Though no additional honors could add to his fame, Dr. Herschel, in 1816, received the decoration of the Guelphic Order of Knighthood. In 1820 he was elected president of the Astronomical Society, and among their Transactions, the next year, he published an interesting memoir on the places of one hundred and forty-five double-stars. This paper was the last which he lived to publish. His health had begun to decline, and on the 24th of August, 1822, he sank under the infirmities of age, having completed his eighty-fourth year. He was survived by his widow, Lady Herschel, an only son, Sir John F. W. Herschel, and his sister Caroline, who died in 1847, in her ninety-eighth year. LAPLACE. The author of “Celestial Mechanics” was born at Beaumont-en-Auge in 1749, just thirteen years later than his renowned friend Lagrange. His father was a farmer, but appears to have been in a position to provide a good education for a son who seemed promising. The subject which first claimed his attention was theology. He was, however, soon introduced to the study of mathematics, in which he presently became so proficient that, while he was still no more than eighteen years old, he obtained employment as a mathematical teacher in his native town. Desiring wider opportunities for study, young Laplace started for Paris, being provided with letters of introduction to D’Alembert, who then occupied the most prominent positions as a mathematician in France, if not in Europe. On presenting these letters, he seems to have had no reply; whereupon, Laplace wrote to D’Alembert, submitting a discussion of some point in dynamics. This letter instantly produced the desired effect. D’Alembert thought that such mathematical talent as the young man displayed was in itself the best of introductions to his favor. It could not be overlooked, and accordingly he invited Laplace to come and see him. Laplace, of course, presented himself, and erelong D’Alembert obtained for the rising philosopher a professorship of Mathematics in the military school in Paris. This gave the brilliant young mathematician the opening for which he sought, and he quickly availed himself of it. Laplace’s most famous work is “Celestial Mechanics,” in which he essayed a comprehensive attempt to carry out, in much greater detail, the principles which Newton had laid down. The fact was that Newton had not only to construct the theory of gravitation, but he had to invent the mathematical processes by which his theory could be applied to the explanation of the movements of the heavenly bodies. In the course of the century which had elapsed between the time of Newton and the time of Laplace, mathematics had been extensively developed. The disturbances which one planet exercises upon the rest can only be fully ascertained by the aid of long calculations, and for these calculations analytical methods are required.