DAVY, SIR HUMPHRY, must be re garded as one whose discoveries have afforded important aid to manufacturing industry, al. though relating in the first instance to scien tific chemistry. He was born at Penzance in 1778. His father was a carver in wood. In the year 1795 he was apprenticed to Mr. Bor lase, a surgeon and apothecary of Penzance, where he appears to have laid down an exten sive plan of study, not merely of the sciences which related to his profession, but the learned languages, mathematics, history, &e. In 1798 he was considered competent by Dr. Beddoes to take charge of an establishment which he had founded at Bristol under the name of the Pneumatic Institution. In the next two years he wrote several essays on chemical subjects ; and in 1801 he came to London, and on the 25th of April he gave his first lecture at the Royal Institution. He began with the history of galvanism, detailed the successive discove ries, and described the different methods of accumulating it; and on the 31st of May, 1802, he was appointed professor. From the year 1800 to 1807 a great variety of subjects a• tracted his attention, especially galvanism and electro chemical science; the examination of astringent vegetable matter in connection with the art of tanning ; and the analysis of rocks and minerals with relation to geology and to agricultural chemistry. In November 1807, his second Bakerian Lecture was read, in which he announced the most important and unexpected discovery of the decomposi tion of the fixed alkalies by galvanism, and of the metallic nature of their bases, to which he gave the names of potassium and sodium.
From the year 1808 to 1814, twelve papers by Davy were read before the Royal Society, and published iu their ' Transactions,' relating to various chemical and electro-chemical subjects, and all containing details of original and im portant researches. He showed that the earths barytes, strontian, lime, and magnesia, are oxides of metals, and he laid the founda tion which has enabled ether chemists to prove the same thing in respect to other earths. He made important additions to the existing knowledge concerning sulphur, phosphorus, carbon, chlorine, and alkalies, and indeed ex tended almost every department of chemical science. In 1810 he published the first volume of his 'Elements of Chemical PhilosOphy,' which, although it bears marks of baste, con tains much interesting matter : no further por tion of this work was printed. His elements of Agricultural Chemistry,' which appeared soon after, is a work containing much useful mat ter, and replete with sound and practical views of the subject. One of his greatest inventions was that of the miner's safety-lamp, the first paper in relation to which appeared in the ('Philosophical Transactions' for 1815, and the last in 1817.
All Davy's discoveries have since been turned to account in industrial processes, especially in manufacturing chemistry. This great chemist died in 1829.