Of the men who were associated with Lavoisier in the creation of what was known at the period as the antiphlogistic chemistry, the most eminent was Berthollet.
Claude-Louis Berthollet was born in Savoy in 1748, and, after a medical education, became physician to the Duke of Orleans. Devoting himself to chemistry, in 1781 he was made a member of the Academy, and he became Government Commissary and Director of the Gobelins, the chief tinctorial establishment of France. Although in the main in agreement with Lavoisier, he never wholly subscribed to the idea that all acids contained oxygen. He discovered the bleaching power of chlorine, prepared potassium chlorate, and investigated prussic acid and fulminating silver.
In his Statique Chimique, published in 1803, he combated the partial and imperfect views of Bergman and Geoffroy with regard to the operation of chemical affinity, and showed that the direction of a chemical change is modified by the relative proportion of the reacting substances and the physical conditions—temperature, pressure, etc.—under which the change is effected. He was one of the first to draw attention to a class of phenomena known as reversible reactions, and gave a number of instances of their occurrence. Berthollet pushed his conclusions so far that he was led to doubt that chemical combination took place in fixed and definite proportions; and his views gave rise to a memorable controversy between him and Proust, in which the latter eventually triumphed.
Berthollet enjoyed a great reputation in his time, and played a considerable part in the political history of his country. It was largely to his zeal, sagacity, and skill in developing her internal resources at a critical period when she was hemmed round by foreign troops and her ports blockaded by British ships, that France was saved from conquest. His life was more than once in jeopardy when France was governed by a Committee of Public Safety; but his honesty, sincerity, and courage even impressed Robespierre, and he escaped the perils of the Great Terror. He was an intimate friend of Napoleon, and accompanied him to Egypt as a member of the Institute. He died at Arcueil in 1822.
Davy, who visited him at his country house in 1813, says of him:—
Berthollet was a most amiable man; when the friend of Napoleon, even, always good, conciliatory, and modest, frank and candid. He had no airs, and many graces. In every way below La Place in intellectual powers, he appeared superior to him in moral qualities. Berthollet had no appearance of a man of genius; but one could not look on La Place’s physiognomy without being convinced that he was a very extraordinary man.
Other notable men of this period were Fourcroy, Vauquelin, Klaproth, and Proust.
Antoine-François Fourcroy, the son of a pharmacist, was born at Paris in 1755, and started his career as a dramatic author. On the advice of Vicq d’Azir, the anatomist, he turned to medicine, and in 1784, by the influence of Buffon, obtained the chair of Chemistry at the Jardin du Roi, in succession to Macquer. He was an excellent teacher—clear, orderly, and methodical. He had, indeed, a talent for oratory. This he assiduously cultivated, and became one of the most popular lecturers of his time in France. Ambitious and time-serving, he became embroiled in the turbulent politics of the period, and, after a chequered career, died, embittered and disappointed, in the fifty-fourth year of his age. His chief services to science consisted in his works, Système des Connaissances Chimiques and Philosophie Chimique. These, no less than his public lectures, did much to popularise the doctrines of Lavoisier among his countrymen.
Louis Nicolas Vauquelin, the son of a Norman peasant, was born in 1763, and while a boy became assistant to an apothecary in Rouen. In 1780 he came to Paris, and entered Fourcroy’s laboratory. Much of the experimental work published in Fourcroy’s name was actually done by Vauquelin. He became a member of the Academy in 1791, Professor of Chemistry at the Mining School, Assayer to the Mint, and subsequently Professor of Chemistry at the Jardin des Plantes. On Fourcroy’s death he was made Professor of Chemistry of the Medical Faculty of Paris. Vauquelin was no theorist; he was, however, an excellent practical chemist, and one of the best analysts of the period. He made a large number of mineral analyses, more particularly for Hauy, the crystallographer. He discovered the element chromium in the so-called red-lead ore (lead chromate) from Siberia. He also first made known the existence of glucinum in beryl. He described a method of separating the platinum metals, and worked upon iridium and osmium. He investigated the hyposulphites, cyanates, and malates. He discovered the presence of benzoic acid in the urine of animals; with Robiqet, he first isolated asparagin; with Buniva, allantoic acid; and with Bouillon de la Grange, camphoric acid.
Vauquelin lived wholly for science, and had no other interests than in his laboratory. He was pensioned in 1822, and died at his birthplace—St. André d’Héberlot—in the sixty-sixth year of his age.