It is pleasant to find Bernard thus steadfastly retaining the friendship of earlier years, but far more satisfactory to perceive that he had preserved his religion pure, and that the source whence his activity in the pursuit of knowledge was derived remained the same. At the close of a pious and laborious life, he remembered there was still something left which he might do. He had learned the wonderful secrets of nature to the glory of Him who had given him the hearing ear, and the seeing and observing eye; and now, recurring to the ruling motive of his life—that solemn idea of responsibility—he says, “It is a just and reasonable thing that the talents a man has received from God, he should endeavour to multiply, following his commandment. For which reason I have studied to bring unto the light the things of which it has pleased God to give me understanding. Having seen how many pernicious errors have been set abroad, I have betaken me to scratch in the earth for the space of forty years, and search into the entrails of the same, in order to understand the things which she produces in herself; and by such means I have found grace before God, who has caused me to understand secrets which have hitherto been unknown even to the learned.” The book, thus dedicated and prefaced, contained the mature fruit of his studies as a naturalist. It is a collection of short treatises upon waters and fountains, metals, salts, stones, and earths, fire, enamels, and many other things, besides a treatise on marl, “very useful and necessary for those concerned in agriculture.” It was published at Paris in the year 1580, when its author was more than seventy years of age. Four years later he was still lecturing in his museum, wandering out, now and then, to the river side and elsewhere to find an illustration of some lesson he was teaching. Thus, one winter’s day, he was seen standing beside the Seine, opposite the Tuileries, surrounded by a throng of listeners and objectors, among whom were several of the boatmen, who persisted in maintaining what Palissy was combatting: namely, that the floating masses of ice upon the river came from the bottom of the water. Among those who listened with interest and discernment to his instruction was the Sieur de la Croix Dumaine, who afterwards, in a volume published in 1584, described Palissy as “a natural philosopher, and a man of remarkably acute and ready wit, flourishing in Paris, and giving lessons in his science and profession.” His was a vigorous old age, and he looked so much younger than he really was, that the Sieur supposed him little more than sixty. He might, in all probability, have continued thus to lecture and discourse about the wonders of the earth and waters some years longer; yet, even a few months later we should have vainly sought him in his beloved museum, or on his pleasant rambles around the environs of Paris. He was no longer there, but immured within the walls of yon grim fortress—