He had now come to the point on which Bennett had written his warning. Quickly he opened the bag and took out the oxygen helmet, which he adjusted carefully over his head. Then he set to work with redoubled energy.
It was that drill as well as his pounding on the rock which had so alarmed Elaine and Aunt Tabby the night before and which now had been the signal for Kennedy's excursion of discovery.
. . . . . . .
Our man, whoever he was, must have heard us approaching down the tunnel, for he paused in his work and the noise of the drill ceased.
He looked about a moment, then went over to the prop and examined it, looking up at the roof of the chamber above him. Evidently he feared that it was not particularly strong.
From our vantage point around the bend in the passageway we could see this strange and uncouth figure.
"Who is it, do you think?" I whispered, crouching back against the wall for fear that he might look even around a corner or through the earth and discover us.
As I spoke, my hand loosened a piece of rock that jutted out and before
I knew it there was a crash.
"Confound it, Walter," exclaimed Kennedy.
Down the passageway the figure was now thoroughly on the alert, staring with his goggle-like eyes into the blackness in our direction. It was not the roof above him that was unsafe. He was watched, and he did not hesitate a minute to act.