Although the electrical system being developed in the United States in the 1880s used direct current (DC), in Europe several alternating-current (AC) systems were being developed. One of the most successful, first demonstrated in 1881 in London, was devised by Lucien Gaulard of France and John Gibbs of England. Four years later, Westinghouse imported a set of Gaulard-Gibbs transformers and a Siemens AC generator and set up an electrical system in Pittsburgh. With the aid of three American electrical engineers, he altered and perfected the transformer and developed a constant-voltage AC generator. In 1886 he incorporated the Westinghouse Electric Company, which three years later was renamed the Westinghouse Electric & Manufacturing Company. He purchased the patents of Nikola Tesla’s AC motor and hired Tesla to improve and modify the motor for use in his power system. When the system was ready for the American market, the advocates of DC power immediately set out to discredit AC power. Their attacks culminated in charges that the use of AC power was a menace to human life; to support their argument, they introduced a standard Westinghouse AC generator as the official means of executing death sentences in the state of New York. This tactic was insufficient to suppress AC power, however, and in 1893 the Westinghouse company was retained to light the World’s Columbian Exposition at Chicago. In addition, Westinghouse secured the rights to develop the great falls of the Niagara River with AC generators. His business flourished until 1907 when a financial panic resulted in his losing control of the company. By 1911 he had severed all connections with his companies. His health failed soon thereafter.