"Wait a bit, there's another crack, smaller still, right along the edge of the step, between it and the upright slab."
They had both lowered their voices to a whisper. Armstrong gave the upright a push, near the middle. It was firm, unyielding. But pushing leftwards, he felt a slight movement, and at the extreme end, a very gentle pressure caused the slab to swing inwards easily, the right half of it at the same time moving outwards.
"By gum, it works on a pivot!" exclaimed Armstrong, under his breath. "We're on the track! But this opening's only about six inches wide; nobody but a baby could crawl through it."
For a few moments they held their breath, listening for sounds. All was silent. Then Warrender dropped on all fours and shone his torch into the dark gap. The space was empty. Armstrong thrust in his hand, and felt over the earthen floor, then along the edge of the flagstone, and finally beneath it.
"There's a hollow space here," he said. "And, I say, here's a metal hand-grip just below the flagstone."
He tugged it; there was no movement. He pushed it on each side in turn, still without result. Baffled, he sat on his haunches.
"What's the hand-grip for?" he said. "Obviously for moving something. Then why doesn't anything move?"
"Perhaps it can only be operated from below," Warrender suggested. "If this is an entrance to the cellar, it may be left open when any one comes this way."
"That's not likely. An entrance that can only be opened from one side isn't worth much. No, something sticks, and if that fellow went through a few minutes ago, it can't be for want of use. Why does it stick, then?"
Armstrong pondered for a few moments, then said suddenly, "Possibly it's my pressure on the stone. Let's try."