We have to evolve means for obtaining energy from stores which are forever inexhaustible, to perfect methods which do not imply consumption and waste of any material whatever. I now feel sure that the realization of that idea is not far off....the possibilities of the development I refer to, namely, that of the operation of engines on any point of the earth by the energy of the medium.

The Nikola Tesla Treasury (ed. Simon and Schuster, 2013) - ISBN: 9781627932561