Humphry Davy

Born Dec. 17, 1778, in Penzance; died May 29, 1829, in Geneva. English chemist and physicist.

In 1798, Davy became a chemist at the Medical Pneumatic Institution. In 1801 he became an assistant lecturer and in 1802 a professor at the Royal Institution. Beginning in 1820 he was president of the Royal Society of London. M. Faraday studied and began to work under Davy. In 1799, Davy discovered the intoxicating effect of nitrous oxide, which was called laughing gas. In 1800 he proposed an electrochemical theory of chemical affinity, later worked out by J. Berzelius. In 1807 he obtained metallic potassium and sodium by electrolysis of their hydroxides, which were considered to be undecomposable substances. In 1808 he obtained by means of electrolysis amalgams of calcium, strontium, barium, and magnesium. Independently of J. Gay-Lussac and L.-J. Thénard, Davy isolated boron from boric acid and in 1810 confirmed the elemental nature of chlorine. He proposed the hydrogen theory of acids, refuting the view of A. Lavoisier that each acid must contain oxygen. In 1808-09, Davy described the phenomenon of the so-called electric arc. In 1815 he designed the miner’s safety lamp with wire gauze. In 1821 he established the dependence of the electrical resistance of a conductor on its length and cross section and noted the dependence of electrical conductivity on temperature. Between 1803 and 1813 he delivered a series of lectures on agricultural chemistry. Davy expressed the thought that mineral salts are necessary for the nourishment of plants and pointed to the necessity of field experiments for solving problems in agriculture. In 1826 he became an honorary foreign member of the St. Petersburg Academy of Sciences.