"Oh, yes, we do," David shouted excitedly. "You bet we do, Peter. We were right! They've been this way. Look!" and he bent down and picked up something small and brown and held it almost reverently in the palm of his hand as the girls jostled him in their eagerness to see the treasure.

"Why," said Jenny, "it's just an old 'conker' with a hole through it."

"That's it," said David. "It's Dickie's 'mastock,' as he calls it. He's had it since last autumn, and it's the most amazing conker in the world. He says it beat the whole school, and I know that he carries it with him wherever he goes. It's the only thing he changes out of his pockets. Haven't you ever seen him with it, Peter?"

Peter shook her head. "No, I haven't, but it sounds like him. What shall we do now, though? Which way shall we go?"

David looked at the ground again and then up at the steep and precipitous sides of the valley over on their left.

"What's that?" he said sharply, and pointed over their heads. "Is this where you heard that odd row in the mist, did you say?"

The girls nodded and then looked up. High above them, stretching right across the sky, were four thin black lines. As their eyes followed David's outstretched hand, they could see that they seemed to reach the cliff face over on their left and disappeared by one of the black openings that Jenny believed to be caves.

"Wires!" said David excitedly. "It's a cable railway, I believe. I expect that's an entrance to a mine over there, and it looks as if the cable takes the cars right across the valley... but I can't see where it finishes on the other side, can you?"

"No," said Jenny. "The trees get in the way. That side of the valley isn't as steep... But what was the noise? Wires can't make a noise, and this was awful... I don't believe it was earthly," she added in an awed whisper.

"I expect it was one of the cable cars rushing across the valley," David said.

Peter looked scared. "But nobody uses the mines. They've been deserted for years, Jenny said. You did say so, didn't you?"

"Of course it wasn't a cable car," Jenny replied. "It couldn't have been. Dad told me once that long before I was born the last miner left these parts... The noise we heard was a beastly noise, and I think it was one of the Seven Whistlers or something... And you needn't ask me to go up to the Chair, because I won't. I'd rather go home and get into trouble there. I'm not going to be left alone, anyway..."

David interrupted. "All right," he said briefly and pocketed the conker. "Come on - we'll go over towards those ruined cottages. The mastock was on this path."