ellow would get up in the middle of the night to do you a dirty trick,
and don't you ever forget it!"

"That's the way he's going to help us!" laughed Elmer. "He'll get up in
the middle of some dark night to do us a dirty trick, and before he
knows what he's about, he'll be doing us a great kindness!"

"Suppose I slip back there and see what he's doing?" asked Tommy.

"Can you find your way back to headquarters alone?" asked Sandy.

"If I can't," asserted Tommy, "I won't be sending any wireless messages
to you! If you think I'm likely to get lost, Dick can go back with me.
He ought to know every corner in the old mine."

"Sure he does!" laughed Jimmie. "We've been travelling this mine for a
good many nights now, and we know it like a book."

So Tommy and Dick started back down the passage, the intention being to
hasten to the spot where Ventner had disappeared from the gangway, and
then return to their companions immediately.

"We can't stay very long, you know," Tommy explained, "because you've
got to have that peroxide dope put on your bites. It doesn't pay to fool
with wounds of that description!"

"We'll be back to the old tool room as soon as they are!" answered Dick.
"It will take only a minute to run down there and back!"

When the boys reached the cross-cutting into which Ventner had
disappeared, they saw his light some distance away. It seemed to be in
one of the chambers connected with the cross-cutting.

As they looked, the detective stepped forward into the circle of
illumination and began working with a pick.

"Is he always doing that when you see him?" asked Tommy.

"You bet he is!" answered Dick.

"What's he doing it for?"

"You'll have to ask Elmer that."

"But you know, don't you?"

"Of course I know, but I'm not going to tell, because we all agreed that
the story should never be told by any member of our party until Elmer
got ready to tell it. So you see you've got to wait!"

"If I had my way about it," gritted Tommy, "I'd go back there and geezle
that bum detective and wall him up in a chamber until he got hungry
enough to tell the story himself. Then we wouldn't have to go sneaking
around the mine in order to keep out of his way!"

"That would be a foolish move," insisted Dick, "because every stroke of
the pick Ventner takes helps us along in the game we're playing."

"You're the original little mystery boy, ain't you?" said Tommy rather
crossly. "All right, I'll get even."

T