Charles P. Steinmetz was a mathematician and electrical engineer whose theories and research fostered the widespread use of electrical energy. A scientist of prodigious inventiveness, Steinmetz was granted some two hundred patents. His discovery of the phenomenon known as magnetic hysteresis led to the development of energy-efficient motors. He worked out mathematical theories that made practical the use of alternating current in long-distance power transmission. His work in changes in electrical circuits of very short duration was used to develop new cables and improved methods of operating transmission systems. He also built artificial lightning generators that led to the development of lightning arrestors to protect electrical apparatus and transmission lines.

Charles Proteus Steinmetz was born in Breslau, Germany (now Wroclaw, Poland), on April 9, 1865. His mother, Caroline Neubert, died when he was one year old; his father, Karl Heinrich, worked for the government-owned railroad. Steinmetz was the third of...