panorama as Ramon, dripping and
cursing, was hauled out of the water by his band, flashed before their
eyes for a brief moment. The next instant dense darkness fell about
them.

At what seemed to be a mile-a-minute pace they were hurried forward
into the unknown.

CHAPTER XI.

THE CAMP OF THE GUN-RUNNER

Jounced against the rough, rock walls, bumped over shoal places, and at
times whirled almost broadside on by the swift current, the queer,
flat-bottomed boat containing our three young friends was hurried
through the darkness. It was the maddest ride any of them had ever
taken, and, as we know, they had been through some thrilling
experiences since they had first stood on the railroad station platform
at Maguez. Had they known it, they could have controlled the boat more
or less with the rough oar--the one with which Ralph had sounded the
depth of the river--but, of course, they were inexpert in the
management of such a craft. They could do nothing but keep still and
trust to luck to bring them safely out of their extraordinary
predicament.

After some ten minutes of this, the current seemed to slacken a little
and the walls narrowed. Jack stretched out a hand and, to his
astonishment, his fingers were swept along a rope stretched down the
side of the tunnel. This solved a problem he had been revolving in his
mind--namely, how did the Mexicans get their boat back after it had
delivered its cargo of arms? The explanation was now a simple one.
Evidently they hauled it back by the use of this rope. "It must have
been hard work, though," thought Jack.

Conversation was impossible in the confines of the tunnel which, in
places, was a mere tube in the rocks; the roar of the water was almost
deafening. It was so black, too, that they could not see one another's
faces. Of real alarm Jack did not feel much, and for an excellent
reason. It was apparent that the Mexicans had used this underground
route across the border many times, and, if they could make the
passage--terrifying as it seemed--in safety, there was every reason to
suppose that the boys could make it with the same security.

What worried Jack most about their situation proceeded from a far
different cause. There was little reason to doubt that at the other
end of the tunnel, wherever that might be, Black Ramon or his
superiors, arming the insurrectionists, had guards posted to receive
the smuggled guns. If no opportunity of escaping from