 have left! The stones are
squared and fitted together as closely as those in the drawing-room.
Then why should that be, except in that one room? The side walls all
the way up are roughly built. Why should they have taken the trouble on
this floor to build these, which are only meant as store-rooms, when
even in the rooms above, which were meant for the habitation of the
chief and his family, the rough work was deemed sufficiently good?
There must have been some motive for this, Dias."

"There must have been, senor; it is certainly strange."

"First of all, let us clear the wall and take a general view of it.
Guessing won't help us; but I have the strongest hopes that behind one
of these stones lies a cavern. By the way, Dias, take a torch and go
into the next chamber and see if the stones are solid there."

"They are just the same as those here," Dias said when he returned.

"I would rather that it had been the other way," Harry said, "for then
I should have been more sure that there was some special reason for
their building them in this way here."

It took them all half an hour's work to move the spears and arrows to
the other side.

"Do you think, Harry, if we were to tap the stones we should be able to
find whether there is a hollow behind any of them?"

Harry shook his head.

"Not in the least. I have no doubt these stones are two or three feet
thick, and there could be no difference in the sound they would make if
struck, whether they were filled in solid behind or had no backing. To
begin with, we will make a careful examination of the walls. Possibly
we shall see some signs of a stone having been moved. It would be very
much more difficult to take one of the great blocks out and put it in
again than it would be to get up one of the paving-stones."

When they had gone about half-way along, examining each stone with the
greatest care, Bertie, who was ahead of the rest, and passing the
candle he held along the edge of every joint, said, "Look here! this
stone projects nearly half an inch beyond the rest."

