For a quarter of an hour or more Atherton prodded the stone and groped for a concealed spring.
"We're done again, I'm afraid," he remarked. "We must retrace our steps. Blow one of the candles out, Mayne. We've none too much left. I didn't reckon on this."
"It won't do to be stranded in this hole without a light," agreed Mayne. "What about the lanterns we left behind us?"
Atherton picked up the two candle-lamps. In one there was less than a quarter of an inch. In the other there was hardly as much, and what made matters worse, the Scouts who took spare candles had not handed them over to their comrades when the latter set out on their second journey through the tunnel.
"Back as fast as we can," ordered Atherton. "Don't wait to bring that bowl with us. It will be quite safe here."
Lighted by the glimmer of the solitary candle, the Scouts hastened on their homeward way.
Presently Green called out:
"I say, Atherton. What's that noise?"
A dull swishing sound came faintly to the ears of the listeners.
"It's like a tap running," remarked Mayne. "Water running into a bath, for example."