he experiment, till they had exactly
mapped out where the solid rock ended and that which seemed to be hollow
began--a space of about eight feet square.

"We've got it," he said triumphantly. "That's the entrance to the place
where the gold is," and the others were inclined to agree with him.

Now it remained to put their theory to the proof--a task of no small
difficulty. Indeed, it took them three days of hard, continual work.
It will be remembered that the floor of the cave was cemented over, and
first of all this cement, which proved to be of excellent quality, being
largely composed of powdered granite, must be broken up. By the help
of a steel crowbar, which they had brought with them in the waggon,
at length that part of their task was completed, revealing the rock
beneath. By this time Benita was confident that, whatever might lie
below, it was not the treasure, since it was evident that the poor,
dying Portuguese would not have had the time or the strength to cement
it over. When she told the others so, however, Meyer, convinced that
he was on the right tack, answered that doubtless it was done by the
Makalanga after the Portuguese days, as it was well known that they
retained a knowledge of the building arts of their forefathers until
quite a recent period, when the Matabele began to kill them out.

When at length the cement was cleared away and the area swept, they
discovered--for there ran the line of it--that here a great stone was
set into the floor; it must have weighed several tons. As it was set in
cement, however, to lift it, even if they had the strength to work the
necessary levers, proved quite impossible. There remained only one thing
to be done--to cut a way through. When they had worked at this task for
several hours, and only succeeded in making a hole six inches deep,
Mr. Clifford, whose old bones ached and whose hands were very
sore, suggested that perhaps they might break it up with gunpowder.
Accordingly, a pound flask of that explosive was poured into the hole,
which they closed over with wet clay and a heavy rock, leaving a
quill through which ran an extemporized fuse of cotton wick. All being
prepared, their fuse was lit, and they left the cave and waited.

Five minutes afterwards the dull sound of an explosion reached their
ears, but more than an hour went by before the smoke and fumes would
allow them to enter the place, and then it was to find that the results
did not equal their ex