THE
GLACIERS OF THE ALPS.

WITH ILLUSTRATIONS.

NEW EDITION.

LONGMANS, GREEN, AND CO.
LONDON, NEW YORK, AND BOMBAY.
1896.

All rights reserved

TO
MICHAEL FARADAY,
THIS BOOK
IS AFFECTIONATELY INSCRIBED.

1860.

PREFACE.

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 such 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 special 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 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 circumstances 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 formation 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 differences 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 controversial 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 considerably 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.

Page
1.—Introductory.1

Visit to Penrhyn; the Cleavage of Slate Rocks; Sedgwick's theory—its difficulties; Sharpe's observations; Sorby's experiments; Lecture at the Royal Institution; Glacier Lamination; arrangement of an expedition to Switzerland

2.—Expedition of 1856: the Oberland.9

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 Grindelwald 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; Hôtel des Neufchâtelois; the Rhone glacier from the Mayenwand; expedition up the glacier; Coloured Rings round the sun; crevasses of the névé; extraordinary meteorological phenomenon; Spirit of the Brocken

3.—The Tyrol.23

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 Hochjoch to Fend; singular hailstorm; wild glacier region; hidden crevasses; First Paper presented to the Royal Society

4.—Expedition of 1857: the Lake of Geneva.33

Blueness of the water; the head of the Lake; appearance of the Rhone; subsidence of particles; Mirage

5.—Chamouni and the Montanvert.37

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

6.—The Mer de Glace.42

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 incapable of detecting differences between intense lights

7.46

Measurements commenced; the "Cleft Station" at Trélaporte; Regelation of snow granules; two chamois; view of the Mer de Glace and its Tributaries; Séracs of the Col du Géant; Sliding and Viscous theories; Rending of the ice; Striæ on its surface; White Ice-seams

8.57

Alone upon the glacier; Lakes and Rivulets; parallel between Glacier and Geological disturbance; splendid rainbow; aspect of the glacier at the base of the Séracs; visit to the Chief Guide at Chamouni; Liberties granted

9.—The Jardin.61

Glacier du Talèfre; Jardin divides the névé; Blue Veins near the summit; surrounding scene; Moraines and Avalanches; Cascade du Talèfre; dangers on approaching it from above

10.64

Lightning and Rain; Spherical hailstones; an evening among the crevasses; Dangerous Leap; ice-practice; preparations for an ascent of Mont Blanc

11.—First Ascent of Mont Blanc (1857).68

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; Séracs of the Dôme du Goûter; 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; cheerless prospect; the Corridor; the Mur de la Côte; 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

12.86

Life at the Montanvert; glacier "Blower;" Cascade of the Talèfre; difficulties in setting out lines; departure from the Montanvert; my hosts; prospect from the Glacier des Bois; Edouard Simond

13.—Expedition of 1858.92

Origin and aim of the expedition; Laminated Structure of the ice

14.—Passage of the Strahleck.93

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

15.99

Ancient Glaciers in the valley of Hasli; Rounded, Polished, and Striated Rocks; level of the ancient ice; Groovings on the Grimsel Pass; glacier of the Rhone; descent of the Rhone valley; the Æggischhorn; Cloud Iridescences; the Aletsch glacier; the Märjelen See; Icebergs; Tributaries of the Aletsch; Grand glacier-region; crevasses; a chamois deceived

16.—Ascent of the Finsteraarhorn.104

Character of my Guide; iridescent cloud; evening on the Faulberg; the Jungfrau and her neighbours; a Mountain Cave; the Jungfrau before dawn; contemplated visit; the Grünhorn Lücke; Magnificent Corridor; sunrise; névé 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

17. 119

Subsequent days at the Æggischhorn; 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 Riffelberg

18.—First Ascent of Monte Rosa.122

The ascent new to myself and my guide; directions; Ulrich Lauener; Ominous Clouds; passage of the Görner Glacier; Roches Moutonnées; 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

19. 133

The Rothe Kumm; pleasant companions; difficult descent; temperatures of rock, air, and grass; Singular Cavern in the ice; Structure and Stratification

20.—The Görner Grat and the Riffelhorn; Magnetic Phenomena.137

Formation and Dissipation of clouds; Scene from the Görner Grat; Magnetism of the Rocks; the Compass and Sun at variance; ascent of the Riffelhorn; Magnetic effects; places of most intense action; Scratched and Polished Rocks; Exfoliation of crust produced by the sliding of ancient glaciers; Magnetic Polarity; Consequent Points; Bearings from the Riffelhorn; action on a Distant Needle

21. 145

Fog on the Riffelberg; its dissipation; Sunset from the Görner Grat; Cloud-wreaths on the Matterhorn; Streamers of Flame; grand Interference Phenomenon; investigation of Structure; the Görnerhorn glacier; Western glacier of Monte Rosa; the Schwarze, Trifti, and Théodule glaciers; welding of the Tributaries to parallel Strips; Temptation

22.—Second Ascent of Monte Rosa (1858).151

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

23. 160

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 Fée glacier; Frozen dust on the Mischabelhörner; Snow, Vapour, and Cloud; curious effect on the hearing; "a Terrible Hole;" singular group; a Song from 'The Robbers'

24. 168

Need of observations on Alpine Temperature; Balmat's intention; aid from the Royal Society; Difficulties at Chamouni in 1858; the Intendant memorialised; his response; the Séracs revisited; Crevasses and Crumples; bad weather; thermometers placed at the Jardin; Avalanches of the Talèfre; wondrous sky

25.—Second Ascent of Mont Blanc (1858).177

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 Mulets; a Comet discovered; start by starlight; the Petit Plateau a reservoir for avalanches; Balmat's 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

26. 192

Hostility of Chief Guide; Procès Verbal; the British Association; application to the Sardinian authorities; President's Letter; Royal Society; Testimonial to Balmat

27.—Winter Expedition to the Mer de Glace, 1859. 195

First defeat and fresh attempt; Geneva to Chamouni; deep snow; Desolation; slow progress; a horse in the snow; a struggle; Chamouni on Christmas night; mountains hidden; Climb to the Montanvert; Snow on the Pines; débris 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; "a rose 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; Farewell

PART II.

1.—Light and Heat. 223

What is Light?—notion of the ancients; requires Time to pass through Space; Römer, Bradley, Fizeau; Emission Theory supported by Newton, 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.

2.—Radiant Heat. 239

The Sun emits a multitude of Non-luminous Rays; Rays of Heat differ from rays of Light as one colour differs from another; the same ray may produce the sensations of light and heat

3.—Qualities of Heat.241

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 Ratchet-wheel; possible heat of a Distant Planet; causes of Cold in the upper strata of the Earth's Atmosphere

4.—Origin of Glaciers. 248

Application of principles; the Snow-line; its meaning; waters piled annually in a solid form on the summits of the hills; the Glaciers furnish the chief means of escape; superior and inferior snow-line

5.249

Whiteness of snow; whiteness of ice; Round air-bubbles; melting and freezing; Conversion of snow into ice by Pressure

6.—Colour of Water and Ice.253

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 molecules; Experiment; Grotto of Capri; the Laugs of Iceland

7.—Colours of the Sky. 257

Newton's idea; Goethe's Theory; Clausius and Brücke; Suspended Particles; singular effect on a painting explained by Goethe; Light separated without Absorption; Reflected 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

8.—The Moraines. 263

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

9.—Glacier Motion,—Preliminary. 269

Névé and Glacier; First Measurements; Hugi and Agassiz; 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

10.—Motion of the Mer de Glace.275

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; Eastern half moves quickest; Locus of Point of Maximum Motion; New Law; Motion of the Géant; motion of the Léchaud; Squeezing of the Tributaries through the Neck of the valley at Trélaporte; the Léchaud a Driblet

11.—Ice Wall at the Tacul,—Velocities of Top and Bottom.289

First attempt by Mr. Hirst; second attempt, stakes fixed at Top, Bottom, and Centre; dense fog; the stakes lost; process repeated; Velocities determined

12.—Winter Motion of the Mer de Glace. 294

First line, Above the Montanvert; second line, Below the Montanvert; Ratio of winter to summer motion

13.—Cause of Glacier Motion,—De Saussure's Theory. 296

First attempt at a Theory by Scheuchzer in 1705; Charpentier's theory, or the Theory of Dilatation; Agassiz's theory; Altmann and Grüner; theory of De Saussure, or the Sliding Theory; in part true; strained interpretation of this theory

14.—Rendu's Theory.299

Character of Rendu; his Essay entitled 'Théorie 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 Regelation; diminution of glaciers réservoirs; Remarkable Passage; announces Swifter Motion of Centre; North British Review; Discrepancies explained by Rendu; Liquid Motion ascribed to glacier; all the phenomena of a River reproduced upon the Mer de Glace; Ratio of Side and Central velocities; Errors removed

15. 308

Anticipations of Rendu 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 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

16.—Forbes's Theory. 311

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

17.—The Crevasses. 315

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 Crevasses; Longitudinal Crevasses; Bergschrunds; Influence of Flexure; why the Convex Sides of glaciers are most crevassed

18. 325

Further considerations on Viscosity; Numerical Test; formation of crevasses opposed to viscosity

19.—Heat and Work. 328

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; Rotten Ice and softened Wax

20. 334

Papers presented to the Royal Society by Professor Forbes in 1846; Capillary Hypothesis of glacier motion; hypothesis examined

21.—Thomson's Theory. 340

Statement of theory; influence of Pressure on the Melting Point of Ice; difficulties of theory; Calculation of requisite Pressure; Actual pressure insufficient

22.—Pressure Theory. 346

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

23.—Regelation.351

Faraday's first experiments; Freezing together of pieces of ice at 32°; Freezing in Hot Water; Faraday's recent experiments; Regelation not due to Pressure nor to Capillary Attraction; it takes place in vacuo; fracture and regelation; no viscidity discovered

24.—Crystallization and Internal Liquefaction. 353

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 Regelation

25.—The Moulins. 362

Their character; Depth of Moulin on Grindelwald Glacier; Explanation the Grand Moulin of the Mer de Glace; Motion of moulins

26.—Dirt-Bands of the Mer de Glace.367

Their discovery by Professor Forbes; view of Bands from a point near the Flégère; 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

27.—Veined Structure of Glaciers.376

General appearance; Grooves upon the glacier; first observations; description by M. Guyot; observations of Professor Forbes; Structure 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

28.—The Veined Structure and Differential Motion.395

Marginal Structure Oblique to sides; Drag towards the centre; difficulties of theory which ascribes the structure to Differential Sliding; it persists across the lines of maximum sliding

29.—The Ripple Theory of the Veined Structure. 398

Ripples in Water supposed to correspond to Glacier Structure; analysis of theory; observation of the MM. Weber; water dropping from an oar; stream cleft by an obstacle; Two Divergent lines of Ripple; Single Line produced by Lateral Obstacle; Direction of ripples compounded of River's motion and Wave motion; Structure and Ripples due to different causes; their positions also different

30.—The Veined Structure and Pressure. 404

Supposed case of pressed prism of glass; Experiments of Nature; Quartz-pebbles flattened and indented; Pressure would produce Lamination; Tangential Action

31.—The Veined Structure and the Liquefaction of Ice by Pressure.408

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; application to the Veined Structure

32.—White Ice-Seams of the Glacier du Géant. 413

Aspect of Seams; they sweep across the glacier concentric with Structure; Structure at the base of the Talèfre cascade; Crumples; Scaling off by pressure; Origin of seams of White Ice

33. 419

Glacier du Géant 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; development of Veined Structure

Summary 422

Appendix427

Index 441

ILLUSTRATIONS.

The Mer de Glace.—Showing the Cleft Station at Trélaporte, the Echelets, the Tacul, the Périades, and the Grand Jorasse.Frontispiece

Fig.Page
1. Ice Minaret14
2. Diagram of an angular reflector16
3, 4. Boats' sails inverted by Atmospheric Refraction35
5. Wave-like forms on the Mer de Glace43
6. Glacier Table44
7. Tributaries of the Mer de Glace53
8. Magnetic Boulder of the Riffelhorn143
9, 10, 11, 12. Luminous Trees projected against the sky at sunrise180, 181
13. Snow on the Pines201
14, 15. Snow Crystals214
16. Chasing produced by waves233
17. Diagram explanatory of Interference234
18. Interference Spectra, produced by DiffractionTo face 235
19. Moraines of the Mer de Glace"     264
20. Typical section of a glacier Table266
21. Locus of the Point of Maximum Motion286
22. Inclinations of ice cascade of the Glacier des Bois313
23. Inclinations of Mer de Glace above l'Angle314
24. Fantastic Mass of ice316
25. Diagram explanatory of the mechanical origin of Crevasses318
26. Diagram showing the line of Greatest Strain319
27a, b. Section and Plan of a portion of the Lower Grindelwald Glacier322
28. Diagram illustrating the crevassing of Convex Sides of glacier323
29. Diagram illustrating test of viscosity326
30, 31, 32, 33. Moulds used in experiments with ice346-348
34. Liquid Flowers in lake ice355
35. Dirt-bands of the Mer de Glace, as seen from a point near the FlégèreTo face 367
36. Ditto, as seen from les Charmoz"     368
37. Ditto, as seen from the Cleft Station, Trélaporte"     369
38. Plan of Dirt-bands taken from Johnson's 'Physical Atlas'374
39. Veined Structure on the walls of crevasses381
40. Figure explanatory of the Marginal Structure383
41. Plan of part of ice-fall, and of glacier below it (Glacier of the Rhone)386
42. Section of ditto386
43. Figure explanatory of Longitudinal Structure388
44. Structure and bedding on the Great Aletsch Glacier391
45, 46. Structure and Stratification on the Furgge glacier394
47. Diagram illustrating Differential Motion395
48, 49. Diagrams explanatory of the formation of Ripples400, 403
50, 51. Appearance of a prism of ice partially liquefied by Pressure.410
52, 53. Figures illustrative of compression and liquefaction of ice.411
54, 55. Sections of White Ice-seams414
56, 57. Variations in the Dip of the Veined Structure414, 415
58. Section of three glacier Crumples416
59. Wall of a crevasse, with incipient crumpling416
60. Plan of a Stream on the Glacier du Géant418
61. Plan of a Seam of White Ice on ditto418