British physicist and chemist, best known for his discoveries of electromagnetic induction and of the laws of electrolysis.
Faraday was born on September 22, 1791, in Newington, Surrey, England. He was the son of a blacksmith and received little formal education. While apprenticed to a bookbinder in London, he read books on scientific subjects and experimented with electricity. In 1812 he attended a series of lectures given by the British chemist Sir Humphry Davy and forwarded the notes he took at these lectures to Davy, together with a request for employment. Davy employed Faraday as an assistant in his chemical laboratory at the Royal Institution and in 1813 took Faraday with him on an extended tour of Europe. Faraday was elected to the Royal Society in 1824 and the following year was appointed director of the laboratory of the Royal Institution. In 1833 he succeeded Davy as professor of chemistry at the institution. Two years later he was given a pension of 300 pounds per year for life. Faraday was the recipient of many scientific honors, including the Royal and Rumford medals of the Royal Society; he was also offered the presidency of the society but declined the honor. He died on August 25, 1867, near Hampton Court, Surrey.
Faraday's earliest researches were in the field of chemistry, following the lead of Davy. A study of chlorine, which Faraday included in his researches, led to the discovery of two new chlorides of carbon. He also discovered benzene. Faraday investigated a number of new varieties of optical glass. In a series of experiments he was successful in liquefying a number of common gases.
The research that established Faraday as the foremost experimental scientist of his day was, however, in the fields of electricity and magnetism. In 1821 he plotted the magnetic field around a conductor carrying an electric current. In 1831 Faraday followed this accomplishment with the discovery of electromagnetic induction and in the same year demonstrated the induction of one electric current by another. During this same period of research he investigated the phenomena of electrolysis and discovered two fundamental laws: that the amount of chemical action produced by an electrical current in an electrolyte is proportional to the amount of electricity passing through the electrolyte; and that the amount of a substance deposited from an electrolyte by the action of a current is proportional to the chemical equivalent weight of the substance.In experimenting with magnetism, Faraday made two discoveries of great importance; one was the existence of diamagnetism, and the other was the fact that a magnetic field has the power to rotate the plane of polarized light passing through certain types of glass.
In addition to a number of papers for learned journals, Faraday wrote Chemical Manipulation (1827), Experimental Researches in Electricity (1844-55), and Experimental Researches in Chemistry and Physics (1859).