Louis Agassiz: His Life and Correspondence

by Louis Agassiz

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 principal 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 partitioned off from a middle room occupied by Agassiz and his friends, while the front space 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 mass 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 Agassiz, 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 Agassiz'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 Agassiz'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 mass 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 crevasses. 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 passage 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, Agassiz 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 circumstances, 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. Agassiz, 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 Agassiz 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 Agassiz, 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 Agassiz 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 crevasses also especially occupied the observers. On the 7th of August, Agassiz 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 Agassiz to M. Arago dated from the Hotel des Neuchatelois, Glacier of the Aar, August 7, 1842.) On this occasion Agassiz saw three crevasses formed in an hour and a half, and heard others opening at a greater distance from him. He counted eight new fissures in a space 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 Agassiz, "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 mass, 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, accumulated 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 circumference 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. Agassiz 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 Agassiz'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 anticipation 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 AGASSIZ TO THE PRINCE OF CANINO.

GLACIER OF THE AAR, September 1, 1842.