"Nobody about except the tall thin chap," he puffed as he reached them and flung himself down in the heather. "He hadn't seen them. They're not there, Peter, and I couldn't find Mrs. Sterling either... If I had I think I'd have told her... Anyway we'd better get on, and I suppose the best thing to do is to go right up to the top if we don't find a clue first."

So Jenny, rather silent now as she realized that the others were really worried, led the way up the track.

Black Dingle looked very different to David this morning. When he had hurried down it two evenings ago in the rain he had noticed little beyond the fact that it was lonely and rocky. Now, in the sunshine, he could see how wild was this country and how difficult it was going to be to find the twins if they were in hiding or if they were hurt. As they climbed the winding track and jumped the stream which all the time tinkled at their feet, David watched anxiously for any sign that Dickie and Mary had come this way.

Every hundred yards they stopped and whistled and called the "Peewit" cry, and then listened anxiously for an answer.

David said suddenly:

"What are all those black marks on that cliff over there, Jenny? What is that place?"

"I was telling Peter the other day. They're caves I think, or the entrances to the old mines."

"Of course," he replied. "I remember Reuben told us about the mines and how dangerous they were. It would be grand to explore up there one day. What are they like, Jenny?"

"I've never been right up there," she said. "But somewhere over on the left there are ruins of some miners' cottages. I hate them. They're old and falling to bits and smelly and full of bit-bats."

"There ought to be a track leading over to them. Have we passed it, Jenny?"

"No, but we're nearly there. It's where Peter and me heard that horrible screaming noise that night the mist came'"

"I wish I knew what that noise was," Peter said. "I told you about it, David, and you laughed - but you didn't jolly well hear it. You'd have hated it too."

"It was here," Jenny said suddenly. "I remember this hawthorn tree. And this path going off to the left here must be the one that leads to the ruined cottages. This was the place, wasn't it, Peter?"

"Yes - I think it was... What are we going to do now, David? Ought we to separate, do you think? Perhaps somebody ought to go up to the top to the Chair? We don't even know if they came this way, do we?"