"Curlie?" says the voice in the receiver. "Got a bad case -- extra bad. Fellow's sending 600-meter waves, with enough power to cross the Atlantic.""Six hundred!" exclaims Curlie. "Why, that's what they use for S.O.S. at sea! That's criminal! Endangers every ship in distress. Get him, can't you?""Can't. That's the trouble. Every time I think I've got him spotted, he seems to move.""To move? I'll be up right away!"Curlie is most at home when surrounded by wire-wrapped frames, coils, keys, buttons, switches, motors, dry-cells, and storage batteries -- all the odds and ends that equip the most perfect listening-in station in the world.