- S. E. Fryer
- , revised by Arne Hessenbruch
Wimshurst, James (1832–1903), electrical engineer and shipwright, was born at Poplar, London, on 13 April 1832, the second son of the four sons and a daughter of Henry Wimshurst (1804–1884), engineer, and his wife, Rebecca (1802–1863). Henry Wimshurst's engineering practice was in steamships: he was one of those who built the Archimedes (launched 1838) and Iris, the first two screw-propelled ships. After education at Steabonheath House, a private school in London, Wimshurst was apprenticed at the Thames ironworks to James Mare. In 1853, on the completion of his apprenticeship, he obtained an appointment in London as a surveyor at Lloyds. On 28 November 1865 he married Clara Tribble, daughter of William Frederick Tribble, a builder; they had two sons and a daughter. Wimshurst was transferred to Liverpool in the same year to become chief of the Liverpool Underwriters' Registry, then a rival establishment to Lloyd's, but since incorporated with it. In 1874 he joined the Board of Trade as chief shipwright surveyor in the consultative department. He attended as its representative the international conference at Washington in 1890, and retired on reaching the age limit in 1899.
Through life Wimshurst devoted his leisure to experimental work, erecting at his house in Clapham large workshops, which he fitted up with various engineering appliances and where he also built electric lighting machinery. About 1878 he became interested in electrical influence machines, that is to say, machines which, through the turning of a winch, were made to amass static electricity. These machines were widely employed to produce sparks of up to 15 inches long. The sparks were not only the subject of scientific investigations, their bright colours (capable of lighting a room) also provided entertainment. Wimshurst himself organized regular meetings in his home where feasting was followed by dancing, cards, science, and smoking. The most efficient influence machines were painful to work but very powerful, sometimes altering the atmosphere of the room so that visitors left the room with pain in the ears and head. From 1860 onwards a number of new designs of influence machines were introduced. They all had a rotating insulated plate with conductors such as metal strips on which an electrical charge was induced and then given up by contact with an external conductor. Through the rotation of the plate this process could be repeated with comparative ease and speed. Several designs became associated with the name of the inventor such as the Varley, the Holtz, the Toepler, or the Carré.
From the early 1880s onwards, Wimshurst introduced modifications of a practical kind to the existing types and then he designed a new type which subsequently became known as the Wimshurst. It consisted of two circular plates rotating in opposite directions having metallic sectors on the outer faces of each. It was self-charging and more robust under all conditions of atmosphere. Wimshurst donated machines to Silvanus P. Thompson, electrical engineer and principal of the City and Guilds Central Technical College, the Charing Cross Hospital, the Royal Institution, and the Royal Society. In all he built more than ninety machines himself. Instrument makers such as Harvey and Peak also developed and sold Wimshurst machines. Wimshurst never took out a patent which he came to regret only, as he insisted, because he was consequently precluded from exercising control over the design or construction of inferior machines put upon the market in his name.
In 1896 Wimshurst found his machines to be an admirable means of exciting X-rays, and showed that for screen observation, where a steady illumination was desired, the steady discharge from one of his eight-plate influence machines was preferable to the intermittent discharge of the usual induction coil. His machines were also used in hospitals at the turn of the century for the production of powerful brush discharges, efficacious in the treatment of lupus and cancer.
Wimshurst also invented a vacuum pump using oil rather than mercury, an improved method for connecting lightships electrically with the shore station, and an instrument for ascertaining the stability of vessels. In 1898, in the wake of the Wimshurst machines' new-found importance in X-ray work, he was elected FRS. After his death, however, influence machines fell out of favour in X-ray work. He was a member of the Institution of Electrical Engineers, the Physical Society, the Röntgen Society, and the Institution of Naval Architects, and was a manager of the Royal Institution. He died at his home, 7 Crescent Grove, Clapham, London, on 3 January 1903.
- S. P. T. [S. P. Thompson], PRS, 75 (1905), 300–01
- S. P. Thompson, ‘The influence machine, from 1788 to 1888’, Journal of the Society of Telegraph Engineers, 17 (1888), 569–635
- J. Wimshurst, ‘Electrical influence machines’, Notices of the Proceedings at the Meetings of the Members of the Royal Institution, 12 (1887–9), 300–05
- J. Wimshurst, ‘Influence machines’, Archives of the Röntgen Ray, 4 (1899–1900), 16–23
- Journal of the Institution of Electrical Engineers, 32 (1902–3), 1157–9
- Nature, 67 (1902–3), 250
- resolution, Notices of the Proceedings at the Meetings of the Members of the Royal Institution, 17 (1902–4), 239
- Archives of the Röntgen Ray, 7 (1902–3), 66
- census returns, 1851
- CGPLA Eng. & Wales (1863) [Rebecca Wimshurst]
- CGPLA Eng. & Wales (1884) [Henry Wimshurst]
- m. cert.
- d. cert.
- private information (1912)
- private information (2004)
- Engineering (9 Jan 1903), 51–2
- WW (1903)
- ‘Electricity’, Encyclopaedia Britannica, 11th edn (1910–11)
- ICL, Silvanus P. Thompson MSS
Wealth at Death
£12,077 2s. 2d.: probate, 3 March 1903, CGPLA Eng. & Wales