Lecture given on August 25, 1983, in the hall adjoining the Agricultural Building at the Chicago World’s Fair. This lecture was not published and the manuscript was not preserved among Tesla’s papers. It was most probably destroyed, along with his other belongings, in the fire of March 13, 1895. Thanks to journalist and publicist T. C. Martin, a detailed overview of the lecture and Tesla’s experiments appeared in the press at the time.
