Marc Séguin (1786–1875)
The engineer and entrepreneur Marc Séguin made important contributions to the industrial development of France, especially in the 1820s and 1830s. He pioneered French railways, patented the multi-tube steam boiler, built the world’s first wire-cable suspension bridge and constructed toll bridges in many parts of France. He published many books to disseminate knowledge of science and technology.
He was born in the town of Annonay in south-eastern France. His background there was rich in technology. His father Marc François Séguin founded a company to manufacture textiles; his mother Thérèse-Augustine de Montgolfier was the niece of the Montgolfier brothers, paper manufacturers of Annonay who also pioneered the hot-air balloon and the hydraulic ram. Séguin and his brothers studied science and technology in Paris with their uncle Joseph Montgolfier at the Conservatoire national des arts et métiers.
On returning to Annonay in 1805, Séguin worked at the family paper mill, where he made innovations in the felt used to form sheets of paper and the design of waterwheels. In 1822 he built an 18-m long trial suspension bridge of wire cable. Wire was stronger than rope but cheaper and lighter than iron bars or chains; it eventually became the preferred material for suspension bridges worldwide. He published his findings in 1824. He demonstrated the technology on a much larger scale with his bridge across the river Rhône at Tournon, opened in 1825, which had two spans of 85 m each. Séguin and his brothers invested in its construction in return for the licence to take tolls. They went on to build at least 90 toll bridges on the same model and influenced hundreds more.
Séguin developed a scheme to improve the navigation of the river Rhône with steam engines that towed vessels from fixed points. His company was bankrupted when a vessel hit a bridge at Lyon and sank with the loss of many passengers.
In 1824, with his brother Camille and other investors, Séguin began the project to build the first French steam railway – from Saint-Étienne to Lyon. He visited the Stockton and Darlington Railway in northern England in 1825 and bought two locomotives from George Stephenson. The railway company was created in 1827 and Séguin designed the 56-km route through challenging territory with tunnels and large bridges. He designed improved locomotives for the railway in 1829. These had fan-assisted draft to the fire, water-jacketed fireboxes and multi-tube boilers that increased the speed of locomotives. He had proposed the multi-tube boiler in December 1827 to enhance the power of steamships. Hot gasses from the firebox were carried through the water body in many copper tubes instead of a single flue. Several people had the idea independently but Séguin was first to obtain a patent and build an example. Stephenson adopted the principle in his famous locomotive Rocket and it influenced later high-pressure steam engines.
The first section of the Saint-Étienne railway opened in 1830 and the rest in 1833. Séguin proceeded in 1837 to design and construct the Invalides railway at Paris. He retired to concentrate on family life and his scientific interests.