Nikola Tesla was a Croatian-born inventor who immigrated to the United States in 1884. He worked for Thomas Edison for a few years but then left to work on alternating current electrical systems, while Edison was still insistent on direct current. In 1893 he gave a famous lecture in Saint Louis in which he predicted wireless telegraphy based on the spark transmission. that Guglielmo Marconi and others were soon to use (a technology that was superseded when the vacuum tube was invented). He refused, however, to admit the potential application of Hertzian (radio) waves. Marconi, credited with the discovery of radio telegraphy in 1895, always denied he had ever heard of the system that Tesla had described in his 1893 lectures. There were suits and countersuits between the two inventors for patent infringement. H. Otis Pond, one of Edison's engineers was with Tesla in December 1901 when Marconi...