Чарльз Дарвин
More Letters of Charles Darwin — Volume 2
The argument of probable proportion of rock dropped by sea ice compared to land glaciers is new to me. I have often thought of the idea of the viscosity and enormous momentum of great icebergs, and still think that the notion I pointed out in appendix to Ramsay's paper is probable, and can hardly help being applicable in some cases. (502/2. The paper by Ramsay has no appendix; probably, therefore Mr. Darwin's notes were published separately as a paper in the "Phil. Mag.") I wonder whether the "Phil. Journal {Magazine?.}" would publish it, if I could get it from Ramsay or the Geological Society. (502/3. "On the Power of Icebergs to make rectilinear, uniformly-directed grooves across a Submarine Undulatory Surface." By C. Darwin, "Phil. Mag." Volume X., page 96, 1855.) If you chance to meet Ramsay will you ask him whether he has it? I think it would perhaps be worth while just to call the N. American geologists' attention to the idea; but it is not worth any trouble. I am tremendously busy with all sorts of experiments. By the way, Hopkins at the Geological Society seemed to admit some truth in the idea of scoring by (viscid) icebergs. If the Geological Society takes so much {time} to judge of truth of notions, as you were telling me in regard to Ramsay's Permian glaciers (502/4. "On the Occurrence of angular, sub-angular, polished, and striated Fragments and Boulders in the Permian Breccia of Shropshire, Worcestershire, etc.; and on the Probable Existence of Glaciers and Icebergs in the Permian Epoch." By A.C. Ramsay, "Quart. Journ. Geol. Soc." Volume XI., page 185, 1855.), it will be as injurious to progress as the French Institut.
LETTER 503. TO J.D. HOOKER. Cliff Cottage, Bournemouth, {September} 21st {1862}.
I am especially obliged to you for sending me Haast's communications. (503/1. "Quart. Journ. Geol. Soc." Volume XXI., pages 130, 133, 1865; Volume XXIII., page 342, 1867.) They are very interesting and grand about glacial and drift or marine glacial. I see he alludes to the whole southern hemisphere. I wonder whether he has read the "Origin." Considering your facts on the Alpine plants of New Zealand and remarks, I am particularly glad to hear of the geological evidence of glacial action. I presume he is sure to collect and send over the mountain rat of which he speaks. I long to know what it is. A frog and rat together would, to my mind, prove former connection of New Zealand to some continent; for I can hardly suppose that the Polynesians introduced the rat as game, though so esteemed in the Friendly Islands. Ramsay sent me his paper (503/2. "On the Glacial Origin of certain Lakes in Switzerland, etc." "Quart. Journ. Geol. Soc." Volume XVIII., page 185, 1862.) and asked my opinion on it. I agree with you and think highly of it. I cannot doubt that it is to a large extent true; my only doubt is, that in a much disturbed country, I should have thought that some depressions, and consequently lakes, would almost certainly have been left. I suggested a careful consideration of mountainous tropical countries such as Brazil, peninsula of India, etc.; if lakes are there, {they are} very rare. I should fully subscribe to Ramsay's views.
What presumption, as it seems to me, in the Council of Geological Society that it hesitated to publish the paper.
We return home on the 30th. I have made up {my} mind, if I can keep up my courage, to start on the Saturday for Cambridge, and stay the last few days of the {British} Association there. I do so hope that you may be there then.
LETTER 504. TO J.D. HOOKER. November 3rd {1864}.
When I wrote to you I had not read Ramsay. (504/1. "On the Erosion of Valleys and Lakes: a Reply to Sir Roderick Murchison's Anniversary Address to the Geographical Society." "Phil. Mag." Volume XXVIII., page 293, 1864) How capitally it is written! It seems that there is nothing for style like a man's dander being put up. I think I agree largely with you about denudation — but the rocky-lake-basin theory is the part which interests me at present. It seems impossible to know how much to attribute to ice, running water, and sea. I did not suppose that Ramsay would deny that mountains had been thrown up irregularly, and that the depressions would become valleys. The grandest valleys I ever saw were at Tahiti, and here I do not believe ice has done anything; anyhow there were no erratics. I said in my S. American Geology (504/2. "Finally, the conclusion at which I have arrived with respect to the relative powers of rain, and sea-water on the land is, that the latter is by far the most efficient agent, and that its chief tendency is to widen the valleys, whilst torrents and rivers tend to deepen them and to remove the wreck of the sea's destroying action" ("Geol. Observations," pages 66, 67).) that rivers deepen and the sea widens valleys, and I am inclined largely to stick to this, adding ice to water. I am sorry to hear that Tyndall has grown dogmatic. H. Wedgwood was saying the other day that T.'s writings and speaking gave him the idea of intense conceit. I hope it is not so, for he is a grand man of science.
...I have had a prospectus and letter from Andrew Murray (504/3. See Volume II., Letters 379, 384, etc.) asking me for suggestions. I think this almost shows he is not fit for the subject, as he gives me no idea what his book will be, excepting that the printed paper shows that all animals and all plants of all groups are to be treated of. Do you know anything of his knowledge?
In about a fortnight I shall have finished, except concluding chapter, my book on "Variation under Domestication"; (504/4. Published in 1868.) but then I have got to go over the whole again, and this will take me very many months. I am able to work about two hours daily.
LETTER 505. TO J.D. HOOKER. Down {July, 1865}.
I was glad to read your article on Glaciers, etc., in Yorkshire. You seem to have been struck with what most deeply impressed me at Glen Roy (wrong as I was on the whole subject) — viz. the marvellous manner in which every detail of surface of land had been preserved for an enormous period. This makes me a little sceptical whether Ramsay, Jukes, etc., are not a little overdoing sub-aerial denudation.
In the same "Reader" (505/1. Sir J.D. Hooker wrote to Darwin, July 13th, 1865, from High Force Inn, Middleton, Teesdale: "I am studying the moraines all day long with as much enthusiasm as I am capable of after lying in bed till nine, eating heavy breakfasts, and looking forward to dinner as the summum bonum of existence." The result of his work, under the title "Moraines of the Tees Valley," appeared in the "Reader" (July 15th, 1865, page 71), of which Huxley was one of the managers or committee-men, and Norman Lockyer was scientific editor ("Life and Letters of T.H. Huxley," I., page 211). Hooker describes the moraines and other evidence of glacial action in the upper part of the Tees valley, and speaks of the effect of glaciers in determining the present physical features of the country.) there was a striking article on English and Foreign Men of Science (505/2. "British and Foreign Science," "The Reader," loc. cit., page 61. The writer of the article asserts the inferiority of English scientific workers.), and I think unjust to England except in pure Physiology; in biology Owen and R. Brown ought to save us, and in Geology we are most rich.
It is curious how we are reading the same books. We intend to read Lecky and certainly to re-read Buckle — which latter I admired greatly before. I am heartily glad you like Lubbock's book so much. It made me grieve his taking to politics, and though I grieve that he has lost his election, yet I suppose, now that he is once bitten, he will never give up politics, and science is done for. Many men can make fair M.P.'s; and how few can work in science like him!
I have been reading a pamphlet by Verlot on "Variation of Flowers," which seems to me very good; but I doubt whether it would be worth your reading. it was published originally in the "Journal d'Hort.," and so perhaps you have seen it. It is a very good plan this republishing separately for sake of foreigners buying, and I wish I had tried to get permission of Linn. Soc. for my Climbing paper, but it is now too late.
Do not forget that you have my paper on hybridism, by Max Wichura. (505/3. Wichura, M.E., "L'Hybridisation dans le regne vegetal etudiee sur les Saules," "Arch. Sci. Phys. Nat." XXIII., page 129, 1865.)
I hope you are returned to your work, refreshed like a giant by your huge breakfasts. How unlucky you are about contagious complaints with your children!
I keep very weak, and had much sickness yesterday, but am stronger this morning.
Can you remember how we ever first met? (505/4. See "Life and Letters," II., page 19.) It was in Park Street; but what brought us together? I have been re-reading a few old letters of yours, and my heart is very warm towards you.
LETTER 506. TO C. LYELL. Down, March 8th {1866}.
(506/1. In a letter from Sir Joseph Hooker to Mr. Darwin on February 21st, 1866, the following passage occurs: "I wish I could explain to you my crude notions as to the Glacial period and your position towards it. I suppose I hold this doctrine: that there was a Glacial period, but that it was not one of universal cold, because I think that the existing distribution of glaciers is sufficiently demonstrative of the proposition that by comparatively slight redispositions of sea and land, and perhaps axis of globe, you may account for all the leading palaeontological phenomena." This letter was sent by Mr. Darwin to Sir Charles Lyell, and the latter, writing on March 1st, 1866, expresses his belief that "the whole globe must at times have been superficially cooler. Still," he adds, "during extreme excentricity the sun would make great efforts to compensate in perihelion for the chill of a long winter in aphelion in one hemisphere, and a cool summer in the other. I think you will turn out to be right in regard to meridional lines of mountain-chains by which the migrations across the equator took place while there was contemporaneous tropical heat of certain lowlands, where plants requiring heat and moisture were saved from extinction by the heat of the earth's surface, which was stored up in perihelion, being prevented from radiating off freely into space by a blanket of aqueous vapour caused by the melting of ice and snow. But though I am inclined to profit by Croll's maximum excentricity for the glacial period, I consider it quite subordinate to geographical causes or the relative position of land and sea and the abnormal excess of land in polar regions." In another letter (March 5th, 1866) Lyell writes: "In the beginning of Hooker's letter to you he speaks hypothetically of a change in the earth's axis as having possibly co-operated with redistribution of land and sea in causing the cold of the Glacial period. Now, when we consider how extremely modern, zoologically and botanically, the Glacial period is proved to be, I am shocked at any one introducing, with what I may call so much levity, so organic a change as a deviation in the axis of the planet...' (see Lyell's "Principles," 1875, Chapter XIII.; also a letter to Sir Joseph Hooker printed in the "Life of Sir Charles Lyell," Volume II., page 410.))
Many thanks for your interesting letter. From the serene elevation of my old age I look down with amazement at your youth, vigour, and indomitable energy. With respect to Hooker and the axis of the earth, I suspect he is too much overworked to consider now any subject properly. His mind is so acute and critical that I always expect to hear a torrent of objections to anything proposed; but he is so candid that he often comes round in a year or two. I have never thought on the causes of the Glacial period, for I feel that the subject is beyond me; but though I hope you will own that I have generally been a good and docile pupil to you, yet I must confess that I cannot believe in change of land and water, being more than a subsidiary agent. (506/2. In Chapter XI. of the "Origin," Edition V., 1869, page 451, Darwin discusses Croll's theory, and is clearly inclined to trust in Croll's conclusion that "whenever the northern hemisphere passes through a cold period the temperature of the southern hemisphere is actually raised..." In Edition VI., page 336, he expresses his faith even more strongly. Mr. Darwin apparently sent his MS. on the climate question, which was no doubt prepared for a new edition of the "Origin," to Sir Charles. The arrival of the MS. is acknowledged in a letter from Lyell on March 10th, 1866 ("Life of Sir Charles Lyell," II., page 408), in which the writer says that he is "more than ever convinced that geographical changes...are the principal and not the subsidiary causes.") I have come to this conclusion from reflecting on the geographical distribution of the inhabitants of the sea on the opposite sides of our continents and of the inhabitants of the continents themselves.
LETTER 507. TO C. LYELL. Down, September 8th {1866}.
Many thanks for the pamphlet, which was returned this morning. I was very glad to read it, though chiefly as a psychological curiosity. I quite follow you in thinking Agassiz glacier-mad. (507/1. Agassiz's pamphlet, ("Geology of the Amazons") is referred to by Lyell in a letter written to Bunbury in September, 1866 ("Life of Sir Charles Lyell," II., page 409): "Agassiz has written an interesting paper on the 'Geology of the Amazons,' but, I regret to say, he has gone wild about glaciers, and has actually announced his opinion that the whole of the great valley, down to its mouth in latitude 0 deg., was filled by ice..." Agassiz published a paper, "Observations Geologiques faites dans la Vallee de l'Amazone," in the "Comptes Rendus," Volume LXIV., page 1269, 1867. See also a letter addressed to M. Marcou, published in the "Bull. Soc. Geol. France," Volume XXIV., page 109, 1866.) His evidence reduces itself to supposed moraines, which would be difficult to trace in a forest-clad country; and with respect to boulders, these are not said to be angular, and their source cannot be known in a country so imperfectly explored. When I was at Rio, I was continually astonished at the depth (sometimes 100 feet) to which the granitic rocks were decomposed in situ, and this soft matter would easily give rise to great alluvial accumulations; I well remember finding it difficult to draw a line between the alluvial matter and the softened rock in situ. What a splendid imagination Agassiz has, and how energetic he is! What capital work he would have done, if he had sucked in your "Principles" with his mother's milk. It is wonderful that he should have written such wild nonsense about the valley of the Amazon; yet not so wonderful when one remembers that he once maintained before the British Association that the chalk was all deposited at once.
With respect to the insects of Chili, I knew only from Bates that the species of Carabus showed no special affinity to northern species; from the great difference of climate and vegetation I should not have expected that many insects would have shown such affinity. It is more remarkable that the birds on the broad and lofty Cordillera of Tropical S. America show no affinity with European species. The little power of diffusion with birds has often struck me as a most singular fact — even more singular than the great power of diffusion with plants. Remember that we hope to see you in the autumn.
P.S. — There is a capital paper in the September number of "Annals and Magazine," translated from Pictet and Humbert, on Fossil Fish of Lebanon, but you will, I daresay, have received the original. (507/2. "Recent Researches on the Fossil Fishes of Mount Lebanon," "Ann. Mag. Nat. Hist." Volume XVIII., page 237, 1866.) It is capital in relation to modification of species; I would not wish for more confirmatory facts, though there is no direct allusion to the modification of species. Hooker, by the way, gave an admirable lecture at Nottingham; I read it in MS., or rather, heard it. I am glad it will be published, for it was capital. (507/3. Sir Joseph Hooker delivered a lecture at the Nottingham meeting of the British Association (1866) on "Insular Floras," published in the "Gardeners' Chronicle," 1867. See Letters 366-377, etc.)
Sunday morning.
P.S. — I have just received a letter from Asa Gray with the following passage, so that, according to this, I am the chief cause of Agassiz's absurd views: —
"Agassiz is back (I have not seen him), and he went at once down to the National Academy of Sciences, from which I sedulously keep away, and, I hear, proved to them that the Glacial period covered the whole continent of America with unbroken ice, and closed with a significant gesture and the remark: 'So here is the end of the Darwin theory.' How do you like that?
"I said last winter that Agassiz was bent on covering the whole continent with ice, and that the motive of the discovery he was sure to make was to make sure that there should be no coming down of any terrestrial life from Tertiary or post-Tertiary period to ours. You cannot deny that he has done his work effectually in a truly imperial way."
LETTER 508. TO C. LYELL. Down, July 14th, 1868.
Mr. Agassiz's book has been read aloud to me, and I am wonderfully perplexed what to think about his precise statements of the existence of glaciers in the Ceara Mountains, and about the drift formation near Rio. (508/1. "Sur la Geologie de l'Amazone," by MM. Agassiz and Continho, "Bull. Soc. Geol. France," Volume XXV., page 685, 1868. See also "A Journey in Brazil," by Professor and Mrs. Louis Agassiz, Boston, 1868.) There is a sad want of details. Thus he never mentions whether any of the blocks are angular, nor whether the embedded rounded boulders, which cannot all be disintegrated, are scored. Yet how can so experienced an observer as A. be deceived about lateral and terminal moraines? If there really were glaciers in the Ceara Mountains, it seems to me one of the most important facts in the history of the inorganic and organic world ever observed. Whether true or not, it will be widely believed, and until finally decided will greatly interfere with future progress on many points. I have made these remarks in the hope that you will coincide. If so, do you think it would be possible to persuade some known man, such as Ramsay, or, what would be far better, some two men, to go out for a summer trip, which would be in many respects delightful, for the sole object of observing these phenomena in the Ceara Mountains, and if possible also near Rio? I would gladly put my name down for 50 pounds in aid of the expense of travelling. Do turn this over in your mind. I am so very sorry not to have seen you this summer, but for the last three weeks I have been good for nothing, and have had to stop almost all work. I hope we may meet in the autumn.
LETTER 509. TO JAMES CROLL. Down, November 24th, 1868.
I have read with the greatest interest the last paper which you have kindly sent me. (509/1. Croll discussed the power of icebergs as grinding and striating agents in the latter part of a paper ("On Geological Time, and the probable Dates of the Glacial and the Upper Miocene Period") published in the "Philosophical Magazine," Volume XXXV., page 363, 1868, Volume XXXVI., pages 141, 362, 1868. His conclusion was that the advocates of the Iceberg theory had formed "too extravagant notions regarding the potency of floating ice as a striating agent.") If we are to admit that all the scored rocks throughout the more level parts of the United States result from true glacier action, it is a most wonderful conclusion, and you certainly make out a very strong case; so I suppose I must give up one more cherished belief. But my object in writing is to trespass on your kindness and ask a question, which I daresay I could answer for myself by reading more carefully, as I hope hereafter to do, all your papers; but I shall feel much more confidence in a brief reply from you. Am I right in supposing that you believe that the glacial periods have always occurred alternately in the northern and southern hemispheres, so that the erratic deposits which I have described in the southern parts of America, and the glacial work in New Zealand, could not have been simultaneous with our Glacial period? From the glacial deposits occurring all round the northern hemisphere, and from such deposits appearing in S. America to be as recent as in the north, and lastly, from there being some evidence of the former lower descent of glaciers all along the Cordilleras, I inferred that the whole world was at this period cooler. It did not appear to me justifiable without distinct evidence to suppose that the N. and S. glacial deposits belonged to distinct epochs, though it would have been an immense relief to my mind if I could have assumed that this had been the case. Secondly, do you believe that during the Glacial period in one hemisphere the opposite hemisphere actually becomes warmer, or does it merely retain the same temperature as before? I do not ask these questions out of mere curiosity; but I have to prepare a new edition of my "Origin of Species," and am anxious to say a few words on this subject on your authority. I hope that you will excuse my troubling you.
LETTER 510. TO J. CROLL. Down, January 31st, 1869.
To-morrow I will return registered your book, which I have kept so long. I am most sincerely obliged for its loan, and especially for the MS., without which I should have been afraid of making mistakes. If you require it, the MS. shall be returned. Your results have been of more use to me than, I think, any other set of papers which I can remember. Sir C. Lyell, who is staying here, is very unwilling to admit the greater warmth of the S. hemisphere during the Glacial period in the N.; but, as I have told him, this conclusion which you have arrived at from physical considerations, explains so well whole classes of facts in distribution, that I must joyfully accept it; indeed, I go so far as to think that your conclusion is strengthened by the facts in distribution. Your discussion on the flowing of the great ice-cap southward is most interesting. I suppose that you have read Mr. Moseley's recent discussion on the force of gravity being quite insufficient to account for the downward movement of glaciers (510/1. Canon Henry Moseley, "On the Mechanical Impossibility of the Descent of Glaciers by their Weight only." "Proc. R. Soc." Volume XVII., page 202, 1869; "Phil. Mag." Volume XXXVII., page 229, 1869.): if he is right, do you not think that the unknown force may make more intelligible the extension of the great northern ice-cap? Notwithstanding your excellent remarks on the work which can be effected within the million years (510/2. In his paper "On Geological Time, and the probable Date of the Glacial and the Upper Miocene Period" ("Phil. Mag." Volume XXXV., page 363, 1868), Croll endeavours to convey to the mind some idea of what a million years really is: "Take a narrow strip of paper, an inch broad or more, and 83 feet 4 inches in length, and stretch it along the wall of a large hall, or round the walls of an apartment somewhat over 20 feet square. Recall to memory the days of your boyhood, so as to get some adequate conception of what a period of a hundred years is. Then mark off from one of the ends of the strip one-tenth of an inch. The one-tenth of an inch will then represent a hundred years, and the entire length of the strip a million of years" (loc. cit., page 375).), I am greatly troubled at the short duration of the world according to Sir W. Thomson (510/3. In a paper communicated to the Royal Society of Edinburgh, Lord Kelvin (then Sir William Thomson) stated his belief that the age of our planet must be more than twenty millions of years, but not more than four hundred millions of years ("Trans. R. Soc. Edinb." Volume XXIII., page 157, 1861, "On the Secular Cooling of the Earth."). This subject has been recently dealt with by Sir Archibald Geikie in his address as President of the Geological Section of the British Association, 1899 ("Brit. Assoc. Report," Dover Meeting, 1899, page 718).), for I require for my theoretical views a very long period BEFORE the Cambrian formation. If it would not trouble you, I should like to hear what you think of Lyell's remark on the magnetic force which comes from the sun to the earth: might not this penetrate the crust of the earth and then be converted into heat? This would give a somewhat longer time during which the crust might have been solid; and this is the argument on which Sir W. Thomson seems chiefly to rest. You seem to argue chiefly on the expenditure of energy of all kinds by the sun, and in this respect Lyell's remark would have no bearing.
My new edition of the "Origin" (510/4. Fifth edition, May, 1869.) will be published, I suppose, in about two months, and for the chance of your liking to have a copy I will send one.
P.S. — I wish that you would turn your astronomical knowledge to the consideration whether the form of the globe does not become periodically slightly changed, so as to account for the many repeated ups and downs of the surface in all parts of the world. I have always thought that some cosmical cause would some day be discovered.
LETTER 511. TO C. LYELL. Down, July 12th {1872}.
I have been glad to see the enclosed and return it. It seems to me very cool in Agassiz to doubt the recent upheaval of Patagonia, without having visited any part; and he entirely misrepresents me in saying that I infer upheaval from the form of the land, as I trusted entirely to shells embedded and on the surface. It is simply monstrous to suppose that the terraces stretching on a dead level for leagues along the coast, and miles in breadth, and covered with beds of stratified gravel, 10 to 30 feet in thickness, are due to subaerial denudation.
As for the pond of salt-water twice or thrice the density of sea-water, and nearly dry, containing sea-shells in the same relative proportions as on the adjoining coast, it almost passes my belief. Could there have been a lively midshipman on board, who in the morning stocked the pool from the adjoining coast?
As for glaciation, I will not venture to express any opinion, for when in S. America I knew nothing about glaciers, and perhaps attributed much to icebergs which ought to be attributed to glaciers. On the other hand, Agassiz seems to me mad about glaciers, and apparently never thinks of drift ice.
I did see one clear case of former great extension of a glacier in T. del Fuego.
LETTER 512. TO J. GEIKIE.
(512/1. The following letter was in reply to a request from Prof. James Geikie for permission to publish Mr. Darwin's views, communicated in a previous letter (November 1876), on the vertical position of stones in gravelly drift near Southampton. Prof. Geikie wrote (July 15th, 1880): "You may remember that you attributed the peculiar position of those stones to differential movements in the drift itself arising from the slow melting of beds of frozen snow interstratified into the gravels...I have found this explanation of great service even in Scotland, and from what I have seen of the drift-gravels in various parts of southern England and northern France, I am inclined to think that it has a wide application.")
Down, July 19th, 1880.
Your letter has pleased me very much, and I truly feel it an honour that anything which I wrote on the drift, etc., should have been of the least use or interest to you. Pray make any use of my letter (512/2. Professor James Geikie quotes the letter in "Prehistoric Europe," London, 1881 (page 141). Practically the whole of it is given in the "Life and Letters," III., page 213.): I forget whether it was written carefully or clearly, so pray touch up any passages that you may think fit to quote.
All that I have seen since near Southampton and elsewhere has strengthened my notion. Here I live on a chalk platform gently sloping down from the edge of the escarptment to the south (512/3. Id est, sloping down from the escarpment which is to the south.) (which is about 800 feet in height) to beneath the Tertiary beds to the north. The (512/4. From here to the end of the paragraph is quoted by Prof. Geikie, loc. cit., page 142.) beds of the large and broad valleys (and only of these) are covered with an immense mass of closely packed broken and angular flints; in which mass the skull of the musk-ox {musk-sheep} and woolly elephant have been found. This great accumulation of unworn flints must therefore have been made when the climate was cold, and I believe it can be accounted for by the larger valleys having been filled up to a great depth during a large part of the year with drifted frozen snow, over which rubbish from the upper parts of the platforms was washed by the summer rains, sometimes along one line and sometimes along another, or in channels cut through the snow all along the main course of the broad valleys.
I suppose that I formerly mentioned to you the frequent upright position of elongated flints in the red clayey residue over the chalk, which residue gradually subsides into the troughs and pipes corroded in the solid chalk. This letter is very untidy, but I am tired.
P.S. Several palaeolithic celts have recently been found in the great angular gravel-bed near Southampton in several places.
