Nikola Tesla´s patent applications therefor patents had not been granted

In this paper are presented the results of an investigation directed to discovery and identification of Nikola Tesla´s patent applications filed with the United States Patent Office, but appropriate patents had not been granted to him. The investigation showed that Tesla had at least 33 American patent applications, but patents had not been granted therefor, that shed light on his inventive activities in the United States of America. The subject matter of these patent applications are different Tesla´s inventions in the fields of electrical engineering, mechanical engineering and processing technology, more precisely metallurgy.