steelmaking technique that for most of the 20th century accounted for the major part of all steel made in the world. William Siemens (Siemens, Sir William), a German living in England in the 1860s, seeking a means of increasing the temperature in a metallurgical furnace, resurrected an old proposal for using the waste heat given off by the furnace; directing the fumes from the furnace through a brick checkerwork, he heated the brick to a high temperature, then used the same pathway for the introduction of air into the furnace; the preheated air materially increased the flame temperature. The first to use the device to produce steel were Pierre and Émile Martin of Sireuil, France, in 1864, charging the furnace with pig iron and some wrought-iron scrap. The ores most readily available in both Great Britain and the United States were especially well suited to the open-hearth process, the product of which proved superior to that from the Bessemer converter.