FAR'ADAY, :MICHAEL (1791-1867). A dis tinguished English chemist and physicist. He was born near London, the son of a blacksmith, and at an early age was apprenticed to a bookbinder. Ile devoted his leisure time to science, and, among other things, made experiments with an electrical machine of his own construction. In 1812 he was able to attend the chemical lectures of Sir H. Davy (q.v.), then at the zenith of his fame, and he ventured to send to Davy the notes he had taken. with a modest expression of his desire to be employed in some intellectual pursuit. Davy engaged him as his assistant at the Royal Insti tution, and later took him to the Continent as assistant and amanuensis. On their return to London Davy confided to him the performance of a number of important experiments, which led in his hands to the liquefaction of certain gases by pressure. Here he showed that extraordinary power and ingenuity which resulted in so ninny important discoveries, and rendered his name familiar to every student of physics. In 182-i he was elected to the Royal Society, and in the following year was appointed director of the laboratory of the Royal Institution, where later he was promoted to Davy's post of professor of chemistry. Faraday's first important discovery was the revolution of a magnetic needle around an electric current (1821), and ten years later came his work on magneto-electricity and induc tion. Following this came the discovery of the action of one current on another, when the de flection was observed as before, and also when a magnet was inserted or withdrawn in a coil cf wire. These discoveries naturally furnished the foundation for the development of magneto and dynamo machines. and other inventions of im portance. Faraday's researches in electrolysis are also of great value, and to him is due the dis covery that the amount of liquid decomposed is proportioned to the current passing through the solution, and that equal quantities of electricity decompose equivalent amounts of different electro lytes. To him we owe the terms 'anode' and 'cathode.' Ile was also the discoverer of 'specific inductive capacity,' or the measure of the electric attraction and repulsion exerted through various dielectrics or insulating substances. According to Faraday, both electrostatic and electro-magnetic induction takes place along curved lines, which he denominated 'lines of force.' Faraday dis
covered that the plane of vibration of a beam of polarized light is rotated under the influence of a powerful magnetic field. The phenomena of diamagnetism, or the repulsion of certain sub stances, were also carefully investigated by Fara day, and many valuable results obtained. In chemistry, also, where most of Faraday's early work was done, many important discoveries are to be recorded, including a number of new chem ical compounds. Of these perhaps the most im portant is an investigation on new compounds of carbon and hydrogen (Philosophical Transactions, 1825), inasmuch as it included the discovery of henzol, which is the basis of aniline dyes. He also carried on a number of experiments looking to the production of optical glass with unusual power of refraction; but while glass with an index of refraction of 1.866 was made, it did not prove available, on account of its softness.
Faraday was one of the most brilliant experi mentalists that science has ever known, and to him credit must be given for much that elec tricity has accomplished. The experimental work that he had done with such care furnished a basis for the mathematical and theoretical dis cussions of Maxwell, and his Experimental Re searches in Electricity ( 1839-55) contains a com plete record of his investigations. In 1835 Fara day received a pension of £300 a year for the rest of his life, and in 1836 he became the scientific adviser of Trinity House. By royal grant he occupied a house at Hampton Court. He was in vited to become the president of the Royal So ciety, hut declined the honor.
Faraday was a deeply religious man, belong ing to a small sect of Christians known as San demanians, and was generous and sympathetic to a high degree. His last years were marked by failing powers of mind and body, yet in spite of this some of his best work was accomplished shortly before his death. In addition to the Ex perimental Researches in Electricity (1839-55), he published Researches in Chemistry and Phys ics (1859), and many papers in the Proceedings of the Royal Institution and the Philosophical Maga;:ine. For his life and work. consult: -Jones, Life and Letters of h'araday (London, 1870) ; Tyndall, Farad-n1 as a Diseorerer (S(1 V(1., London, ; and Thompson, Michael h'araday: His Life and Work (London, 1898).