“If it’s connected up with any signalling apparatus a complete revolution of that lever also might sound an S.O.S.,” suggested Buck Granger.
“Or it might mean ‘slip out’ while the slippin’s good,” put in Ollie.
“Oh, it might mean any one of a thousand things, such as ‘stop orating’” George Harper spoke up, impatiently, “but I’m inclined to believe Tom’s right. Let’s try it, anyway.”
Tom was just reaching for the small lever when another suppressed moan, unquestionably from directly beneath their feet, arrested his hand.
“There’s someone down there under the ground,” said Tom, in an awed whisper. “I believe there’s some connection between that person and this thing here. I’m going to try it anyway. Suppose you fellows stand back there against the opposite wall, in case anything happens to me when I turn this lever. And Ollie, you hold the light so that it will be directly on the dial.”
Not knowing what to expect, the three youths stood with their backs against the opposite wall, staring at Tom’s hand as the fingers closed on the lever and he began turning it toward the mark O, in the direction the arrow indicated.
Slowly he pushed it round until the point was directly over the O. Tom stepped over to where the others were, and he was just in time. There was a sucking sound, such as is made by drawing one’s boot out of oozy mud, and then the ground where Buck Granger had slept began to move upward!
The lads stood huddled together. The ground, which proved to be but a very thin layer, gave way, and a trap door lifted itself slowly into the air.
Tom was the first to move. He stepped over and peered down into the hole.
“Great guns!” he gasped, in a quivering voice.