One of three

CHAPTER I
Contact!
The bit of whitish substance fluoresced, which of course was quite natural. It also vibrated very faintly, which was unnatural. At least, this property had not been known previously—which is really saying little since the material had been compounded from artificial radioisotopes from the big piles. All too little was known about such items and the fact that this one was vibrating ever so faintly whenever the electron beam struck it was interesting both from a scientific and a lay curiosity standpoint.
Ed Bronson blinked a bit and decided that he had made some mistake. It had ceased to vibrate.
Ed cracked the experimental tube and removed the irregular lump. It had been hoped to produce a more brilliant and higher-contrast phosphor for television screens. But if it was going to vibrate—
Ed inserted the lump of phosphor back in the tube, pumped it and restarted the whole gear.
It vibrated again, ever so faintly, against the bottom of the glass. Bronson listened carefully, his engineer's mind trying to identify the sound. It was not the sixteen kilocycle sweep circuit—not the one that scanned the face of the television tube, because this was not a complete set-up and there was no scanning energy necessary. It was vaguely familiar.
It came and it went, that faint vibration. Sometimes it rattled violently, other times it purred gently. Always very faintly of course—for the term 'violently' means only by comparison.
Ed adjusted the field strength of the focusing magnet about the neck of the tube and the vibration strengthened to a noticeable degree. He juggled the controls but found he had hit the maximum or optimum response.
There was something about it.... It was like human whisperings too faint to be understood but not too faint to be unheard. Like the bloop-bleep of a leaky faucet that seems to be saying things about you just too quietly to be really understood. Like the imagined whisperings heard by the paranoiac....