John Farey, Jr. (1791-1851) was a mechanical engineer. He was the eldest son of John Farey, Sr., the geologist, and was born at Lambeth, London 20 March, 1791. Details of his education are obscure, but he undertook a systematic study of the manufacturing industry of London between 1804-5. At the age of 14, in 1805 he began making drawings for Rees's Cyclopaedia.

Farey was polymathic in his interests and contributed text and drawings to a number of periodicals and encyclopaedias.

He worked as a consulting engineer for many well-known inventors of the later industrial revolution, and was a witness to a number of parliamentary enquiries, inquests and court cases, and on occasion acted as an arbitrator.

Farey wrote a Treatise on the Steam Engine (1827) which has been described as the finest work on technology published in the industrial revolution.

He died in Sevenoaks, Kent, on 17 July, 1851 and was buried in Highgate cemetery.

Reference

Woolrich, A. P., 'Farey, John, Jr.', in Biographical Dictionary of Civil Engineers , 2002, Vol 1, pp 223-224