Gay-Lussac

Gay-Lussac, LOUIS JOSEPH, chemist and physicist, was born 6th December 1778, at St Léonard (Haute Vienne). Entering the Polytechnic School in 1797, he was in 1801 promoted to the department of Ponts et Chaussées; and shortly afterwards Berthollet selected him as his assistant in the government chemical works at Arcueil. He now began a series of original researches on the dilatation of gases, the tension of vapours, the improvement of thermometers and barometers, the density of vapours, hygrometry, evaporation, and capillary action. Next, first with Biot, and a month later alone, he made two balloon ascents for the purpose of investigating the temperature and moisture of the air and the laws of terrestrial magnetism. Along with Alexander von Humboldt he analysed the properties of air brought down from a height of nearly 23,000 feet, and their joint memoir to the Academy of Sciences (read 1st October 1804) contained the first announcement of the fact that oxygen and hydrogen unite to form water in the proportion of one volume of the former to two volumes of the latter (see ATOMIC THEORY). This result induced him to study the combining volumes of other gases, and thus led him to the important discovery of the law of volumes, which was announced in 1808. A year later he was appointed professor of Chemistry at the Polytechnic School, and from 1832 also filled the corresponding chair in the Jardin des Plantes. Davy's discoveries of potassium and sodium, by the decomposing action of the voltaic pile, stimulated Gay-Lussac and Thénard to pursue this class of researches. The results appeared in their Recherches Physico-chimiques (2 vols. 1811). Amongst the most important of the discoveries announced in these volumes were a purely chemical process for obtaining potassium directly, the separation of boron from boracic acid, and new and improved methods of analysing organic compounds. (Boron was, however, simultaneously discovered in England by Davy.) Although the discovery of iodine (in 1811) is due to Courtois, Gay-Lussac shares with Davy the merit of having (in 1813) first described its distinctive properties, and proved that it is an elementary body; he was also the first to form synthetically the compounds of iodine with hydrogen and oxygen, known as hydriodic and iodic acids. In 1815 he succeeded in isolating the compound radicle Cyanogen (q.v.), the first known example of a compound body which will unite with elementary bodies in the same way as these unite with one another. Later in life he experimented upon fermentation, and in conjunction with Liebig made an examination of fulminic acid, and further improved the methods of organic analysis. From this time a good deal of his attention was given to the practical applications of chemistry. In this department his investigations regarding the manufacture of sulphuric acid (which led to the introduction of the Gay-Lussac tower, first erected by him for the recovery of waste oxides of nitrogen), his essays on the bleaching chlorides, his method of using the centesimal alcoholometer, and his improvements in assaying silver by the wet method by means of a standard solution of common salt, are the most important. In 1805 he was appointed a member of the Committee of Arts and Manufactures, established by the minister of Commerce, in 1818 superintendent of the government manufactory of gunpowder and saltpetre, and in 1829 chief assayer to the mint. In 1839 he was made a peer of France. From the year 1816 he was the editor, in association with Arago, of the Annales de Chimie et de Physique. He died at Paris, 9th May 1850. As a chemist Gay-Lussac is distinguished by great accuracy, descriptive clearness, and undoubted genius. A complete list of his papers is given in the Royal Society's catalogue. His larger works, besides that already mentioned, include Mémoires sur l'Analyse de l'Air Atmosphérique (1804), Cours de Physique (1827), and Leçons de Chimie (1828).