nting up towards the ceiling, he said,--

"There is where the criminals were hung. Up where I point there is a
beam built into the rock; and from that the rope was suspended."

The boys all crowded round the spot, and looked eagerly up, but they
could not see any beam.

"You cannot see it," said the guide, "now, because you have just come
out from the light of day. We shall come back this way pretty soon, and
then you will be able to see it; for your eyes will then get accustomed
a little to the darkness of the dungeon."

So the guide went on, and the boys followed him.

They next came into a very large apartment. The front side and the back
side of it were both curved. The back side consisted of the living rock.
The front side was formed of the outer castle wall, which was built on
the rock at the very margin of the water. In the centre was a range of
seven massive stone columns, placed there to support the arches on which
rested the floor of the principal story of the castle above. The roof of
this dungeon of course was vaulted, the arches and groins being carried
over from this range of central pillars towards the wall in front, and
towards the solid rock behind. All this you will plainly see represented
in the engraving.

[Illustration: THE DUNGEON IN THE CASTLE OF CHILLON.]

This great dungeon was lighted by means of very small loopholes cut in
the wall, high up from the floor. The light from these windows,
instead of coming _down_, and shining upon the floor, seemed to go _up_,
and to lose itself in a faint attempt to illuminate the vaulted roof
above. The reason was, that at the particular hour when the boys made
their visit, the beams of the sun which shone directly from it in the
sky were excluded, and only those that were reflected upward from the
waters of the lake could come in.

The guide led the boys to one of the central pillars, and pointed to an
iron ring which was built into the stone. He told them that there was
the place where one prisoner was confined in the dungeon for six years.
He was chained to that ring by a short chain, which enabled him only to
walk to and fro a few steps each way about the pillar. These steps had
worn a place in the rock.

After the boys had looked at this pillar, and at the iron ring, and at
the place worn in the floor by the footsteps of the prisoner, as long as
they wished, they followed the guide on to the end of the dungeon, where
they were stopped by the soli