The Electric Chair
Although most people associate electricity with Thomas Edison and the late 19th Century, it was harnessed and put to use much earlier by several scientists in various countries. The Leyden jar, a device for storing and discharging static electricity, was invented in 1745. The amount of charge stored in the Leyden jar was enough to kill small animals such as birds, fish and mice, and its demonstrators did just that to show its capabilities. In 1786 Luigi Galvani posited that electricity was the essence of life. He and others ran charges through dead animals and eventually corpses, reanimating them in frightening ways.
What these predecessors of Edison could not do was manipulate electricity in any way that was meaningful to common people. Although Zenobe Theophile Gramme had proven in 1873 that electricity could be transmitted from place to place via overhead conductors, the production and control of the voltages necessary to serve society remained theoretical until Edison worked them out. His incandescent light bulb was a practical, universal use to which the science of electricity could be put; his power plants and distribution systems bridged the gap between the scientists in their labs and the common man in his home.
Edison built his first power plant in 1879; almost immediately representatives from cities around the country were clamoring for contracts to have their cities wired for the new marvel. City after city was illuminated, all using Edison's system, which ran on direct current. Direct current was not without its problems, though. In DC systems, the electricity always flowed in one direction. An extra piece of equipment, the commutator, was necessary to ensure that the flow always went in the proper direction. Hence, DC systems were complicated. Another problem was that voltages in a DC system dropped off sharply after a relatively short distance. Many power plants would have to be built to supply reliable power to even a medium-size city.
There was an alternative. Nikola Tesla, a bizarre Croatian genius, recognized the problems inherent in DC systems and envisioned a system which ran on alternating current. In AC systems the electricity changes direction many times a second, creating a magnetic field which allows for the transport of huge voltages without loss along the way. These voltages are then stepped down through transformers to a level which is safe for use by the public. A few cities were wired with early AC systems (not of Tesla's design). Though these were inferior to the systems Tesla imagined, they piqued the interest of a few investors. One of these was George Westinghouse, who had made his first fortune with the invention of the railroad airbrake. Westinghouse intended to make alternating current profitable, but for the time being Edison's direct current was by far the more popular technology.
Tesla was employed by Edison for less than a year; during this time he told Edison of his theories. Edison dismissed them, and Tesla left his employ in frustration. In 1887 he finally secured patents for his system and, more important, financial backing. He was now able to demonstrate the theories he had carried in his head for years. Westinghouse took notice. In 1888 he bought 40 patents from Tesla, and within a few years over 100 cities and towns were wired for Westinghouse AC power. Edison was losing business and employees to Westinghouse, and he was angry.