Not alone from the men who had made these subjects their special study, did Agassiz meet with discouragements. The letters of his beloved mentor, Humboldt, in 1837, show how much he regretted that any part of his young friend's energy should be diverted from zoology, to a field of investigation which he then believed to be one of theory rather than of precise demonstration. He was, perhaps, partly influenced by the fact that he saw through the prejudiced eyes of his friend Von Buch. "Over your and Charpentier's moraines," he says, in one of his letters, "Leopold von Buch rages, as you may already know, considering the subject, as he does, his exclusive property. But I too, though by no means so bitterly opposed to new views, and ready to believe that the boulders have not all been moved by the same means, am yet inclined to think the moraines due to more local causes."
The next letter shows that Humboldt was seriously anxious lest this new field of activity, with its fascinating speculations, should draw Agassiz away from his ichthyological researches.
HUMBOLDT TO AGASSIZ.
BERLIN, December 2, 1837.
I have this moment received, my dear friend, by the hand of M. de Werther, the cabinet minister, your eighth and ninth numbers, with a fine pamphlet of text. I hasten to express my warm thanks, and I congratulate the public on your somewhat tardy resolution to give a larger proportion of text. One should flatter neither the king, nor the people, nor one's dearest friend. I maintain, therefore, that no one has told you forcibly enough how the very persons who justly admire your work, constantly complain of this fragmentary style of publication, which is the despair of those who have not the leisure to place your scattered sheets where they belong and disentangle the skein.* (* Owing to the irregularity with which he received and was forced to work up his material, Agassiz was often either in advance or in arrears with certain parts of his subject, so that his plates and his text did not keep pace with each other, thus causing his readers much annoyance.)
I think you would do well to publish for a while more text than plates. You could do this the better because your text is excellent, full of new and important ideas, expressed with admirable clearness. The charming letter (again without a date) which preceded your package impressed me painfully. I see you are ill again; you complain of congestion of the head and eyes. For mercy's sake take care of your health which is so dear to us. I am afraid you work too much, and (shall I say it frankly?) that you spread your intellect over too many subjects at once. I think that you should concentrate your moral and also your pecuniary strength upon this beautiful work on fossil fishes. In so doing you will render a greater service to positive geology, than by these general considerations (a little icy withal) on the revolutions of the primitive world; considerations which, as you well know, convince only those who give them birth. In accepting considerable sums from England, you have, so to speak, contracted obligations to be met only by completing a work which will be at once a monument to your own glory and a landmark in the history of science. Admirable and exact as your researches on other fossils are, your contemporaries claim from you the fishes above all. You will say that this is making you the slave of others; perfectly true, but such is the pleasing position of affairs here below. Have I not been driven for thirty-three years to busy myself with that tiresome America, and am I not, even yet, daily insulted because, after publishing thirty-two volumes of the great edition in folio and in quarto, and twelve hundred plates, one volume of the historical section is wanting? We men of letters are the servants of an arbitrary master, whom we have imprudently chosen, who flatters and pets us first, and then tyrannizes over us if we do not work to his liking. You see, my dear friend, I play the grumbling old man, and, at the risk of deeply displeasing you, place myself on the side of the despotic public. . .
With reference to the general or periodical lowering of the temperature of the globe, I have never thought it necessary, on account of the elephant of the Lena, to admit that sudden frost of which Cuvier used to speak. What I have seen in Siberia, and what has been observed in Captain Beechey's expedition on the northwest coast of America, simply proves that there exists a layer of frozen drift, in the fissures of which (even now) the muscular flesh of any animal which should accidentally fall into them would be preserved intact. It is a slight local phenomenon. To me, the ensemble of geological phenomena seems to prove, not the prevalence of this glacial surface on which you would carry along your boulders, but a very high temperature spreading almost to the poles, a temperature favorable to organizations resembling those now living in the tropics. Your ice frightens me, and gladly as I would welcome you here, my dear friend, I think, perhaps, for the sake of your health, and also that you may not see this country, always so hideous, under a sheet of snow and ice (in February), you would do better to come two months later, with the first verdure. This is suggested by a letter received yesterday by M. d'O—, which alarmed me a little, because the state of your eyes obliged you to write by another hand. Pray do not think of traveling before you are quite well. I close this letter, feeling sure that it does not contain a line which is not an expression of friendship and of the high esteem I bear you. The magnificence of your last numbers, eight and nine, cannot be told. How admirably executed are your Macropoma, the Ophiopris procerus, Mantell's great beast, the minute details of the Dercetis, Psammodus,. . .the skeletons. . . There is nothing like it in all that we possess upon vertebrates. I have also begun to study your text, so rich in well arranged facts; the monograph of the Lepidostei, the passage upon the bony rays, and, dear Agassiz, I could hardly believe my eyes, sixty-five continuous pages of the third volume, without interruption! You will spoil the public. But, my good friend, you have already information upon a thousand species; "claudite jam rivos!" You say your work can go on if you have two hundred subscribers; but if you continue to support two traveling draughtsmen, I predict, as a practical man, that it cannot go on. You cannot even publish what you have gathered in the last five years. Consider that in attempting to give a review of all the fossil fishes which now exist in collections, you pursue a phantom which ever flies before you. Such a work would not be finished in less than fifteen years, and besides, this NOW is an uncertain element. Cannot you conquer yourself so far as to finish what you have in your possession at present? Recall your artists. With the reputation you enjoy in Europe, whatever might essentially change your opinion on certain organisms would willingly be sent to you. If you continue to keep two ambassadors in foreign lands, the means you destine for the engraving and printing will soon be absorbed. You will struggle with domestic difficulties, and at sixty years of age (tremble at the sight of this number!) you will be as uncertain as you are to-day, whether you possess, even in your collection of drawings, all that is to be found among amateurs. How exhaust an ocean in which the species are indefinitely increasing? Finish, first, what you have this December, 1837, and then, if the subject does not weary you, publish the supplements in 1847. You must not forget that these supplements will be of two kinds: 1st. Ideas which modify some of your old views. 2nd. New species. Only the first kind of supplement would be really desirable. Furthermore, you must regain your intellectual independence and not let yourself be scolded any more by M. de Humboldt. Little will it avail you should I vanish from the scene of this world with your fourteenth number! When I am a fossil in my turn I shall still appear to you as a ghost, having under my arm the pages you have failed to interpolate and the volume of that eternal America which I owe to the public. I close with a touch of fun, in order that my letter may seem a little less like preaching. A thousand affectionate remembrances. No more ice, not much of echinoderms, plenty of fish, recall of ambassadors in partibus, and great severity toward the book-sellers, an infernal race, two or three of whom have been killed under me.
A. DE HUMBOLDT.
I sigh to think of the trouble my horrible writing will give you.
A letter of about the same date from Von Buch shows that, however he might storm at Agassiz's heterodox geology, he was in full sympathy with his work in general.