Part 1

Transcriber Note

Text emphasis denoted by _Italics_.

THE FORMS OF WATER IN CLOUDS AND RIVERS ICE AND GLACIERS

BY

JOHN TYNDALL, LL.D., F. R. S.

_WITH TWENTY-FIVE ILLUSTRATIONS DRAWN AND ENGRAVED UNDER THE DIRECTION OF THE AUTHOR_

NEW YORK D. APPLETON AND COMPANY 1899

Copyright, 1872, By D. APPLETON AND COMPANY.

Electrotyped and Printed at the Appleton Press, U. S. A.

AMERICAN PREFACE TO THE INTERNATIONAL SCIENTIFIC SERIES.

The rapid development of science in the present age, and the increasing public interest in its results, make it desirable that the most efficient measures should be adopted to elevate the character of its popular literature. The tendency of careless and unscrupulous book-makers to cater to public ignorance and love of the marvellous, and to foist their crude productions upon those who are too little instructed to judge of their real quality, has hitherto been so strong as to cast discredit upon the idea of "popular science." It is highly important to counteract this evil tendency by furnishing the public with popular scientific books of a superior character. The publication of the present volume is the first step in carrying out a systematic enterprise of this kind. It initiates a series of such works on a wide range of scientific subjects, to be prepared by the leading thinkers of different countries, and known as the "International Scientific Series."

It is designed to consist of compendious scientific treatises, representing the latest advances of thought upon subjects of general interest, theoretical and practical, to all classes of readers. The familiar phenomena of surrounding Nature, in their physical and chemical aspects, the knowledge of which has recently undergone marked extension or revision, will be considered in their latest interpretations. Biology, or the general science of life, which has lately come into prominence, will be explained in its leading and most important principles. The subject of mind, which, under the inductive method and on the basis of its physical accompaniments and conditions, is giving rise to a new psychology, will be treated with the fulness to which it is entitled. The laws of man's social development, or the natural history of society, which are now being studied by the scientific method, will also receive a due share of attention. While the books of this series are to deal with a wide diversity of topics, it will be a leading object of the enterprise to present the bearings of inquiry upon the higher questions of the time, and to throw the latest light of science upon the phenomena of human nature and the economy of human life.

As the first requisite of such a series of works is trustworthiness, their preparation has been confided only to men of eminent ability, and who are recognized authorities in their several departments. As they are to address the non-scientific public, it is a further requisite that they should be written in familiar and intelligible language. It is not to be expected that the authors will all attain to the same standard in this respect, but they are pledged to the utmost simplicity of exposition that is possible consistently with clear and accurate representation.

As science is now the supreme interest of civilization, and concerns alike the people of every country, and as, moreover, it affords a common ground upon which men of all races, tongues, faiths, and nationalities, may work together in harmony, it seemed fitting that an undertaking of this kind should be of comprehensive scope and stand upon an international basis. With the growing sentiment of sympathy and brotherhood among the most widely-separated students of Nature, and the extensive facilities of business intercourse that now exist, there appeared no reason why an international combination of authors and publishers should not be effected that would be equally favourable to their own private interests and advantageous to the public. To gain this end and guarantee to authors better remuneration for their work, is a distinctive purpose of the present enterprise. But there was this difficulty in the way of any such arrangement, that, while the rights of foreign authors are guarded by all other civilized governments, they are not protected by the government of the United States. To escape this difficulty, and secure American coöperation, the first thing needed was to obtain the consent of an American publishing-house to grant voluntarily to foreign authors the justice which our government denies them. It was agreed by Messrs. Appleton that they would pay the foreign contributors to this series the full rates of copyright that are usually allowed to American authors. When this was done, engagements were made with distinguished scientists of England, France, Germany, and the United States, to prepare works for the series, and with Henry S. King & Co., of London, Germer Baillière, of Paris, and Messieurs Brockhaus, of Leipsic, to publish them. Negotiations are pending for the reproduction of the series in other countries, but the present arrangements secure to the authors the benefits of the four leading markets of the world.

It is a fact not without significance, that the proposal of this enterprise was received with the most cordial favour by the eminent scientific men who were solicited to aid in carrying it forward. Most of them consented at once; but, while some were so heavily burdened with work that they could enter into no immediate engagements, not one of them declined to coöperate, and all promised to do so at the earliest practicable opportunity. The feeling of the desirableness of such an undertaking was strong and unanimous. The old dislike of the cultivators of science to participate in the work of popular teaching, seems very much to have passed away; and in England, France, and Germany, alike it was freely acknowledged that _savants_ have an imperative duty to discharge in relation to the work of general scientific education. As remarked by Prof. Virchow, of Berlin, "the destiny of science is the service of humanity."

It was stipulated by the authors that they should have ample time for the preparation of their books, and, as the arrangements were recently made, only a few of the works are yet ready. Several, however, are now in press, and will shortly appear.

Those interested in the series are under many obligations to Prof. Tyndall for his kindness in consenting to furnish its commencing volume. Being prepared in a short time, amid great pressure both of laboratory and literary work, it contains somewhat less matter than may be expected in the ensuing volumes. It treats of subjects upon which he is perhaps the highest living authority; and it is an admirable example of that vivid, stirring, impressive style for which its author is so distinguished. Prof. Tyndall is not only a master in the "scientific use of the imagination," but in kindling the action of that faculty in his readers. He writes in pictures, so as to make them see what he sees. In this volume he addresses himself directly to his juvenile friends, groups them around him, takes them with him to his favourite mountains, and thus adds a dramatic element and the effect of personal sympathy to familiar colloquial exposition.

The "International Scientific Series" will form an elegant and valuable library of popular science, fresh in treatment, attractive in form, strong in character, moderate in price, and indispensable to all who care for the acquisition of solid and serviceable knowledge; and it is commended to American readers as a help in the important work of sound public education.

E. L. Y.

New York, _September, 1872_.

AUTHOR'S PREFACE.

After an absence of twelve years, I visited the Mer de Glace last June. It exhibited in a striking degree that excess of consumption over supply which, if continued, would eventually reduce the Swiss glaciers to the mere spectres of their former selves. When I first saw the Mer de Glace its ice-cliffs towered over Les Mottets, and an arm of the Arveiron, issuing from the cliffs, plunged as a powerful cascade down the rocks. The ice has now shrunk far behind them. A huge moraine, left behind by the retreating glacier, will mark, for some time to come, its recent magnitude. The vault of the Arveiron has dwindled considerably. The way up to the Chapeau lies on the top of a lateral moraine, reached a few years ago by the surface of the glacier, the present surface lying far below. The visible and continual breaking away of the moraines, left thus stranded on the mountain flank, explains the absence of ancient ridges on the mountains where the slopes are steep. The ice-cascades of the Géant has suffered much from the general waste. Its crevasses are still wild, but the ice-cliffs and séracs of former days are but poorly represented to-day.

The great Aletsch and its neighbours exhibit similar evidences of diminution. I found moreover this year that the two ancient moraines mentioned in paragraph 364 are parts of the same great lateral moraine which flanked the glacier for a long period, during which its magnitude must have remained practically constant. The place occupied by the ancient ice-river is rendered strikingly conspicuous by this well-preserved boundary.

During my residence at the Bel Alp this year, a catastrophe occurred which renders, for the time being, the description of the Märgelin See given in § 50 inappropriate. In company with two young friends I had descended the glacier and passed through the gorge of the Massa. On our return to the Bel Alp we found the domestics of the hotel leaning out of the windows and looking excitedly towards the glacier. From it proceeded a sound which resembled the roar of a cataract. The servants remarked that the Märgelin See must have broken loose. This was the case. For a time, however, the water flowed beneath the glacier; but at a point about midway between the Bel Alp and the Æggischhorn, it broke forth on the Æggischhorn side, and formed a torrent between the glacier and the slope of the mountain. In some places this river was more than sixty yards wide, at others it was contracted to less than one-fifth of this width. Broken cascades of great height were formed here and there by successive ledges of ice, the torrent leaping with indescribable fury from ledge to ledge, and sending a smoke of spray into the air. At one place the bottom of the torrent was deep soft sand, which, after the water had passed, could be seen to have been tortured into huge funnels by the whirling eddies overhead.

Soon after we reached the Bel Alp, on the occasion just referred to, the front of the torrent appeared at the opposite side of the valley carrying everything movable before it, and immediately afterwards swept through the hollow that we had traversed a little earlier in the day. When at the end of the glacier I was struck by the force and volume of the Massa, and the grandeur of its vault, but I could not then account for the huge blocks of ice which it incessantly carried down. Doubtless the eruption above had been partial before the grand rush set in. The Rhone was considerably swollen, crops were damaged or ruined, and the driver of the diligence was sorely perplexed to find himself in three feet of water, without any apparent reason, on the public highway. Two or three days subsequently I learned at the Æggischhorn that an engineer had been sent up to report on the possibility of opening a channel, so as to prevent any future accumulation of water in the Märgelin See. If this be done a useful end will be gained, by the abolition, however, of one of the most beautiful objects in Switzerland.

J. Tyndall.

_September, 1872._

PREFACE TO THE FOURTH EDITION.

At a meeting of the Managers of the Royal Institution held on December 12, 1825, "the Committee appointed to consider what lectures should be delivered in the Institution in the next session," reported "that they had consulted Mr. Faraday on the subject of engaging him to take a part in the juvenile lectures proposed to be given during the Christmas and Easter recesses, and they found his avocations were such that it would be exceedingly inconvenient for him to engage in such lectures."

At a general monthly meeting of the members of the Royal Institution, held on December 4, 1826, the Managers reported "that they had engaged Mr. Wallis to deliver a course of lectures on Astronomy, adapted to a juvenile auditory, during the Christmas vacation."

In a report dated April 16, 1827, the Board of Visitors express "their satisfaction at finding that the plan of juvenile courses of lectures had been resorted to. They feel sure that the influence of the Institution cannot be extended too far, and that the system of instructing the younger portion of the community is one of the most effective means which the Institution possesses for the diffusion of science."

Faraday's holding aloof was but temporary, for at Christmas 1827 we find him giving a "Course of Six Elementary Lectures on Chemistry, adapted to a Juvenile Auditory."[A]

[A] There is no record to show that Mr. Wallis gave the Astronomical lectures referred to, and our librarian believes that the _Christmas_ courses were opened by Faraday.

The Easter lectures were soon abandoned; but from the date here referred to to the present time the Christmas lectures have been a marked feature of the Royal Institution.

In 1871 it fell to my lot to give one of these courses. I had been frequently invited to write on Glaciers in encyclopædias, journals, and magazines, but had always declined to do so. I had also abstained from making them the subject of a course of lectures, wishing to take no advantage of my position here, and indeed to avoid writing a line or uttering a sentence on the subject for which I could not be held personally responsible. In view of the discussions which the subject had provoked, I thought this the fairest course.

But, in 1871, the time (I imagined) had come when, without risk of offence, I might tell our young people something about the labours of those who had unravelled for their instruction the various problems of the ice-world. My lamented friend and ever-helpful counsellor, Dr. Bence Jones, thought the subject a good one, and accordingly it was chosen. Strong in my sympathy with youth, and remembering the damage done by defective exposition to my own young mind, I sought, to the best of my ability, to confer upon these lectures clearness, thoroughness, and life.

Wishing, moreover, to render them of permanent value, I wrote out copious Notes of the course, and had them distributed among the boys and girls. In preparing these Notes I aimed at nothing less than presenting to my youthful audience, in a concentrated but perfectly digestible form, every essential point embraced in the literature of the glaciers, and some things in addition, which, derived as they were from my own recent researches, no book previously published on the subject contained.

But my theory of education agrees with that of Emerson, according to which instruction is only half the battle, what he calls _provocation_ being the other half. By this he means that power of the teacher, through the force of his character and the vitality of his thought, to bring out all the latent strength of his pupil, and to invest with interest even the driest matters of detail. In the present instance I was determined to shirk nothing essential, however dry; and, to keep my mind alive to the requirements of my pupil, I proposed a series of ideal ramblings, in which he should be always at my side. Oddly enough, though I was here dealing with what might be called the abstract idea of a boy, I realised his presence so fully as to entertain for him, before our excursions ended, an affection consciously warm and real.

The "Notes" here referred to were at first intended for the use of my audience alone. At the urgent request of a friend I slightly expanded them, and converted them into the little book here presented to the reader.

The amount of attention bestowed upon the volume induces me to give this brief history of its origin.

A German critic, whom I have no reason to regard as specially favourable to me or it, makes the following remark on the style of the book: "This passion [for the mountains] tempts him frequently to reveal more of his Alpine wanderings than is necessary for his demonstrations. The reader, however, will not find this a disagreeable interruption of the course of thought; for the book thereby gains wonderfully in vividness." This, I would say, was the express aim of the breaks referred to. I desired to keep my companion fresh as well as instructed, and these interruptions were so many breathing-places where the intellectual tension was purposely relaxed and the mind of the pupil braced to fresh action.

Of other criticisms, flattering and otherwise, I forbear to speak. As regards some of them, indeed, it would be a reproach to that manliness which I have sought to encourage in my pupil to return blow for blow. If the reader be acquainted with them, this will let him know how I regard them; and if he be not acquainted with them, I would recommend him to ignore them, and to form his own judgment of this book. No fair-minded person who reads it will dream that I, in writing it, had a thought of acting otherwise than justly and generously towards my predecessors, the last of whom, to the grief of all who knew him, has recently passed away.

John Tyndall.

_April, 1874._

CONTENTS.

Cloud-banner of the Aiguille du Dru _Frontispiece_

PAGE

§ 1, 2. Clouds, Rains, and Rivers 1, 6

3. The Waves of Light 8

4. The Waves of Heat which produce the Vapour of our Atmosphere and melt our Glaciers 11

5. Experiments to prove the foregoing statements 14

6. Oceanic Distillation 19

7. Tropical Rains 23

8. Mountain Condensers 27

9. Architecture of Snow 29

10. Atomic Poles 32

11. Architecture of Lake Ice 35

12. The Source of the Arveiron. Ice Pinnacles, Towers, and Chasms of the Glacier des Bois. Passage to the Montanvert 38

13. The Mer de Glace and its Sources. Our First Climb to the Cleft Station 43

14. Ice-cascade and Snows of the Col du Géant 46

15. Questioning the Glaciers 48

16. Branches and Medial Moraines of the Mer de Glace from the Cleft Station 51

17. The Talèfre and the Jardin. Work among the Crevasses 52

18. First Questions regarding Glacier Motion. Drifting of Bodies buried in a Crevasse 54 19. The Motion of Glaciers. Measurements by Hugi and Agassiz. Drifting of Huts on the Ice 69

20. Precise Measurements of Agassiz and Forbes. Motion of a Glacier proved to resemble the Motion of a River 60

21. The Theodolite and its Use. Our own Measurements 62

22. Motion of the Mer de Glace 66

23. Unequal Motion of the two Sides of the Mer de Glace 70

24. Suggestion of a new Likeness of Glacier Motion to River Motion. Conjecture tested 72

25. New Law of Glacier Motion 76

26. Motion of Axis of Mer de Glace 78

27. Motion of Tributary Glaciers 79

28. Motion of Top and Bottom of Glacier 80

29. Lateral Compression of a Glacier 81

30. Longitudinal Compression of a Glacier 84

31. Sliding and Flowing. Hard Ice and Soft Ice 86

32. Winter on the Mer de Glace 88

33. Winter Motion of the Mer de Glace 93

34. Motion of the Grindelwald and Aletsch Glacier 93

35. Motion of Morteratsch Glacier 95

36. Birth of a Crevasse: Reflections 98

37. Icicles 99

38. The Bergschrund 102

39. Transverse Crevasses 103

40. Marginal Crevasses 105

41. Longitudinal Crevasses 109

42. Crevasses in relation to Curvature of Glacier 110

43. Moraine-ridges, Glacier Tables, and Sand-Cones 112

44. The Glacier Mills or Moulins 116

45. The Changes of Volume of Water by Heat and Cold 118

46. Consequences flowing from the foregoing Properties of Water. Correction of Errors 122

47. The Molecular Mechanism of Water-Congelation 125

48. The Dirt Bands of the Mer de Glace 127

49. Sea-ice and Icebergs 132

50. The Æggischhorn, the Märgelin See and its Icebergs 136

51. The Bel Alp 139

52. The Riffelberg and Görner Glacier 140

53. Ancient Glaciers of Switzerland 145

54. Erratic Blocks 147

55. Ancient Glaciers of England, Ireland, Scotland, and Wales 150

56. The Glacier Epoch 152

57. Glacial Theories 155

58. Dilatation and Sliding Theories 155

59. Plastic Theory 156

60. Viscous Theory 161

61. Regelation Theory 163

62. Cause of Regelation 167

63. Faraday's View of Regelation 171

64. The Blue Veins of Glaciers 176

65. Relation of Structure to Pressure 183

66. Slate Cleavage and Glacier Lamination 187

67. Conclusion 191

THE FORMS OF WATER

IN CLOUDS AND RIVERS, ICE AND GLACIERS.

§ 1. _Clouds, Rains, and Rivers._

1. Every occurrence in Nature is preceded by other occurrences which are its causes, and succeeded by others which are its effects. The human mind is not satisfied with observing and studying any natural occurrence alone, but takes pleasure in connecting every natural fact with what has gone before it, and with what is to come after it.

2. Thus, when we enter upon the study of rivers and glaciers, our interest will be greatly augmented by taking into account not only their actual appearances, but also their causes and effects.