Joseph Proust

Joseph Louis Proust (* September 26, 1754 in Angers, † July 5, 1826 ) was a French chemist.

Life and work

As the third son of a pharmacist Joseph Proust and his wife Marie Rosalie, born Sartre, Proust first completed a pharmacist trained by his father. His parents were married to each other since 30 April 1748. He attended a local College of Oratory, Collège des Oratoriens. After that he studied, among others in Paris at Hilaire Marin Rouelle (1718-1779) in the Jardin des Plantes chemistry and became his student. After his studies he worked first as a teacher at the Lycée du Palais Royal, and later in the function as chief pharmacist at the Hôpital de la Salpêtrière.

End of 1778 for the first time on Proust took his professional career in Spain, the country where he was to spend most of his professional life. From 1778 to 1780 he was professor of chemistry in the Real Seminario de Vergara. Proust remained only a short time in Vergara and returned in June 1780 back to France.

On December 11, 1781 Jean -François de Rozier Pilâtre founded the first museum of art ( musée technique), where he organized physical experiments and lectures on natural science especially for the noble audience. Until 1784 Proust taught chemistry at the musée technique. During this time in Paris Proust was closely associated with Pilâtre and collected aerostatic experiences ( hot air balloon). Both conducted a balloon flight on 23 June 1784 in Versailles.

At the request of the Spanish government of the year 1785, and by an agreement between the Spanish King Charles III. (Spain) and France's Louis XVI. and to a recommendation by Antoine Laurent de Lavoisier Proust began again chemistry in Spain zulehren. The offering consisted of a financially lucrative for him items and so he went in 1786 to Spain again. He first taught in Madrid, but in 1788 he moved to Segovia as a professor of chemistry at the Real Colegio de Artillería de Segovia, where the chemical had been made ​​a compulsory subject. Proust taught and experimented there and also led by more geological and mineralogical investigations and analyzes for the government.

From the year 1791, he was then held the same position in Salamanca and in consequence, in April 1799, again in the Spanish capital. On a Saturday, June 30, 1798 married Proust, who lives in Segovia French Roseanne Chêtelain Daubigné († 1817). Both had no children.

In Madrid it was a newly organized chemical laboratory, which was one of the best existing facilities available. This laboratory was destroyed during the occupation by Napoleonic troops. Proust returned early as the end of 1806 for reasons unclear to France. He first lived in modest circumstances in Craon ( Mayenne ) and spent much time in his family, which he had taken in the Loire Valley, Val de Loire. Proust and his wife suffering around the year 1810. She died in 1817 and Proust moved his center of life again to Angers, where he led the pharmacy of his brother François Jacques Proust ( 1756-1808 ), who was in poor health took over in 1820.

Scientific achievements

He formulated the law of constant proportions to one of the basic chemical principles. The formulation of the law, in its various versions between 1794 and 1799, brought him into a public dispute with another French chemist Claude Louis Berthollet, who defended the variability in the composition of the compounds.

« Deux ou plusieurs corps Lorsque simple s'unissent pour former un composé défini, leur combinaison s'effectue toujours selon un même rapport Ponderal. »

"If two or more simple substances constitute a particular chemical compound combined, the combination is always to be understood along a constant weight ratio and characteristic mass ratio. "

He dealt with the chemistry of the tannin (1798 ) and citric acid ( 1801). More food chemistry problems were taken up by him, 1802, the detection of glucose in the must he succeeded. The carbohydrate chemistry and, in particular, the sugar was absorbed in the years 1806-1809. 1818 found the cheese making his interest. He discovered the amino acid leucine.

Proust was a leading analyst of his time and made after extensive studies on copper, tin oxides and iron sulfides, the law of definite proportions (see also Chemical reaction).

He also developed the hydrogen sulfide precipitation as an analytical method.

Honors

Works (selection)

• Annales de Historia Natural, along with Christian Herrgen, Domingo García Fernández and Antonio José Cavanilles, 1799
• Différentes observations de chimie (1805 )
• Mémoire sur le sucre de raisin (1808 )
• Recherches sur le meilleur emploi of patates, pommes de terre ou, Paris: Mme Huzard, juin 1818, in-8 ° ( uncertain )
• Sur une entre les eaux de analogy Remarquable quelques parties you gulfs de Californie et celles des lacs de Sodome et d' Urmia en Perse (1821 )
• Sur l' existence du mercure dans les eaux vraisemblable de l' Océan (1821 )
• Essai sur une des Causes qui peuvent amener la formation du calcul (1824 )