Davy, SIR HUMPHRY, one of the greatest chemists, was born 17th December 1778, at Penzance, Cornwall, where his father was a carver in wood. At the school at Penzance, and afterwards at Truro, he developed a taste for storytelling, poetry, and angling, and for experimental science, in which he was aided by Dunkin, a saddler. In 1795 he became apprentice to a surgeon and apothecary in Penzance, wrote verses, and indulged in chemical experiments. He at the same time entered upon a course of study all but universal. 'Speculations on religion and politics, on metaphysics and morals, are placed in his notebooks in juxtaposition with stanzas of poetry and fragments of romance.' The study of natural philosophy brought him near to that department which was to be his own; but it was not till he had reached his nineteenth year that he entered seriously upon the study of chemistry. He was then introduced to the notice of Dr Beddoes (q.v.), who in 1798 established a Pneumatic Institute at Clifton, and took him as his assistant. Here he made the acquaintance of the Earl of Durham, of Coleridge, and Southey, and carried on a course of experiments on the respiration of different gases, in which he had more than once nearly sacrificed his life. He thus discovered the singular exhilarating effect of nitrous oxide when breathed. The account which he published in his Researches Chemical and Philosophical (1799), although afterwards regretted, established his reputation, and led to his appointment, at the age of twenty-two, as lecturer to the Royal Institution of London. He delivered his first lecture in 1801; and his eloquence, and the novelty and variety of his experiments, soon attracted crowded and brilliant audiences. In 1803 he began researches connected with agriculture, on which he delivered a course of epoch-making lectures, which were published under the title of Elements of Agricultural Chemistry (1813). The discoveries, however, on which Davy's fame as a chemist chiefly rests, took their origin in the views which he developed in 1806, in his Bakerian lecture, On Some Chemical Agencies of Electricity. This essay was universally regarded as one of the most valuable contributions ever made to chemical science, and obtained the prize of the French Institute. Following out his principle, he was led to the grand discovery that the alkalies and earths are compound substances formed by oxygen united with metallic bases. It was potash that he first suc- ceeded in decomposing, on the 19th October 1807. When he first saw the globules of the new metal, potassium, his delight is said to have been so ecstatic that it required some time for him to compose himself to continue the experiment. He next decomposed soda and the alkaline earths, baryta, strontia, lime, and magnesia; and discovered the new metals, sodium, barium, strontium, calcium, and magnesium. With regard to the earths proper, he succeeded in proving that they consist of metals united to oxygen. It was reserved for Wöhler and others to exhibit the metals by themselves. He lectured in Dublin in 1808-9, and received the honorary degree of LL.D. from Trinity College.
On 8th April 1812 Davy was knighted; he married Mrs Apreece, a lady of considerable wealth, daughter and heiress of Charles Kerr of Kelso, and resigned the chemical chair of the Royal Institution, April 1813. In order to mark the high sense of his merits, he was elected honorary professor of Chemistry. He discovered the talents of Faraday (q.v.), for whom he secured the appointment as assistant in the laboratory of the Royal Institution. That he might investigate his new theory of volcanic action, he received permission from the French government—though the two countries were then at war—to visit the Continent, and was received with the greatest distinction by the scientific men of France. He was accompanied by Faraday. On returning to England in 1815, he entered on the investigation of the nature of fire-damp, which is the cause of explosions in coal-mines. This resulted in the invention of the Safety-lamp (q.v.). A public subscription of about £1500 was collected as a testimonial by those interested in 1817, and he was entertained to dinner, and presented with a service of plate. He was created a baronet, 20th October 1818. On the death of Sir Joseph Banks in 1820, Sir Humphry Davy was elected President of the Royal Society. In 1820-23 his researches on electromagnetism were communicated to the Society. He invented an ingenious plan for preventing the corrosion of the copper-sheathing of ships by altering the electric condition of the copper by means of bands of zinc; but the bottoms of the vessels became so foul from the adhesion of weeds and shells that the plan had to be abandoned.
Early in 1825 Sir Humphry Davy had begun to complain of the loss of strength, and in 1826 he had an apoplectic attack. He made two journeys to the Continent for the recovery of his health, and died at Geneva on the 29th May 1829, at the early age of fifty-one. The Genevan government evinced their respect by a public funeral. He was a member of almost all the scientific institutions in the world. Cuvier, in his Éloge, says: 'Davy, not yet fifty-two years of age, occupied, in the opinion of all that could judge of such labours, the first rank among the chemists of this or of any other age.' Another critic has said: 'He was not only one of the greatest, but one of the most benevolent and amiable of men.' His widow placed a tablet to his memory in Westminster Abbey, and a statue was erected to him in Penzance. Besides the works already mentioned, and a great number of contributions to the Philosophical Transactions, Sir Humphry Davy was author of Elements of Chemical Philosophy (1812); On the Safety-lamp in Coal-mines (1818); Salmonia, or Days of Fly-fishing (1828); and Consolations in Travel (1830)—all included in his Collected Works (9 vols. 1839-40).
See Memoirs of the Life of Sir Humphry Davy, by his brother, John Davy (1836); his Fragmentary Remains (1858); the Life by Dr Paris (1831); and that by Dr T. E. Thorpe (1896).