Louis Agassiz: His Life and Correspondence Part 15

. . ."Have the kindness to accept for the library of the Academy the fifth number of a work upon the sources of zoological criticism, the publication of which I have just begun. It is a work of patience, demanding long and laborious researches. I had conceived the plan in the first years of my studies, and since then have never lost sight of it. I venture to believe it will be a barrier against the Babel of confusion which tends to overwhelm the domain of zoological synonymy. My book will be called 'Nomenclator Zoologicus.'". . .

The Bibliographia (4 volumes, octavo) was in some measure a complement of the Nomenclator, and contained a list of all the authors named in the latter, with notices of their works. It appeared somewhat later, and was published by the Ray Society in England, in 1848, after Aga.s.siz had left Europe for the United States. The material for this work also had been growing upon his hands for years. Feeling more and more the importance of such a register as a guide for students, he appealed to naturalists in all parts of Europe for information upon the scientific bibliography of their respective countries, and at last succeeded in cataloguing, with such completeness as was possible, all known works and all scattered memoirs on zoology and geology. Unable to publish this costly but unremunerative material, he was delighted to give it up to the Ray Society. The first three volumes were edited with corrections and additions by Mr. H.E. Strickland, who died before the appearance of the fourth volume, which was finally completed under the care of his father-in-law, Sir William Jardine.

The ability, so eminently possessed by Aga.s.siz of dealing with a number of subjects at once, was due to no superficial versatility.

To him his work had but one meaning. It was never disconnected in his thought, and therefore he turned from his glaciers to his fossils, and from the fossil to the living world, with the feeling that he was always dealing with kindred problems, bound together by the same laws. Nowhere is this better seen than in the records of the scientific society of Neuchatel, the society he helped to found in the first months of his professorship, and to which he always remained strongly attached, being a constant attendant at its sessions from 1833 to 1846. Here we find him from month to month, with philosophic breadth of thought, treating of animals in their widest relations, or describing minute structural details with the skill of a specialist. He presents organized beings in their geological succession, in their geographical distribution, in their embryonic development. He reviews and remodels laws of cla.s.sification. Sometimes he ill.u.s.trates the fossil by the living world, sometimes he finds the key to present phenomena in the remote past. He reconstructs the history of the glacial period, and points to its final chapter in the nearest Alpine valleys, connecting these facts again with like phenomena in distant parts of the globe. But however wide his range and however various his topics, under his touch they are all akin, all coordinate parts of a whole which he strives to understand in its entirety. A few extracts from his correspondence will show him in his different lines of research at this time.

The following letter is from Edward Forbes, one of the earliest explorers of the deep-sea fauna. Aga.s.siz had asked him for some help in his work upon echinoderms.

EDWARD FORBES TO LOUIS AGa.s.sIZ.

21 LOTHIAN ST., EDINBURGH, February 13, 1841.

. . .A letter from you was to me one of the greatest of pleasures, and with great delight (though, I fear, imperfectly) I have executed the commission you gave me. It should have been done much sooner had not the storms been so bad in the sea near this that, until three days ago, I was not able to procure a living sea-urchin from which to make the drawings required. . .You have made all the geologists glacier-mad here, and they are turning Great Britain into an ice-house. Some amusing and very absurd attempts at opposition to your views have been made by one or two pseudo-geologists; among others, poor--, who has read a paper at the Royal Society here, maintaining that all the appearances you refer to glaciers were caused by blocks of ice which floated this way in the Deluge! and that the fossils of the pleistocene strata were mollusks, etc., which, climbing upon the ice-blocks, were carried to warmer seas against their will!! To my mind, one of the best proofs of the truth of your views lies in the decidedly arctic character of the pleistocene fauna, which must be referred to the glacier time, and by such reference is easily understood. I mean during the summer to collect data on that point, in order to present a ma.s.s of geological proofs of your theory.

Dr. Traill tells me you are proposing to visit England again during the coming summer. If you do, I hope we shall meet, when I shall have many things to show you, which time did not permit when you were here. I look anxiously for the forth-coming number of your history of the Echinodermata. . .

FROM SIR RODERICK MURCHISON.

June 13, 1842.

. . .Your letters have given me great pleasure: first, in a.s.suring me that your zeal in ichthyology is undiminished, and that you are about to give such striking proofs of it to the British a.s.sociation; and next that you still pursue with enthusiasm your admirable researches upon the glaciers. I should be charmed to put myself under your guidance for a walk on the glaciers of the Aar, but I hardly dare promise it yet. . .Even were I to make every haste, I doubt if it be possible to reach your Swiss meeting in time. It is just possible that I may find you in your glacial cantonment after your return, but even this will depend upon circ.u.mstances over which I have no control.

I send this letter to you by my friend, Admiral Sir Charles Malcolm, who pa.s.ses through Neuchatel on his way to Geneva.

Accompanying it is a copy of my last discourse, which I request you to accept and to read all parts of it. You will see that I have grappled honestly and according to my own faith with your ice, but have never lost sight of your great merit. My concluding paragraph will convince you and all your friends that if I am wrong it is not from any preconceived notions, but only because I judge from what you will call incomplete evidence. Your "Venez voir!" still sounds in my ears. . .

Murchison remained for many years an opponent of the glacial theory in its larger application. In the discourse to which the above letter makes allusion (Address at the Anniversary Meeting of the Geological Society of London, 1842.* (* Extract from Report in volume 33 of the "Edinburgh New Philosophical Journal".)) is this pa.s.sage: "Once grant to Aga.s.siz that his deepest valleys of Switzerland, such as the enormous Lake of Geneva, were formerly filled with snow and ice, and I see no stopping place. From that hypothesis you may proceed to fill the Baltic and the northern seas, cover southern England and half of Germany and Russia with similar icy sheets, on the surfaces of which all the northern boulders might have been shot off. So long as the greater number of the practical geologists of Europe are opposed to the wide extension of a terrestrial glacial theory, there can be little risk that such a doctrine should take too deep a hold of the mind. . .

The existence of glaciers in Scotland and England (I mean in the Alpine sense) is not, at all events, established to the satisfaction of what I believe to be by far the greater number of British geologists."

Twenty years later, with rare candor, Murchison wrote to Aga.s.siz as follows; by its connection, though not by its date, the extract is in place here: "I send you my last anniversary address, which I wrote entirely myself; and I beg you to believe that in the part of it that refers to the glacial period, and to Europe as it was geographically, I have had the sincerest pleasure in avowing that I was wrong in opposing as I did your grand and original idea of my native mountains. Yes! I am now convinced that glaciers did descend from the mountains to the plains as they do now in Greenland."

During the summer of 1842, at about the same date with Murchison's letter disclaiming the glacial theory, Aga.s.siz received, on the other hand, a new evidence, and one which must have given him especial pleasure, of the favorable impression his views were making in some quarters in England.

FROM DR. BUCKLAND.

OXFORD, July 22, 1842.

You will, I am sure, rejoice with me at the adhesion of C. Darwin to the doctrine of ancient glaciers in North Wales, of which I send you a copy, and which was communicated to me by Dr. Tritten, during the late meeting at Manchester, in time to be quoted by me versus Murchison, when he was proclaiming the exclusive agency of floating icebergs in drifting erratic blocks and making scratched and polished surfaces. It has raised the glacial theory fifty per cent, as far as relates to glaciers descending inclined valleys; but Hopkins and the Cantabrigians are still as obstinate as ever against allowing the power of expansion to move ice along great distances on horizontal surfaces. . .

The following is the letter referred to above.

C. DARWIN TO DR. TRITTEN.

Yesterday (and the previous days) I had some most interesting work in examining the marks left by EXTINCT glaciers. I a.s.sure you, an extinct volcano could hardly leave more evident traces of its activity and vast powers. I found one with the lateral moraine quite perfect, which Dr. Buckland did not see. Pray if you have any communication with Dr. Buckland give him my warmest thanks for having guided me, through the published abstract of his memoir, to scenes, and made me understand them, which have given me more delight than I almost remember to have experienced since I first saw an extinct crater. The valley about here and the site of the inn at which I am now writing must once have been covered by at least 800 or 1,000 feet in thickness of solid ice! Eleven years ago I spent a whole day in the valley where yesterday everything but the ice of the glaciers was palpably clear to me, and I then saw nothing but plain water and bare rock. These glaciers have been grand agencies. I am the more pleased with what I have seen in North Wales, as it convinces me that my view of the distribution of the boulders on the South American plains, as effected by floating ice, is correct. I am also more convinced that the valleys of Glen Roy and the neighboring parts of Scotland have been occupied by arms of the sea, and very likely (for in that point I cannot, of course, doubt Aga.s.siz and Buckland) by glaciers also.

It continued to be a grief to Aga.s.siz that Humboldt, the oldest of all his scientific friends, and the one whose opinion he most reverenced, still remained incredulous. Humboldt's letters show that Aga.s.siz did not willingly renounce the hope of making him a convert. Aga.s.siz's own letters to Humboldt are missing from this time onward. Overwhelmed with occupation, and more at his ease in his relations with the older scientific men, he had ceased to make the rough drafts in which his earlier correspondence is recorded.

HUMBOLDT TO AGa.s.sIZ.

BERLIN, March 2, 1842.

. . .When one has been so long separated, even accidentally, from a friend as I have been from you, my dear Aga.s.siz, it is difficult to find beginning or end to a letter. The kindly remembrance which you send me is evidence that my long silence has not seemed strange to you. . .It would be wasting words to tell you how I have been prevented, by the distractions of my life, always increasing with old age, from acknowledging the admirable things received from you, --upon living and fossil fishes, echinoderms, and glaciers. My admiration of your boundless activity, of your beautiful intellectual life, increases with every year. This admiration for your work and your bold excursions is based upon the most careful reading of all the views and investigations, for which I have to thank you. This very week I have read with great satisfaction your truly philosophical address, and your long treatise in Cotta's fourth "Jahresschrift." Even L. von Buch confessed that the first half of your treatise, the living presentation of the succession of organized beings, was full of truth, sagacity, and novelty.

I in no way reproach you, my dear friend, for the urgent desire expressed in all your letters, that your oldest friends should accept your comprehensive geological view of your ice-period. It is very n.o.ble and natural to wish that what has impressed us as true should also be recognized by those we love. . .I believe I have read and compared all that has been written for and against the ice-period, and also upon the transportation of boulders, whether pushed along or carried by floods or gliding over slopes. My own opinion, as you know, can have no weight or authority, since I have not myself seen the most decisive points. Indeed I am, perhaps wrongly, inclined to look upon all geological theories as having their being in a mythical region, in which, with the progress of physics, the phantasms are modified century by century. But the "elephants caught in the ice," and Cuvier's "instantaneous change of climate," seem to me no more intelligible today than when I wrote my Asiatic fragments. According to all that we know of the decrease of heat in the earth, I cannot understand such a change of temperature in a s.p.a.ce of time which does not also allow for the decaying of flesh. I understand much better how wolves, hares, and dogs, should they fall to-day into clefts of the frozen regions of Northern Siberia (and the so-called "elephant-ice" is in plain prose only porphyritic drift mixed with ice-crystals, true drift material), might retain their flesh and muscles. . .But I am only a grumbling rebellious subject in your kingdom. . .Do not be vexed with a friend who is more than ever impressed with your services to geology, your philosophical views of nature, your profound knowledge of organized beings. . .

With old attachment and the warmest friendship, your

A. DE HUMBOLDT.

In the same strain is this extract from another letter of Humboldt's, written two or three months later.

. . ."'Grace from on high,' says Madame de Sevigne, 'comes slowly.'

I especially desire it for the glacial period and for that fatal cap of ice which frightens me, child of the equator that I am. My heresy, of little importance, since I have seen nothing, does not, I a.s.sure you, my dear Aga.s.siz, diminish my ardent desire that all your observations should be published. . .I rejoice in the good news you give me of the fishes. I should pain you did I add that this work of yours, by the light it has shed on the organic development of animals, makes the true foundation of your glory.".

LOUIS AGa.s.sIZ TO SIR PHILIP EGERTON.

NEUCHATEL, June, 1842.

. . .I am hard at work on the fishes of the "Old Red," and will send you at Manchester a part at least of the plates, with a general summary of the species of that formation. I aim to finish the work with such care that it shall mark a sensible advance in ichthyology. I hope it will satisfy you. . .You ask me how I intend to finish my Fossil Fishes? As follows: As soon as the number on the species of the "Old Red" is finished, I shall complete the general outline of the work as I did with volume 4, in order that the arrangement and character of all the families in the four orders may be studied in their zoological affinities, with their genera and princ.i.p.al species. But as this outline can no longer contain the innumerable species now known to me, I take up monographically the species from the different geological formations in the order of the deposits, and publish as many supplements as there are great formations rich in fossil fishes. I shall limit myself to the species described in the body of the work, merely adding the description of the new species in each deposit, and such additions as I may have to make for those already known. In this way, those who wish to study fossil fishes from the zoological stand-point can turn to the work in the original form, while those who wish to study them in their geological relations can confine themselves to the supplements. By means of double registers at the end of each volume, these two distinct parts of the work will be again united as a complete whole. This is the only plan I have been able to devise by which I could publish in succession all my materials without burdening my first subscribers, who will thus be free to accept the supplements or not, as they prefer. Should you have occasion to mention this arrangement to the friends of fossil ichthyology, pray do so; it seems to me for the interest of the matter that it should be known. . .I propose to resume with new zeal my researches upon the fossil fishes as soon as I return from an excursion I wish to make in July and August to the glacier of the Aar, where I hope, by a last visit this year, to conclude my labors on this subject. You will be glad to learn that the beautiful barometer you gave me has been my faithful companion in the Alps. . .I have the pleasure to tell you that the King of Prussia has made me a handsome gift of nearly 200 pounds for the continuance of my glacial work. I feel, therefore, the greater certainty of completing what remains for me to do. . .

The campaign of 1842 opened on the 4th of July. The boulder had ceased to be a safe shelter, and was replaced by a rough frame cabin covered with canvas. If the party had some regrets in leaving their picturesque hut beneath the rock, the greater comfort of the new abode consoled them. It had several divisions. A sleeping-place for the guides and workmen was part.i.tioned off from a middle room occupied by Aga.s.siz and his friends, while the front s.p.a.ce served as dining-room, sitting-room, and laboratory. This outer apartment boasted a table and one or two benches; even a couple of chairs were kept as seats of honor for occasional guests. A shelf against the wall and a few pegs accommodated books, instruments, coats, etc., and a plank floor, on which to spread their blankets at night, was a good exchange for the frozen surface of the glacier.*

(* In bidding farewell to the boulder which had been the first "Hotel des Neuchatelois" we may add a word of its farther fortunes.

It had begun to split in 1841, and was completely rent asunder in 1844, after which frost and rain completed its dismemberment.

Strange to say, during the last summer (1884) certain fragments of the ma.s.s have been found, inscribed with the names of some of the party; one of the blocks bearing beside names, the mark "Number 2".

The account says "The middle stone, the one numbered 2, was at the intersecting point of two lines drawn from the Pavilion Dollfuss to the Scheuchzerhorn on the one part, and from the Rothhorn to the Thierberg on the other." According to the measurements taken by Aga.s.siz, the Hotel des Neuchatelois in 1840 stood at 797 metres from the promontory of Abschwung. We are thus enabled, by referring to the large glacier map of Wild and Stengel, to compare the present with the then position of the stone, and thereby ascertain the progress of the glacier since the time in question. Thus the boulder still contributes something toward the sequel of the work begun by those who once found shelter beneath it.--E.C.A.)

Mr. Wild, an engineer of known ability, was now a member of their party, as a topographical survey was to be one of the chief objects of the summer's work. The results of this survey, which was continued during two summers, are embodied in the map accompanying Aga.s.siz's "Systeme Glaciaire." Experiments upon the extent and connection of the net-work of capillary fissures that admitted water into the interior of the glaciers, occupied Aga.s.siz's own attention during a great part of the summer. In order to ascertain this, colored liquids were introduced into the glacier by means of boring, and it was found that they threaded their way through the ma.s.s of the ice and reappeared at lower points with astonishing rapidity. A gallery was cut at a depth of ten metres below the surface, through a wall of ice intervening between two creva.s.ses.

The colored liquid poured into a hole above soon appeared on the ceiling of the gallery. The experimenters were surprised to find that at night the same result was obtained, and that the liquid penetrated from the surface to the roof of the gallery even more quickly than during the day. This was explained by the fact that the fissures were then free from any moisture arising from surface melting, so that the pa.s.sage through them was unimpeded.* (*

Distrust has been thrown upon these results by the failure of more recent attempts to repeat the same experiments. In reference to this, Aga.s.siz himself says "The infiltration has been denied in consequence of the failure of some experiments in which an attempt was made to introduce colored fluids into the glacier. To this I can only answer that I succeeded completely myself in the self-same experiment which a later investigator found impracticable, and that I see no reason why the failure of the latter attempt should cast a doubt upon the success of the former. The explanation of the difference in the result may perhaps be found in the fact that as a sponge gorged with water can admit no more fluid than it already contains, so the glacier, under certain circ.u.mstances, and especially at noonday in summer, may be so soaked with water that all attempts to pour colored fluids into it would necessarily fail."--See "Geological Sketches" by L. Aga.s.siz, page 236.)

The comparative rate of advance in the different parts of the glacier was ascertained this summer with greater precision than before. The rows of stakes planted in a straight line across the glacier by Aga.s.siz and Escher de la Linth, in the previous September, now described a crescent with the curve turned toward the terminus of the glacier, showing, contrary to the expectation of Aga.s.siz, that the centre moved faster than the sides. The correspondence of the curve in the stratification with that of the line of stakes confirmed this result. The study of the stratification of the snow was a marked feature of the season's work, and Aga.s.siz believed, as will be seen by a later letter, that he had established this fact of glacial structure beyond a doubt.

The origin and mode of formation of the creva.s.ses also especially occupied the observers. On the 7th of August, Aga.s.siz had an opportunity of watching this phenomenon in its initiation.

Attracted to a certain spot on the glacier by a commotion among his workmen, he found them alarmed at the singular noises and movements in the ice. "I heard," he says, "at a little distance a sound like the simultaneous discharge of fire-arms; hurrying in the direction of the noise, it was repeated under my feet with a movement like that of a slight earthquake; the ground seemed to shift and give way under me, but now the sound differed from the preceding, and resembled a crumbling of rocks, without, however, any perceptible sinking of the surface. The glacier actually trembled, nevertheless; for a block of granite three feet in diameter, perched on a pedestal two feet high, suddenly fell down. At the same instant a crack opened between my feet and ran rapidly across the glacier in a straight line."* (* Extract from a letter of Louis Aga.s.siz to M. Arago dated from the Hotel des Neuchatelois, Glacier of the Aar, August 7, 1842.) On this occasion Aga.s.siz saw three creva.s.ses formed in an hour and a half, and heard others opening at a greater distance from him. He counted eight new fissures in a s.p.a.ce of one hundred and twenty-five feet. The phenomenon continued throughout the evening, and recurred, though with less frequency, during the night. The cracks were narrow, the largest an inch and a half in width, and their great depth was proved by the rapidity with which they drained any standing water in their immediate vicinity. "A boring-hole," says Aga.s.siz, "one hundred and thirty feet deep and six inches in diameter, full of water, was completely emptied in a few minutes, showing that these narrow cracks penetrated to great depths."

The summer's work included observations also on the comparative movement of the glacier during the day and night, on the surface waste of the ma.s.s, its reparation, on the neve and snow of the upper regions, on the meridian holes, the sun-dials of the glaciers, as they have been called.* (* "Here and there on the glacier there are patches of loose material, dust, sand, or gravel, acc.u.mulated by diminutive water-rills and small enough to become heated during the day. They will, of course, be warmed first on their eastern side, then still more powerfully on their southern side, and, in the afternoon, with less force again, on their western side, while the northern side will remain comparatively cool. Thus around more than half of their circ.u.mference they melt the ice in a semicircle, and the glacier is covered with little crescent-shaped troughs of this description, with a steep wall on one side and a shallow one on the other, and a little heap of loose materials in the bottom. They are the sun-dials of the glacier, recording the hour by the advance of the sun's rays upon them."--"

Geological Sketches" by L. Aga.s.siz page 293.) On the whole, the most important result of the campaign was the topographical survey of the glacier, recorded in the map published in Aga.s.siz's second work on the glacier.

At about this time there begin to be occasional references in his correspondence to a journey of exploration in the United States.

Especially was this plan in frequent discussion between him and Charles Bonaparte, Prince of Canino, a naturalist almost as ardent as himself, with whom he had long been in intimate scientific correspondence. In April, 1842, the prince writes him: "I indulge myself in dreaming of the journey to America in which you have promised to accompany me. What a relaxation! and at the same time what an amount of useful work!" Again, a few months later, "You must keep me well advised of your plans, and I, in my turn, will try so to arrange my affairs as to find myself free in the spring of 1844 for a voyage, the chief object of which will be to show my oldest son the country where he was born, and where man may develop free of shackles. The mere antic.i.p.ation of this journey is delightful to me, since I shall have you at my side, and may thus feel sure that it will make an epoch in science." This letter is answered from the glacier; the first part refers to the Nomenclator, in regard to which he often consulted the prince.

LOUIS AGa.s.sIZ TO THE PRINCE OF CANINO.

GLACIER OF THE AAR, September 1, 1842.

. . .I thank you most sincerely for the pains you have so kindly taken with my proof, and for pointing out the faults and omissions you have noticed in my register of birds. I made the corrections at once, and have taken the liberty of mentioning on the cover of this number the share you have consented to take in my Nomenclator. I shall try to do better and better in the successive cla.s.ses, but you well know the impossibility of avoiding grave errors in such a work, and that they can be wholly weeded out only in a second and third edition. I should have written sooner in answer to your last, had not your letter reached me on the Glacier of the Aar, where I have been since the beginning of July, following up observations, the results of which become every day more important and more convincing. The most striking fact, one which I think I have placed beyond the reach of doubt, is the primitive stratification of the neve, or fields of snow,--stratified from the higher regions across the whole course of the glacier to its lower extremity. I have prepared a general map, with transverse sections, showing how the layers lift themselves on the borders of the glacier and also at their junction, where two glaciers meet at the outlet of adjoining valleys; and how, also, the waving lines formed by the layers on the surface change to sharper concentric curves with a marked axis, as the glacier descends to lower levels. For a full demonstration of the matter, I ought to send you my map and plans, of which I have, as yet, no duplicates; but the fact is incontestable, and you will oblige me by announcing it in the geological section at Padua.

M. Charpentier, who is going to your meeting, will contest it, but you can tell him from me that it is as evident as the stratification of the Neptunic rocks. To see and understand it fully, however, one must stand well above the glacier, so as to command the surface as a whole in one view. I would add that I am not now alluding to the blue and white bands in the ice of which I spoke to you last year; this is a quite distinct phenomenon.