Biographies of Scientific Men/Berthelot



IN 1827 the Government of Charles X. sent a fleet to the coast of Morea to join the English in putting a stop to the barbarous warfare between the Greeks and the Turks. De Rigny and Codrington, the two admirals, acted in concert in a battle fought in the Bay of Navarino, in which the Turkish fleet was destroyed. It will be remembered that Lord Byron, the poet, fought in this battle, and had the great pleasure of seeing Greece made an independent state. In the same year Pierre Eugène Marcellin Berthelot was born on 25th October 1827, at Paris, and for half a century was a most famous chemist, writer, and philosopher. He was the son of a distinguished physician, Dr Jacques Martin Berthelot, and received his education at the Lycée Henri IV. In early life he won an important prize at an open competition for philosophy, and then devoted himself to scientific studies, beginning with investigations on acids and fermentation. In 1851, at the age of twenty-four, he entered the Collège de France, as préparateur of the lectures on chemistry
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prof. m. berthelot

(under Balard, the discoverer of bromine). In 1854 he took his degree of docteur ès sciences with a remarkable thesis on the "Combinaisons de la Glycérine avec les Acides et Réproduction Artificelle des Corps gras neutres."

In 1859 he was appointed to the chair of chemistry in L'École de Pharmacie, holding the post for five years. In 1864 a new chair, that of organic chemistry, was created for him at the Collège de France, which he occupied until his death; and here it was that he worked with a determination unequalled by any other chemist. He produced over a thousand memoirs, embracing every department of chemistry. Although Wöhler, in 1828, produced urea artificially, and Kolbe synthetized acetic acid in 1845, Berthelot was undoubtedly the creator or founder of organic synthesis. Monsieur Henri Poincaré says of Berthelot that "c'est non seulement un grand chimiste, mais aussi un grand philosophe. Il possédait un esprit universel. Sa déouverte sur la synthèse des corps organiques suffirait pour immortalizer son nom. Ses travaux sur les corps explosifs ont rendu également au pays d'inappréciables services."

This remarkable man had "many irons in the fire," for he was not only a great chemist, but a politician, philosopher, and author.

The theories and discoveries of Berthelot are grouped round two great ideas—the synthesis of organic compounds, and the investigation of the laws of dynamical chemistry. Probably the most important syntheses of his are the production of acetylene from carbon and hydrogen, and methane or marsh gas, by means of the well-known Berthelot's reaction; and of dynamical chemistry, his most important discovery is "the law of maximum work." His scientific labours were immense, and he completely revolutionized chemistry in more departments than one. He transformed agriculture; proved that inorganic and organic bodies obey the same laws; established "la théorie des affinités"; and invented thermo-chemistry.

In 1861 he was awarded the Jecker prize by the Académie des Sciences for his researches on the syntheses of organic compounds. The first half of the nineteenth century was devoted to analytical chemistry—this being due to the great work of Berzelius. The second half, however, was the era of Berthelot or synthetical chemistry. Since his discovery of the synthesis of acetylene, a vast number of organic bodies have been discovered by the aid of synthesis; and there is no limit to these discoveries in organic chemistry. Tartaric acid, citric acid, alcohol, lactic acid, and a host of other compounds, both vegetable and animal, have been synthetized. It is not improbable that even albumen or protoplasm will yield to synthetical methods. It is quite within the bounds of possibility that chemistry some day will discover something that will make the world independent of wheat and meat. Berthelot believed in the possibility of wheat-growing and cattle-raising being superseded by the discovery of artificial substitutes for the necessaries of life. It may seem to the uninitiated a mere dream, but to the chemists this vision of the future is quite within the bounds of possibility. Chemistry in the past sixty years has done more to make mankind independent of Nature than all the other agencies in the world since the beginning of time. This is a big statement, but it is literally true. Chemistry, by its application to agriculture this past half-century, has doubled the world's producing power, has, in fact, put Nature in harness and made her do double work by the stimulation of growth.

It is only within the past sixty years that synthetic chemistry has come to take its proper place in the scientific world: what a powerful instrument of research it has proved; and this is due to the original stimulus given to it by Berthelot. Berthelot's idea of the synthesis of substances that will take the place of wheat and meat is the most audacious flight of fancy that scientific imagination has ever yet taken, but it need not, because of that, be classed among the impossibilities. Berthelot was justified by accomplished facts in stating that applied science has done more for mankind in the last three-quarters of a century than all the progress in all ages that preceded it. And yet, applied science is only in the first early dawn of its power.

Berthelot was quite sure that physics and chemistry would soon solve the problem of aerial navigation, and he significantly remarked that when they do so "custom-houses will fall of themselves." That would be something like a revolution in the world's institutions, but it would be second to the discovery of artificial wheat and meat.

Although glycerine was discovered by Scheele in 1779, and its formula established by Pelouze in 1836, it was not until 1854 that its true composition was known. This was due to Berthelot, who proved that it is an alcoholic compound capable of interacting with three molecules of such acids as acetic and palmitic.

In 1860 Berthelot's book, Chimie Organique fondée sur la Synthèse, was published. It was the first of its kind, being based entirely on synthesis. His methods were simple and direct. By means of the electric spark, carbon and hydrogen united to form acetylene; or by the action of electricity on a mixture of hydrogen and carbon monoxide, the same gas is formed; also by the action of the spark on a mixture of hydrogen with carbon disulphide vapour or cyanogen. The conversion of acetylene into ethylene, and the synthesis of alcohol were also important reactions. Acetylene polymerizes, under the influence of the electric spark, into benzene, and many of its derivations were formed by Berthelot. He also formed methane by passing the vapour of carbon disulphide and sulphuretted hydrogen over hot copper; and by the action of carbon monoxide on a hot solution of caustic potash, potassium formate was produced, the formate yielding formic acid on distillation with hydrochloric acid. He formed hydrocyanic acid by the action of the electric spark on a mixture of nitrogen and acetylene.

Such were a few of the numerous syntheses of Berthelot, or the building up of chemical compounds, many of which were only obtained through the instrumentality of life, either animal or vegetable.

His contributions to chemical literature range over practically every department of the science: philosophical, historical, physical, pure, and applied.

In 1864 Berthelot began his great work on thermo-chemistry, and in 1879 he published his Essai de Mécanique Chimique fondée sur la Thermo-chimie. Although Favre, Silbermann, Andrews, Hess, and Thomsen had previously worked on problems bearing on heat and chemical changes, Berthelot is generally looked upon as the founder of thermo-chemistry.

His laws are the following:—(1) The heat disengaged in any reaction is a measure of the chemical and physical work accomplished in the reaction. (2) The total thermal value of a reaction is dependent only on the initial and final states of the changing system. (3) "The Law of Maximum Work," or "the theorem of the necessity of reactions": every chemical change accomplished without the aid of external energy tends to the formation of a body, or system of bodies, the production of which evolves the maximum amount of heat. This law of Berthelot is of considerable importance, as it will often enable the chemist to decide beforehand whether a contemplated reaction is or is not possible by direct means, and if, because accompanied by absorption of heat, not possible in the direct way, it may enable him to bring it about by making it one of a series of reactions, the total effect of which is an evolution of heat. … This law is the fundamental principle of Berthelot's thermo-chemistry: "The quantity of heat evolved in a reaction measures the sum of the physical and chemical changes which occur in that reaction"—"ce principe fournit la mesure des affinités chimiques."

Berthelot's agricultural station and laboratory were at Meudon, and here experiments on vegetable soils, the fixation of atmospheric nitrogen in soils by the agency of microbes, the action of electricity on the growth of plants, etc., were conducted. Berthelot states that twenty-five pounds of nitrogen per annum per acre might be fixed by bacteria.

Berthelot's work on the explosive wave, his classical experiments on the union of carbon and hydrogen, and his work on thermo-chemistry have served as the starting-point of numerous investigations by other chemists in various parts of the world. Berthelot's genius and activity are unparalleled in the history of chemistry. In 1862 he published Leçons sur la Principes Sucrés; in 1863, Leçons sur l'Isomérie; and in 1864, Leçons sur les Méthodes Générales de Synthèse en Chimie Organique.

In 1889 he was elected Secrétaire perpétuel de l'Académie des Sciences, and thereby became the most influential man of science in the French capital. On the death of Pasteur, in 1895, he was elected a member of the Académie Française.

A few words about the world-famed Institut de France may not be out of place, as Berthelot was an illustrious member of that body. It was erected in the seventeenth century on the Quai Conti, opposite the Louvre. It is a handsome building, with a façade in the form of a crescent, flanked with wings, and surmounted by a dome. Five different academies (Berthelot belonged to two) have their homes here namely, the Académie Française (devoted to the superintendence of the French language), the Académie des Sciences (devoted to the sciences), the Académie des Belles-Lettres (devoted to the study of the ancient languages), the Académie des Beaux-Arts (for painting, sculpture, and music), and the Académie des Sciences Morales et Politiques (for moral philosophy and politics).

The Académie des Sciences was founded by Louis XIV.—the Royal Society of London being founded, about the same time, by Charles II.

During the siege of Paris, Berthelot was President of the Scientific Committee of National Defence, and was occupied in the manufacture of explosives, and in 1883 he published, in two volumes, his work, Sur la Force des Matières Explosives. It is a valuable contribution to the science of the subject.

His other books are: Science et Philosophie (1886); La Révolution Chimique Lavoisier (1890); Traité Pratique de Calorimetrie Chimique (1893); Thermo-chimie Données et Lois Numériques, in two volumes (1897); La Synthèse Chimique (1897); Science et Morale (1897); Renan et Berthelot, Correspondance (1898); Chimie Végétale et Agricole, in four volumes (1899); Chimie Animale, Principes Chimiques de la Production de la Chaleur chez les Étres Vivants, in two volumes (1899); Science et Education (1901); and several volumes on historical chemistry which will be alluded to later in this chapter.

Berthelot was also a politician, and he formed part of the Cabinet of Monsieur Goblet, as Ministre de l'Instruction Publique in 1885, and was also a member of the Bourgeois Cabinet as Ministre des Affaires Étrangeres in 1895. He was always a friend of England, and by his colleagues "was accused of having made too many concessions to this country." This led to Berthelot's retirement, as Baron de Mohrenheim of Eussia (that country being France's ally) was dissatisfied with him. There was no entente cordiale in those days, and Russia was jealous of any concession made to England! France's friends abroad were uneasy on the subject of her foreign policy, as she was caught coquetting with England and Italy, and it was asked whether her policy had suddenly changed. In those days Russian jealousy of England was everywhere visible, and every attempt was made by the Czar's Government to thwart her policy. It is all changed now, as Berthelot suggested, and England is on the best of terms with France and Russia.

Concerning the Boer War, the following details may be of interest. It was stated that after sending the ever-memorable telegram to Kruger in January 1896, the German Emperor made overtures to France with a view to assist the Transvaal, but the French Government offered to support England if Germany intervened in favour of the Boers. Having been asked whether the above statements were true, Berthelot replied, on 21st October 1899, as follows:—

I see no harm, no State secret at stake, to prevent me from answering your letter, or from authorizing you to publish this. While I was at the Quai d'Orsay events in the Transvaal did not fail to engage my attention from the humanitarian point of view, from that of our natural interests in Madagascar, and also from that of the important private interests concerned in the gold mines. I had occasion to correspond on this subject with our excellent Consul, Monsieur Aubert, and to give him all the help in my power. I also received the Envoy of the Boer Republic kindly, but without wishing to play with him that immoral game which consists in encouraging the weak in resistance in which one is not resolved to take part. Neither England nor Germany ever suggested to me an exchange of their views with those of the French Government on the question. I do not even remember what was the object of any conversation started either by Lord Dufferin, the Ambassador of England, or by Count Minister, the Ambassador of Germany, at my Wednesday receptions.

French sympathy was strongly enlisted in favour of the Transvaal, but France never dreamt of intervention in any form.

Berthelot had a remarkable memory, as the following words of one of his most intimate friends testify:—

One day I remember he was turning over before me the leaves of a copy of one of our important reviews. In a quarter of an hour he had reached the last page. I chaffed him, saying that he did not seem to attach much importance to its contents. He affirmed that he had read it. So I put him to the test, questioning him on each of the articles in the review. He replied without hesitation or error; he had actually read more than a hundred pages in a few minutes. Another recollection at the Académie des Sciences on one occasion someone made an allusion to a certain work, almost unknown, and two or three hundred years old. Berthelot gave the name of the author, mentioned the subject of the book, and indicated the place it occupied in the library of the Institut de France. I have seen at close quarters a good many illustrious men in my time, and there have only been three before whom I had the sentiment of grandeur: Berthelot, Renan, and Taine. What was most admirable about Berthelot was that, although he was universally acknowledged as a great scientist, he never lost his tenderness of heart. Madame Berthelot, it may be said, was all in all to him. He had often said that if she died he would not long survive her. But no one thought his prophecy would he realized so suddenly. His death is a great loss for the scientific world and for France, but it is a still greater loss for his friends.

Berthelot had a good heart in other circles than those of his own family. Although the most influential man of science in France, he greatly appreciated and aided the work of others. As an example of his goodness, it may be stated, en passant, that he presented over forty of the author's memoirs to the Académie des Sciences, all of which have been published in the Comptes Rendus de l'Académie des Sciences. Dozens, yea hundreds, of scientists owe Berthelot a deep debt of gratitude.

His public works will best attest his fame,
Whilst private worth adds value to his name.

Most of the honours awarded to men of science were bestowed upon Berthelot: besides these he was a Grand-Croix de la Légion d'Honneur (an order founded by Napoleon I.); Grand-Croix de l'Ordre Royal de Charles III. of Spain; Grand-Croix de l'Ordre Royal de l'Étoile de Roumanie; and he possessed other orders. Berthelot was made a senator for life. Life members of the French Senat are now fast dying out, and will become as extinct as the dodo.

Berthelot commenced his career in 1851—eight days before Louis Napoleon overthrew the Constitution by a coup d'état, and to commemorate the fiftieth anniversary (1851-1901), or his scientific jubilee, there was an imposing demonstration of esteem and regard organized in honour of the event. Representatives of all countries, academies, societies, universities, etc., were present at this great meeting of 24th November 1901. It was more like the vast gatherings of ancient times than one in these democratic days. It was held in the amphitheatre of the historic Sorbonne,[1] and here Berthelot received addresses and a beautiful gold medal (by Chaplain), the latter being subscribed for by most of the chemists of the world. The medal (the author possesses a replica in bronze of this medal) has on its obverse side a portrait of Berthelot in profile, and the following words: "Marcellin Berthelot. La Synthèse Chimique. La Science Guide l'Humanité"; and the reverse side pictures the great chemist at his table, Truth illuminating him with a torch, while France, holding a flag, presents him with a laurel crown. The inscription is as follows: "1851. Pour la Patrie et la Verité. 1901."

Not content with his great discoveries in every department of pure and applied chemistry, Berthelot produced the following unique and erudite books on historical chemistry:—Les Origines de l'Alchimie (1885); Collection des Alchimistes Grecs, in three volumes (1887-88); Introduction à la Chimie des Anciens et du Moyen Âge (1889); and La Chimie au Moyen Âge, in three volumes (1893): the first is an "essai sur la transmission de la science antique"; the second on "l'alchimie syriaque"; and the third volume is on "l'alchimie arabe." These historical works are of the most learned kind, necessitating laborious researches in the libraries of Leyden, London, and Paris. Manuscripts in the Bibliotheque Nationale, that of St Mark at Venice, the palæographs of the tenth century, the alchemical papyri of Leyden of the third century, the ancient philosophies of Syria, Arabia, Greece, and those of the Middle Ages, were all utilized by Berthelot in writing the works mentioned above.

Concerning these books the Société Alchimique de France addressed him, at his jubilee, in the following words:—

La Société Alchimique de France adresse à l'occasion de son glorieux Jubilé, à Monsieur Marcellin Berthelot, l'hommage de sa respectueuse et profonde admiration.

Elle's'incline devant le génie de Berthelot, qui a réellement constitué la Chimie Synthétique et qui écrit ce volume immortal: "Les Origines de l'Alchimie."

The Society was founded for the purpose of investigating the researches, doings and sayings of the old alchemists.

The Finale! On 18th March 1907 a terribly dramatic event occurred, for both Monsieur and Madame Berthelot died within a few minutes of each other.

On the afternoon of 18th March he attended a meeting of the Académie des Sciences. Returning, he went to his wife's bedside, and devoted himself to cheering her in her suffering. At half-past five he withdrew with his sons to his study. There, with tears in the old man's eyes and trembling voice, he said to them: "My boys, if your mother were to die I could not survive her." His sons returned to their mother's room while the savant set himself resolutely to work in an effort to forget his troubles.

A quarter of an hour later Madame Berthelot's illness came to a sudden crisis, and before her husband could be called she had passed away. The eldest son went to his father's study and informed him of Madame Berthelot's death. The scientist, who was sitting writing, turned round in his chair as his son entered. Hearing the terrible news, he gasped "Mon Dieu!" and fell back in his seat with his hands clasped over his eyes. A minute later his hands fell limply to his side. Berthelot was dead! The great chemist succumbed to heart failure in the eightieth year of his age.[2]

Berthelot received a public funeral, and his remains were placed in the Panthéon on 25th March 1907, side by side with those of his wife. The crowds which gathered to see the two bodies laid to rest together in the nation's great mausoleum proved the popularity and universal renown of Berthelot, who did perhaps as much for chemistry as Pasteur did for medicine, if not more; for not only did he open up new fields of inquiry and lead the way to innumerable discoveries and developments, but he practically founded new branches of science, namely, synthetic and thermo-chemistry. Berthelot was one of those "prodigious" men who honour every country and every epoch. He made science the highest and noblest end of man. With Berthelot science became a real creative power. He proved that organic and inorganic chemical laws are identical. He did not get so far, by the imperfect means at his disposal in his laboratory, as to create a leaf or a fruit, but he did produce certain essential parts of the whole. What a field did he open up to human activity! Chemistry at once created artificial substances akin to natural ones, and by leading the way in this immense field of discovery Berthelot placed himself in the foremost ranks of the benefactors of humanity.

A few words about the burial-place of Berthelot will form a suitable conclusion to the present chapter. The Panthéon (the Westminster Abbey of Paris) was the church of St Geneviève, and its foundation stone was laid by Louis XV. in 1764. In 1885 it was secularized, under the name it now bears, and all traces of religious worship were removed. The frescoes in the interior, by Puvis de Chavannes, Laurens, Cabanel, and others, are among the finest compositions of the nineteenth century. In the crypt were buried the remains of Voltaire, Rousseau, Mirabeau, Marat, Victor Hugo, and others; and it was Berthelot who, in 1897, was instrumental in having Voltaire's and Rousseau's sarcophagi opened to see if their bodies had been tampered with, as stated, but the great philosophers' remains had not been removed. Berthelot, in examining the remains of Rousseau, found fragments of the winding-sheet substances of an antiseptic and aromatic nature, such as are used in embalming, some teeth, and even a little hair still adhering to the frontal part of the skull, and forming a sort of crown, or tonsure, like that of monks.

  1. The Sorbonne was erected by Cardinal Richelieu in 1629. The amphitheatre is a splendid oak-panelled room, adorned with the celebrated fresco by Puvis de Chavannes.
  2. Berthelot and his wife were passionately attached to each other, and their married life was one of the most beautiful on record. As Monsieur Leygues said, addressing Berthelot: "Durant ces sombres jours (1870), votre courage fut soutenu par la femme éminente qui est la grace et le charme de votre foyer."