mmie was about to say "Emerald mines," but Peter's anxious face warned
him to check the words on his lips.

"Oh, I've heard of all kinds of mines about there," he said, instead.

"The mines are farther south," said the stranger. "Are you boys with a
party?" he added, in a moment. "If not, I would like to have you spend the
night as my guests."

"We've got a camp back here," Peter said, "and the others will be
expecting us."

"I see," said the other. "You are the boys who are here in search of
specimens. I recall something Lieutenant Gordon said about you. But you
are a long way from the cottage in the jungle near Gatun."

"When did you see Lieutenant Gordon last?" asked Peter, suspiciously.

"I met him something over half an hour ago," was the reply, "on his way
back to the Tivoli at Ancon. You came here in his machine?"

"Yes," was the reply.

"Well, I'm going to Gatun to-night, and you may ride with me."

The stranger turned away, as if to get his motor car, and Peter nudged
Jimmie in the ribs with his elbow.

"Now we've done it," he whispered.

"Done what?"

"Got a man after us."

"Do you think he is one of the men we came here to look up?" asked Jimmie.
"I've been thinking he looks like a Jap. Perhaps he's one of the men at
the bottom of that bomb business. Well, we don't have to go with him."

"I'd like to see where he would take us," Peter whispered.

"Not for your uncle," Jimmie replied. "It is me for the jungle. This thing
is gettin' worse 'n' a Bowery drama. The villain comes on in every scene
here. Say! Suppose we take a run into the woods before he gets back?"

"I'm not in love with the jungle at night," Peter said. "Besides, I'd like
to know what this Jap has in mind."

The chug-chug of the stranger's motor was now heard, and, without waiting
for further discussion, the boys ducked away into the jungle, which
crowded close on the cut at this point.

They heard the car stop at the point where they had been standing, and
heard a low exclamation of impatience, indicative of disappointment, from
the lips of the driver, and then crept farther into the tangle of vines.

Finally Peter stopped and faced toward Gatun.

"We'd better be working toward home," he said. "This thicket is no place
for a civilized human being at night."

Although there was a moon, and the sky showed great constellations with
which the boys were unfamiliar, the jungle was dark and creepy. Keeping
the lights from the w