This money made it possible for Agassiz to work in Paris, until a professorship of Natural History was created for him at Neuchâtel, through the influence of Humboldt and others. Humboldt wrote: "Agassiz is distinguished by his talents, by the variety and substantial character of his attainments, and by that which has a special value in these troubled times, his natural sweetness of disposition." This "sweetness of disposition" was worth more to Agassiz, all through life, than a fortune. It drew everybody to him. It opened the pockets of the wealthy to carry forward his great projects. It won the hearts of his pupils on two hemispheres. It made his home a delight, and his presence a constant blessing. He assumed the duties of his professorship at Neuchâtel in the autumn of 1832, giving his first lecture, "Upon the Relations between the different branches of Natural History and the then prevailing tendencies of all the Sciences," November 12, at the Hôtel de Ville. A society for the study of the natural sciences was soon formed, and Agassiz became its secretary. So natural, so enthusiastic, so full of his subject, was he, that everybody became interested. To little companies of his friends and neighbors he lectured on botany, on zoölogy, and the philosophy of nature. Even the children were delighted to gather and be told how lakes, springs, rivers, and valleys are formed. "When it was impossible to give the lessons out-of-doors, the children were gathered around a large table, where each one had before him or her the specimens of the day, sometimes stones and fossils, sometimes flowers, fruits, or dried plants.... When the talk was of tropical or distant countries, pains were taken to procure characteristic specimens, and the children were introduced to dates, bananas, cocoa-nuts, and other fruits, not to be easily obtained in those days in a small inland town. They, of course, concluded the lesson by eating the specimen, a practical illustration which they greatly enjoyed." Three months after his settlement at Neuchâtel, where eighty louis had been guaranteed to him for three years, he was invited to Heidelberg, to succeed his former professor, Leuckart, in zoölogy. He would receive a salary of five hundred florins, besides about fifteen hundred gulden for lectures and literary work. He declined the honor, because he wished more time to devote to his writing. The following year Neuchâtel purchased his collections in natural history, thus affording him some pecuniary aid in his work. A serious misfortune now threatened him in the loss of sight. Having injured his eyes by microscopic work, for several months he was shut up in a dark room, practising the study of his fossils by touch alone; by the tongue when the fingers were not sufficiently sensitive to feel out the impression. With great care his eyes improved, so that he was able to use them through life more constantly than most persons.