Page:Popular Science Monthly Volume 27.djvu/567

Rh ancestry. His father, Michel Chevreul, a distinguished physician of his day, according to Larousse's "Cyclopædia" (born 1754, died 1845), was ninety-one years old at the time of his death; while the "Lancet" finds somewhere nineteen additional years, and makes his age a hundred and ten years. If discrepancies like this can occur in writing exact biographies of our own times, why should we be surprised at the variances in the legends of ancient days?

was born at Angers, France, where his father was hospital physician and a professor in the Obstetrical School, on the 31st of August, 1786. He studied the course of the Central School of his native city, and then, when seventeen years old, went to Paris, where he became associated with Vauquelin in the manufacture of chemicals, and was made director of his laboratory. He was afterward, in 1810, selected by Vauquelin as preparator in the course of Applied Chemistry at the Museum of Natural History. In 1813 he was given the title of Officer of the University, and was placed in the chair of Chemistry of the Lycée Charlemagne. In 1824 he was made special Professor of Chemistry at the Gobelins factory, and director of the dye houses connected with that establishment. In 1826 he was admitted to the Academy of Sciences, in the place of M. Proust, in whose favor he had retired from the candidacy in 1816, when he had had an opportunity of being elected. In 1830 he succeeded his former master, Vauquelin, in the chair of Applied Chemistry in the Museum of Natural History. He has been charged with the administration of the Jardin des Plantes, where he has had occasion to defend the ancient prerogatives of the body he represented against the encroachments of the political administration, and where he made a formal protest during the siege of Paris against the barbarous bombardment of the buildings of the institution.

The enumeration of the discoveries that science owes to M. Chevreul would far pass the limits which it is possible to assign to this sketch. The most important of them have been perhaps in the fields of researches on fatty bodies of animal origin, and of colors, their contrasts, their harmonies, and the graduation of their shades. The "Recherches chimiques sur les corps gras d'origine animal" ("Chemical Researches on Fatty Bodies of Animal Origin"), on which the foundation of his reputation was laid, appeared in 1823. In this work the author developed his new ideas on the relations of fatty bodies and the ethers, and propounded the first exact theory of saponification, whether produced by acids or by bases, by showing that either of those two classes of bodies tend to speed the decomposition of fat-substances in acids and in glycerine, through the absorption of a certain number of equivalents of water. The same decomposition takes place spontaneously but slowly in the open air, and is the cause of the rancidity of fats. The water absorbed in the course of the transformation contributes to the formation of the resultant fat-acid, and the glycerine is separated. When a