Having done extensive research into the man, I think he was an INFJ. Reason being, an INTJ would have released their experiments with impunity out into the world. Tesla, on the other hand, ALWAYS considered the affect it would have on people first and changed his actions accordingly. In fact, he ended up a pauper because he put people first. As well, he trusted the "ether", he admits that he received most of his ideas through meditating and connecting with the "ether". That is pretty definitive. Carl Jung was also INFJ.