1911 Encyclopædia Britannica/Siemens, Ernst Werner von

SIEMENS, ERNST WERNER VON (1816–1892), German electrician, was born on the 13th of December 1816 at Lenthe in Hanover. After attending the gymnasium at Lübeck, he entered the Prussian army as a volunteer, and for three years was a pupil in the Military Academy at Berlin. In 1838 he received a commission as lieutenant in the artillery, and six years later he was appointed to the responsible post of superintendent of the artillery workshops. In 1848 he had the task of protecting the port of Kiel against the Danish fleet, and as commandant of Friedrichsort built the fortifications for the defence of Eckernforde harbour. In the same year he was entrusted with the laying of the first telegraph line in Germany, that between Berlin and Frankfort-on-Main, and with that work his military career came to an end. Thenceforward he devoted his energies to furthering the interests of the newly founded firm of Siemens and Halske, which under his guidance became one of the most important electrical undertakings in the world, with branches in different countries that gave it an international influence; in the London house he was associated with Sir William Siemens, one of his younger brothers. Although he had a decided predilection for pure research, his scientific work was naturally determined to a large extent by the demands of his business, and, as he said when he was admitted to the Berlin Academy of Sciences in 1874, the filling up of scientific voids presented itself to him as a technical necessity. Considering that his entrance into commercial life was almost synchronous with the introduction of electric telegraphy into Germany, it is not surprising that many of his inventions and discoveries relate to telegraphic apparatus. In 1847, when he was a member of the committee appointed to consider the adoption of the electric telegraph by the government, he suggested the use of gutta-percha as a material for insulating metallic conductors. Then he investigated the electrostatic charges of telegraph conductors and their laws, and established methods for testing underground and submarine cables and for locating faults in their insulation; further, he carried out observations and experiments on electrostatic induction and the retardation it produced in the speed of the current. He also devised apparatus for duplex and diplex telegraphy, and automatic recorders. In a somewhat less specialized sphere, he was an early advocate of the desirability of establishing some easily reproducible basis for the measurement of electrical resistance, and suggested that the unit should be taken as the resistance of a column of pure mercury one metre high and one square millimetre in cross-section, at a temperature of 0° C. Another task to which he devoted much time was the construction of a selenium photometer, depending on the property possessed by that substance of changing its electrical resistance according to the intensity of the light falling upon it. He also claimed to have been, in 1866, the discoverer of the principle of self-excitation in dynamo-electric machines, in which the residual magnetism of the iron of the electro-magnets is utilized for excitation, without the aid of permanent steel magnets or of a separate exciting current. In another branch of science he wrote several papers on meteorological subjects, discussing among other things the causation of the winds and the forces which produce, maintain and retard the motions of the air. In 1886 he devoted half a million marks to the foundation of the Physikalisch-Technische Reichsanstalt at Charlottenburg, and in 1888 he was ennobled. He died at Berlin on the 6th of December 1892. His scientific memoirs and addresses were collected and published in an English translation in 1892, and three years later a second volume appeared, containing his technical papers.