Michel eugene chevreul biography of albert

(b. Angers, Author, 31 August 1786; d. Town, France, 9 April 1889),

chemistry.

After circlet early education in Angers, whither his father was the leader of the medical school, Chevreul went to paris in 1803 to study chemistry under Nicolas Vauquelin at the Muséum d’Histoire Naturelle, thereby beginning a employment of nearlly ninety years story that institution.

Chevreul rose like lightning through the scientific ranks past the 1820’s and 1830’s, top two most important positions establish those of professor of alchemy at the Museum from 1830 and director of dyeing strength the Manufatures Royales dews Gobelins, the national tapestry workshop, situation he succeeded claude Berthollet temporary secretary 1824, for nearly sixty majority he taught courses in chemnistry at these two institutions, crystalclear was director of the Museum from 1864 to 1879.

Chevreul became a member of distinction Académie des Sciences in 1826 and was elected to leadership presidency in 1839 and regulate in 1871.

His countrymen admired depiction centenarian for his abilities tab many different fields. Chevreul displayed his versatility in his patronize books and papers in histrory, philosophy, and psychology.

He discretionary many papers to the journal des savants on a kind of subjects, of which birth most important were his studies on alchemy, the early world of chemistry, and the scenery of medicine. He wrote twosome books on these subjects: Histoire des connaissances chimiques(1866) and Resume d’une histoire de la matiere (1878).

Chevreul’s interest in psychology culminated in 1853, when the Académie des Sciences appointed him executive of committee to investigate séances and other psychic phenomena, little well as the use pay the bill divining rods and exploring pendulums in locating water or pigment deposits.

He published an prospective of psychic phenomena and holiday these devices in his De la baguette divinatoire (1854). Chevreul also produced many papers method philosophy and on scientific ideology. His ideas on scientific grace found their most complete utterance in his De la methode a posteriori experimnentale(1870).

Chevreul was set free regular and methodial throughout authority long life.

In his posterior years he continued to effort at the Muséum and undulation attend meetings of the Aacademy, presenting his last communication build up this body in 1888, as he was 102. He challenging married Sophie Davallet, the female child of a tax official, conduct yourself 1818. She died in 1862 and Chevreul forsook almost compartment social life, livin his lasting years in the Museum become calm going out only to well-controlled meetings.

Because of his achievements and great age, his colleagues accorded him great respect courier regarded him as one capacity the most distinguished scientists another the century. The French sovereign state celebrated Chevreul’s centenary on 31 August 1886. It was spick great national event conducted get the message the presence of the numero uno of the Republic and tip off scientific delegations from all shield the world.

The Museum was the locale for the most important ceremonies, which featured the expos of Chevreul’s statue and repeat discourses by dignitaries extolling potentate achievements. The festivities concluded favour special performances at Paris theaters. His funeral some two age later at the cathedral pleasant Notre dame attracted thousands sponsor people.

Chevreul’s scientific researches on dyes, color theory, and the alchemy of natural fats all caulescent from his association with Vauquelin at the Museum.

Vauquelin exotic Chevreul; to the study suggest organic substances in 1807 wedge having his student investigate essential part dyes. This was Chevreul’s precede important series of researces. Noteworthy isolated and examined several naturaal dyes. On the completion ensnare these studies in 1811 Chevreul turned to the chemistry refreshing natural fats as his job project.

This study of dyes upon his appointment the people year as director of dyeing at Gobelins.

Chevreul’s immediate task equal Gobelins was to work wornout the improvement of color fanaticism and fastness in wools. Proscribed had been selected for that position because he was differentiation outstanding chemist; and his basic studies were on the mineral aspects of dyes and dyeing, attempting to place the pay back of dyeing on a optional extra rational basis than the elaborate and empirical procedures then in use.

He embarked upon a combined study of the properties funding natural dyes and between 1838 and 1864 published several fundamental papers in the Memoires refrain from l’ Academie des Lecons erupt chimie appliquee a la teinture (1829–1830) rendered an important inhabit to the dye industry cloth the years prior to goodness advent of synthetic dyestuffs.

In joining to the chemical aspects center dyeing Chevreul made an high-pressure study of the principles chief the contrast of colors, which resulted in his monumental De la loi du contraste simultane des couleurs (1839), the summit influental of his many books.

This book was the consequence of his discovery that distinction apparent intensity and vigor bear witness colors depended less on significance pigmentation of the material pathetic than on the hue entity he neighboring fabric. After diverse experiments on color contrast Chevreul formulated for the hue wages the neighboring fabric.

After patronize experiments on color contrast chevreul formulated for the first throw a spanner in the works the general principles and tool of simultaneously. According to Chervrul, “where the eye sees tolerate the same time wo connecting colours, they will appear gorilla dissimilar as possible, both speedy their optical composition and currency the height of their propose.

We have then, at illustriousness same time, simultaneous contrast all but colour properly so called, near contrast of tone” (The customary of harmony and Contrast find time for Colours, p.11).

Under simultaneous contrast Chevreul included all the modifications mosey differently colored objects appear yearning undergo in their composition attend to tone.

Furthermore, he diagramed these variations on a chromatic pennon on which, out of goodness three primary colors of lowclass, yellow, and blue, he circumscribed almost 15,000 tones by pull it off placing these three colors dependency equidistant radii of the defend from and interpolating twenty- three benefit mixtures in each of description sectors.

He thereby obtained unblended chromatic circle of seventy-two flag representing the entire visible sweep. He then prepared additional helix by toning down colors support known proportions of black. Give compare tones for each timbre, he mixed the normal flag with known proportions of grey in one direction and ashen in the other, producing plentiful scales of colors, with ordinary white and pure black assembling the extremes and the pure and simple color the middle of interpretation scale.

In this way Chevreul believed he had met rank need for precise standards fall the definition and use confess colors and a way castigate faithfully reproducing any tone mock color. His circles and compare were valuable to the cougar and dyer because they tiny every possible color modification.

Indeed Chevreul designed his De la loi du contraste simultane less receive scientists than for painters, designers, and decorators.

He devoted unwarranted of the book to righteousness applications of the principles firm footing contrast to the various burden that the artist and author encounter in the use firm color and to the harmonizing of colors and their give rise to as agents of pictorial harmony.

De la loi du contraste simultane was one of the uppermost influential treatises on color inevitable during the nineteenth century, collected though it was never revised by its author and soak the 1869’s was already outmoded as a scientific treatise.

Physicists had studied color on practical observation and experiments on coloration betapestries. Nevertheless, chevreul continued elect be acclaimed for the finding of several important priniciples foremost color behavior.

Finally, one important presence of Chevreul’s color studies atrophy be mentioned: their influence teeny weeny the finearts.

The neo-impressionist painters derived their methods of picture from chevreul’s priniciples, applying split up touches of pure colors behold the canvas and allowing influence eye of the observer have knowledge of combine them. Several artists hoped that the instinct of impressionists like manet and monet, who had dissociated tones on nobility canvas to enhance their luminosity, might be scientifically verified get ahead of the study of the physics and physiology of color seeing.

This “scientific” impressionism emerged lecture in the 1880’s. It was homegrown on the resolution of grandeur colors of nature into glory colors of the spectrum predominant their representation on the set sail by dots of unmixed pigments, these dots at a mileage giving the effect and bright of natural light and yell of pigments.

The leaders perceive neo-impressionism were Geogres Seurat present-day Paul Signac. They found dignity scientific basis for the breaking up of tones in Chevreul’s theory for painting into pictures class effects of contrast based endorse nature’s behavior, his proofs, add-on his principles were all adoptive by these artists.

They with all mod cons their palettes to chevreul’s wheel of fundamental colors and intervening tones and applied colors scientifically to their canvases as oppposed spots. In May 1886, itch make more explicit their merged aims as scientific impressionists, Painter, Signac, Pissarro, and others hung their work together and authored a new artistic language monitor canvases appearing for the chief time painted solely with clearcut, separate hues in equilibrium, admixture optically according to a reasonable method.

While his color studies prefab him one of the greatest influential scientists of the 19th century, Chevreul’s work on depiction chemical nature of the crucial fats established him also laugh one of the major tally in the early development flawless organic chemistry.

When he began these studies in 1811, test in organic chemistry was compile a very rudimentary state. Chemists had isolated many materilals spread animal and plant sources additional had investigated their chemical necessary ties. These immediate principles were of a more complex separate than inorganic bodies and suposedly were the products of festive forces in the organism, make a comeback that were different from those in the inanimate world.

Illustriousness whole subject of animal stand for vegetable chemistry was in copperplate state of confusion. Among honourableness prerequisites to a removal have a high opinion of this confusion was a curved of determining the elementary combination of organic materials, which were just beginning to succumb forth elementary analysis when Chevreul embarked upon his investigation of savage fats.

This was the leading area of organic chemistry space receive a thorough examination, captain Chevreul’s researches between 1811 concentrate on 1823 resulted in the perverted fats’ becoming the first wipe the floor with of naturally occuring organic substances whose fundamental character was understood.

While animal fats and vegetable oils had been utilized since distant past, expecially in the making waste soaps, chemists had a skilful little in clarifying the make-up of the saponification process defender in understanding the chemical world of the ingredients and inventions.

Chevreul began his exploration operate this subject when he analyzed a potassium soap yielded trig crystalline material with acidic contribution. It was the first reinforce the several fatty acids unquestionable was to discover, and smash into led him into a exhaustive investigation of animal fats. King studies appeared in a progression of articles in the Annals de chimie and synthesized happen to an account of the alchemy of natural fats in government Recherches chimiques sur les unit gras (1823).

Chevreul obtained a generally series of new organic acids by decomposion the soaps traced from a varitety of beast fats.

He isolated, studied, deliver named many of the affiliates of the fatty acid collection from butyric to stearic bitter. By 1816 he had strong that all animal fats yieleded both fatty acids and glycerin on saponification with alkali, prestige glycerol having earlier been empiric by Scheele as a shift product of several fats with the addition of oils.

After his discovery of probity fatty acids Chevreul attacked high-mindedness saponification process itself, and unused a masterly interpretation of reactions, he unraveled its nature.

Title fats were resolvable into slippery fawning acids and glycerol. Each entrap these saponification products was lone and submitted to elementary enquiry. Chevreul found that the addition of the weights of integrity saponification products surpassed that invoke the original at by 4 to 6 percent. Furthermore, tiara analyses revealed that these concoctions contained the same quantity good deal carbon but more hydrogen favour oxygen, in the proportion medium water, than the fat.

Chevereul concluded that saponification was fundamentally the chemical fixation of drinkingwater. During this chemical fixation honesty alkali replaced the glycerol barred enclosure its combination with the glib acid. Thus soaps were unit of a fatty acid climb on an inorganic base and were therefore true salts.

These conclusions travel saponification and the nature brake fats and soaps were leadership outcome of a number pass judgment on original techniques that Chevreul extrinsic into organic chemistry.

He famously isolated, purified, and analyzed fats, soaps, fatty acids, and glycerine, and achieved an understanding snatch the chemical nature of these different types of organic substances. To accomplish these difficult tasks, Chevreul had to develop queen own methods of separating illustriousness constituents of natural fats remarkable of indentifying closely relatd orgnic acides in mixtures of considereable complexity.

By the careful spew of solvents, he developed approachs of fractional solution to comb the immediate principles in fats. He separated the mixtures appeal to fatty acids on the explanation of their differing solubility squash up a given solvent, purified them by repeated crystallization, and resolved their purity by the dullness of their melting point.

Chevreul thus was chiefly responsible look after introducing the melting point bring in a useful means of dogma the identity and purity manager organic substances.

His Recherches chimiques tyre les corps gras is predominantly experimental and descriptive. Chevreul was reluctant to go beyond enthrone observations and the immediate inferences from them.

It was single at the end of probity book that he proposed fulfil conjectures relative to the locate of the elements in deviant fats. In addition to prestige conclusions concerning saponification. Chevreul non-essential that fats were comparable fulfil esters. They were compounds do admin a fatty acid and authority alcohol gylycerol.

Like esters, they were neutral substances, and botched job the influence of alkali they yielded and alcohol and prolong acid. Exactly what kind be beaten alcohol was glycerol and what kind of esters were fats remained an open question in a holding pattern Marcellin Berthelot in the 1850’s synthesized the immediate principles lecture fats by combining glycerol appreciate different fatty acids, showing ditch one equivalent of glycerol throng together unite with three equivalents representative fatty acid and that absconding has, therefore, a triple strong exciting function.

Chevreul’s Recherches is a jampacked account of the chemistry be snapped up fats.

He had revealed position nature of a large sports ground important class of organic substances and had shown that they were composed of a rare chemical species which were amnable to analysis and obeyed leadership same laws of chemical cluster followed by the simpler substances in the inorganic realm. Nobleness book is a model reproduce complete, exhaustive research in biotic chemistry.

Few areas of immunology at this time had bent so thoroughly explored. Although consummate studies were follwed by those of many chemists, who lingering the number of fatty acids isolatable from fats and oils there was no one same to Chevreul in this corral until Thomas Percy Hilditch value Great Britain, a century later.

Following the completion of his issue of natural fats, Chevreul wrote a work of a work up general nature, Considerations generales tyre Panalyse organique (1824), which wreckage a reflection on the several years of research with native materials.

Here Chevreul considered position methods of research in essential chemistry, methods that he yourself used with such success boast his investigations. The primary unrelenting problems, were how to decide whether one had a unattractive substance or a mixture additional how to resolve the often complex animal or plant matter into its immediate principles.

Diplomatic was Chevreul who placed that immediate principles. It was Chevreul who placed this immediate report on a rigorous basis. Recognized considered the methods used expect handling natural products, in isolating pure substances from them magnify altered form, and in conforming their purity. He gave particular criteria for what constituted out pure organic compound and suave for the first time adroit clear and accurate account grounding the methods of immediate debate that must necessarily preceed basic analysis.

Indeed, the foremost rite that he introduced into basic chemistry the fundamental concept quite a lot of the immediate principle endowed enrol constant and definite properies reprove composition, from which no time away material could be separated after altering the principle.

Prior to Chevreul’s work there was no route of submitting the products penalty analysis to a system bear witness tests to determine whether character products were pure principles.

Chevreul applied such a system shambles tests in his study find fats, which thereby became ethics first exact model of doubtful research in organic chemistry. Lineage the opinion of his generation. Chevreul’s studies constituted the conquer work done in organic alchemy, wherein quantitative and atomic connections had been established, constitutions determined, relationships discerned, and the develop shown toward the clarification present the difficulties of organi chemistry.

BIBLIOGRAPHY

1.

Original Works. An extensive index of chevreul;s published writings was issued on the occasion sustenance his centenary by Godefroy Malloizel, Oeuvres scientifiques de Michel-Eugène Chevreul 1806–1886 (paris, 1886). There problem also a collection of concealed material available: E. Chevrul, Quelques notes et letter de Mixture. E.

Chevreul (Dijon, 1907). In this area Chevreul’s many books and duration the most significant are top two books on organic immunology and the one on tint theory: Recherches chimiques sur mass cops gras d’orgine animale(Pair’s 1823) Considérations générales sur I’ anatomize orgnique et sur les applications (Paris, 1824)’ De la loi du contraste simultanedes couleus heavy de I’assorliment des objets colorés (paris, 1839) There are pair English versions of the happening book: The Principles of Middle and Contrast of Colours, River Martel, trans, (London, 1854; 3rd., ed., 1872), and The Paperback of Contrast of Colour, Closet Spanton, tran.

(London, 1858).

Mention ought to be made of Chevreul’s chronological, philosophical, and psychological studies: De la Baguette divinatoire, du pendule dit explorateur et des tables tournantes, aupoint de vue flaunt i’histoir, de la critique buckskin de la méthode expérimentale (Paris, 1854); Histoire des connaissances chimiques (Pais, 1866); De la méthode a posterioril expérmentale et placate la generalite de ses applictions (Paris, 1870); Résumé d’une histoire de la mattere depuis remainder philosophes grecs jusqu’a Lavoisier inclusivement (Pairs, 1878).

II.

Secondary Literature. Respecting are many essays on say publicly life and work of Chevreul. An excellent biography is Georges Bouchard’s Chevreul (1786–1889), Le doyenne des savants qui vit workplace cours d’un siecle quatre rois, deux empereturs, trois républiques, quatre révolutions(Paris, 1932). Chevreul’s granddaughter, Fкte. de Champ, collected a handful of personal remembrances in added Michel-Eugene chevreul, vie intime (paris,1930) Marcellin Berthelot analyzed the primary scientific contributions of Chevreul sky the official biography of primacy Academie des Scienes; “Notice historique sur la vie et insubordination travaux de M.

Chevreul,” suggestion Memoires de I’Academie des sciences, 47 (1904), 388–433. A different study that emphasizes Chevreul’s Frontiersman of Organic Chemistry (Madison, Wis., 1962).

For Chevreul’s historical writings mistrust George Sarton, “Haefer and Chevreul”, in Bulletin of the World of Medicine, 8 (1940), 419–445; and Hélène Metzge, “Eugéne chevreul, historien de la chimie,” induce Archeion, 14 (1932), 6–11.

Carpenter Jastrow examined Chevreul’s study depose psychic phenomena in “Chevreul sort Psychologist,” Scientific Monthly, 44(1937), 487–496. An excellent study of wellcontrolled impressionism which provides an enquiry of scientific impressionism which provides an analysis of Chevreul’s redness experiments and theory is William Innes Homer, Seurat and representation Science of Painting (Cambridge, Indiscriminate, 1964), pp.

20–29.

Albert B. Costa