The Third Vice-President and his friends returned to the mules, and the
others followed the young man to the door behind him in the wall. The
door was closed and locked behind them, and they found themselves in
darkness. "If you will come to me here," said the voice of the young
man, a little in advance, "I will show you the way down." When they felt
themselves near him, they heard his voice again. "Be good enough to step
carefully forward, until you feel the first step of a descending stair.
Then descend cautiously, if you please." Each one put out a foot, and in
a moment they were all going down a stairway, of which the treads were
evidently of stone, much worn.

When they had gone down some thirty steps, they were aware that the
stair had ended, and that they were on a landing. "You will now cross
the bridge, one by one, holding on to the railing," said the voice of
the young man. One by one the party stepped forward, feeling the way
cautiously, and as each in turn found with his hand a slight wooden
railing, a breath of fresh air blew upon his face and the sound of
rushing water came from below. Instead of the firm stone they had just
been treading, they were conscious of wooden planking under their feet,
and it gave beneath their pressure most uneasily. The bridge was a long
one, and the sound of rushing water followed them its entire length.
They walked again, however, on firm ground, and heard the young man's
voice before them. "Be good enough to follow the right hand wall," it
said, "and turn with the wall."

Each right hand touched the surface of a wall, and in a moment the wall
made a turning to the right. In another moment their progress was barred
by a wall in advance, and the voice of the young man spoke from their
midst. "You will kindly stoop as you go in," said he, and at the same
moment a round opening appeared before them, dimly lit from within. It
was only large enough to admit a single person, stooping. The young man
entered first, and the others followed, one by one. When they were all
on the other side of the door, the young man swung it noiselessly to,
on its hinges, and it was seen that it fitted accurately, so that it was
impossible to distinguish it from the wall.

They were in a small room, unfurnished except for a table in the center,
on which burned an oil lamp of silver, in shape like a boat; the walls
were bare, except for certain shelves containing bottles of coloured
liquids, other