Carl Wilhelm Siemens invented many industrial processes and held some 113 patents. He was also a successful entrepreneur who spent most of his active life in his adopted country. He was born in Hanover, and studied at several German universities, before visiting England in 1843 to seek markets for an electro-plating process, already patented by his brother in Prussia.

In his early years in England he made experiments with superheated steam, for which he was awarded the gold medal of the Society of Arts in 1850. He was naturalized in Britain in 1859. In 1858 he established an English branch of his brother’s company Siemens & Halske in London, which subsequently employed more than 2000 people in a factory built in 1866 at Charlton, in the south of the city, which made telegraphic equipment. He patented the electric arc furnace, used in steelmaking and other metallurgical processes, in 1867. He designed the Faraday, the prototype of the cable-laying ship.

Many of his innovations derived from his experiments with heat, and from his appreciation that it was a form of energy rather than a substance. In 1857 he suggested that the regenerative furnace, originally used in glassmaking, could be used to melt steel. The Frenchman Pierre-Emile Martin (1824-1915) successful used a Siemens furnace to make steel in 1863. Siemens developed the concept into the open hearth method of making mild steel, which he patented in 1866 and applied in a small works at Birmingham in 1866, and from 1869 in a works at Landore near Swansea. The open hearth furnace could be used either with phosphoric or non-phosphoric iron, by applying basic or acid lining. An open hearth plant is preserved at Munkfors, where a regenerative furnace was first used to make steel in 1864.

Siemens was knighted in Britain in 1882 and received honours for his achievements throughout Europe.