SIEMENS, Ze'llIrDIS, ERNST WERNER VON (1816-92). A German electrical engineer. He was born at Lenthe. near Hanover, and was edu cated in the Gymnasium of Lfibeck and in the school of artillery and engineering at Berlin, becoming an artillery officer in 1838. He studied chemistry and electro-magnetism. and invented a process for electroplating in 1841. In 1848 he became commandant of the artillery arsenal in Berlin. He was the first to explode a submarine mine by electricity (1848). Devoting himself to electrical engineering, he was engaged after 1849 in the establishment of telegraph lines, particn larly through Russia. Brazil, Spain, and North ern Germany. in 1856 lie devised the improved shuttle armature which increased the efficiency of the magneto-machine, and in 1876 demon strated that its electro-maguets could be used without separate exciters, the current being passed through the field coils. He proposed as the unit of resistance a column of mercury one meter long and one square millimeter in cross-section at Centigrade. This was known as the
mens unit. Siemens was also active in promot ing electric traction in Germany, and the first electric railway was erected at the Berlin Indus trial Exhibition of 1879 by Siemens & Halske. His researches in electricity resulted in discov eries and improvements of great value, one of which was the determining of the locations of injuries in submerged cables, and also of charging them in order to reduce the disturbing inlluence of induced currents. In 1834, by the gift of about $125,000, he made possible the foundation of the Imperial Physico-Technical Institute (Reichs anstalt), which has been an important factor in German scientific research and manufacturing. I See LABORATORY.) lie wrote numerous scien tific works and also a volume of Personal Remi niscences which has been translated into English.