tter
success in trying to find a way to open the place through which
he had descended.

"Nobody on earth knows that I am down here," he thought, "and
with Santiago sick and maybe dying, no one on earth probably
knows that there is such a passage."

But Billie was not the lad to sit down and cry. He had been in
tight places before and he had an abiding faith in his own
ability to do things. Therefore, he called up his courage and
slowly mounted the stairs leading to Santiago's patio.

At the top of the stairs he found himself confronted by exactly
the same condition as he had found on the opposite side.

"But there is this difference," muttered Billie. "I know that
there must be some sort of a crack where that slab fell back."

He held the electric bull's-eye close to the stone and
scrutinized every spot.

Not a single crack could he spy.

Then he took out his big jack-knife and prodded with it clear
across the width of the stairway.

There was nothing but solid stone.

"Looks kind o' desperate," he told himself, "but I have simply
got to find an opening."

Again he prodded the place over without result.

"It's no use," he finally said to himself. "If I am to get out of
here, help will have to come from somewhere outside. But how can
it?"

He sat down on the stairs and thought deeply.

"If it is as I think," he mused, "these stairs have been used
recently. The very fact that Ambrosio is prowling around here is
proof that Strong must have been here at some time. But where is
Strong?"

He slid down several steps and threw the light of his torch
across to the opposite stairs.

"Bang!" went something that sounded like a falling stone.

Billie sprang to his feet.

"Click! Bang!" and down the opposite stairway streamed a ray of
light.

Billie shut off his electric torch and waited.

Then on the steps there appeared a foot, then another, until a
whole human body was in sight. Then "click, snap!" and the light
disappeared.

"By George!" exclaimed Billie under his breath, "there's a man on
the stairs right opposite to me. Who on earth can it be?"

His first inclination was to turn on the light, but on second
thought he decided not to.

"I'll let him set the copy," thought Billie. "It's a mighty good
thing to be able to spring the surprise."

He drew his automatic and stood ready for any emergency.

It was still as a tomb.

He could hear his own heart beat and he could also hear the heavy
brea