They heard the beating of their hearts, though, and a
choking sensation rose to their throats as they stood in the narrow way
between the two caverns, asking themselves the same question--What to
do?

For they were between two fires. The caves were in foreign occupation,
that was plain enough; and the whistle had not come from young Carnach,
but from some one else.

There could be no doubt about it: these were not strangers, but the
smuggling crew come to life again after being dead a hundred years, if
Mike was right; a crew of the present day, come to see about their
stores, if Vince's was the right version.

Whichever it was, they seemed to be quite at home, for a second whistle
came chirruping out of the long passage, as the boys hurried into the
gloomy inner cave for safety, and this was answered by the Frenchman,
who roared:

"Ah, tousan tonderres! Make you cease if I come;" but all the same an
answering whistle came from the outer cave.

What to do? Where to hide? They were hemmed in; and it was evident
that either the party in the long passage was coming down, and might
even now be close to the slope, or the Frenchman and the others were
going to him.

It took little time to grasp all this, and almost as little to decide
what to do. The boys had but the two courses open to them--to face it
out with the foreign-looking man, who seemed to be leader, and his
followers; or to hide.

They felt that they dared not do the former then, and on the impulse of
the moment, and as if one spirit moved them both, they decided to hide--
if they could!

The inner cavern was gloomy enough, and they could only dimly make out
the top of the opening above the slope; all below was deep in shadow,
for the faint pearly light only bathed the roof. But still they felt
sure that if they entered from the upper entrance or from below they
must be seen, unless they did one thing--and that was, carried out the
idea suggested for hiding from young Carnach.

They had no time for hesitation; and any hope of its being still
possible to escape by the upper passage was extinguished by a clinking
noise, as of a big hammer upon stone, coming echoing out of the opening,
suggestive of some novel kind of work going on up there; so, dashing to
the darkest part of the cave--that close down by where the slope came
from above--the boys thrust the lanthorn and tinder-box on one side and
began to scoop away at the deep, loose sand near the wa