Michael Faraday

Michael Faraday was an English chemist and physicist who rose from a bookbinder's apprenticeship to become one of the most important experimental scientists of the 19th century. Working at the Royal Institution in London, he discovered electromagnetic induction, the principle behind the electric generator and transformer, and showed that electricity, magnetism and light are linked.

Faraday was born on 22 September 1791 at Newington Butts in Surrey, now part of south London. His father, a blacksmith from Westmorland, had brought the family to the capital the year before, and money was always short. Michael received only the most basic schooling. At 14 he was apprenticed to George Riebau, a bookbinder and bookseller in Blandford Street, and over seven years he read widely among the books that passed through the shop. Jane Marcet's Conversations on Chemistry fired his interest in science.

In 1812, as his apprenticeship ended, Faraday went to lectures by the chemist Humphry Davy at the Royal Institution. He wrote up his notes into a book of some 300 pages and sent it to Davy. When Davy injured his eyes in a laboratory accident the following year, he took the young man on, and on 1 March 1813 Faraday became chemical assistant at the Institution.

His early work was largely chemical. He liquefied several gases, made new compounds of carbon and chlorine, and discovered benzene, which he called bicarburet of hydrogen. He later worked out the laws of electrolysis and popularised the words anode, cathode, electrode and ion.

In 1821, shortly after the Danish scientist Hans Christian Ørsted had discovered electromagnetism, Faraday built a device in which a current-carrying wire turned continuously around a magnet, an ancestor of the electric motor. His decisive breakthrough came in 1831. Winding two coils of wire around an iron ring, he found that switching on a current in one produced a brief current in the other, and that moving a magnet through a loop of wire also generated a current. This electromagnetic induction made possible the dynamo and, eventually, the electric power industry.

In 1845 he showed that a magnetic field can rotate the plane of polarised light, now called the Faraday effect, and that many materials are weakly repelled by magnets, which he named diamagnetism. He thought in pictures rather than equations, and it was James Clerk Maxwell who later turned his lines of force into a mathematical theory.

In 1833 the Royal Institution made Faraday its first Fullerian Professor of Chemistry, a post held for life. He founded its Friday Evening Discourses in 1825 and between 1827 and 1860 gave nineteen of its Christmas lectures for young people, including the celebrated series on the chemical history of a candle in 1848.

He also gave his expertise to government and industry. He worked on lighthouses and, in 1846, with the geologist Charles Lyell, reported on a colliery explosion at Haswell in County Durham, pointing for the first time to coal dust as a cause. In 1855 he wrote to The Times about the filthy state of the River Thames. He declined, on ethical grounds, to advise on chemical weapons for the Crimean War.

Faraday belonged to the Sandemanians, a small Christian sect, and served as one of its elders. He married Sarah Barnard in 1821; they had no children. His beliefs led him to refuse a knighthood and, twice, the presidency of the Royal Society. In 1848 he was granted a grace-and-favour house at Hampton Court, where he lived in retirement from 1858 and died on 25 August 1867. He was buried in the dissenters' section of Highgate Cemetery.

The unit of capacitance, the farad, bears his name, and Albert Einstein kept a picture of him on his study wall.

Faraday's career unfolded in the United Kingdom during the Industrial Revolution. Our 1815 map shows Britain as he was beginning work under Davy, and the 1878 map shows the country in the decade after his death, with London at the centre of a global empire.