre ' an effect of wave- mot ion which it is very
easy to obtain. When a boat moves through perfectly
smooth water, and the rower raises his oar out of the
water, drops trickle from its blade, and each drop where it
falls produces a system of concentric rings. The cir-
cular waves as they widen become depressed, and, it
the drops succeed each other with sufficient speed, the
rings cross each other at innumerable points. The effect
of this is to blot out more or less completely all the
400 RIPPLES DEDUCED FROM RINGS.
circles, and to leave behind two straight divergent
ripple-lines, which are tangents to all the external rings ;
being in fact formed by the intersections of the latter,
as a caustic in optics is formed by the intersection of
luminous rays. Fig. 48, which is virtually copied from
Fig. 48.
M. Weber, will render this description at once intelli-
gible. The boat is supposed to move in 1^ie direction ot
the arrow, and as it does so the rings hich it leaves
behind widen, and produce the diverge*" e of the two
straight resultant lines of ripple.
The more quickly the drops succeed each other, the
more frequent will be the intersections of the rings ; but as
the speed of succession augments we apr -oach the case
of a continuous vein of liquid ; and if we sr ose the con-
tinuity to be perfectly established, the ripp will still be
produced with a smooth space between f n as before.
This experiment may indeed be made witt i well-wetted
oar, which on its first emergence from the water sends into
it a continuous liquid vein. The same effect is produced
when we substitute for the stream of liquid a solid rod —
a common walking-stick for example. A water-fowl swim-
ming in calm, water produces two divergent lines of ripples
of a similar kind.
We have here supposed the water of the lake to be at
rest, and the liquid vein or the solid rod to uove through
MEASUKE OF DIVEKGENCE OF KIPPLES. 401
it ; but precisely the same effect is produced if we suppose
the rod at rest and the liquid in motion. Let a post, for
example, be fixed in the middle of a flowing river ; diverg-
ing from that post right and left we shall have lines of
ripples exactly as if the liquid were at rest and the post
moved through it with the velocity of the river. If the
same post be placed close to the bank, so that one of its
edges only shall act upon the water, diverging from that
edge we shall have a single line of ripples which will cross
the river obliquely towards its centre. It is manifest that
any other obstacu- will produce the same effect as our
hypothetical post. In the words of Professor Forbes, " the
slightest prominence of any kind in the wall of such a
conduit, a bit oFj wood or a tuft of grass, is sufficient to
produce a well-marked ripple-streak from the side towards
the centre."
The foregoing considerations show that the divergence
of the two liner, of ripple^ from the central post, and of
the single line ^n the case of the lateral post, have their
mechanical elei vent, if I may use the term, in the
experiment of ,ae Messrs. Weber. In the case of a
swimming duck the connexion between the diverging
lines of ripples and the propagation of rings round a
disturbed poir; &, often very prettily shown. When the
creature swir ,- ,vith vigour the little foot with which
it strikes the later often comes sufficiently near to the
surface to proc ve an elevation. — sometimes indeed emerg-
ing from the w^ier altogether. Kouiid the point thus dis-
turbed rings are immediately propagated, and the widening
of those rings is the exact measure of the divergence of the
ripple lines. The rings never cross the lines ; — the lines
never retreat from the rings.
If we compare the mechanical actions here traced out
with those which take place upon a glacier, I think it will
be seen that the analogy between the ripples and the
D D
402 KIPPLES AND VEINS DUE TO DIFFEKENT CAUSES.
veined structure is entirely superficial. How the struc-
ture ascribed to the Glacier de Lys is to be explained I
do not know, for I have never seen it ; but it seems im-
possible that it could be produced, as ripples are, by a fixed
obstacle which "cleaves a descending stream." No one
surely will affirm that glacier-ice so closely resembles a
fluid as to be capable of transmitting undulations, as water
propagates rings round a disturbed point. The difficulty
of such a supposition would be augmented by taking into
account the motion of the individual liquid particles which
go to form a ripple ; for the Messrs. Weber have shown
that these move in closed curves, describing orbits more
or less circular. Can it be supposed that the particles of
ice execute a motion of this kind? If do, their orbital
motions may be easily calculated, being deducible from
the "motion of the glacier compounded with the inclination
of the veins. If so important a result could be established,
all glacier theories would vanish Ji^ comparison with it.
There is another interesting point involved in the pas-
sage above quoted. Professor Forbes considers that the
ripple is occasioned by the variation of speed from the side
to the centre of the stream, and that its inclination depends
on the ratio of the central and lateral velocity. If I am
correct in the above analysis, this cannot be the case. The
inclination of the ripple depends solely on the ratio of the
river's translatory motion to the velocity of its wave-
motion. Were the lateral and central velocities alike, a
momentary disturbance it the side would produce a straight
ripple-mark, whose inclination would be compounded of
the two elements just mentioned. If the motion of the
water vary from side to centre, the velocity of wave-pro-
pagation remaining constant, the inclination of the ripple
will also vary, that is to say, we shall have a curved ripple
instead of a straight one. This, of course, is the case which
we find in Nature, but the curvature of such ripples is
POSITION OF RIPPLES NOT THAT OF STRUCTURE. 403
totally different from that of the veined structure. Owing
to the quicker translatory movement, the ripples, as they
approach the centre, tend more to parallelism with the
direction of the river ; and after having passed the centre,
and reached the slower water near the opposite side, their
inclination to the axis gradually augments. Thus the
ripples from the two sides form a pair of symmetric curves,
which cross each other at the centre, and possess the form
a o b, c o dj shown in Fig. 49. A similar pair of curves
Fig. 49.
would be produced by the reflection of these. Knowing
the variation of motion from side to centre, any competent
mathematician could find the equation of the ripple-curves ;
but it would be out of place for me to attempt it here.
404 POSSIBLE EXPERIMENT WITH GLASS PRISM.
THE VEINED STRUCTURE AND PRESSURE.
(30.) -
IF a prism of glass be pressed by a sufficient weight, the
particles in the line of pressure will be squeezed more
closely together, while those at right angles to this line
will be forced further apart. The existence of this state of
strain may be demonstrated by the action of such squeezed
glass upon polarised light. It gives rise to colours, and
it is even possible to infer from the tint the precise amount
of pressure to which the glass is subjected. M. Wert-
heim indeed has most ably applied these facts to the
construction of a dynamometer, or instrument for measuring
pressures, exceeding in accuracy any hitherto devised.
When the pressure applied becomes too great for the
glass to sustain, it flies to pieces. But let us suppose the
sides of the prism defended by an extremely strong jacket,
in which the prism rests like a closely-fitting plug, and
which yields only when a pressure more than sufficient to
crush the glass is applied. Let the pressure be gradually
augmented until this point is attained ; afterwards both the
glass and its jacket will shorten and widen ; the jacket will
yield laterally, being pushed out with extreme slowness by
the glass within.
Now I believe that it would be possible to make this
experiment in such a manner that the glass should be
flattened, partly through rupture, and partly through lateral
molecular yielding ; the prism would change its form, and
yet present a firmly coherent mass when removed from its
jacket. I have never made the experiment ; nobody has,
as far as I know ; but experiments of this kind are often
made by Nature. In the Museum of the Government
POSSIBLE EXPERIMENT WITH PRISM OF ICE. 405
School of Mines, for example, we have a collection of
quartz stones placed there by Mr. Salter, and which have
been subjected to enormous pressure in the neighbourhood
of a fault. These rigid pebbles have, in some cases, been
squeezed against each other so as to produce mutual flat-
tening and indentation. Some of them have yielded along
planes passing through them, as if one half had slidden over
the other ; but the reattachment is very strong. Some of
the larger stones, moreover, which have endured pressure
at a particular point, are fissured radially around this
point. In short, the whole collection is a most instructive
example of the manner and extent to which one of the
most rigid substances in Nature can yield on the applica-
tion of a sufficient force.
Let a prism of ice at 32° be placed in a similar jacket
to that which we have supposed to envelop the glass prism.
The ice yields to the pressure with incomparably greater
ease than the glass ; and if the force be slowly applied, the
lateral yielding will far more closely resemble that of a
truly plastic body. Supposing such a piece of ice to be
filled with numerous small air-bubbles, the tendency of the
pressure would be to flatten these bubbles, and to squeeze
them out of the ice. Were the substance perfectly homo-
geneous, this flattening and expulsion would take place
uniformly throughout its entire mass ; but I believe there
is no such homogeneous substance in nature ; — the ice will
yield at different places, leaving between them spaces
which are comparatively unaffected by the pressure. From
the former spaces the air-bubbles will be more effectually
expelled; and I have no doubt that the result of such
pressure acting upon ice so protected would be to pro-
duce a laminated structure somewhat similar to that which
it produces in those bodies which exhibit slaty cleavage.
I also think it certain that, in this lateral displace-
ment of the particles, these must move past each other.
406 LAMINATION PRODUCED BY PRESSURE.
This is an idea which I have long entertained, as the
following passage taken from the paper published by
Mr. Huxley and myself will prove :—" Three principal
causes may operate in producing cleavage: first, the
reducing of surfaces of weak cohesion to parallel planes ;
second, the flattening of minute cavities; and third,
the weakening of cohesion by tangential action. The
third action is exemplified by the state of the rails near
a station where a break is habitually applied to a loco-
motive. In this case, while the weight of the train presses
vertically, its motion tends to cause longitudinal sliding of
the particles of the rail. Tangential action does not, how-
ever, necessarily imply a force of the latter kind. When
a solid cylinder an inch in height is squeezed to a vertical
cake a quarter of an inch in height, it is impossible, phy-
sically speaking, that the particles situated in the same
vertical line shall move laterally with the same velocity ;
but if they do not, the cohesion between them will be
weakened or ruptured. The pressure, however, will pro-
duce new contact ; and if this have a cohesive value equal
to that of the old contact, no cleavage from this cause can
arise. The relative capacities of different substances for
cleavage appear to depend in a great measure upon their
different properties in this respect. In butter, for ex-
ample, the new attachments are equal, or nearly so, to the
old, and the cleavage is consequently indistinct ; in wax
this does not appear to be the case, and hence may arise
in a great degree the perfection of its cleavage. The
further examination of this subject promises interesting
results." I would dwell upon this point the more distinctly
as the advocates of differential motion may deem it to be
in their favour ; but it appears to me that the mechanical
conceptions implied in the above passage are totally
different from theirs. If they think otherwise, then it
seems to me that they should change the expressions which
NO SLIDING OF FILAMENTS. 407
refer the differential motion to a "drag" towards the
centre, and the structure to the sliding of " filaments " past
each other in consequence of this drag. Such filamentary
sliding may take place in a truly viscous body, but it does
not take place in ice.
In one particular the ice resembles the butter referred
to in the above quotation ; for its new attachments appear
to be equal to the old, and this, I think, is to be ascribed
to its perfect regelation. As justly pointed out by Mr.
John Ball, the veined ice of a glacier, if unweathered,
shows no tendency to cleave; for though the expul-
sion of the air-bubbles has taken place, the reattach-
ment of the particles is so firm as to abolish all evidence
of cleavage. When the ice, on the contrary, is weathered,
the plates become detached, and I have often been able to
split such ice into thin tablets having an area of two or
three square feet.
In his Thirteenth Letter Professor Forbes throws out a
new and possibly a pregnant thought in connexion with the
veins. If I understand him aright — and I confess it is
usually a matter of extreme difficulty with me to make
sure of this— he there refers the veins, not to the expulsion
of the air from the ice, but to its redistribution. The pres-
sure produces " lines of tearing in which the air is distri-
buted in the form of regular globules." I do not know
what might be made of this idea if it were developed, but
at present I do not see how the supposed action could
produce the blue bands ; and I agree with Professor Wm.
Thomson in regarding the explanation as improbable.*
* For an extremely ingenious view of the origin of the veined struc-
ture, I would refer to a paper by Professor Thomson, in the ' Proceedings
of the Eoyal Society,' April, 1858.
408 INFLUENCE OF PRESSURE ON BOILING POINT.
THE VEINED STRUCTURE AND THE LIQUEFAC-
TION OF ICE BY PRESSURE.
(31.)
I HAVE already noticed an important fact for which we
are indebted to Mr. James Thomson, and have referred to
the original communications on the subject. I shall here
place the physical circumstances connected with this fact
before my reader in the manner which I deem most likely
to interest him.
When a liquid is heated, the attraction of the molecules
operates against the action of the heat, which tends to tear
them asunder. At a certain point the force of heat
triumphs, the cohesion is overcome, and the liquid boils.
But supposing we assist the attraction of the molecules by
applying an external pressure, the difficulty of tearing
them asunder will be increased ; more heat will be re-
quired for this purpose ; and hence we say that the boiling
point of the liquid, has been elevated by the pressure.
If molten sulphur be poured into a bullet-mould, it will
be found on cooling to contract, so as to leave a large
hollow space in the middle of each sphere. Cast musket-
bullets are thus always found to possess a small cavity
within them produced by the contraction of the lead.
Conceive the bullet placed within its mould and the
latter heated ; to produce fusion it is necessary that the
sulphur or the lead should swell. Here, as in the case of
the heated water, the tendency to expand is opposed by the
attraction of the molecules ; with a certain amount of heat
however this attraction is overcome and the solid melts.
But suppose we assist the molecular attraction by a suitable
force applied externally, a greater amount of heat than
before will be necessary to tear them asunder ; and hence
INFLUENCE OF PEESSUEE ON FUSING POINT. 409
we say that the fusing point has been elevated by the pres-
sure. This fact has been experimentally established by
Messrs. Hopkins and Fairbairn, who applied to spermaceti
and other substances pressures so great as to raise their
points of fusion a considerable number of degrees.
Let us now consider the case of the metal bismuth. If
the molten metal be poured into a bullet-mould it will
expand on solidifying. I have myself filled a strong cast-
iron bottle with the metal, and found its expansion on
cooling sufficiently great to split the bottle from neck to
bottom. Hence, in order to fuse the bismuth the substance
must contract ; and it is manifest that an external pressure
which tends to squeeze the molecules more closely together
here assists the heat instead of opposing it. Hence, to
fuse bismuth under great pressure, a less amount of
heat will be required than when the pressure is removed ;
or, in other words, the fusing point of bismuth is lowered
by the pressure. Now, in passing from the solid to the
liquid state, ice, like bismuth, contracts, and if the con-
traction be promoted by external pressure, as shown by
the Messrs. Thomson, a less amount of heat suffices to
liquefy it.
These remarks will enable us to understand a singular
effect first obtained by myself at the close of 1856 or in
January 1857, noticed at the time in the ' Proceedings of
the Koyal Society,' and afterwards fully described in a
paper presented to the Society in December of that year.
A cylinder of clear ice two inches high and an inch in
diameter was placed between two slabs of box- wood, and
subjected to a gradual pressure. I watched the ice in a
direction perpendicular to its length, and saw cloudy lines
drawing themselves across it. As the pressure continued,
these lines augmented in numbers, until finally the prism
presented the appearance of a crystal of gypsum whose
planes of cleavage had been forced out of optical contact.
410
EXPERIMENTS.
When looked at obliquely it was found that the lines were
merely the sections of flat dim surfaces, which lay like
laminae one over the other
throughout the length of
the prism. Fig. 50 repre-
sents the prism as it ap-
peared when looked at in a
direction perpendicular to
its axis ; Fig. 51 shows the
appearance when viewed
Fig. so. Fig. 51. obliquely.*
At first sight it might appear as if air had intruded itself
between the separated surfaces of the ice, and to test this
point I placed a cylinder two inches long and an inch wide
upright in a copper vessel which was filled with ice-cold
water. The ice cylinder rose about half an inch above the
surface of the water. Placing the copper vessel on a slab
of wood, and a second slab on the top of the cylinder of
ice, the latter was subjected to the gradual action of a
small hydraulic press. When the hazy surfaces were well
developed in the portion of the ice above the water, the
cylinder was removed and examined : the planes of rupture
extended throughout the entire length of the cylinder,
just as if it had been squeezed in air. I subsequently
placed the ice in a stout vessel of glass, and squeezed it,
as in the last experiment : the surfaces of discontinuity
were seen forming under the liquid quite as distinctly as
in air.
To prove that the surfaces were due to compression and
not to any tearing asunder of the mass by tension, the fol-
lowing experiment was made : — A cylindrical piece of ice,
one of whose ends, however, was not parallel to the other,
was placed between the slabs of wood, and subjected to
* This effect projected upon a screen is a most striking and instructive
class experiment.
LIQUID LAYERS PRODUCED BY PRESSURE. 411
pressure. Fig. 52 shows the disposition of the experiment.
The effect upon the ice cylinder was that shown in
Fig. 52.
Fig. 53.
Fig. 53, the surfaces being developed along that side which
had suffered the pressure. On examining the surfaces by
a pocket lens they resembled the effect produced upon a
smooth cold surface by breathing on it.
The surfaces were always dim ; and had the spaces been
filled with air, or were they simply vacuous, the reflection
of light from them would have been so copious as to render
them much more brilliant than they were observed to be. To
examine them more particularly I placed a concave mirror
so as to throw the diffused daylight from a window full
upon the cylinder. On applying the pressure dim spots
were sometimes seen forming in the very middle of the
ice, and these as they expanded laterally appeared to be
in a state of intense motion, which followed closely the
edge of each surface as it advanced through the solid ice.
Once or twice I observed the hazy surfaces pioneered
through the mass by dim offshoots, apparently liquid, and
constituting a kind of decry stallisation. From the closest
examination to which I was able to subject them, the
surfaces appeared to me to be due to internal lique-
faction ; indeed, when the melting point of ice, having
already a temperature of 32°, is lowered by pressure, its
excess of heat must instantly be applied to produce this
effect.
I have already given a drawing (p. 386) showing the deve-
412 APPLICATION TO THE VEINED STRUCTURE.
lopment of the veined structure at the base of the ice-cascade
of the Rhone ; and if we compare that diagram with Fig.
53 a striking similarity at once reveals itself. The ice of
the glacier must undoubtedly be liquefied to some extent
by the tremendous pressure to which it is here subjected.
Surfaces of discontinuity will in all probability be formed,
which facilitate the escape of the imprisoned air. The
small quantity of water produced will be partly im-
bibed by the adjacent porous ice, and will be refrozen
when relieved from the pressure. This action, associated
with that ascribed to pressure in the last section, appears
to me to furnish a complete physical explanation of the
laminated structure of glacier-ice.
GENERAL APPEARANCE OF WHITE ICE-SEAMS. 413
WHITE ICE-SEAMS IN THE GLACIER
DU GEANT.
(32.)
ON the 28th of July, 1857, while engaged upon the Glacier
du Geant, iny attention was often attracted by protuberant
ridges of what at first appeared to be pure white snow,
but which on examination I found to be compact ice filled
with innumerable round air-cells ; and which, in virtue of
its greater power of resistance to wasting, often rose to a
height of three or four feet above the general level of the ice-
As I stood amongst these ridges, they appeared detached
and without order of arrangement, but looked at from a
distance they were seen to sweep across the proper Glacier
du Geant in a direction concentric with its dirt-bands and
its veined structure. In some cases the seams were ad-
mirable indications of the relative displacement of two
adjacent portions of the glacier, which were divided from
each other by a crevasse. Usually the sections of a
seam exposed on the opposite sides of a fissure accurately
faced each other, and the direction of the seam on both
sides was continuous ; but at other places they demon-
strated the existence of lateral faults, being shifted asunder
laterally through spaces varying from a few inches to six
or seven feet.
On the following day I was again upon the same glacier,
and noticed in many cases the white ice-seams exquisitely
honeycombed. The case was illustrative of the great
difference between the absorptive power of the ice itself
and of the objects which lie upon its surface. Deep cylin-
drical cells were produced by spots of black dirt which had
been scattered upon the surface of the white ice, and
which sank to a depth of several inches into the mass. I
examined several sections of the veins, and in general I
414
SECTIONS OF SEAMS.
found that their deeper portions blended gradually with the
ice on either side of them. But higher up the glacier I
found that the veins penetrated only to a limited depth, and
did not therefore form an integrant portion of the glacier.
Fig. 54.
Fig. 55.
Figs. 54 and 55 show the sections of two of the seams
which were exposed on the wall of a crevasse at some
distance below the great ice-fall of the Glacier du Geant.
It was at the base of the Talefre cascade that the expla-
nation of these curious seams presented itself to me. In
one of my earliest visits to this portion of the glacier I
was struck by a singular dispo-
sition of the blue veins on the
vertical wall of a crevasse. Fig.
56 will illustrate what I saw.
The veins, within a short dis-
tance, dipped backward and. forward, like the junctions 01
Fig. 56.
VARIATIONS IN "DIP" OF STRUCTURE. 415
stones used to turn an arch. In some cases I found this
variation of the structure so great as to pass in a short
distance from the vertical to
the horizontal, as shown in
Fig. 57.
Further examination taught
me that the glacier here is
crumpled in a most singular
manner; doubtless by the
great pressure to which it '• Fig
is exposed. The following
illustration will convey a notion of its aspect: Let one
hand be laid flat upon a table, palm downwards, and let
the fingers be bent until the space between the first joint
and the ends of the fingers is vertical ; one of the crumples
to which I refer will then be represented. The ice seems
bent like the fingers, and the crumples of the glacier are
cut by crevasses, which are accurately typified by the
spaces between the fingers. Let the second hand now be
placed upon the first, as the latter is upon the table, so
that the tops of the bent fingers of the second hand shall
rest upon the roots of the first : two crumples would thus
be formed ; a series of such protuberances, with steep
fronts, follow each other from the base of the Tal£fre cas-
cade for some distance downwards.
On Saturday the 1st of August I ascended these rounded
terraces in succession, and observed among them an ex-
tremely remarkable disposition of the structure. Fig. 58
is a section of a series of three of the crumples, on which
the shading lines represent the direction of the blue veins.
At the base of each protuberance I found a seam of white
ice wedged firmly into the glacier, and each of the seams
marked a place of dislocation of the veins. The white seams
thinned off gradually, and finally vanished where the
violent crumpling of the ice disappeared. In Fig. 59 I
416
CRUMPLES OF THE TALEFEE.
have sketched the wall of a crevs.
what may be regarded as the incipie
which represents
Crumpling. The
Fig. 58.
undulating line shows the contour of the surface, and the
shading lines the veins. It will be observed that the
direction of the veins yields in conformity wit i the undu-
lation of the surface ; and an augmentation r the effect
would evidently result in the crumples shown Fig. 58.
The appearance of the white seams at those «ces where
a dislocation occurred was, as far as I coulc observe, in-
variable ; but in a few instances the seams were observed
upon the platforms of the terraces, and also up <n their slopes.
The width of a seam was very irregular varying from a
few inches at some places to three or four feet at others.
On the 3rd of August I was again at the base of the
Talefre cascade, and observed a fact the significance of
which had previously escaped me. The rills which ran
MOULDS OF WHITE ICE-SEAMS. 417
down the ic£-^iSp-^ elected at the base of each protu-
berance byto a str whirh, at the time of my visit, had
hollowec1 tout for i a deep channel in the ice. At some
places tul stream iened, at others its banks of ice ap-
proached e&ch oth «.', and rapids were produced ; in fact.
the channels q/| sue 'treams appeared to be the exact moulds
of the seams o/Wii ? ice.
Instructed tftu r, I ascended the Glacier du Geant on
the 5th of Auglt and then observed on the wrinkles of
this glacier the . e leaning backwards and forwards of
the blue veins as t d previously observed upon the
Talefre. I also noticed on this day that a seam of white
ice would sometimes open out into two branches, which,
after remaining for some distance separate, would reunite
and thus enclose a little glacier-island. At other places
lateral branches v^re thrown off from the principal seam,
thus suggesting j ie form of a glacier-rivulet which had
been fed by tributary branches. On the 7th of August
I hunted the seams still farther up the glacier ; and found
them at one place descending a steep ice-hill, being crossed
by other similar bands, which however were far less white
and compact. I followed these new bands to their origin,
and found it to be a system of crevasses formed at the
summit of the- hill, some of which were filled with snow.
Lower dow? ^he crevasses closed, and the snow thus
jammed bet ^n their walls was converted into white ice.
These seams, -wever, never attained the compactness and
prominence oi '-be larger ones which had their origin far
higher up. I ^ir gled out one of the best of the latter, and
traced it througl ^a'll the dislocation and confusion of the
ice, until I found it to terminate in a cavity filled with
snow.
This was near the base of the seracs, and the streams
here were abundant. Comparing the shapes of some of
them with that of the ice-bands lower down the glacier, a
EE
418
STREAMS AND SEAMS.
striking resemblance was observed. Fig. 60 is the plan of
a deep-cut channel through which a stream flowed on the
Fig. 60.
day to which I now refer. Fig. 61 is the plan of a seam of
white ice sketched on the same day, low down upon the
Fig. 61.
glacier. Instances of this kind might be multiplied ; and
the result, I think, renders it certain that the white ice-
seams referred to are due to the filling up of the channels
of glacier-streams by snow during winter, and the sub-
sequent compression of the mass to ice during the descent
of the glacier. I have found such seams at the bases of all
cascades that 1 have visited ; and in all cases they appear
to be due to the same cause. The depth to which they
penetrate the glacier must be profound, or the ablation of
the ice must be less than what is generally supposed ; for
the seams formed so high up on the Glacier du Geant may
be traced low down upon the trunk-stream of the Mer de
Glace.*
These observations on the white ice-seams enable us to
add an important supplement to what has been stated
regarding the origin of the dirt -bands of the Mer de
* The more permanent seams may possibly be due to the filling of
the profound crevasses of the cascade.
SCALING- OFF BY PRESSURE. 419
Glace. The protuberances at the base of the cascade are
due not only to the toning down of the ridges produced
by the transverse fracture of the glacier at the summit of the
fall, but they undergo modifications by the pressure locally
exerted at its base. The state of things represented in
Fig. 57 is plainly due to the partial pushing of one crumple
over that next in advance of it. There seems to be a
differential motion of the parts of the glacier in the same
longitudinal line ; showing that upon the general motion of
the glacier smaller local motions are superposed. The occur-
rence of the seams upon the faces of the slopes seems also
to prove that the pressure is competent, in some cases, to
cause the bases of the protuberances to swell, so that what
was once the base of a crumple may subsequently form a
portion of its slope. Another interesting fact is also ob-
served where the pressure is violent : the crumples scale
off, bows of ice being thus formed which usually span the
crumples over their most violently compressed portions.
I have found this scaling off at the bases of all the cascades
which I have visited, and it is plainly due to the pressure
exerted at such places upon the ice.
(33.)
Not only at the base of its great cascade, but throughout
the greater part of its length, the Glacier du Geant is in a
state of longitudinal compression. The meaning of this
term will be readily understood : Let two points, for ex-
ample, be marked upon the axis of the glacier ; if these
during its descent were drawn wider apart, it would show
that the glacier was in a state of longitudinal strain or
tension ; if they remained at the same distance apart, it
would indicate that neither strain nor pressure was exerted ;
whereas, if the two points approached each other, which
E E 2
420 COMPRESSION OF GLACIER DU GEANT.
could only be by the quicker motion of the hinder one,
the existence of longitudinal compression would be thereby
demonstrated.
Taking " Le Petit Balmat" with me, to carry my theodo-
lite, I ascended the Glacier du Geant until I came near
the place where it is joined by the Glacier des Periades,
and whence I observed a patch of fresh green grass upon
the otherwise rocky mountain-side. To this point I climbed,
and made it the station for my instrument. Choosing a
well-defined object at the opposite side of the glacier, I
set, on the 9th of August, in the line between this object
and the theodolite, three stakes, one in the centre of
the glacier, and the other two at opposite sides of the
centre and about 100 yards from it. This done, I de-
scended for a quarter of a mile, when I again climbed
the flanking rocks, placing my theodolite in a couloir,
down which stones are frequently discharged from the
end of a secondary glacier which hangs upon the heights
above. Here, as before, I fixed three stakes, chiselled
a mark upon the granite, so as to enable me to find
the place, and regained the ice without accident. A day
or two previously we had set out a third line at some
distance lower down, and I was thus furnished with a
succession of points along the glacier, the relative motions
of which would decide whether it was pressed or stretched
in the direction of its length. On the 10th of August
Mr. Huxley joined us ; and on the following day we all
set out for the Glacier du Geant, to measure the progress
of the stakes which I had fixed there. Hirst remained
upon the glacier to measure the displacements; I shouldered
the theodolite ; and Huxley was my guide to the mountain-
side, sounding in advance of me the treacherous-looking
snow over which we had to pass.
Calling the central stake of the highest line No. 1, that
of the middle line No. 2, and that of the line nearest the
STRUCTURE IN WHITE ICE-SEAMS. 421
Tacul No. 3, the following are the spaces moved over by
these three points in twenty- four hours :
Inches. Distances asunder.
No. 1. ... 20-551 545 yards.
No. 2. 15-43 '
No. 3. ... 12-75J 487 yards.
Here we have the fact which the aspect of the glacier
suggested. The first stake moves five inches a day more
than the second, and the second nearly three inches a day
more than the third. As surmised, therefore, the glacier
is in a state of longitudinal compression, whereby a portion
of it 1000 yards in length is shortened at the rate of eight
inches a day.
In accordance with this result, the transverse undulations
of the Glacier du Geant, described in the chapter upon
Dirt-Bands, shorten as they descend. A series of three of
them measured along the axis of the glacier on the 6th of
August, 1857, gave the following respective lengths:—
955 links, 855 links, 770 links, the shortest undulation
being the farthest from the origin of the undulations.
This glacier then constitutes a vast ice-press, and en-
ables us to test the explanation which refers the veined
structure of the ice to pressure. The glacier itself is
transversely laminated, as already stated; and in many
cases a structure of extreme definition and beauty is
developed in the compressed snow, which constitutes the
seams of white ice. In 1857 I discovered a well-developed
lenticular structure in some of these seams. In 1858 I
again examined them. Clearing away the superficial por-
tions with my axe, I found, drawn through the body of the
seams, long lines of blue ice of exquisite definition ; in
fact, I had never seen the structure so delicately exhibited.
The seams, moreover, were developed in portions of the
white ice which were near the centre of the glacier, and
where consequently filamentous sliding was entirely out of
the question.
422 PAETIAL SUMMARY.
PARTIAL SUMMARY.
1. GLACIERS are derived from mountain snow, which has
been consolidated to ice by pressure.
2. That pressure is competent to convert snow into ice
has been proved by experiment.
3. The power of yielding to pressure diminishes as the
mass becomes more compact ; but it does not cease even
when the substance has attained the compactness which
would entitle it to be called ice.
4. When a sufficient depth of snow collects upon the
earth's surface, the lower portions are squeezed out by the
pressure of the superincumbent mass. If it rests upon a
slope it will yield principally in the direction of the slope,
and move downwards.
5. In addition to this, the whole mass slides bodily along
its inclined bed, and leaves the traces of its sliding on the
rocks over which it passes, grinding off their asperities, and
marking them with grooves and scratches in the direction
of the motion.
6. In this way the deposit of consolidated and uncon-
solidated snow which covers the higher portions of lofty
mountains moves slowly down into an adjacent valley,
through which it descends as a true glacier, partly by
sliding and partly by the yielding of the mass itself.
7. Several valleys thus filled may unite in a single
valley, the tributary glaciers welding themselves together
to form a trunk-glacier.
8. Both the main valley and its tributaries are often
sinuous, and the tributaries must change their direction to
form the trunk ; the width of the valley often varies. The
glacier is forced through narrow gorges, widening after it
has passed them ; the centre of the glacier moves more
PARTIAL SUMMARY. 423
quickly than the sides, and the surface more quickly than
the bottom ; the point of swiftest motion follows the same
law as that observed in the flow of rivers, shifting from
one side of the centre to the other as the flexure of the
valley changes.
9. These various effects may be reproduced by experi-
ments on small masses of ice. The substance may more-
over be moulded into vases and statuettes. Straight bars
of it may be bent into rings, or even coiled into knots.
10. Ice, capable of being thus moulded, is practically
incapable of being stretched. The condition essential to
success is that the particles of the ice operated on shall be
kept in close contact, so that when old attachments have
been severed new ones may be established.
1 1 . The nearer the ice is to its melting point in tem-
perature, the more easily are the above results obtained ;
when ice is many degrees below its freezing point it is
crushed by pressure to a white powder, and is not capable
of being moulded as above.
12. Two pieces of ice at 32° Fahr., with moist surfaces,
when placed in contact freeze together to a rigid mass ;
this is called Regelation.
13. When the attachments of pressed ice are broken,
the continuity of the mass is restored by the regelation of
the new contiguous surfaces. Regelation also enables two
tributary glaciers to weld themselves to form a continuous
trunk ; thus also the crevasses are mended, and the dis-
locations of the glacier consequent on descending cascades
are repaired. This healing of ruptures extends to the
smallest particles of the mass, and it enables us to account
for the continued compactness of the ice during the descent
of the glacier.
14. The quality of viscosity is practically absent in
glacier-ice. Where pressure comes into play the pheno-
mena are suggestive of viscosity, but where tension comes
424 .PARTIAL SUMMARY.
into play the analogy with a viscous body breaks down.
When subjected to strain the glacier does not yield by
stretching, but by breaking ; this is the origin of the
crevasses.
15. The crevasses are produced by the mechanical strains
to which the glacier is subjected. They are divided into
marginal, transverse, and longitudinal crevasses ; the first
produced by the oblique strain consequent on the quicker
motion of the centre ; the second by the passage of the
glacier over the summit of an incline ; the third by
pressure from behind and resistance in front, which causes
the mass to split at right angles to the pressure [strain ?].
16. The moulins are formed by deep cracks intersecting
glacier rivulets. The water in descending such cracks scoops
out for itself a shaft, sometimes many feet wide, and some
hundreds of feet deep, into which the cataract plunges with
a sound like thunder. The supply of water is periodically
cut off from the moulins by fresh cracks, in which new
moulins are formed.
17. The lateral moraines are formed from the debris
which loads the glacier along its edges ; the medial mo-
raines are formed on a trunk-glacier by the union of the
lateral moraines of its tributaries ; the terminal moraines
are formed from the debris carried by the glacier to its
terminus, and there deposited. The number of medial
moraines on a trunk glacier is always one less than the
number of tributaries.
18. When ordinary lake-ice is intersected by a strong sun-
beam it liquefies so as to form flower-shaped figures within
the mass ; each flower consists of six petals with a vacuous
space at the centre ; the flowers are always formed parallel
to the planes of freezing, and depend on the crystallization
of the substance.
19. Innumerable liquid disks, with vacuous spots, are
also formed by the solar beams in glacier-ice. These empty
PARTIAL SUMMARY. 425
spaces have been hitherto mistaken for air-bubbles, the flat
form of the disks being erroneously regarded as the result
of pressure.
20. These disks are indicators of the intimate constitution
of glacier-ice, and they teach us that it is composed of an
aggregate of parts with surfaces of crystallization in all
possible planes.
21. There are also innumerable small cells in glacier-
ice holding air and water ; such cells also occur in lake-
ice ; and here they are due to the melting of the ice in
contact with the bubble of air. Experiments are needed
011 glacier-ice in reference to this point.
22. At a free surface within or without, ice melts with
more ease than in the centre of a compact mass. The
motion which we call heat is less controlled at a free sur-
face, and it liberates the molecules from the solid condition
sooner than when the atoms are surrounded on all sides
by other atoms which impede the molecular motion.
Regelation is the complementary effect to the above ; for
here the superficial portions of a mass of ice are made
virtually central by the contact of a second mass.
23. The dirt-bands have their origin in the ice-cascades.
The glacier, in passing the brow, is transversely fractured ;
ridges are formed with hollows between them ; these trans-
verse hollows are the principal receptacles of the fine
debris scattered over the glacier ; and after the ridges have
been melted away, the dirt remains in successive stripes
upon the glacier.
24. The ice of many glaciers is laminated, and when
weathered may be cloven into thin plates. In the sound
ice the lamination manifests itself in blue stripes drawn
through the general whitish mass of the glacier ; these blue
veins representing portions of ice from which the air-
bubbles have been more completely expelled. This is the
veined structure of the ice. It is divided into marginal,
426 PARTIAL SUMMARY.
transverse, and longitudinal structure ; which may be
regarded as complementary to marginal, longitudinal, and
transverse crevasses. The latter are produced by tension,
the former by pressure, which acts in two different ways :
firstly, the pressure acts upon the ice as it has acted upon
rocks which exhibit the lamination technically called cleav-
age ; secondly, it produces partial liquefaction of the ice.
The liquid spaces thus formed help the escape of the air
from the glacier ; and the water produced, being refrozen
when the pressure is relieved, helps to form the blue veins.
APPENDIX.
COMPARATIVE VIEW OF THE CLEAVAGE OF
CRYSTALS AND SLATE-ROCKS.
A LECTURE DELIVEEED AT THE ROYAL INSTITUTION, ON
FRIDAY EVENING THE 6TH OF JUNE, 1856.*
WHEN the student of physical science has to investigate the character
of any natural force, his first care must be to purify it from the mix-
ture of other forces, and thus study its simple action. If, for example,
he wishes to know how a mass of water would shape itself, supposing
it to be at liberty to follow the bent of its own molecular forces, he
must see that these forces have free and undisturbed exercise. We
might perhaps refer him to the dew-drop for a solution of the ques-
tion ; but here we have to do, not only with the action of the molecules
of the liquid upon each other, but also with the action of gravity upon
the mass, which pulls the drop downwards and elongates it. If he
would examine the problem in its purity, he must do as Plateau has
done, withdraw the liquid mass from the action of gravity, and he
would then find the shape of the mass to be perfectly spherical.
Natural processes come to us in a mixed manner, and to the unin-
structed mind are a mass of unintelligible confusion. Suppose half-a-
dozen of the best musical performers to be placed in the same room,
each playing his own instrument to perfection : though each indivi-
dual instrument might be a well-spring of melody, still the mixture
of all would produce mere noise. Thus it is with the processes of
nature. In nature, mechanical and molecular laws mingle, and
create apparent confusion. Their mixture constitutes what may
be called the noise of natural laws, and it is the vocation of the
man of science to resolve this noise into its components, and thus
to detect the " music " in which the foundations of nature are laid.
The necessity of this detachment of one force from all other forces
is nowhere more strikingly exhibited than in the phenomena of
crystallization. I have here a solution of sulphate of soda. Prolong-
ing the mental vision beyond the boundaries of sense, we see the atoms
of that liquid, like squadrons under the eye of an experienced general,
* Referred to in the Introduction,
428 APPENDIX.
arranging themselves into battalions, gathering round a central
standard, and forming themselves into solid masses, which after a
time assume the visible shape of the crystal which I here hold in my
hand. I may, like an ignorant meddler wishing to hasten matters, in-
troduce confusion into this order. I do so by plunging this glass rod
into the vessel. The consequent action is not the pure expression of
the crystalline forces ; the atoms rush together with the confusion
of an unorganized mob, and not with the steady accuracy of a disci-
plined host. Here, also, in this mass of bismuth we have an example
of this confused crystallization ; but in the crucible behind me a
slower process is going on : here there is an architect at work " who
makes no chips, no din," and who is now building the particles into
crystals, similar in shape and structure to those beautiful masses
which we see upon the table. By permitting alum to crystallize in
this slow way, we obtain these perfect octahedrons ; by allowing
carbonate of lime to crystallize, nature produces these beautiful rhom-
boids; when silica crystallizes, we have formed these hexagonal prisms
capped at the ends by pyramids ; by allowing saltpetre to crystallize,
we have these prismatic masses ; and when carbon crystallizes, we
have the diamond. If we wish to obtain a perfect crystal, we must
allow the molecular forces free play : if the crystallizing mass be per-
mitted to rest upon a surface it will be flattened, and to prevent this
a small crystal must be so suspended as to be surrounded 011 all sides
by the liquid, or, if it rest upon the surface, it must be turned daily
so as to present all its faces in succession to the working builder. In
this way the scientific man nurses these children of his intellect,
watches over them with a care worthy of imitation, keeps all influ-
ences away which might possibly invade the strict morality of
crystalline laws, and finally sees them developed into forms of sym-
metry and beauty which richly reward the care bestowed upon them.
In building up crystals, these little atomic bricks often arrange
themselves into layers which are perfectly parallel to each other, and
which can be separated by mechanical means ; this is called the
cleavage of the crystal. I have here a crystallized mass which has
thus far escaped the abrading and disintegrating forces which, sooner
or later, determine the fate of sugar-candy. If I am skilful enough,
I shall discover that this crystal of sugar cleaves with peculiar facility
in one direction. Here, again, I have a mass of rock-salt : I lay my
knife upon it, and with a blow cleave it in this direction ; but I find on
further examining this substance that it cleaves in more directions than
one. Laying my knife at right angles to its former position, the crystal
cleaves again ; and, finally placing the knife at right angles to the
APPENDIX. 429
two former positions, the mass cleaves again. Thus rock-salt cleaves
in three directions, and the resulting solid is this perfect cube, which
may be broken up into any number of smaller cubes. Here is a mass
of Iceland spar, which also cleaves in three directions, not at right
angles, but obliquely to each other, the resulting solid being a rhom-
boid. In each of these cases the mass cleaves with equal facility in
all three directions. For the sake of completeness, I may say that
many substances cleave with unequal facility in different directions,
and the heavy spar I hold in my hand presents an example of this
kind of cleavage.
Turn we now to the consideration of some other phenomena to
which the term cleavage may be applied. This piece of beech- wood
cleaves with facility parallel to the fibre, and if our experiments were
fine enough we should discover that the cleavage is most perfect when
the edge of the axe is laid across the rings which mark the growth
of the tree. The fibres of the wood lie side by side, and a compara-
tively small force is sufficient to separate them. If you look at this
mass of hay severed from a rick, you will see a sort of cleavage de-
veloped in it also ; the stalks lie in parallel planes, and only a small
force is required to separate them laterally. But we cannot regard
the cleavage of the tree as the same in character as the cleavage of
the hayrick. In the one case it is the atoms arranging themselves
according to organic laws which produce a cleavable structure ; in the
other case the easy separation in a certain direction is due to the me-
chanical arrangement of the coarse sensible masses of the stalks of hay.
In like manner I find that this piece of sandstone cleaves parallel
to the planes of bedding. This rock was once a powder, more or less
coarse, held in mechanical suspension by water. The powder was
composed of two distinct parts, fine grains of sand and small plates
of mica. Imagine a wide strand covered by a tide which holds such
powder in suspension : * how will it sink ? The rounded grains of
sand will reach the bottom first, the mica afterwards, and when the
tide recedes we have the little plates shining like spangles upon the
surface of the sand. Each successive tide brings its charge of mixed
powder, deposits its duplex layer day after day, and finally masses
of immense thickness are thus piled up, which, by preserving the
alternations of sand and mica, tell the tale of their formation. I do
not wish you to accept this without proof. Take the sand and mica,
mix them together in water, and allow them to subside, they will
* I merely use this as an illustration ; the deposition may have really
been due to sediment carried down by rivers. But the action must have
been periodic, and the powder duplex.
430 APPENDIX.
arrange themselves in the manner I have indicated ; and by repeat-
ing the process you can actually build up a sandstone mass which
shall be the exact counterpart of that presented by nature, as I have
done in this glass jar. Now this structure cleaves with readiness
along the planes in which the particles of mica are strewn. Here
is a mass of such a rock sent to me from Halifax : here are other
masses from the quarries of Over Darwen in Lancashire. With a
hammer and chisel you see I can cleave them into flags ; indeed these
flags are made use of for roofing purposes in the districts from which
the specimens have come, and receive the name of "slate -stone."
But you will discern, without a word from me, that this cleavage is
not a crystalline cleavage any more than that of a hayrick is. It
is not an arrangement produced by molecular forces; indeed it
would be just as reasonable to suppose that in this jar of sand and
mica the particles arranged themselves into layers by the forces of
crystallization, instead of by the simple force of gravity, as to
imagine that such a cleavage as this could be the product of crystal-
lization.
This, so far as I am aware of, has never been imagined, and it has
been agreed among geologists not to call such splitting as this
cleavage at all, but to restrict the term to a class of phenomena
which I shall now proceed to consider.
Those who have visited the slate quarries of Cumberland and
North Wales will have witnessed the phenomena to which I refer.
We have long drawn our supply of roofing- slates from such quarries ;
schoolboys ciphered on these slates, they were used for tombstones
in churchyards, and for billiard-tables in the metropolis ; but not
until a comparatively late period did men begin to inquire how
their wonderful structure was produced. What is the agency which
enables us to split Honister Crag, or the cliffs of Snowdon, into
laminsB from crown to base? This question is at the present
moment one of the greatest difficulties of geologists, and occupies
their attention perhaps more than any other. You may wonder at
this. Looking into the quarry of Penrhyn, you may be disposed to
explain the question as I heard it explained two years ago. " These
planes of cleavage," said a friend who stood beside me on the
quarry's edge, " are the planes of stratification which have been lifted
by some convulsion into an almost vertical position." But this was
a great mistake, and indeed here lies the grand difficulty of the pro-
blem. These planes of cleavage stand in most cases at a high angle
to the bedding. Thanks to Sir Eoderick Murchison, who has kindly
permitted me the use of specimens from the Museum of Practical
APPENDIX. 431
Geology (and here I may be permitted to express my acknowledg-
ments to the distinguished staff of that noble establishment, who,
instead of considering me an intruder, have welcomed me as a
brother), I am able to place the proof of this before you. Here is a
mass of slate in which the planes of bedding are distinctly marked ;
here are the planes of cleavage, and you see that one of them makes
a large angle with the other. The cleavage of slates is therefore not
a question of stratification, and the problem which we have now to
consider is, " By what cause has this cleavage been produced ? "
In an able and elaborate essay on this subject in 1835, Professor
Sedgwick proposed the theory that cleavage is produced by the action
of crystalline or polar forces after the mass has been consolidated.
" We may affirm," he says, " that no retreat of the parts, no con-
traction of dimensions in passing to a solid state can explain such
phenomena. They appear to me only resolvable on the supposition
that crystalline or polar forces acted upon the whole mass simul-
taneously in one direction and with adequate force." And again,
in another place : " Crystalline forces have rearranged whole moun-
tain-masses, producing a beautiful crystalline cleavage, passing alike
through all the strata." * The utterance of such a man struck deep,
as was natural, into the minds of geologists, and at the present day
there are few who do not entertain this view either in whole or in part.f
The magnificence of the theory, indeed, has in some cases caused
speculation to run riot, and we have books published, aye and largely
sold, on the action of polar forces and geologic magnetism, which
rather astonish those who know something about the subject. Ac-
cording to the theory referred to, miles and miles of the districts of
North Wales -and Cumberland, comprising huge mountain-masses,
are neither more nor less than the parts of a gigantic crystal. These
masses of slate were originally fine mud ; this mud is composed of
the broken and abraded particles of older rocks. It contains silica,
* ' Transactions of the Geological Society,1 Ser. ii. vol. iii. p. 477.
f In a letter to Sir Charles Lyell, dated from the Cape of Good Hope,
February 20, 1836, Sir John Herschel writes as follows :— " If rocks have
been so heated as to allow of a commencement of crystallization, that is
to say, if they have been heated to a point at which the particles can
begin to move amongst themselves, or at least on their own axes, some
general law must then determine the position in which these particles
will rest on cooling. Probably that position will have some relation to
the direction in which the heat escapes. Now when all or a majority of
particles of the same nature have a general tendency to one position, that
must of course determine a cleavage plane."
432 APPENDIX.
alumina, iron, potash, soda, and mica, mixed in sensible masses
mechanically together. In the course of ages the mass became con-
solidated, and the theory before us assumes that afterwards a process
of crystallization rearranged the particles and developed in the mass
a single plane of crystalline cleavage. With reference to this hypo-
thesis, I will only say that it is a bold stretch of analogies ; but still
it has done good service : it has drawn attention to the question ;
right or wrong, a theory thus thoughtfully uttered has its value ; it
is a dynamic power which operates against intellectual stagnation ;
and, even by provoking opposition, is eventually of service to the
cause of truth. It would, however, have been remarkable, if, among
the ranks of geologists themselves, men were not found to seek an
explanation of the phenomena in question, which involved a less
hardy spring on the part of the speculative faculty than the view to
which I have just referred.
The first step in an inquiry of this kind is to put oneself into con-
tact with nature, to seek facts. This has been done, and the labours
of Sharpe (the late President of the Geological Society, who, to the
loss of science and the sorrow of all who knew him, has so suddenly
been taken away from us), Sorby, and others, have furnished us with
a body of evidence which reveals to us certain important physical
phenomena, associated with the appearance of slaty cleavage, if they
have not produced it. The nature of this evidence we will now pro-
ceed to consider.
Fossil shells are found in these slate-rocks. I have here several
specimens of such shells, occupying various positions with regard to
the cleavage planes. They are squeezed, distorted, and crushed. In
some cases a flattening of the convex shell occurs, in others the
valves are pressed by a force which acted in the plane of their junc-
tion, but in all cases the distortion is such as leads to the inference
that the rock which contains these shells has been subjected to
enormous pressure in a direction at right angles to the planes of
cleavage ; the shells are all flattened and spread out upon these
planes. I hold in my hand a fossil trilobite of normal proportions.
Here is a series of fossils of the same creature which have suffered
distortion. Some have lain across, some along, and some oblique
to the cleavage of the slate in which they are found ; in all cases the
nature of the distortion is such as required for its production a com-
pressing force acting at right angles to the planes of cleavage. As
the creatures lay in the mud in the manner indicated, the jaws of
a gigantic vice appear to have closed upon them and squeezed them
into the shape you see. As further evidence of the exertion of
APPENDIX. 433
pressure, let me introduce to your notice a case of contortion which
has been adduced by Mr. Sorby. The bedding of the rock shown in
this figure* was once horizontal; at A we have a deep layer of mud,
and at m n a layer of comparatively unyielding gritty material ;
below that again, at B, we have another layer of the fine mud of
which slates are formed. This mass cleaves along the shading lines
of the diagram ; but look at the shape of the intermediate bed : it
is contorted into a serpentine form, and leads irresistibly to the
conclusion that the mass has been pressed together at right angles
tor the planes of cleavage. This action can be experimentally imi-
tated, and I have here a piece of clay in which this is done and the
same result produced on a small scale. The amount of compression,
indeed, might be roughly estimated by supposing this contorted bed
m n to be stretched out, its length measured and compared with the
distance c d ; we find in this way that the yielding of the mass has
been considerable.
Let me now direct your attention to another proof of pressure.
You see the varying colours which indicate the bedding on this mass
of slate. The dark portion, as I have stated, is gritty, and composed
of comparatively coarse particles, which, owing to their size, shape,
and gravity, sink first and constitute the bottom of each layer.
Gradually from bottom to top the coarseness diminishes, and near
the upper surface of each layer we have a mass of comparatively
fine clean mud. Sometimes this fine mud forms distinct layers in
ci mass of slate-rock, and it is the mud thus consolidated from which
are derived the German razor-stones, so much prized for the sharpen-
ing of surgical instruments. I have here an example of such a
stone. When a bed is thin, the clean white mud is permitted to rest,
as in this case, upon a slab of the coarser slate in contact with it :
when the bed is thick, it is cut into slices which are cemented to
pieces of ordinary slate, and thus rendered stronger. The mud thus
deposited sometimes in layers is, as might be expected, often rolled
up into nodular masses, carried forward, and deposited by the rivers
from which the slate-mud has subsided. Here, indeed, are such
nodules enclosed in sandstone. Everybody who has ciphered upon
a school-slate must remember the whitish-green spots which some-
times dotted the surface of the slate ; he will remember how his
slate-pencil usually slid over such spots as if they were greasy. Now
these spots are composed of the finer mud, and they could not, on
account of their fineness, bite the pencil like the surrounding gritty
portions of the slate. Here is a beautiful example of the spots : you
* Omitted here.
434 APPENDIX.
observe them on the cleavage surface in broad patches ; but if this
mass has been compressed at right angles to the planes of cleavage,
ought we to expect the same marks when we look at the edge of the
slab ? The nodules will be flattened by such pressure, and we ought
to see evidence of this flattening when we turn the slate edgeways.
Here it is. The section of a nodule is a sharp ellipse with its major
axis parallel to the cleavage. There are other examples of the same
nature on the table ; I have made excursions to the quarries of
Wales and Cumberland, and to many of the slate-yards of London,
but the same fact invariably appears, and thus we elevate a common
experience of our boyhood into evidence of the highest significance
as regards one of the most important problems of geology. In ex-
amining the magnetism of these slates, I was led to infer that these
spots would contain a less amount of iron than the surrounding
dark slate. The analysis was made for me by Mr. Hambly in the
laboratory of Dr. Percy at the School of Mines. The result which
is stated in this Table justifies the conclusion to which I have
referred.
Analysis of Slate.
Purple Slate. Two Analyses.
1. Percentage of iron .' . . 5*85
2. „ „ . . . 6-13
Mean . . . 5-99
Greenish Slate.
1. Percentage of iron . ,t . 3-24
2. 3-12
Mean . . . 3-18
The quantity of iron in the dark slate immediately adjacent to the
greenish spot is, according to these analyses, nearly double of the
quantity contained in the spot itself. This is about the proportion
which the magnetic experiments suggested.
Let me now remind you that the facts which I have brought
before you are typical facts — each is the representative of a class.
We have seen shells crushed, the unhappy trilobites squeezed, beds
contorted, nodules of greenish marl flattened ; and all these sources
of independent testimony point to one and the same conclusion,
namely, that slate-rocks have been subjected to enormous pressure
in a direction at right angles to the planes of cleavage.*
* While to my mind the evidence in proof of pressure seems per-
fectly irresistible, I by no means assert that the manner in which I stated
APPENDIX. 435
In reference to Mr. Sorby's contorted bed, I have said that by
supposing it to be stretched out and its length measured, it would
give us an idea of the amount of yielding of the mass above and
below the bed. Such a measurement, however, would not quite
give the amount of yielding ; and here I would beg your attention
to a point, the significance of which has, so far as I am aware of,
hitherto escaped attention. I hold in my hand a specimen of slate,
with its bedding marked upon it ; the lower portions of each bed
are composed of a comparatively coarse gritty material, something
like what you may suppose this contorted bed to be composed of.
Well, I find that the cleavage takes a bend in crossing these gritty
portions, and that the tendency of these portions is to cleave more
at right angles to the bedding. Look to this diagram : when the
forces commenced to act, this intermediate bed, which though
comparatively unyielding is not entirely so, suffered longitudinal
pressure ; as it bent, the pressure became gradually more lateral,
and the direction of its cleavage is exactly such as you would infer
from a force of this kind — it is neither quite across the bed, nor yet
in the same direction as the cleavage of the slate above and below
it, but intermediate between the two. Supposing the cleavage to be
at right angles to the pressure, this is the direction which it ought
to take across these more unyielding strata.
Thus we have established the concurrence of the phenomena 01
cleavage and pressure — that they accompany each other ; but the
question still remains, Is this pressure of itself sufficient to account
for the cleavage ? A single geologist, as far as I am aware, answers
boldly in the affirmative. This geologist is Sorby, who has attacked
the question in the true spirit of a physical investigator. You remem-
ber the cleavage of the flags of Halifax and Over Darwen, which
is caused by the interposition of plates of mica between the layers.
Mr. Sorby examines the structure of slate-rock, and finds plates of
mica to be a constituent. He asks himself, what will be the effect
of pressure upon a mass containing such plates confusedly mixed up
in it ? It will be, he argues — and he argues rightly — to place the
plates with their flat surfaces more or less perpendicular to the
direction in which the pressure is exerted. He takes scales of the
oxide of iron, mixes them with a fine powder, and, on squeezing
it is incapable of modification. All that I deem important is the fact
that pressure has been exerted ; and provided this remain firm, the
fate of any minor portion of the evidence by which it is here established
is of comparatively little moment.
436 APPENDIX.
the mass, finds that the tendency of the scales is to set themselves
at right angles to the line of pressure. Now the planes in which
these plates arrange themselves will, he contends, be those along
which the mass cleaves.
I could show you, by tests of a totally different character from
those applied by Mr. Sorby, how true his conclusion is, that the
effect of pressure on elongated particles or plates will be such as he
describes it. Nevertheless, while knowing this fact, and admiring
the ability with which Mr. Sorby has treated this question, I cannot
accept his explanation of slate-cleavage. I believe that even if these
plates of mica were wholly absent, the cleavage of slate-rocks would
be much the same as it is at present.
I will not dwell here upon minor facts, — I will not urge that
the perfection of the cleavage bears no relation to the quantity of
mica present ; but I will come at once to a case which to my mind
completely upsets the notion that such plates are a necessary element
in the production of cleavage.
Here is a mass of pure white wax : there are no mica particles
here ; there are no scales of iron, or anything analogous mixed up
with the mass. Here is the self-same substance submitted to
pressure. I would invite the attention of the eminent geologists
whom I see before me to the structure of this mass. No slate ever
exhibited so clean a cleavage ; it splits into laminae of surpassing
tenuity, and proves at a single stroke that pressure is sufficient to
produce cleavage, and that this cleavage is independent of the inter-
mixed plates of mica assumed in Mr. Sorby's theory. I have pur-
posely mixed this wax with elongated particles, and am unable to
say at the present moment that the cleavage is sensibly affected by
their presence, — if anything, I should say they rather impair its
fineness and clearness than promote it.
The finer the slate the more perfect will be the resemblance of
its cleavage to that of the wax. Compare the surface of the wax
with the surface of this slate from Borrodale in Cumberland. You
have precisely the same features in both : you see flakes clinging
to the surfaces of each, which have been partially torn away by
the cleavage of the mass : I entertain the conviction that if any
close observer compares these two effects, he will be led to the con-
clusion that they are the product of a common cause.*
* I have usually softened the wax by warming it, kneaded it with
the fingers, and pressed it between thick plates of glass previously
wetted. At the ordinary summer-temperature the wax is soft, and tears
rather than cleaves; on this account I cool my compressed specimens in
APPENDIX. 437
But you will ask, how, according to my view, does pressure pro-
duce this remarkable result ? This may be stated in a very few
words.
Nature is everywhere imperfect! The eye is not perfectly
achromatic, the colours of the rose and tulip are not pure colours,
and the freshest air of our hills has a bit of poison in it. In like
manner there is no such thing in nature as a body of perfectly
homogeneous structure. I break this clay which seems so inti-
mately mixed, and find that the fracture presents to my eyes
innumerable surfaces along which it has given way, and it has
yielded along these surfaces because in them the cohesion of the
mass is less than elsewhere. I break this marble, and even this
wax, and observe the same result : look at the mud at the bottom
of a dried pond ; look to some of the ungravelled walks in Kensing-
ton Gardens on drying after rain, — they are cracked and split, and
other circumstances being equal, they crack and split where the
cohesion of the mass is least. Take then a mass of partially con-
solidated mud. Assuredly such a mass is divided and subdivided
by surfaces along which the cohesion is comparatively small.
Penetrate the mass, and you will see it composed of numberless
irregular nodules bounded by surfaces of weak cohesion. Figure
to your mind's eye such a mass subjected to pressure, — the mass
yields and spreads out in the direction of least resistance ; * the
little nodules become converted into laminae, separated from each
other by surfaces of weak cohesion, and the infallible result will be
that such amass will cleave at right angles to the line in which the
pressure is exerted.
Further, a mass of dried mud is full of cavities and fissures. If
you break dried pipe-clay you see them in great numbers, and there
are multitudes of them so small that you cannot see them. I have
here a piece of glass in which a bubble was enclosed ; by the com-
pression of the glass the bubble is flattened, and the sides of the
bubble approach each other so closely as to exhibit the colours of
thin plates. A similar flattening of the cavities must take place in
squeezed mud, and this must materially facilitate the cleavage of
the mass in the direction already indicated.
Although the time at my disposal has not permitted me to develop
a mixture of pounded ice and salt, and when thus cooled they split
beautifully.
* It is scarcely necessary to say that if the mass were squeezed equally
in all directions no laminated structure could be produced ; it must have
room to yield in a lateral direction.
438 APPENDIX.
this thought as far as I could wish, yet for the last twelve months
the subject has presented itself to me almost daily under one aspect
or another. I have never eaten a biscuit during this period in which
an intellectual joy has not been superadded to the more sensual
pleasure, for I have remarked in all such cases cleavage developed
in the mass by the rolling-pin of the pastrycook or confectioner. I
have only to break these cakes, and to look at the fracture, to see
the laminated structure of the mass ; nay, I have the means of
pushing the analogy further : I have here some slate which was
subjected to a high temperature during the conflagration of Mr.
Scott Bussell's premises. I invite you to compare this structure
with that of a biscuit ; air or vapour within the mass has caused it
to swell, and the mechanical structure it reveals is precisely that
of a biscuit. I have gone a little into the mysteries of baking while
conducting my inquiries on this subject, and have received much
instruction from a lady-friend in the manufacture of puff-paste.
Here is some paste baked in this house under my own superinten-
dence. The cleavage of our hills is accidental cleavage, but this is
cleavage with intention. The volition of the pastrycook has entered
into the formation of the mass, and it has been his aim to preserve
a series of surfaces of structural weakness, along which the dough
divides into layers. Puff-paste must not be handled too much, for
then the continuity of the surfaces is broken ; it ought to be rolled
on a cold slab, to prevent the butter from melting and diffusing
itself through the mass, thus rendering it more homogeneous and
less liable to split. This is the whole philosophy of puff-paste ; it
is a grossly exaggerated case of slaty cleavage.
As time passed on, cases multiplied, illustrating the influence of
pressure in producing lamination. Mr. Warren De la Hue informs
me that he once wished to obtain white-lead in a fine granular state,
and to accomplish this he first compressed the mass : the mould
was conical, and permitted the mass to spread a little laterally under
the pressure. The lamination was as perfect as that of slate, and
quite defeated him in his effort to obtain a granular powder. Mr.
Brodie, as you are aware, has recently discovered a new kind of
graphite : here is the substance in powder, of exquisite fineness.
This powder has the peculiarity of clinging together in little con-
federacies ; it cannot be shaken asunder like lycopodium ; and when
the mass is squeezed, these groups of particles flatten, and a perfect
cleavage is produced. Mr. Brodie himself has been kind enough to
furnish me with specimens for this evening's lecture. I will cleave
them before you : you see they split up into plates which are per-
APPENDIX. 439
pendicular to the line in which the pressure was exerted. This
testimony is all the more valuable, as the facts were obtained with-
out any reference whatever to the question of cleavage.
I have here a mass of that singular substance Boghead Cannel.
This was once a mass of mud, more or less resembling this one,
which I have obtained from a bog in Lancashire. I feel some
hesitation in bringing this substance before you, for, as in other
cases, so in regard to Boghead Cannel, science — not science, let me
not libel it, but the quibbling, litigious, money-loving portion of
human nature speaking through the mask of science— has so con-
trived to split hairs as to render the qualities of the substance
somewhat mythical. 1 shall therefore content myself with showing
you how it cleaves, and with expressing my conviction that pressure
had a great share in the production of this cleavage.
The principle which I have enunciated is so simple as to be
almost trivial ; nevertheless, it embraces not only the cases I have
mentioned, but, if time permitted, I think I could show you that it
takes a much wider range. When iron is taken from the puddling
furnace, it is a more or less spongy mass : it is at a welding heat,
and at this temperature is submitted to the process of rolling :
bright smooth bars such as this are the result of this rolling. But
I have said that the mass is more or less spongy or nodular, and,
notwithstanding the high heat, these nodules do not perfectly
incorporate with their neighbours : what then ? You would say
that the process of rolling must draw the nodules into fibres— it
does so ; and here is a mass acted upon by dilute sulphuric acid,
which exhibits in a striking manner this fibrous structure. The
experiment was made by my friend Dr. Percy, without any reference
to the question of cleavage.
Here are other cases of fibrous iron. This fibrous structure is
the result of mechanical treatment. Break a mass of ordinary iron
and you have a granular fracture ; beat the mass, you elongate
these granules, and finally render the mass fibrous. Here are
pieces of rails along which the wheels of locomotives have slidden ;
the granules have yielded and become plates ; they exfoliate or
come off in leaves. All these effects belong, I believe, to the great
class of phenomena of which slaty cleavage forms the most
prominent example.*
* An eminent authority informs me that he believes these surfaces
of weak cohesion to be due to the interposition of films of graphite, and
not to any tendency of the iron itself to become fibrous : this of course
does not in any way militate against the theory which I have ventured
440 APPENDIX.
Thus, ladies and gentlemen, we have reached the termination
of our task. I commenced by exhibiting to you some of the phe-
nomena of crystallization. I have placed before you the facts which
are found to be associated with the cleavage of slate-rocks. These
facts, as finely expressed by Heluiholtz, are so many telescopes
to our spiritual vision, by which we can see backward through
the night of antiquity, and discern the forces which have been in
operation upon the earth's surface
" Ere the lion roared,
Or the eagle soared." .
From evidence of the most independent and trustworthy cha-
racter, we come to the conclusion that these slaty masses have been
subjected to enormous pressure, and by the sure method of experi-
ment we have shown— and this is the only really new point which
has been brought before you — how the pressure is sufficient to pro-
duce the cleavage. Expanding our field of view, we find the
self-same law, whose footsteps we trace amid the crags of Wales
and Cumberland, stretching its ubiquitous fingers into the domain
of the pastrycook and ironfounder ; nay, a wheel cannot roll over
the half- dried mud of our streets without revealing to us more or
less of the features of this law. I would say, in conclusion, that
the spirit in which this problem has been attacked by geologists
indicates the dawning of a new day for their science. The great
intellects who have laboured at geology, and who have raised it to
its present pitch of grandeur, were compelled to deal with the sub-
ject in mass ; they had no time to look after details. But the desire
for more exact knowledge is increasing ; facts are flowing in, which,
while they leave untouched the intrinsic wonders of geology, are
gradually supplanting by solid truths the uncertain speculations
which beset the subject in its infancy. Geologists now aim to imi-
tate, as far as possible, the conditions of nature, and to produce her
results ; they are approaching more and more to the domain of
physics ; and I trust the day will soon come when we shall interlace
our friendly arms across the common boundary of our sciences,
and pursue our respective tasks in a spirit of mutual helpfulness,
encouragement, and good-will.
to propose. All that the theory requires is surfaces of weak cohesion,
however produced, and a change of shape of such surfaces consequent
on pressure or rolling.
441
INDEX.
^GGISCHHOEN.
JEggischhorn, 100, 105.
Agassiz on glacier motion, 270,
310.
Air-bubbles, 359, 376.
Aletsch Glacier, 101.
— , bedding and structure ob-
served on, 120, 391.
Alefcschhorn, cloud iridescences on,
LOO, 238.
Allalein Glacier, 162.
Alpine climbers, suggestions to,
169.
Alps, winter temperature of, 168.
Altmann's theory of glacier motion,
296.
Ancient glaciers, action of, 99, 141.
Arveiron, arch of, 38, 217.
Atmosphere, permeability of, to
radiant heat, 105, 243-247.
Atmospheric refraction, 35.
Avalanche at Saas, 164.
— , sound of, explained, 12, 14.
Bakewell, Mr., on motion of Glacier
des Bossons, 337.
Balmat, Auguste, 169, 188.
Bedding, lines of, 391.
Bennen, Johann Joseph, 104, 118.
Bergschrund, 98, 325.
"Blower," glacier, 87.
Blue colour of ice, 256.
— snow, 29, 83, 132, 203.
- water, 33, 253, 259-262.
Blueness of sky, 22, 174, 257-261.
Blue veins, 376, 381.
Boiling-point, influence of pressure
on, 408.
— at different altitudes, 105,
106, 113, 120, 129, 175,
190.
Bois, Glacier des, 39, 275, 368.
Brevent, ascent of, 172.
Brocken, Spirit of the, 22, 238.
Bubbles in ice, 44, 147, 359, 425.
— in snow, 18, 251.
CEYSTALS.
Capillaries of glacier, 335-339.
Cave of ice, 135.
Cavities in ice, 163, 356, 424.
Cells in ice, 147, see Bubbles.
Chamouni, 37.
— , difficulties at, 170, 192.
— in winter, 198, 336.
Charmoz, view from, 45, 68, 368.
Charpentier's theory of glacier mo-
tion, 296.
Chemical action, rays producing,
240.
Chromatic effects, 235.
Cleavage, 406.
— and stratification distinct, 2,
390, 431.
— caused by pressure, 6, 436.
— , contortions of, 9, 59.
— of crystals and slate rocks,
lecture on, 427.
- of glaciers, 26, 393, 425-426.
— ice, 352, 407.
slate, &c., 1, 430.
" Cleft station," the, 47, 369.
Clouds, formation and dissipation
of, 22, 97, 137, 146.
— , iridescent, 100, 105, 147. 154,
238.
— on Mont Blanc, 82.
— on Monte Bosa, 124.
— , winter, at Montanvert, 208.
Colour answers to pitch, 227.
Colours of sky, 257.
— , subjective, 37.
Comet, discovery of, 186.
Compass affected by rocks, 140.
Crepitation of glaciers, 44, 357.
Crevasses, 315 (marginal, 318 ;
transverse, 320 ; longitudinal,
322), 424.
— , first opening of, 317, 327.
Crumples in ice, 174, 415, 419.
Crystallization of ice, 353.
Crystals, cleavage of, 3, 428.
— of snow, 130, 205, 212.
442
INDEX.
DEAFNESS.
Deafness, artificial, 167.
Differential motion, 395.
— , Dr. Whewell on, 396.
Diffraction, explanation of, 237.
Dirt-bands, 45, 46, 68, 95, 367, 373. '
— maps of, 367, 368, 369.
, Forbes on, 371.
— , source of, 369, 425.
Disks in ice, planes of, 163, 358,
425.
Dollfuss, M., hut of, 18, 112.
Dome du Gouter, 68, 75.
Donny, M., on cohesion of liquids,
355.
Echoes, theory of, 15.
Eismeer, the, 13, 362.
Expedition of 1856, Oberland and
Tyrol, 9-32.
— 1857, Montanvert and Mer
de Glace, 33-91.
— 1858, Oberland, Valais, and
Monte Kosa district, 92-
192.
— 1859, winter, Chamouni, and
Mer de Glace, 195-219.
Faraday, Prof., on Eegelation, 351.
Faulberg, cave of, 107.
Fee, glacier of, 165.
Fend, 32.
Finsteraarhorn, 104, 110.
— , summit of, 112.
Flowers, liquid, in ice, 147, 354-
358, 424.
Forbes, Prof., comparison of glacier
to river, 306, 308.
— , on glacier motion, 272, 304,
308.
, on magnetism of rocks, 145.
, on veined structure, 379.
, viscous theory, 311, 327,
333, 335.
Freezing, planes of, 163, 358, 424.
Frost-bites, 191.
Frozen flowers, 130, 212.
Furgge glacier, structure crossing
strata on, 160, 392-394.
Gases, passage of heat through,
243.
Geant, Col du, 50, 173.
HANDECK.
G6ant, glacier du, 53-57, 280, 369-
373.
— , measurements on, 419-421.
— , motion of, 281, 286.
— , white ice seams of, 56, 413.
Gebatsch Alp, 23.
— , glacier of, 24, 26.
Geneva, Lake of, 33, 259-262.
' Glaciers, ancient, action of, 99, 163.
— " blower," 87.
— , capillaries of, 335-339.
— , crepitation of, 44, 357.
— d'ecoulement, 301.
— de L6chaud, see Le'chaud.
- des Bois, 39, 275, 368.
— du Geant, see Geant.
- du Talefre, see Talefre.
— , groovings on, 20, 56, 377.
— , measurement of, 276.
— motion, 52, 269-295, 422.
, earlier theories of, 296-314.
— , pressure theory of, 346.
— , origin of, 248-252.
— reservoirs, 301.
— , ridges on, 42, 55.
— , structure of, 136, 148, see
Veined structure.
— tables, 44, 265.
— , veins of, 54, 376, 381.
— , wrinkles on, 370.
Goethe's theory of colours, 258.
Gorner glacier, 120, 138.
Gorner grat, 137, 145.
Gornerhorn glacier, 147, 149.
Grand Plateau, 187.
Grands Mulcts, 73, 185.
Graun, 29.
Grimsel, the, 18, 99.
Grindelwald, lower glacier of, 13,
92, 321, 384.
Groovings on glaciers, 20, 56, 377.
Griiner's theory of glacier motion,
296.
Guides of Chamouni, rules of, 60,
170, 192.
— lost in crevasse, 76.
Guyot, M., on veined structure,
378.
Hailstones, conical, 31.
— , spherical, 65.
Handeck, waterfall of, 17.
INDEX.
443
Hasli, valley of, 17, 99.
Heat and light, 223, 239, 241.
work, 328.
— , luminous, 241-247.
— , mechanical equivalent of, 329.
— , obscure, 240.
— , passage through gases, 243-245.
— , radiant, 239.
, permeability of atmosphere
to, 105, 243-247.
— , radiated, 242.
— , specific, 331.
Heisse Platte, the, 13.
Hirst, Mr., measurements on Mer
de Glace, 38, 46, 275, 283, 289,
313,420.
Hoch-joch, 32.
Hochste Spitze of Monte Rosa, 128.
Hopkins, Mr., on crevasses, 318,
383.
Hotel des Neufchatelois, 19, 112,
270.
Hugi on glacier motion, 270.
Huxley, Mr., on glacier capillaries,
338.
— , on water-cells, 251, 359.
Hydrogen, effect on rays, 253.
Ice, blue colour of, 256.
— cascades, 94, 384, 391.
— cave, 135.
— cells, 147, see Bubbles.
— cones, 266.
— , cracking of, 317, 326.
— , crystallization of, 353.
— , effects of pressure on, 405, 409.
— , experiments on, 346.
— , friability of, 333.
— , liquefaction of, 353, 408.
— , liquid flowers in, 354-358, 424.
— , Thomson's theory of plasticity
of, 340.
— , softening of, 333.
— , structure of, 136, 148.
— , temperature of, 241, 332.
— , white, seams of, 56, 413, 421.
Illumination of trees, &c., at sun-
rise and sunset, 178, 238.
Interference rings, 229.
— spectra, 76, 178, 235, 238.
Iridescent clouds, 100, 105, 147,
J54, 238.
MONTE ROSA.
Jardin, the, 61, 174.
Joch, the passage of a, 28.
Joule, M., on heat and work, 328.
Jungfrau, the, 11.
— , evening near, 106.
Laminated structure, 376, 378,
426.
Lechaud, glacier de, 53, 387.
— , motion of, 60, 286-288.
Lenticular structure, 381.
Light and heat, 223, 239, 241.
— , undulation theory of, 224.
Linth, M. Escher de la, 271.
Liquefaction of ice, 353, 408.
Liquid flowers, 147, 354-358, 424.
Magnetic force, 144.
Magnetism of rocks, 140, 143, 145.
Marjelen See, 101, 119.
Mastic, Briicke's solution of, 259.
Mattmark See, 162.
Maximum motion, locus of point
of, 285, 323.
Mayen wand, summit of, 20, 100, 323.
Mayer, on connexion of heat with
work, 328.
Measurement of glaciers, 276.
Mer de Glace, 42-67, 86-90, 173.
, dirt-bands of the, 367
(seen from Charmoz ,
45, 368; from Cleft
station, 47, 369 ; from
the Flegere, 367).
, map of, 53, 264.
— , motion of, 275-293.
— , winter motion of, 294,
343.
, winter visit to, 195, 206-
218.
Milk, cause of blueness of, 261.
Mirage, 36.
Montanvert, 40, 89, 173.
— in winter, 204.
Mont Blanc, first ascent of, 68.
— , second ascent of, 177.
— , summit of, 81, 189.
Monte Kosa, first ascent of, 122.
, second ascent of, 151.
, summit of, 128, 156.
, western glacier of, 138, 147.
, zones of colour, 154, 238.
444
INDEX.
MORAINES.
Moraines, 263.
- of Talefre, 54, 63, 267, 387.
Motion of glaciers, 52, 269-295,
422.
Moulins, 362, 424.
— , depth of, 365.
— , motion of, 364.
Necker, letter from, 178.
Neufchatelois, Hotel des, 19, 112,
270.
Nev<§ ice, 249, 251.
Oberland, the, visited, 9-22; 92-
120 ; 390.
Oils, effect of films of, 236.
Person, M., on softening of ice, 333.
Pistol fired on summit of Mont
Blanc, 82, 83, 224.
Pitch of musical sounds, 225.
Planes of freezing, 163, 358, 424.
Plasticity of ice, Thomson's theory
of, 340.
Polar forces, 4.
Pressure and cleavage,'see Cleavage.
— and liquefaction of ice, 340, 408.
— veined structure, 404 ; 147-
149, 382-394, 412, 425-426.
— , effects of, on boiling point, 408.
— ice, 405, 409.
— theory of glacier motion, 346.
Eadiant heat, 105, 239.
Eays, calorific, 240.
-- transmission of, 242.
Redness of sunset, 175.
Refraction on lake of Geneva, 35.
Regelation, 347, 351.
Reichenbach fall, 17.
Rendu, comparison of glacier to
river, 306.
— , measurements of glaciers, 304.
— , notice of regelation, 301.
— on conversion of snow into ice,
301.
- on ductility, 298.
— on law of circulation, 300.
— on motion of glaciers, 305.
— on veined structure, 301.
— theory of glaciers, 299.
Rhone at lake of Geneva, 34, 261.
STELVIO.
Rhone glacier, 20, 100, 323, 386.
— , chromatic effects, 21, 238.
Ridges on glaciers, 42, 55.
Riffelhorn, the, 133, 141-145.
Rings, interference, 229.
— round sun, 21, 238.
Ripples deduced from rings, 400.
Ripple theory, Forbes on, 398.
— of veined structure, 398
— waves, movement of, 232.
River and glacier, analogies be-
tween, 281-285, 423 ; 368.
Rocks, magnetism of , 140, 143, 145.
Saas, avalanche at, 164.
Sabine, Gen., on veined structure,
378.
Sand-cones, 266.
Saussure's theory of glacier motion,
52, 296.
Scheuchzer's theory of glacier
motion, 296.
Seams, white, in ice, 56, 88, 413,
421.
Sedgwick, Prof., on cleavage, 2-5,
390, 431.
Seracs, 51, 75.
Serpentine, boulders of, 161.
Shadows, coloured, 38.
Sharpe, on slaty cleavage, 5, 432.
Silberhorn, the, 11.
Sky, blueness of, 22, 174, 175.
— , colours of, explained, 257.
Slate, cleavage of, 1, 430.
Snow, blue colour of, 29, 132, 203.
— crystals, 130, 205, 212.
— , dry, 250.
— line, 29, 248.
— , perpetual, 248.
— , sound of breaking, 202.
— storm, sound through, 215.
— , whiteness of, explained, 250.
Sorby, Mr., on slaty cleavage, 5,
435.
Sound in a vacuum, 224.
— , intensity of, 83.
— , rate of motion of, 226.
Spectra, interference, 76, 178, 235,
238,
Spectrum, rays of, 240.
Stars, twinkling of, 72, 238.
Stelvio, pass of, 29.
INDEX.
445
Storm on Grands Mulets, 185.
— Mer de Glace, 210.
Strahleck, glacier of, 94, 384.
- passage of, 93, 97.
Strata of ice, 136.
Stratification of neve*, 392.
— slate, 1, 430.
Structure, doubts regarding, 44,
92, 389.
— of ice, 136, 148, see Veined
structure.
Subjective colours, 37.
Summary of glacier theory, 422.
Sun, rings round, 21, 238.
Sunrise at Chamouni, 39.
— and sunset, illumination of
trees, &c., at, 178, 238.
Sunset, gorgeous, 184.
Tables, glacier, 44, 265-266.
Tacul, motion of ice-wall at, 289.
Talefre, glacier of, 43, 61-62, 87.
— , moraines of, 54, 63, 267, 387.
Temperature, winter, of Alps, 168.
Theodolite, use of, 275.
Theory of cleavage, 5.
Thermometer at Jardin, 174.
— buried on Mont Blanc, 190.
— on Finsteraarhorn, 113.
Thomson, Prof., theory of plasticity,
340.
regelation, 352.
Twinkling of stars, 72, 238.
Tyrol, the, 23.
Undulation theory of light, 224.
YOUNG.
Unteraar, glacier of, 18, 265, 388.
Vacuum in ice-cavities, 163, 356.
Veined structure, 376 (marginal,
383 ; transverse, 384 ; longitudi-
nal, 387), 395, 404, 408.
— , experiments on, 382, 388.
— caused by pressure, 147-149,
382-389, 412, 425-426.
— crossing strata, 389-394.
— , Forbes on, 379.
— , Gen. Sabine on, 378.
- — , M. Guyot on, 378.
— , ripple theory of, 398.
Viesch, glacier of, 109, 118.
Viscosity, 312, 325, 334, 350, 423.
Water absorbs red rays, 254.
— , blue colour of, 254; 33, 259,
261.
— , rippling waves of, 232.
Waves, frozen, 43, 55.
— , interference of, 231.
— motion, Weber on, 232, 399.
— of sound, 225.
Wengern Alp, 9.
Wetterhorn, echoes of, 15.
White ice, seams of, 56, 57, 88,
413, 421.
Whiteness of ice, 250, 268, 376.
Winter motion of Mer de Glace,
294.
Wrinkles on glacier, 370.
Young, Thomas, theory of light,
224.
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