in five minutes the
schooner is so completely lost to sight among the rocks that even the
tip of her mast could not be seen from the sea.

Who in Bermuda imagines that a vessel is accustomed to lay up in
this secret creek? Who in America would have any idea that the rich
yachtsman so well known in all the eastern ports abides in the
solitude of Back Cup mountain?

Twenty minutes later the dinghy returns with the four men towards the
tug which was evidently waiting for them before proceeding--where?

They climb on board, the little boat is made fast astern, a movement
is felt, the screw revolves rapidly and the tug skims along the
surface to Back Cup, skirting the reefs to the south.

Three cable's lengths further on, another tortuous canal is seen that
leads to the island. Into this the tug enters. When it gets close
inshore, an order is given to two men who jump out and haul the dinghy
up on a narrow sandy beach out of the reach of wave or weed, and where
it will be easily get-at-able when wanted.

This done the sailors return to the tug and Engineer Serko signs to me
to go below.

A short iron ladder leads into a central cabin where various bales and
packages are stored, and for which no doubt there was not room in the
hold of the schooner. I am pushed into a side cabin, the door is shut
upon me, and here I am once more a prisoner in profound darkness.

I recognize the cabin the moment I enter it. It is the place in which
I spent so many long hours after our abduction from Healthful House,
and in which I was confined until well out at sea off Pamlico Sound.

It is evident that Thomas Roch has been placed in a similar
compartment.

A loud noise is heard, the banging of the lid as it closes, and the
tug begins to sink as the water is admitted to the tanks.

This movement is succeeded by another--a movement that impels the boat
through the water.

Three minutes later it stops, and I feel that we are rising to the
surface again.

Another noise made by the lid being raised.

The door of my cabin opens, and I rush out and clamber on to the
platform.

I look around and find that the tug has penetrated to the interior of
Back Cup mountain.

This is the mysterious retreat where Count d'Artigas lives with his
companions--out of the world, so to speak.

CHAPTER IX.

INSIDE BACK CUP.

The next morning I am able to make a first inspection of the vast
cavern of Back Cup. No one seeks to prevent me.