At the age of eleven, Marcellin Berthelot entered the Lycée Henri-IV. He showed himself reserved in the extreme but brilliant at his lessons, distinguishing himself, particularly in Latin verse. In 1846 he won first prize for philosophy among pupils from lycées throughout France.
College/University
Gallery of Marcellin Berthelot
75005 Paris, France
In 1847 Berthelot became bachelierés lettres and then attended courses in the Paris Faculty of Science, graduating from in 1849.
At the age of eleven, Marcellin Berthelot entered the Lycée Henri-IV. He showed himself reserved in the extreme but brilliant at his lessons, distinguishing himself, particularly in Latin verse. In 1846 he won first prize for philosophy among pupils from lycées throughout France.
Marcellin Berthelot is a French chemist, politician, and philosopher. His creative thought and work significantly influenced the development of chemistry in the latter part of the 19th century. He also served as a Senator and occupied some important positions in the French government.
Background
Marcellin Berthelot was born on October 25, 1827, in Paris, France. His father, Jacques Martin Berthelot, had married Ernestine Sophie Claudine Biard in 1824. Marcellin was the second of three children; the first died in infancy. The father, who was from a family of ironsmiths in the region of Orléans, had come to Paris in 1822 to study medicine. After qualifying, he spent most of his life tending the sick in the poorer districts of Paris. Only in his heroic work during the cholera epidemic of 1832, about which he wrote a book, did he rise above obscurity. His income was just sufficient to support his family, and his wife, who came from the bourgeoisie, brought only a small dowry.
Education
At the age of eleven, Marcellin Berthelot entered the Lycée Henri-IV. He showed himself reserved in the extreme but brilliant at his lessons, distinguishing himself, particularly in Latin verse. In 1846 he won first prize for philosophy among pupils from lycées throughout France.
At fourteen Berthelot became a boarder; four years later he met Ernest Renan, whose room was adjacent to his in the pension. Renan was twenty-two and was employed as an assistant master. In 1847 Berthelot became bachelierés lettres and then attended courses in the Paris Faculty of Science, graduating from in 1849. He undertook a rigorous program of reading, including languages and the main branches of science.
Berthelot asserted his independence by deliberately avoiding the two great educational institutions, the École Polytechnique and the École Normale, the training ground of so many French men of science. He returned in 1851 as an assistant to chemist Antoine-Jérôme Balard. Bertholot’s doctoral dissertation (1854) was entitled “The Combinations of Glycerin with Acids and the Synthesis of Immediate Principles of Animal Fats.”
In February 1851 there was a vacancy for the post of demonstrator to Balard at the Collège de France. Berthelot accepted the post although it carried only a nominal salary, in his spare time he prepared for his doctorate.
Berthelot was appointed to a chair of organic chemistry created at the École de Pharmacie on 2 December 1859. The success of his book La chimie Organique fondée sur la synthése resulted in his giving a course of lectures at the College de France (1863–1864), and on 8 August 1865 this course was attached to a chair of organic chemistry entrusted to Berthelot. From that time until his death, if Berthelot was in Paris he went daily to his laboratory at the Collège de France. Although he gave more attention to research than to teaching, he had a number of distinguished students, including Jungfteisch, Sabatier, and A. Werner.
When Paris came under siege in the Franco-Prussian War (1870–1871), Berthelot was made the president of the Comité Scientifique pour la Défense de Paris. His activities during the siege of Paris called much attention to himself, and in the election of 1871 he was given a large vote, although he had not put himself forward as a candidate. He first took his seat in the Senate in 1871. He was a minister of public instruction and fine arts (1886–87). In 1895 he was appointed a foreign minister in the cabinet of Léon Bourgeois but resigned after five months because of disagreements over policy on Egypt and Sudan.
In 1869, on the occasion of the opening of the Suez Canal, Berthelot visited Egypt, the country traditionally associated with the birth of chemistry; but it was not until 1884 that he committed to paper a few ideas on alchemy. Attracted both by the mysticism of the alchemists and by the connection of other parts of their art with the rational science he professed he began, to use his knowledge of Greek to interpret unpublished alchemical manuscripts.
On a more practical plane, Berthelot’s analysis of metallic objects from ancient Egypt and Mesopotamialaid the foundations of chemical archaeology. In 1889, to celebrate the centenary of the French Revolution, Berthelot, as secretary of the Académie des Sciences, was called upon to commemorate men of science. He prepared material for a lecture on Lavoisier, and on the basis of this and Grimaux’s study of 1888 he produced a book, La révolution chimique, Lavoisier. One detects special sympathy by the patriotic nineteenth-century French chemist for the eighteenth-century liberal who had also used his scientific knowledge to help his country. Berthelot’s publication of extracts from the laboratory notebooks of Lavoisier, which were in the possession of the Academy, performed a valuable service to the history of science. Whatever criticisms may be leveled at Berthelot’searlier publications on the history of chemistry, this study was an astonishing achievement for a man who was simultaneously carrying out important research on thermochemistry and agricultural chemistry.
In the last years of his life Berthelot published books that suggest his concept of science as an all-embracing philosophy: Science et philosophie (1886), Science et morale (1897), Science et education (1901), Science et libre pensée (1905).
Berthelot’s publications were particularly numerous. Jungfleisch lists 1,600 titles of papers on inorganic, organic, physical, analytical, technical, agricultural, and physiological chemistry, as well as on the history of chemistry. His work in organic chemistry may, however, be singled out as being of special importance; and if his contributions to physical chemistry hold second place, even they may be considered as originating in the context of his interest in the reactions and formation of organic compounds.
Berthelot’s first publication, read to the Académie des Sciences on 27 May 1850, was concerned with a simple method of liquefying a gas by applying pressure. The choice of this physical topic may have been inspired by his admiration for Regnault, but in the next year his deep interest in organic chemistry revealed itself. He studied the action of red heat on alcohol and acetic acid. It was already known that at high temperatures alcohol could be transformed into a crystalline solid, naphthalene. Berthelot was able to show that in addition benzene and phenol were formed. Acetic acid at red heat produced naphthalene and benzene. He concluded very significantly that the synthesis (synthèse) of naphthalene, benzene, and possibly phenol, could now be considered as an established fact, since they could all be obtained from acetic acid, which in turn could be prepared via the respective Stages: carbon disulfide, carbon tetrachloride, trichloracetic acid. This was one of the first examples of the use of the word synthesis to denote the production of organic compounds from their elements.
The classical work on fats had been carried out by Chevreul. In 1853 and 1854, Berthelot established his reputation in this field by his research on the derivatives of glycerin. By heating glycerin with hydrochloric acid and a selection of fatty acids, he obtained compounds of glycerin with acetic, valeric, benzoic, and sebacic acids. He went on to obtain compounds of glycerin with one, two, or three molecules of acid, the other product being contained in natural fats, e.g., tristearin. Thus, with stearic acid and glycerin he obtained successively monostearin, distearin, and tristearin.
Whichever of the above esters was hydrolyzed, the product was glycerin. From these reactions Berthelot concluded that glycerin in organic chemistry corresponded to phosphoric acid in inorganic chemistry as alcohol corresponded to nitric acid. In other words, this was the beginning of the idea that, corresponding to polybasic acids in inorganic chemistry, there were polyatomic alcohols in organic chemistry. Berthelot’s younger contemporary and rival, Adolphe Wurtz, is sometimes given credit for this work, although Wurtz’s contribution in 1855 was to make the correct analogy between different salts of the same (ortho-phosphoric) acid rather than the three different acids of phosphorus to which Berthelot had referred. Berthelot’s most important contribution in his work on glycerin was to introduce the concept (and name) of polyatomic alcohols, but hardly less important was his synthesis of stearin and palmitin, the chief constituents of ordinary hard fats. He also carried out further work on the esterification of glycerin, some of it in collaboration with his pupil S. de Luca.
One of the earliest of Berthelot’s triumphs in his program of synthesis was in the preparation of alcohol. This was, of course, traditionally the product of fermentation of sugars with yeast; but in 1854 Berthelot showed that it could be prepared from ethylene. When ethylene was subjected to prolonged and vigorous shaking with sulfuric acid, it dissolved; and when the product was heated with water and distilled, the alcohol passed over. An obvious objection to this preparation was that the ethylene had itself been obtained from alcohol. Berthelot therefore obtained ethylene from coal gas as ethylene iodide by passing the crude gas into a solution containing iodine. Hennel had already suggested in 1828 thatethylene could be converted to alcohol by treatment with sulfuric acid but had been criticized by Liebig, so that most chemists in the mid-nineteenth century regarded the possibility of this conversion as doubtful. The fact that previous work had been done on the subject was emphasized by Chevreul in an attack on Berthelot, who had neglected to mention this. By a similar method Berthelot synthesized isopropyl alcohol from propylene.
Berthelot then synthesized methane (contaminated with a little ethylene) by passing a mixture of carbondisulfide vapor and hydrogen sulfide over red-hotcopper. Then in 1857, by reacting methane with chlorine, he obtained methyl chloride, which, on hydrolysis, formed methyl alcohol. There is an obvious parallel between the success of Cannizzaro two years earlier in obtaining benzyl alcohol from toluenevia benzyl chloride. Berthelot, nevertheless, achieved the first true synthesis of an aliphatic alcohol, and in 1858 he summarized his achievements in a long table, “Sur la synthèse des carbures d’hydrogène,” in which he described his preparation of the hydrocarbons methane, ethylene, propylene, butylene, amylene, ethane, and propane, as well as benzene and naphthalene.
Berthelot opened a new field when he carried out a systematic investigation of hydrocarbons obtained by heating suitable substances in the temperature range from red to white heat. His most famous experiment was that in which he heated acetylene in a glass tube; polymerization took place, forming benzene with some toluene. This was the first demonstration that it was possible to effect a simple conversion of an aliphatic to an aromatic compound. By passing benzene vapor through a red-hot iron tube filled with broken glass, Berthelot obtained diphenyl. Similarly, he obtained styrolene and naphthalene from benzene and acetylene, and acenaphthene from naphthalene and ethylene.
Berthelot’s last major research in organic chemistry was the application of hydrogen iodide as a reducing agent - he called it “une méthode universelle d’hydrogenation.” His publications on this research covered the period 1867–1870. Although he claimed that they were a continuation of work published in 1855, it must be mentioned that meanwhile Lautemann had already used hydrogen iodide as a reducing agent in organic chemistry. Berthelot, anxious to carry out even the most difficult reductions, was prepared to use concentrated hydriodic acid saturated at 0°C and heated with the substance to be reduced in an oil bath up to 280°C. He succeeded in reducing a large number of unsaturated aliphatic hydrocarbons. His results with aromatic hydrocarbons were less definite. His study of the mechanism of decomposition of hydrogen iodide provides a further link with his work in physical chemistry.
Berthelot enunciated the principle that the heat evolved or absorbed in a chemical change depends only on the initial and final states of the reactants and products, provided no external work is done. This is Berthelot’s “second principle,” analogous to Hess’s law of constant heat summation. He based this principle on the assumption of an equivalence between internal work (Ie travail moléculaire) and heat changes in a chemical reaction (Berthelot’s “first principle”). Best known is Berthelot’s “third principle,” or “law maximum work,” which was first published in its complete form in 1873: “Every chemical change accomplished without the intervention of energy from outside tends toward the production of a body or system of bodies which produce the most heat.” In the same publication Berthelot introduced the expression “principle of maximum work.”
Berthelot tried to improve the experimental technique of thermochemistry. Recognizing the unreliability of the mercury calorimeter used by Favre and Silbermann, for example, he used a water calorimeter and either a platinum reaction chamber or one made of glass to facilitate direct observation. By the use of a water jacket, a mechanical stirrer, and a thermometer reading to .005°C., he was able to carry out experiments accurately over small temperature ranges. After more than ten years’ research on thermochemistry, Berthelot published a major two-volume work for which he significantly chose the title Essai de mécanique chimique fondée sur la thermochimie.
He introduced the use of the bomb calorimeter, in which the gas under test was mixed with excess oxygen compressed to 20–25 atmospheres and then sparked. This method enabled him to determine heats of combustion with an accuracy hitherto unattainable. With his bomb calorimeter, Berthelot made a fundamental contribution to both pure and applied chemistry. This was immediately recognized, and a stream of foreign scientists came to Paris to acquire firsthand knowledge from Berthelot of the new thermochemical methods. Through Berthelot, his pupils, and such collaborators as Vieille and Recoura, there was established a substantial body of reliable data of heats of combustion, solution, neutralization, and so on. Berthelot’s continuing interest in thermochemistry is suggested by the publication in 1897, when he was seventy years old, of another two-volume work, Thermochimie. Données et lois’ numériques. He had already devoted to practical methods the smaller work Traité pratique de calorimétrie chimique (1893).
While serving as president of the scientific commission appointed to bring any possible aid from science to help in the defense of Paris during the Franco-Prussian War, Berthelot investigated the possibility within the city of extracting saltpeter for gunpowder. Also in November 1870 he presented to the Académie des Sciences three memoirs on explosives, which were published in full in the Comptes rendus under the heading “Art militaire.” Combining his patriotic duty as a Frenchman and his interest in thermochemistry, Berthelot showed how the power of explosive materials could be quantitatively expressed. He expanded this research in his book Sur la force des matières explosives d’après la thermochimie, first published in 1871 but greatly expanded in the two-volume definitive work published as a third edition in 1883. In the intervening period, Berthelot had made a particular study of the thermochemistry of nitrogen compounds used as the basis of explosives. But it was his work carried out in collaboration with Vieille that laid the foundations of a new scientific study of the mechanism of explosions. They found that explosions were propagated in a manner in many ways analogous to that of a sound wave.
Berthelot’s first study of animal heat was in 1865, and in this he followed the thermal tradition of Lavoisier and Laplace. In 1890 he took up the subject again, carefully distinguishing the heat produced in the lungs by the action of oxygen in the blood from the later reaction in which carbon dioxide is produced, and he was able to show that the former reaction produced only one-seventh of the total heat.
In other experiments, Berthelot was able to show that the combustion of foodstuffs in the laboratory produced no less heat than in the body. There was, therefore, no energy to relate to any vital force, a conclusion in which Berthelot took particular satisfaction. He opposed Pasteur’s vitalistic interpretation of fermentation, preferring a theory of fermentation fully analogous to that of inorganic catalysts, thus once more championing the view of the strict parallel between the organic and the inorganic.
In 1883 Berthelot founded a research establishment for vegetable chemistry, and during the last twenty-five years of his life he undertook research into aspects of chemistry useful to agriculture. He found that certain carbohydrates, such as cellulose, could be made to absorb nitrogen under the action of a silent electric discharge. By treating them with lime, the absorbed nitrogen was liberated as ammonia. He was able to demonstrate that the fixation of atmospheric nitrogen by sparking is parallel to the natural process in plants. In 1885 he made his first reference to microorganisms capable of fixing nitrogen and in 1893, in collaboration with Guignard, he succeeded in isolating and forming a culture of such bacteria. In accordance with his usual practice, he brought together work done by himself and his collaborators (particularly G. André) and published it in book form. The result was his Chimie végétale et agricole (1899). Berthelot’s last chemical book, Traité pratique de l’analyse des gaz (1906), concerned a subject he had studied practically from the time of his early syntheses of hydrocarbons.
Although Berthelot had been raised as a Catholic, his exposure to philosophy had led him to question his religion. Throughout his life, he resisted clerical influence in education and promoted a greater emphasis on science in the classroom. He was an atheist but was very influenced by his wife, who was a Calvinist.
Politics
Since the 18th century, scientists, particularly chemists, had played a role on the French political stage (a role that intensified during the French Revolution), and, through the 19th century, chemists held leading positions in successive French governments. This tradition culminated with Berthelot, who became a politician under the Third Republic. During the Franco-German War (1870–71), he was head of the Scientific Commitee for the Defense of Paris. This experience led Berthelot to a detailed study on the strength of explosives, which culminated in a two-volume publication in 1883. From 1881 Berthelot was a permanent member of the Senate, where he belonged to the Republican Union Party.
Views
Like Hermann Kopp, Berthelot took the view that alchemy had developed as a misunderstanding of the earlier empirical knowledge of Egyptian metalworkers. He and Kopp were the two nineteenth-century figures who were able not only to make outstanding contributions to chemistry but also to undertake an extensive study of its history.
Berthelot studied the transmission of ancient alchemy to the Middle Ages. He distinguished a practical tradition, exemplified by the Liberignium of Marcus Graecus, from a theoretical approach transmitted through Syriac and Arabic sources. He argued that the Latin author Geber was distinct from Jābir ibn Ḥayyān. In much of his alchemical studies, Berthelot was dependent on his collaborators, who translated the original Syriac and Arabic manuscripts. His interpretation was, therefore, not faultless.
He regarded it as unreasonable to assign limits to the possible progress of science. He foresaw a Utopia through science that could be realized by the year 2000. In this new world he considered chemistry to have a central place not only because of its almost unlimited powers of synthesis but also through the exploitation of agriculture and natural resources. Berthelot continually fought against clerical influence in education. He wanted a greater place for science in the school curriculum, but not at the expense of classical studies. The moral value of science for Berthelot lay not only in its respect for truth but also in its justification for work. Berthelot, like Claude Bernard, favored a positivistic philosophy. It was in this spirit of accepting only the observable that he regarded atomic and molecular theories with great suspicion.
Berthelot fought against the burdening of scholars with examinations, declaring it to be "one of the most foolish of ideas to use the time of inventive and distinguished men in order to give beginners an opportunity to utter nonsense."
Quotations:
"Chemistry is not a primitive science like geometry and astronomy; it is constructed from the debris of a previous scientific formation; a formation half chimerical and half positive, itself found on the treasure slowly amassed by the practical discoveries of metallurgy, medicine, industry, and domestic economy. It has to do with alchemy, which pretended to enrich its adepts by teaching them to manufacture gold and silver, to shield them from diseases by the preparation of the panacea, and, finally, to obtain for them perfect felicity by identifying them with the soul of the world and the universal spirit."
"I do not want chemistry to degenerate into a religion; I do not want the chemist to believe in the existence of atoms as the Christian believes in the existence of Christ in the communion wafer."
"Within a hundred years of physical and chemical science, men will know what the atom is. It is my belief when science reaches this stage, God will come down to earth with His big ring of keys and will say to humanity, 'Gentlemen, it is closing time."
Membership
Marcellin Berthelot was a Freemason. He was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1880. In 1881 he became a foreign member of the Royal Netherlands Academy of Arts and Sciences. He was also elected a member of the Académie Française.
American Academy of Arts and Sciences
,
United States
1880
Royal Netherlands Academy of Arts and Sciences
,
Netherlands
1881
Académie Française
,
France
Personality
He was one of those men who are permitted to witness the success of their work in full flower and who reap from this experience the strength for further undertakings. The wealth of his scholarly publications demonstrates the breadth of his scientific activity and his interest in the most varied subjects, not only within the realm of chemistry but far beyond its boundaries.
He never had many assistants, and those he did have were engaged solely in carrying out his own ideas.
Interests
history, philosophy
Connections
On 30 May 1861 Berthelot married Sophie Caroline Niaudet, a girl from a Protestant family and ten years Younger than he. His wife was a descendant of the famous clockmaker Breguet. The couple had six children. They were devoted to each other for forty-five years, and within an hour of the death of Sophie Berthelot, Marcellin, who had tended her night and day, also died. A special law was passed to permit Berthelot and his wife to be buried together in the Panthéon.