John Rennie, mechanical engineer

While John Rennie is now remembered as the leading civil engineer of his day, his contributions to mechanical engineering are largely forgotten. With his iron gearing and shafting, he had probably developed corn milling as far as was possible until the advent of roller milling in the 1880s. We have few details of the machinery he installed at places such as Kirkstall forge and the dockyard at Copenhagen and few drawings of his mechanical inventions have survived to enable us to judge them and compare them with others. If they had, perhaps Rennie might be remembered alongside his contemporaries such as Joseph Bramah and Henry Maudslay. Archives show that he was extensively involved in this industry but few details of his work remain. This, sadly, is also true of so much of his mechanical engineering and prevents his work in this field becoming better recognised. His major achievement in mechanical engineering was his use of steam power in so many applications for civil engineering.