Uncle Micah shook his head.

"Not unless the old engine other side of Dingle pulls her back. But why was that lad riding her?"

The policeman had removed his helmet and was mopping his forehead. He was beyond words. Nothing like this had ever happened before, and he seemed bewildered as well as out of breath. Then David stepped up to the overhanging cliff and shouted again and again for Tom. Jenny echoed him, while Mr. Sterling and the policeman went down on their knees and examined the stones blocking the entrance. When no answer came to their calling, David and Jenny turned to help, and then there came from somewhere above their heads the unmistakable voice of Dickie.

"Except that we're high up and they're all low down, it's like that story where a man came stalkin' through the jungle after months and months of weary explorin'..."

"Oh, I know, Dickie," Mary interrupted, "and then they came to a place full of black men, except just for the man they were seekin' and said..."

"Dr. Livingstone, I presume?"

"All right, David, don't make such faces. We can see you."

"And a jolly long time you've been coming," Dickie went on indignantly. "We were getting worried 'bout you."

David's fury at being addressed so patronizingly quite swamped his relief, and he rushed back to where he could see the twins leaning precariously over the rock ledge and grinning down at the rescue party. Behind them was the cheery face of Tom, who called:

"Gosh, David. That was some trip. Did you see us come over? I thought we were goners, though, for the brakes didn't work, but it stops itself in there somehow and comes rolling back. Say, David, we must all have a go on this tomorrow. It beats anything on the pictures."

But before any of the rescuers could answer, the twins started again.

"Hello, old Uncle Micah!" Mary called cheekily. "We want to see you very badly. We've got a lot of things to ask you."

"Jus' look what they've brought for us, twin," said Dickie. "It's a policeman. A real policeman."

An unmistakable snort came from the representative of the law, but it was Jenny who asked the sensible question:

"How did you two get in there?"

The twins looked at each other and David took the opportunity to speak again.

"Are you all right, Tom? And are those kids all right? And have any of you seen Peter?"

Tom pulled the twins back by the seats of their shorts and leaned forward.

"We're all O.K. as far as I can see. Peter's here, too, wanting to have a word, but from what they tell me they can't get out of here 'cos the mine is blocked up the front as well as the back. You'll have to chuck up a rope to us here, I reckon. All right, Peter. Give me a chance."