he communicator's input to the
feed-in for preamplified signal. The communicator's screen went dark.
It no longer received a simulated broadcast signal. It was now
signalling--calling. But the instant the new signal started out, the
standby light flickered horribly. Sergeant Bellews grimly plugged in
other machines--to the three scientists they looked like duplicates of
Gus and Al--to closed-circuit relationship with Betsy's twin. The
standby light calmed.

"Now we test," he said grimly. "Got a watch?"

Lecky extended his wrist.

"Watch it," said Sergeant Bellews.

He stepped up the output.

"My watch has stopped," said Lecky, through white lips.

Graves looked at his own watch. He shook it and held it to his ear. He
looked sick. Howell growled and looked at his own.

"That wave stops watches," he admitted unwillingly.

"But not Mahon machines easy," said Sergeant Bellews heavily, "and not
us. There was almost three micro-micro-watts goin' out then. That's
three-millionths of a millionth of a ampere-second at one volt. We--"

* * * * *

His voice stopped, as if with a click. The screen of Betsy's
factory-twin communicator lighted up. A man's face peered out of it. He
was bearded and they could not see his costume, but he was frightened.

"_What--what is this?_" cried his voice shrilly from the speakers.

Sergeant Bellews said very sharply:

"Hey! You ain't the guy we've been talking to!"

The screen went dark. Sergeant Bellews put his hand over the microphone
opening. He turned fiercely upon the rest.

"Look!" he snapped. "We were broadcastin' their trick wave--the wave
they used to talk to us! And they picked it up! But they weren't
expectin' it! They were set to pick up the wave they told us to
transmit! See? That guy'll come back. He's got to! So we got to play
along! He'll want to find out if we got wise and won't broadcast
ourselves to death! If he finds out we know what we're doin', they'll
parachute a transmitter down on us before we can do it to them! Back me
up! Get set!"

He removed his hand from the microphone.

"Callin' 2180!" he chattered urgently. "Calling the guy that just
contacted us! Come in, 2180! You're not the guy we've been talking to,
but come in! Come in, 2180!"

Howell said stridently:

"But if that's 2180, how'd we parachute--".

Lecky clapped a hand over his mouth with a fierceness surprising in so
small a man. He whispered desperately i