Woolrich, John Stephen

SUBJECT AREA: Electricity, Metallurgy

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b. 1821 Birmingham, England

d. 27 February 1850 King's Norton, England

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English chemist who found in the electroplating process one of the earliest commercial applications of the magneto-electric generator.

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The son of a Birmingham chemist, Woolrich was educated at King Edward's Grammar School, Birmingham, and later became a lecturer in chemistry. As an alternative to primary cells for the supply of current for electroplating, he devised a magneto generator.

His original machine had a single compound permanent magnet; the distance between the revolving armature and the magnet could be varied to adjust the rate of deposition of metal. A more ambitious machine designed by Woolrich was constructed by Thomas Prime \& Sons in 1844 and for many years was used at their Birmingham electroplating works. Faraday, on a visit to see the machine at work, is said to have expressed delight at his discovery of electromagnetic induction being put to practical use so soon. Similar machines were in use by Elkington's, Fern and others in Birmingham and Sheffield. One of Woolrich's machines is preserved in the Birmingham Science Museum.

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Bibliography

1 August 1842, British patent no. 9,431 (the electroplating process; describes the magnetic apparatus and the electroplating chemicals).

Further Reading

1843, Mechanics Magazine 38:145–9 (fully describes the Woolrich machine). 1889, The Electrician 23:548 (a short account of a surviving Woolrich machine constructed in 1844 and its subsequent history).

S.Timmins, 1866, Birmingham and the Midland Hardware District, London, pp. 488– 94.

GW