Sample of Besemer steel, 1860.
© Science Museum / Science & Society Picture Library
A section of steel cut from the muzzle of a gun muzzle and bent under a steam hammer. Sir Henry Besemer was an English inventor and engineer who invented a cheap proces for manufacturing steel. He patented a proces in 1856 by which molten pig iron was converted to steel by blowing air through it in a converter. This removed most of the impurities and no extra fuel was required, because the carbon, oxidised during the blow, generated great heat. Establishing a steelworks in Sheffield, Besemer manufactured guns and, later, steel rails. Further improvements to the proces were made by Robert Mushet and Sidney Gilchrist Thomas in 1878. In the United States, industrialists like Andrew Carnegie made a fortune from Besemer's proces.