Karl Wilhelm Siemens was born into a family of scientists and inventors at Lenthe, near Hanover, Prussia, on April 4, 1823. After his father's death in 1840, he was encouraged by his brother Ernst Werner von Siemens to enter technical school at Magdeburg. Siemens also apprenticed at a steam engine factory there.

In 1843 he traveled to England to promote Werner's inventions, in particular an electroplating process. For the same reason, Siemens's younger brother, Friedrich (1826-1904), joined him in 1847.

The two brothers collaborated on their own inventions. Karl Wilhelm's first success was a water meter, from which he lived comfortably from the royalties. Financially secure, the brothers set about working on a new smelting process, the open hearth furnace, which would become the foremost steelmaking process of the twentieth century.

The Siemens brothers' process used heat regeneration. Heat that otherwise would have been lost to the atmosphere was recaptured and used to...