M. Coulon told me the day before yesterday that he had spoken with M. de Montmollin, the Treasurer, who would write to M. Ancillon concerning the purchase of my collection. . .Will you have the kindness, when occasion offers, to say a word to M. Ancillon about it?. . .Not only would this collection be of the greatest value to the museum here, but its sale would also advance my farther investigations. With the sum of eighty louis, which is all that is subscribed for my professorship, I cannot continue them on any large scale.
I await now with anxiety Cotta's answer to my last proposition; but whatever it be, I shall begin the lithographing of the plates immediately after the New Year, as they must be carried on under my own eye and direction. This I can well do since my uncle, Dr. Mayor in Lausanne, gives me fifty louis toward it, the amount of one year's pay to Weber, my former lithographer in Munich. I have therefore written him to come, and expect him after New Year. With my salary I can also henceforth keep Dinkel, who is now in Paris, drawing the last fossils which I described. . .
No answer to this letter has been found beyond such as is implied in the following to M. Coulon.
HUMBOLDT TO M. COULON, FILS.
BERLIN, January 21, 1833.
. . .It gives me great pleasure to acknowledge the flattering welcome offered by you and your fellow-citizens to M. Agassiz, who stands so high in science, and whose intellectual qualities are enhanced by his amiable character. They write me from Heidelberg that they intend the place of M. Leuckart in zoology for my young friend. The choice is proposed by M. Tiedemann, and certainly nothing could be more honorable to M. Agassiz. Nevertheless, I hope that he will refuse it. He should remain for some years in your country, where a generous encouragement facilitates the publication of his work, which is of equal importance to zoology and geology.
I have spoken with M. Ancillon, and have left with him an official notice respecting the purchase of the Agassiz collection. The difficulty will be found, as in all human affairs, in the prose of life, in money. M. Ancillon writes me this morning: "Your paper in favor of M. Agassiz is a scientific letter of credit which we shall try to honor. The acquisition of a superior man and a superior collection at the same time would be a double conquest for the principality of Neuchatel. I have requested a report from the Council of State on the means of accomplishing this, and I hope that private individuals may do something toward it." Thus you see the affair is at least on the right road. I do not think, however, that the royal treasury will give at present more than a thousand Prussian crowns toward it. . .
Regarding the invitation to Heidelberg, Agassiz's decision was already made. A letter to his brother toward the close of December mentions that he is offered a professorship at the University of Heidelberg, but that, although his answer has not actually gone, he has resolved to decline it; adding that the larger salary is counterbalanced in his mind by the hope of selling his collection at Neuchatel, and thus freeing himself from a heavy burden.
Agassiz was now threatened with a great misfortune. Already, in Paris, his eyes had begun to suffer from the strain of microscopic work. They now became seriously impaired; and for some months he was obliged to abate his activity, and to refrain even from writing a letter. During this time, while he was shut up in a darkened room, he practiced the study of fossils by touch alone, using even the tip of the tongue to feel out the impression, when the fingers were not sufficiently sensitive. He said he was sure at the time that he could bring himself in this way to such delicacy of touch that the loss of sight would not oblige him to abandon his work. After some months his eyes improved, and though at times threatened with a return of the same malady, he was able, throughout life, to use his eyes more uninterruptedly than most persons. His lectures, always delivered extemporaneously, do not seem to have been suspended for any length of time.
The following letter from Agassiz to Humboldt is taken from a rough and incomplete draught, which was evidently put aside (perhaps on account of the trouble in his eyes), and only completed in the following May. Although imperfect, it explains Humboldt's answer, which is not only interesting in itself, but throws light on Agassiz's work at this period.