In the maturity of his powers he devoted himself and his fortune to historical investigations concerning the art of cookery. For several years he was to be daily seen in the Imperial Library, studying the cookery, so renowned, of the ancient Greeks and Romans, desiring especially to know whether they possessed any secrets which had been lost. His conclusion was, that the dishes served upon the tables of Lucullus, Augustus Caesar, and others, were "utterly bad and atrociously stupid." But he commended the decoration of their tables, the cups and vases of gold, the beautiful pitchers, the chased silver, the candles of white Spanish wax, the fabrics of silk whiter than the snow, and the beautiful flowers with which their tables were covered. He published the results of his labors in a large octavo volume, illustrated by a hundred and twenty-eight engravings. He continued his studious labors, and published at various periods "Ancient and Modern Cookery Compared," in two volumes, octavo, "The Paris Cook, or the Art of Cooking in the Nineteenth Century," and others. Toward the close of his life, he wrote a magazine article upon Napoleon's way of eating at St. Helena. He dedicated one of his works to his great instructor and master in the art of cookery, Guipiere. To give the reader an idea of his way of thinking and feeling I will translate a few sentences of this dedication:-- "Rise, illustrious Shade! Hear the voice of the man who was your admirer and your pupil! Your distinguished talents brought upon you hatred and persecution. By cabal you were obliged to leave your beautiful native land, and go into Italy to serve a prince (Murat) to whose enjoyment you had once ministered in Paris. You followed your king into Russia. But alas, by a deplorable fatality, you perished miserably, your feet and body frozen by the frightful climate of the north. Arrived at Vilna, your generous prince lavished gold to save you, but in vain. O great Guipiere, receive the public homage of a faithful disciple. Regardless of those who envied you, I wish to associate your name with my labors. I bequeath to your memory my most beautiful work. It will convey to future ages a knowledge of the elegance and splendor of the culinary art in the nineteenth century; and if Vatel rendered himself illustrious by a point of honor, dear to every man of merit, your unhappy end, O Guipiere, renders you worthy of the same homage! It was that point of honor which made you follow your prince into Russia, when your gray hairs seemed to assure you a happier destiny in Paris. You shared the sad fate of our old veterans, and the honor of our warriors perishing of hunger and cold."