Popular Science Monthly/Volume 27/August 1885/Sketch of M. Chevreul

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MICHEL EUGÈNE CHEVREUL.

 

SKETCH OF M. CHEVREUL.

"PERHAPS never in the history of science," said the London "Lancet" a year and a half ago,^[1] "has a distinguished career equaled in its length that of M. Chevreul; . . . and it is probably altogether unique for a savant to be able, at one of the most distinguished scientific societies in the world, to refer to remarks which he made before the same society more than seventy years previously." The allusion is to a reference with which the veteran chemist had supplemented a communication he had read a few days before to the French Academy of Sciences: "Moreover, gentlemen, the observation is not a new one to me. I had the honor to mention it here, at the meeting of the Academy of Sciences, on the 10th of May, 1812." When asked in 1883 if he had seen a certain piece at one of the theatres, he answered, "No, I have not been inside the doors of a theatre since Talma's death—in 1824," or fifty-nine years previously. Talking of the weather during a mild period in the winter of 1883, he said, "The severest winter I ever experienced was that of 1793," indicating the recollection of a fact ninety years old. M. Chevreul appears to have come from a long-lived 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?

Michel Eugène Chevreul 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 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 year of his membership. The fiftieth year would not strictly have occurred till 1876; but it was generally understood that he would have been elected in 1816, had he not urged the Academy to give the vacant place to M. Proust, who was old and infirm, and could not afford to wait. M. Dumas, the Permanent Secretary of the Academy, in a "gracefully-worded speech," recounted the many valuable services rendered by M. Chevreul, "the dean of French students," as he was modestly accustomed to style himself, and at the same time bore warm testimony to the personal character of the man. M. Élie de Beaumont, who had been a pupil of M. Chevreul, added a few words of veneration and respect for his old master, after which the latter, attempting to respond, could only express his inability to do so. In 1873 the Albert gold medal was awarded him by the English Society of Arts, for his valuable researches in connection with saponification, dyeing, agriculture, and natural history. In November, 1876, he was entertained at dinner by eighty savants in celebration of the fiftieth anniversary of his professorship and membership of the Academy of Sciences. The American Association for the Advancement of Science, at its Boston meeting in 1880, sent him a congratulatory telegram on his reaching his ninety-fifth year, and expressed the hope that he might be spared to continue his labors until the end of his century, which only a few months are lacking to see fulfilled. In the same year, he completed the fiftieth course of his lectures at the Museum, on the application of chemistry to organized bodies. Each course consisted of forty lectures, so that the fifty courses included in all two thousand lectures.

According to "Nature," M. Chevreul first important work was published in 1806. Among his other works than those we have already named, are one on organic analysis and its applications (1824); "Théorie des effets optiques que présentent les étoffes de soie" ("Theory of the Optical Effects presented by Silken Cloths," 1848); "De la baguette divinatoire, du pendule, et des tables tournantes" ("Of the Divining-Rod, the Pendulum, and Turning-Tables," 1854); "The History of Chemical Science," of which the first volume was published in 1866; "Memoirs of the Academy," completed in 1872, "a most interesting work, which throws light on many of the most scientific questions of the day"; and numerous papers, articles in encyclopædias, and books of less general interest than those mentioned. A curious illustration of his vigor and activity, lasting into extreme old age, is afforded by a communication which he made to the Academy of Sciences on the 4th of February, 1884, which was on the varying color-effects produced by the glare of a conflagration playing upon a gas-light that stood in front of the Museum, which he observed for an hour. Delicate work that for the eyes of a man ninety-eight years old! That vigor still continued till the beginning of the present year, when M. Chevreul presided at the meeting of the new Association of French Students, the "Scientia"; and when his name was mentioned in connection with those of Jamin, Pasteur, De Lesseps, and Léon Say, as one of the persons whose co-operation was expected to insure the success of the organization. In his address at this meeting, he declared himself still a student.

On the 4th of January last the students of Paris made a manifestation before M. Chevreul's house, with their flags flying, in honor—anticipating the day by a few months—of the one hundredth anniversary of his birth. Twenty delegates from the body were received in person by M. Chevreul, when M. Delcambre, President of the Association of Students, spoke in eulogy of the great savant by whom France is honored, and who, reaching his hundredth year, still remained robust and valiant, and preserved all the force of his genius and his old energy in work. In concluding his address, M. Delcambre said: "Illustrious and beloved master, the students of all the schools have joined in this manifestation because you are to us all—I say it with full assurance—a dean, and, I hope I may be permitted to add, a comrade. As a savant, you have contributed to the progress of humanity; as a Frenchman, you have added to the grandeur of France. The students by my lips transmit to you their good wishes and felicitations." M. Chevreul appeared much touched by this demonstration, and thanked the students with a voice marked by emotion. M. Delcambre then presented him a register containing the signatures of all the participants.

An interesting account of M. Chevreul's habits is given by a writer who is quoted in the "Lancet": "He is generally lightly clad, and wears no hat unless under circumstances in which he is obliged to appear in one; indeed, he hardly needs a hat, as he has most luxuriant hair. He is constantly at work, allowing only ten minutes for each of his meals, of which he has but two a day. He breakfasts at seven, the repast consisting of a plate of meat and another of vegetables, which he eats together, the whole being washed down with two tumblers of water. He is said to have never drunk a glass of wine in his life. He dines at seven in the evening, and takes nothing between the two meals except a small loaf at noon, which he eats standing and by the side of his alembics. The writer who relates this states that on a visit to M. Chevreul he found him in the attitude just described, and on expressing his surprise at the frugal manner in which he lived, M. Chevreul observed, 'I am very old' (this was in 1874), 'and I have yet a great deal to do, so I do not wish to lose my time in eating.'" In his work he is said to follow a motto that he has chosen from a maxim by Malebranche, and which is regarded by "Nature" as affording a true key to his life, his works, and his discoveries: "Chercher toujours l'infaillibilité, sans avoir prétention de l'atteindre jamais" ("Always to seek infallibility, without having the pretension of ever reaching it").

1. December 24, 1883.