"Sounds rather like a smuggler's ghost pelting us," said Jimmy. "A damned dangerous thing to do in a place like this without shouting 'Heads' or 'Fore' or any kind of warning." "Jimmy," said Beth, "I'm terrified." She was experiencing for the first time in her life a kind of fear which she had often laughed at. It is easy enough to be cheerfully sceptical about ghosts in broad daylight and among familiar things, or to boast of immunity from spookiness when nothing unusual is happening. It is quite another matter when stones take to falling out of a black unknown into a narrow, gloomy place, where every movement and every word make hollow sounds, horribly suggestive of infernal things, when the terrifying crash echoes from rocks on the right, on the left and above, when there is no way of accounting for such happenings. Then cheery scepticism is likely to be chased away by awe. Beth was a prey to the kind of fear in which investigators of the occult find a painful delight, an excruciating ecstasy, which, in apologising to the rest of us, the experimenters call scientific curiosity. She clung tight to Jimmy's arm with both hands. For a minute or two they stood waiting and listening. No more stones dropped down the chimney. The noise of tapping and scratching which they had heard ceased. There was complete silence, as dull and heavy as the atmosphere of the cave. It was Jimmy who broke it. He had been puzzled by the noise above him and startled by the falling stone, but he had not felt the fear of the supernatural which had swept over Beth. When he spoke it was in a tone very reassuring to the girl who clung to him. "Futile sort of old ghost," he said. "I don't call one stone much of a demonstration, do you?" "But," said Beth, who was recovering her self-possession, "it wasn't really a ghost. I mean to say, it couldn't have been. But what was it? Who dropped the stone?" "If you ask me, I'm inclined to think----" There he stopped abruptly. The noises of tapping and scraping had begun again. Tap, tap, tap, far up above their heads, and then a crunching sound. It was as if someone at a considerable distance was striking with a pickaxe and shovelling up loose earth. Jimmy listened intently. "If you ask me," he repeated, "I'm inclined to think that somebody is trying to knock a hole in the roof of this cave. What's above us here, Beth?" "I don't know," said Beth. "The cliff, I suppose." "Well, then, there's somebody on the top of the cliff digging a hole. Can't imagine what he wants to do such a thing for!" He struck a match and looked up. The hole, a large space of inky blackness, was some six feet from the ground. It was wide and the rocks at its side were jagged. "If I could get a grip on that craggy bit that is sticking out," said Jimmy, "I could pull myself up into the hole. It's probably easy enough climbing after that. Just stand clear for a minute while I jump. I'll have a try at it."