Scarcely known today, Elihu Thomson was arguably the most important early contributor to the development of electricity as a power and light source. An outstanding scientist as well as a brilliant engineer, Thomson applied his insights in theoretical science to practical devices in a way that few others have.
Thomson was born in Manchester, England, on March 29, 1853, and his family moved to Philadelphia five years later. The son of an engineer and machinist, Thomson was tinkering and inventing before he had even reached his teens. Keenly interested in electricity, Thomson constructed a crude electrostatic device from a wine bottle at the age of eleven, as well as experimented with telegraphy, electromagnets, and other electrical devices.
Shortly after graduating from Central High School, Thomson became a faculty member there, and began working with another teacher, Edwin J. Houston. Appointed professor of chemistry and mechanics in 1876, Thomson spent his time lecturing on electricity at the Franklin Institute, building lenses and optical devices,and constructing new electrical motors. It was around this time that Thomson made what was almost certainly the earliest demonstration of the existence and behavior of radio waves. Just a few years before, James Clerk Maxwell (1831-1879) had established a theory that finally showed the relationship of electricity to magnetism. One of the predictions of Maxwell's theory was that the oscillation of an electric charge would produce an electromagnetic pulse, composed of long waves, that traveled out from its source. Thomson generated such waves, passing them through brick walls and floors, ten years beforeHeinrich Hertz's (1857-1894) independent discovery of radio waves would leadto the invention of the radio receiver. Apparently not seeing the potentialof his radio experiments (the kind of blunder he seldom made), the prolific Thomson moved on, more interested in projects to make electrical power generation and lighting practical.
Toward this end, Thomson collaborated with Houston on an improved arc lighting system. Thomson constructed a number of devices, and with the help of financial backers, Thomson and Houston opened a factory in 1879. Their successfularc lighting predated Thomas Edison's incandescent light bulb and launched Thomson on a commercial career. Resigning his position as professor, Thomson began to devote all of his time to his new enterprise.
Before long, Thomson expanded their lighting company, known as Thomson-Houston Electric, into the manufacture of incandescent lights, motors, dynamos, andeven electric trains. In 1892 the Thomson-Houston Electric Company merged with the Edison General Electric Company to become General Electric, becoming the largest manufacturer of electrical devices in the world. Thomson stayed with the company as an engineer and consultant for the rest of his life, whilepouring out invention after invention. By the time he died in 1937 he had accumulated a remarkable 700 patents.
Thomson's impressive list of inventions includes the watt-hour meter (used tomeasure electricity consumption), the first method of welding metals with electricity, a high-frequency generator, a type of objective lens for a refracting telescope, a constant-current transformer, an electrically-operated pipeorgan, a cream separator, a type of lighting rod, and an alternating currentrepulsion motor which helped introduce the use of AC as a source of power.
After x-rays were discovered in 1895, Thomson worked on improving the designof x-ray devices, devising a means of producing stereoscopic x-ray photographs. He is even credited with first suggesting that, in order to avoid suffering the bends, divers working at great depths (or workers deep in caissons) should use a helium-oxygen air supply rather than one of nitrogen-oxygen.