A bit later in 1940 he offered for 3 million dollars to build a device which could knock every plane out of the sky within a 200 mile radius and would take 3 months to make,he never got the funding-then of course 1 year later Pearl Harbour happened,we now know what he was on about an emp weapon,like
THIS-STARTING AT $400In addition to EMP he postulated on the use of Particle Beams as weapons, he was right, but for the wrong reasons. An EMP weapon would not have been to effective against 1940 technology as there was little electronics used then.
As an aside, he also built remote controlled submarines which were offered to the Navy, which they of course refused. The man was WAY ahead of his contemporaries and in some areas and respects, ahead of where we are today. On the other hand, he was quite eccentric to say the least.
---max
He also created a kind of resonator that could bring down every building in the world simply by a little shaking. He was a brilliant man.