"Yeah," drawled Wes Farrell, "but what makes it vibrate?"
Don Channing looked down at the crystal. "Where did you get it?" he
asked.
Walt Franks chuckled. "I bet you've been making synthetic elements
again with the heterodyned duplicator."
Farrell nodded. "I've found a new series sort of like the
iron-nickel-cobalt group."
Channing shook his head. There was a huge permanent magnet that poured
a couple of million gauss across its gap, and in this magnetic field
Farrell had the crystal supported. A bank of storage batteries drove
several hundred amperes--by the meter--through the crystal from face
to face on another axis, and down from above there poured an intense
monochromatic light.
"Trouble is," complained Wes, "that there isn't a trace of a ripple
in any of the three factors that work on the thing. Permanent magnet,
battery current, and continuous gas-arc discharge. Yet--"
"It vibrates," nodded Channing. "Faintly, but definitely it is
vibrating."
Walt Franks disappeared for a moment. He returned with a portable
phonograph, which caused Don Channing to grin and ask, "Walt, are you
going to make a recording of this conversation, or do you think it will
dance to a Strauss waltz?"
"It's slightly bats, so I brought the overture to _Das Fledermaus_
for it," snorted Franks. As he spoke, he removed the pick-up from the
instrument and added a length of shielded wire. Then he set the stylus
of the phonograph against the faintly vibrating crystal and turned up
the gain.
At once a whining hum came from the loud speaker.
"Loud, isn't it?" he grinned. "Can you identify that any better?"
Wes Farrell threw up his hands. "I can state with positiveness that
there isn't any varying field of anything that I know of that is at
that frequency."
Channing just grinned. "Maybe it's just normal for that thing to
vibrate."
"Like an aspen leaf?" asked Walt.