"Experiments with Alternate Currents of Very High Frequency and Their Application to Methods of Artificial Illumination" lecture is given before the American Institute of Electrical Engineers (now the IEEE) at Columbia University in New York.
L.L. Nunn, a Colorado lawyer and manager of the Gold King Mine, signed a contract with Westinghouse to install the Tesla A.C. power system. The plan was to harness a river below the mine and replace the costly coal powered steam generators. This facility became known as the Ames Power Plant and was the first power station in the world to transmit alternating current at high voltage for power purposes, for a long distance.
Tesla becomes an American citizen. He often told friends that he valued this citizenship more than any scientific honors he'd received.
One could argue that Nikola Tesla was the first to discover the electron. This is evidenced by his article "Reply to J.J. Thomson's note," published on this date in "Electrical Engineer, New York." In this article, Tesla claims that his experiments prove the existence of charged particles ("small charged balls"), while J.J. Thomson denied this. It was only five years later that Thomson proved the existence of electrons using another experiment.
Maybe not the most successful of Tesla's invention, but certainly the invention he is most famous for. The Tesla coil was originally developed to power Tesla's new wireless lighting systems, but later became the basis of the ill-fated World-Wide Wireless System, otherwise known as Wardenclyffe.