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.