John Rennie was born at Phantassie, near East Linton, East Lothian, on 7 June 1761. He was the son of a farmer but showed an interest in mechanics from an early age, often spending time in the workshop of Andrew Meikle (1719-1811) the millwright and inventor of the threshing-machine. He was educated at a local school in Prestonkirk and then in Dunbar, and studied at Edinburgh University until 1783. After his education, Rennie worked as a millwright and established his own business. In 1784 he went to England, visiting James Watt in Staffordshire, and then took charge of the works at Albion Flour Mills in Blackfriars, London, for which Boulton and Watt were building a steam-engine. In 1791 he established himself as a mechanical engineer, setting up in business in Blackfriars. Rennie then directed himself towards canal construction, carrying out work on the Kennet and Avon Canal, the Rochdale Canal, the Lancaster Canal, and the Royal Canal of Ireland. He was also involved in the extensive drainage operations in the Lincolnshire Fens, the construction of the London docks, the East and West India Docks, Holyhead harbour, Hull docks, Ramsgate harbour, and the dockyards at Sheerness and Chatham. Rennie also worked on the construction of bridges and was involved with bridges in Kelso and Musselburgh in Scotland, and the former was his blueprint for Waterloo Bridge. He also designed London Bridge (completed after his death) and Southwark Bridge. Rennie gave advice during the construction of Bell Rock Lighthouse, built between 1807 and 1810 (off the Angus coast near Arbroath). His most imaginative and enduring work is probably the colossal breakwater at Plymouth, constructed across the Sound in deep water. Rennie had been elected a Fellow of the Royal Society on 29 March 1798. John Rennie died on 4 October 1821, and was buried in St. Paul's Cathedral.
Rennie's second son, Sir John Rennie (1794-1874) was born in London. He acquired his engineering skills in his father's firm and assisted in the building of Southwark Bridge. He worked in partnership with his brother, George Rennie. His most important undertaking was the building of London Bridge, opened in 1831. Rennie was knighted the same year. Like his father, he carried out work for the Admiralty, and also in the Lincolnshire Fens. He and his brother also conducted some early railway work, and in 1852 he laid out a system of railways for Sweden for which he received the Swedish Order of Gustavus Vasa (riddare av Kungl. Vasaordern).
From the guide to the Papers of John Rennie (1761-1821), 1791-1817, (Edinburgh University Library)
