Berthelot, Pierre Eugène Marcelin

Born Oct. 25,1827, inParis;diedMar. 18,1907, in Paris. French chemist and public figure. Professor of chemistry at the Higher Pharmaceutical School in Paris (1859) and the Collège de France (1864). Member of the Paris Academy of Sciences (1873) and its permanent secretary (1889). Corresponding member of the St. Petersburg Academy of Sciences (1876). Minister of education (1886–87) and foreign affairs (1895). Berthelot was the author of numerous works on organic chemistry, thermochemistry, agrochemistry, the history of chemistry, and so on.

Berthelot synthesized a huge number of organic compounds belonging to various classes and thereby dealt the final blow to concepts of a life-force. By the interaction of glycerin and fatty acids, Berthelot produced analogues of natural fats (1853–54) and thus proved the possibility of their synthesis. At the same time, he established that glycerin was a triatomic alcohol. The synthesis of ethyl alcohol by the hydration of ethylene in the presence of sulfuric acid (1854) was of great importance; until this time ethyl alcohol had been produced only by the fermentation of sugar substances. Another area of Berthelot’s work was the synthesis of many of the simple hydrocarbons—methane, ethylene, acetylene, benzene—and later, on the basis of these, the synthesis of more complicated compounds. Berthelot laid the foundation for the study of terpenes. In 1867 he proposed a general method for the reduction of organic compounds by hydrogen iodide.

Berthelot generalized his studies in organic chemistry in many monographs in which he showed that chemistry had no need of a life-force and that any organic compound could be produced by means of material factors.

From 1861 to 1863, Berthelot, in collaboration with the French chemist L. Péan de Saint-Gilles (1832–63), published studies of the rate of formation of complex esters from alcohols and acids. These studies occupy an important place in the history of chemical kinetics. Berthelot deserves an honored place among the founders of thermochemistry. He conducted extensive calorimetric studies leading in particular to the invention of the calorimeter bomb in 1881. He also introduced the concepts of exothermic and endothermic reactions. Berthelot studied the action of explosive materials; the temperature of explosion, the rate of combustion, and the diffusion of explosion waves. He elucidated the importance of carbon, hydrogen, nitrogen, and other elements in plants and indicated the possibility of the fixation of free nitrogen by soil containing microorganisms but not covered with vegetation.

In 1885, Berthelot’s work The Origin of Alchemy was published. Between 1887 and 1893, Berthelot published collections of ancient Greek, western European (Latin), Syrian, and Arabic alchemic manuscripts with translations, commentaries, and criticism. Berthelot is the author of the book Revolution in Chemistry: Lavoisier (1890).

Berthelot was in close contact with A.M. Butlerov. He met with D. I. Mendeleev, V. F. Luginin, P. D. Khrushchev, V. V. Markovnikov, and others; several of them worked for a long period in his laboratory. Beginning in 1876, Berthelot devoted himself to educational problems; he was general inspector for higher education, and from 1886 to 1887, minister of national education. In 1870, during the German siege of Paris, Berthelot headed a scientific committee for the defense of Paris which performed a great deal of work in the search for explosive materials, in the casting of long-range guns, and in the preparation of other means for the defense of the city.

Berthelot continued in the traditions of the enlightener-encyclopedists of the 18th century and fought for the broadening of education and the union of natural science and philosophy. As a consistent atheist, Berthelot earned the hatred of clerics. Deeply believing in the transforming power of science, Berthelot thought that with its help even social problems could be solved without revolutionary upheaval.

Although he was the author of celebrated “chemical syntheses” and a broadly educated scientist, Berthelot was inconsistent in many instances and permitted methodological errors in his opinions. Recognizing the important role of science, he nevertheless belittled the significance of theory in the development of natural science. For a long time Berthelot persistently rejected the atomicmolecular theory, the theory of chemical structure, the periodic law, and the theory of electrolytic dissociation. He felt that concept of the molecule to be imprecise; of the atom, hypothetical; and of valence, an illusory category. However, since he was an authentic scientist, he found within himself, late in life, when he was bathed in glory, the courage to renounce his former ideas and espouse progressive attitudes. He expressed his renunciation in the following words: “The main obligation of a scientist is not to attempt to prove the infallibility of his opinions, but to always be ready to reject any outlook that cannot be proved and any experiments which turn out to be mistaken” (Iu. S. Musabekov, Marselen Bertlo, 1965, p. 213).