Werner von Siemens

Born Dec. 13, 1816, in Lenthe, near Hanover; died Dec. 6, 1892, in Berlin. German electrical engineer and entrepreneur. Member of the Berlin Academy of Sciences (1874). Founder and chief proprietor of such large electrical engineering concerns as Siemens and Halske and Siemens and Schuckert.

Siemens graduated from the Berlin Artillery and Engineering School. Early in his career, in the 1840’s, his work was concerned with electroforming. In 1845, together with his brother Wilhelm, he invented a differential governor for steam engines. Having developed B. S. Iakobi’s (M. H. von Jacobi) idea for a synchronous cophasal telegraph apparatus, he obtained a patent in 1847 in Prussia for a telegraph of this type, and with the help of the mechanic J. G. Halske, he began to fill orders and obtain contracts for telegraph equipment. The large profits from these contracts, especially from the construction of a telegraph line from St. Petersburg to Sevastopol’ during the Crimean War of 1853–56, enabled Siemens to convert a small Berlin workshop into what was considered at that time a large plant.

In the 1870’s Siemens became active in such engineering projects involving heavy currents as electric lighting, trolley cars, and power plants. He invented a machine for applying rubber insulation to wire, proposed a cylindrical armature with a double T-shaped cross section for electrical machines (1856), carried out measurements of the dielectric permittivity of many substances (1859), and defined a unit of electrical resistance in terms of the length of a column of mercury (1860). In 1879, Siemens developed the world’s first experimental city electric railroad, that is, a streetcar line (shown at the industrial exhibition in Berlin). In 1867 he applied and developed the design of a self-excited generator, and in 1887 he created a selenium photometer.