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Faraday, Michael | Foale, William | Foster, John | Fresnel, Augustine |
Faraday, Michael

Faraday, Michael (1791-1867), British physicist and chemist who made major advances in the study of magnetism, electricity, and the chemical effect of a current.

He started his working life as a bookbinder, but in 1813 became laboratory assistant to Humphry Davy at the Royal Institution, where he eventually became director. Working as an analytical chemist, he discovered benzene in 1825 and prepared the first known compounds of carbon and chlorine.

He also investigated the composition of alloy steels and optical glasses. But his greatest achievements were in electromagnetism. In 1821 he constructed a simple form of electric motor, applying Hans Christian Oersted's discovery that electric currents produce a magnetic effect. After much research Faraday showed that the converse was also true--that a magnetic field can induce an electric current.

In 1831 he published his laws of electromagnetic induction and put them to practical use in the dynamo and the transformer, two inventions that are fundamental to large-scale electricity generation and supply.

His laws of electrolysis, published in 1834 and named after him, described the changes caused by electric current passing through liquids. Other discoveries included diamagnetism (a weak magnetic effect present in all materials), and the rotation of light waves by strong magnetic fields. Arguably one of the most outstanding experimental scientists, he refused a knighthood and the Presidency of the Royal Society because he feared that such honours would undermine his integrity and his intellectual freedom.

Electromagnetic induction, the production of an electrical potential difference (p.d.) or voltage across a conductor situated in a changing magnetic field. Faraday was able to describe this behaviour mathematically: he found that the size of the p.d. produced is proportional to the rate of change of the magnetic flux. This applies whether the flux itself changes in strength or the conductor is moved through it.

Electromagnetic induction fundamentally underlies the operation of generators, electric motors, and most other electrical machines, along with the complementary law ascribed to Andre-Marie Ampere, who in 1820 demonstrated that if a conductor carrying an electrical current is placed in a magnetic field at right angles to current flow, the conductor will experience a force on it at right angles to both field and current.





Foale, William  (Life Span Unknown)

Very little is known about this engineer, but he is recorded in the Trinity House archives as being the designer of the North Low light at Killingholme established in 1852.





Foster, John (1786-1846)

This engineer/architect was associated with another architect named Cockerell. He was appointed as the Chief Architect/Surveyor for the Corporation of Liverpool in 1824. He took over this position from his father who died the same year. He is recorded as being the designer for the Rock Lighthouse on the Mersey in 1830.





Fresnel, Augustine Jean (1788-1827)

French physicist and civil engineer. He took up the study of polarized light in 1814 and postulated that light moved in a wave-like motion, which had already been suggested by, among others, Christiaan Huygens and Thomas Young.

They, however, assumed the waves to be longitudinal, while by 1821 Fresnel was sure that they vibrated transversely to the direction of propagation, and he used this to explain successfully the phenomenon of double refraction. He invented a large lens, made up of a series of concentric rings, for lighthouses and searchlights (Fresnel lens).

He is accredited with the developement and invention of dioptric and catadioptric principles with glass.

His optical invention was originally based upon the refracting qualities of glass. Like an object viewed in water it looks distorted. This is the easiest way to understand refraction or the bending properties.

His original discovery relating to lenses appears to have been an accident, when he noticed how the sun's rays were concentrated or magnified as the beams passed through bull's eye panes of glass used in domestic windows. He also noticed how it singed the curtains.

Experiments were then carried out with prism shaped sections of glass laid along side a bull's eye pane of glass. It was then noticed that the sun's rays were redirected back through the central piece of glass, if these prisms were set at specific angles.

When first tested with a 20 candle power (candelas) oil lamp, it was recorded that the beam was increased by 500 times.

The first Fresnel optic was installed in the Corduan lighthouse in France on the 23rd July 1823.

The first Fresnel optic used in a Scottish light was in October 1825 by Alan Stevenson, the Engineer-in-Chief for the Commissioners of the Northern Lights.

The first Fresnel optic was not introduced to the Trinity House lights until 1836.