admitting water and
not air. However, they approached the gap and examined it with their
torches.

"Here goes," Ward said after a moment's hesitation, and clambered
through the opening, followed by his friend. When they were able to
make out their surroundings, they saw that they were in a vast tunnel
or cavern, the extent of which was shrouded in darkness. How the
submarine had left the ocean and penetrated to this cavern it was
impossible to say; but evidently it had come so far over a shining
rail, a break in which had caused the disaster. The cavern or tunnel
was paved with disjointed blocks of stone which once might have been
smooth and even, but which now were disarranged by time and slimy with
dampness and seagrowths. In the clammy air Miles involuntarily
shuddered. "Good Lord, Rusty, we're certainly up against it! The only
fellow who could tell us our whereabouts is dead!"

Ward's jaw tightened. "That rail leads somewhere: it's our only hope.
But first let us get our guns and some food."

* * * * *

They were fortunate enough to discover several thermos bottles
unbroken. Hot coffee revived their fainting spirits. Treating their
bruises and cuts as well as they could, they left the submarine or
car--it seemed to have been convertible for use either in water or on
rail--and trudged ahead.

Beyond the break that had caused the wreck, the rail stretched away
into illimitable blackness. Over rough stones, stumbling into shallow
pools of water, the light of their torches serving but faintly to show
the depressing surroundings, the two men plunged. Neither of them was
without fear, but both possessed the enduring courage of men
habituated to facing danger and sudden death without losing control of
their faculties.

Time passed, but they had no means of telling how much, since their
wrist watches no longer functioned. But after a while they noticed
that the grade was upward and the going easier. At the same moment,
Ward called attention to the fact that, even without electric torches,
it was possible to see. All around the two Americans grew a strange
light--a weird, phosphorescent glow, revealing far walls and massive
pillars.

Now they could see that they were in a vast chamber, undoubtedly the
work of human hands; a room awe-inspiring to behold, and even more
than awe-inspiring in the reflections it forced upon their minds.
Passages radiated on either hand to mysterious depth