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History - People - Samuel Rideal

Samuel Rideal

Samuel Rideal
(1863 - 1929)

Assistant lecturer 1883 -1889

A leading analytical and consulting chemist in his day, Samuel Rideal may have worked with Ramsay. He is mentioned in the poem that Ramsay composed for Collie's promotion to a Chair in 1896 . He left UCL in 1889 to take up a lectureship in Chemistry at St George's Medical School.

Much of his work was in the area of water purification and disinfection. He is best remembered for the "Rideal-Walker test" (with J T Ainslie Walker published in in J. Sanit. Inst. 1903). This is still used to test the effectiveness of a disinfectant and you will often see a value quoted on bottles of "Pine" or "Dettol". A series of dilutions of disinfectant are tested with a typhoid broth culture (ie a suspension of live bacteria). Samples are taken at short intervals and dilutions are incubated on agar plates. The standard for this test (to which the results are compared) is carbolic acid (phenol).

His most famous book, published in 1903, was catchily entitled 'Disinfection and the preservation of food, together with an account of the chemical substances used as antiseptics and preservatives.' The entire book may be downloaded from the Cornell Library of Core Historical Literature of Agriculture and contains a detailed description of the Rideal-Walker test on pages 461 onwards.

He also wrote 'Sewage and the Bacterial Purification of Sewage' and with his son, E K Rideal, 'Water and its Purification' (1914).


He was president of the Society of Public Analysts 1918-1919.

He died at Hartley, N. Rhodesia (currently known as Chegutu in Zimbabwe) on 13 November 1929.

The portrait above is an oil painting by Arthur Trevor Hadden RA. There is also a portrait photo of him by Maul & Fox, artists and photographer to the Royal Family. This photo is undated, but is possibly from 1892 when Rideal was given the freedom of London and admitted to the Company of Fan makers!

Rideal was the father of (Sir) Eric Keightly Rideal (of Eley- Rideal fame), who we believe was a part-time lecturer at UCL.

Rideal's great-granddaughter is a lecturer at the Slade School and his great-great-graddaughter is in her second year (in 2003) of her Biochemistry degree at UCL - small world!

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This page last modified 20 September, 2010

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