 The ideal operating frequency was described as being between 35 and 40 hertz.The device has been described as being built by Westinghouse engineer Charles F. Scott, who was in charge of development of the induction motor for the company, although a March 1919 Electrical Experimenter article claimed it was built by Westinghouse Electric Superintendent Albert Schmid.The Columbian Exposition "Egg of Columbus" ended up at Tesla's 46 & 48 East Houston Street New York City laboratory where he would demonstrate it to visitors.