little screw on the
centerpiece? Turn that a little, one way or the other, and the operator
on the other side might send until doomsday, we wouldn't know it. I'll
show you the living rooms and the laboratory now."

Just then the door at the other end of the room opened, and a man, whom
Captain Eri recognized as one of the operators, came in. He started when
he saw Hazeltine and turned to go out again. Ralph spoke to him:

"Peters," he said, "where is Mr. Langley?"

"Don't know," answered the fellow gruffly.

"Wait a minute. Tell me where Mr. Langley is."

"I don't know where he is. He went over to the village a while ago."

"Where are the rest of the men?"

"Don't know."

The impudence and thinly veiled hostility in the man's tone were
unmistakable. Hazeltine hesitated, seemed about to speak, and then
silently led the way to the hall.

"I'll show you the laboratory later on," he said. "We'll go up to the
testing room now." Then he added, apparently as much to himself as to
his visitor, "I told those fellows that I wouldn't be back until noon."

There was a door at the top of the stairs. Ralph opened this quietly. As
they passed through, Captain Eri noticed that Peters had followed them
into the hall and stood there, looking up.

The upper hall had a straw matting on the floor. There was another door
at the end of the passage, and this was ajar. Toward it the electrician
walked rapidly. From the room behind the door came a shout of laughter;
then someone said:

"Better give it another turn, hadn't I, to make sure? If two turns fixes
it so we don't hear for a couple of hours, another one ought to shut it
up for a week. That's arithmetic, ain't it?"

The laugh that followed this was cut short by Hazeltine's throwing the
door wide open.

Captain Eri, close at the electrician's heels, saw a long room, empty
save for a few chairs and a table in the center. Upon this table stood
the testing instruments, exactly like those in the receiving room
downstairs. Three men lounged in the chairs, and standing beside the
table, with his fingers upon the regulating screw at the centerpiece
of the recorder, was another, a big fellow, with a round, smooth-shaven
face.

The men in the chairs sprang to their feet as Hazeltine came in. The
face of the individual by the table turned white and his fingers fell
from the regulating screw, as though the latter were red hot. The
Captain recognized the men; they were day operators