? It was folly, especially when he might be
precipitated at any moment into some hidden chasm. But folly though it
might be, Paul could not turn back. A mysterious voice within him seemed
to be urging him on. If Mr. Weevil had passed along that tunnel in
safety, why shouldn't he? It must have an outlet somewhere, and Paul
grew more and more curious to find out what that outlet could be.

"I feel very much like an explorer in darkest Africa," he smiled to
himself. "Shall I be coming across an unknown lake presently, or a race
of pigmies? Hallo! What's that? Light at last."

Light it was but of the faintest. It came with a faint streak into the
tunnel. The darkness was only darkness before, but now fantastic shadows
seemed to menace Paul at every footstep he took. Feeble though the
light was, it was enough to show him that the tunnel had broadened
considerably. Stepping warily along, the light grew stronger at every
step, until he at length discovered that the path along which he was so
cautiously travelling led into a cave lit with oil-lamps.

Then he came to a sudden pause again, and his heart beat wildly against
his ribs, as he caught the sound of voices. The cave was not empty.
There was some one inside. Who?

As he approached nearer he saw that a curtain was partly drawn over the
entrance. Paul knew that a false step might betray him.

To lessen the risk of detection, therefore, he crawled on hands and
knees to the curtain, and eagerly peered through the space nearest the
wall.

The cave looked quite warm and comfortable. A fire of anthracite, which
sent out plenty of heat but no smoke, burnt on a hearth cut out of the
sandstone. Two or three lamps suspended from the roof diffused an
Oriental glow, while several warm bear-skin rugs were scattered over the
ground.

A couple of guns and two or three cutlasses were hanging on the wall;
and what was more astonishing to Paul, several maps and designs. The
nature of these it was impossible for him to ascertain. He further
noticed that in one niche of the wall was a photographic camera. In
another were ship models, in the third the models of torpedoes, engines,
and machinery of various kind.

Paul had taken all this in at a glance. He had not yet seen the
occupants of the cave, but there appeared from what he could hear, to be
only two. They were conversing in low tones at the far end, where the
lights from the lamps dimly penetrated. After a while the conversation