Arthur B. Reeve,
The Stolen War Secret — XIII. The Wireless Wire-Tapper
(1914)
“ In it we saw a sheet of flame several feet long, a veritable artificial bolt of lightning. The rest of us shrank back in momentary fear at the apparently gigantic forces of nature which seemed let loose in the room. “Don’t be afraid,” called Kennedy. “I’ve seen all this before. It won’t hurt you. It’s an application of a high-frequency current.” Whatever it was I could not overcome the awe which it inspired in me. I wondered how the arch-fiend had restrained himself from turning the deadly power on us. Kennedy continued to experiment gingerly with the apparatus, and finally shut it off. ”
