Celebrating Great British Science

Frank James, Professor of the History of Science at the Royal Institution, has nominated Faraday’s electro-magnetic induction ring as his Great British Scientific breakthrough

After about ten years of searching Michael Faraday discovered electro-magnetic induction on 29th August 1831 in his basement laboratory at the Royal Institution in central London. The significance of this discovery is perhaps best illustrated by the celebrations held to mark its centenary. In 1931, the Royal Albert Hall hosted an exhibition for two weeks celebrating Faraday’s life and work at a time of increasing electrification, whilst the Prime Minister, Ramsay MacDonald, addressed a grand commemorative meeting including 25 winners or future winners of the Nobel Prize. What these enormous celebrations signified was the recognition that Faraday’s discovery of induction included his invention both of the electric transformer and generator, the critical devices that from the 1880s have permitted the electrification of the world.

[caption id="attachment_38541" align="alignright" width="200"] Michael Faraday (1791-1867), British chemist and physicist, holding a heavy glass bar which he used to show the action of magnetism on light. Despite lacking a formal education, Faraday made several major advances in the fields of chemistry, magnetism and electricity. He devised the first electric motor and equipment such as transformers and dynamos. He worked at the Royal Institution, London, where his lectures helped popularise science among the general public. Photographed in the 1850s by Maull and Polyblank as part of their 'Living Celebrities' series. The Faraday volume was published in October 1857.[/caption]

Despite several attempts to discover induction during the 1820s, it was not until 1831 that Faraday first observed it. He recorded his observation his laboratory notebook with the simple heading: ‘Expts on the production of Electricity from Magnetism, &c &c’. In the weeks before, though there is, frustratingly for the historian, no written record, Faraday had built his induction ring now on display in the Royal Institution’s museum. This sophisticated device, which would have taken him several days to make, is an iron ring wound with two coils of wire on opposite sides. On passing an electric current through one coil he induced a transient current in the other coil before the galvanometer needle returned to rest, while the wire adopted what Faraday called the electrotonic state. When he broke the circuit this electric tension was released and the needle registered a transient current in the opposite direction – this was, in effect, the first electric transformer. Faraday’s great insight here was that induction was a transient phenomenon – until then he and others had been seeking a continuous effect.

At the end of 1831, Faraday sought to induce an electric current in a wire from the rotation of the Earth. He tried first by laying out a 120 foot wire in the Royal Institution, but with no result. Just over a week later, after obtaining the permission of the King, William IV, Faraday repeated the experiment using just under 500 feet of wire at the pond in Kensington Gardens, again unsuccessfully. Finally, in mid-January 1832, using nearly 1,000 feet of wire he tried again at Waterloo Bridge, but did not obtain any effect.

Although this marked the end of the first phase of Faraday’s researches into electricity in the 1830s, it was his discovery of electro-magnetic induction that initiated an enormously creative decade for him. During the 1830s he changed the understanding of electricity from comprising one or two imponderable fluids, to arguing instead, especially following his construction of the first Faraday cage in 1836, that electricity was a form of force. In terms of both understanding and practical application, Faraday’s ring is thus one of the key objects in the development of both science and engineering.

Faraday's induction ring is currently on display in the Faraday Museum at the Royal Institution. More information here