Page:Popular Science Monthly Volume 27.djvu/568

550 fatty substance is submitted to the action of a strong acid, the decomposition takes place instantaneously, because the acid separates the glycerine and unites with it. If, on the other hand, the action is accomplished by means of an energetic base, the base determines the formation of a fat-acid, and combines with it, so as to leave the glycerine isolated. Glycerine had been discovered by Scheele in 1775, but, until M. Chevreul's experiments, was regarded as only accidentally present in some fats; and to M. Chevreul is due the discovery that it is always separated in the saponification of fats, and that those bodies are now regarded as salts, formed of glycerine as a base, combined with some acid. This theory led up to the invention of star-candles, a boon to mankind, of the value of which the present generation, with its gas-lights and petroleum-lamps, can have no conception. For this discovery M. Chevreul was awarded the grand prize of twelve thousand francs founded by the Marquis d'Argenteuil, in conferring which the Société d'Encouragement pour l'Industrie Nationale declared with justice that it was only registering the opinion of all Europe concerning researches which might serve as models to all chemists. M. Chevreul, it may be added, never thought of turning his discoveries to his personal profit, but gave them freely to the world, and was satisfied with being a student of science.

M. Chevreul's researches in coloring-matters at the Gobelins factory and at the Museum gave occasion to the publication of "Leçons de chimie appliquée à la teinture" ("Lessons on the Application of Chemistry to Dyeing," 1828-1831); of a memoir on the law of the simultaneous contrast of colors, and on the arrangement of colored objects according to that law in its relations to painting ("Sur la loi du contraste simultane des couleurset sur l'assortiment des objets colorées, considéré d'après cette loi dans ses rapports avec la peinture," 1829), and of a memoir on colors and their application in the industrial arts ("Des couleurs et de leur application aux arts industriels a l'aide des cercles chromatiques," 1864); works embodying novel ideas, the application of which in manufactories and workshops has been attended with important results. M. Chevreul was much grieved when, in his advanced age, the management of the Gobelins factory placed him on the retired list; but, in order to appease his feelings, he was allowed to retain his appointment with the full salary attached to it. In 1879 he was retired from the directory of the Museum, but was permitted to retain his chair as professor.

Among the honors that have been accorded to him are membership of the Royal Society; President of the Agricultural Society; Commander, Grand Officer, and Grand Cross of the Legion of Honor; and other memberships and decorations at home and abroad. He was a member of the International Juries at the Expositions of London and Paris. In September, 1872, the French Academy of Sciences presented him with a medal in anticipatory commemoration of the fiftieth