John Dollond
John Dollond Achromatic doublet | |
---|---|
Spouse |
Elizabeth Sommelier (m. 1729) |
Children | 5 |
Awards | Copley Medal (1758) |
Scientific career | |
Fields |
John Dollond FRS (21 June [O.S. 10 June] 1706 – 30 November 1761)[1] was an English optician, known for his successful optics business and his patenting and commercialization of achromatic doublets.
Biography
Dollond was the son of a
In 1758 he published an "Account of some experiments concerning the different refrangibility of light" (Phil. Trans., 1758), describing the experiments that led him to the achievement with which his name is specially associated, the discovery of a means of constructing achromatic lenses by the combination of crown and flint glasses, reducing or eliminating chromatic aberration (distortion due to colour fringes). Leonhard Euler in 1747 had suggested that achromatism might be obtained by the combination of glass and water lenses. Relying on statements made by Sir Isaac Newton, Dollond first disputed this possibility (Phil. Trans., 1753), but subsequently, after the Swedish physicist, Samuel Klingenstierna (1698–1765), had pointed out that Newton's law of dispersion did not harmonize with certain observed facts, Dollond began experiments to settle the question.
Early in 1757 Dollond succeeded in producing achromatic refraction by the aid of glass and water lenses, and a few months later he made a successful attempt to get the same result by a combination of glasses of different qualities (see
In 1761, Dollond became the optician of King George III. He died of apoplexy on 30 November, of that year in London.[3]
Family
He married to Elizabeth Sommelier in 1729,[3] who had two sons and three daughters.[4] His daughter, Sarah Dollond, married his neighbour and friend, Jesse Ramsden.[5]
Priority of invention
A theoretical approach to reduce chromatic aberration was worked out by
Dollond appears to have known of the prior work and refrained from enforcing his patent.[7] After his death, his son, Peter, did take action to enforce the patent. A number of his competitors, including Bass, Benjamin Martin, Robert Rew and Jesse Ramsden, took action. Dollond's patent was upheld, as the court found that the patent was valid due to Dollond's exploitation of the invention while prior inventors did not. Several of the opticians were ruined by the expense of the legal proceedings and closed their shops as a result. The patent remained valid until it expired in 1772.[7] Following the expiry of the patent, the price of achromatic doublets in England dropped by half.[9]
See also
References
- ^ John Dollond at the Encyclopædia Britannica
- ^ public domain: Chisholm, Hugh, ed. (1911). "Dollond, John". Encyclopædia Britannica. Vol. 8 (11th ed.). Cambridge University Press. p. 392. One or more of the preceding sentences incorporates text from a publication now in the
- ^ a b "Boots Hidden Heroes - John Dollond". Boots UK. Retrieved 29 July 2023.
- ISBN 978-0-387-31022-0.
- ^ "Jesse Ramsden - Biography".
- ^ ISBN 978-1-74175-383-7.
- ^ ISBN 978-0-7134-0727-3
- S2CID 144123672.
- ISBN 0-7153-6354-9
External links
- Media related to John Dollond at Wikimedia Commons
- Encyclopædia Britannica. Vol. VII (9th ed.). 1878. p. 345. .
- "An account of some experiments concerning the different refrangibility of light", Phil. Trans., vol. 50, 1759, p. 733