From what I've read, it sounds like the idea worked in principle, but the tower itself was insufficient for the task he had proposed, which was the wireless transmission of energy by using the conducting properties of the atmosphere.

So, I have four questions:

1) What would it take to make it work?

2) If it worked, and this part of the atmosphere was conducting electricity, what risks would it pose to people/life/the environment to have an artificially excited part of the atmosphere? Would there be an altitude limit to human/animal flight imposed by this excited layer or is it much higher than that?

3) What would the capacity of such a system be? I.E. how much energy could you transmit in such a field and make usable on the receiving end?

4) How would a receiver work?