“We might as well take a picnic lunch and go off somewhere,” said Julian. “How about it?”

“Yes,” said Dick. “Can you pack us dinner and tea, Anne? We’ll help. What about hard-boiled eggs?”

It wasn’t long before they had a picnic meal packed in greaseproof paper.

“You won’t get lost, will you?” said Mr. Luffy.

“Oh no, sir,” said Julian, with a laugh. “I’ve got a compass, anyway, and a jolly good bump of locality, too. I usually know the way to go. We’ll see you this evening, when we get back.”

“You won’t get lost, Mr. Luffy, will you?” said Anne, looking worried.

“Don’t be cheeky, Anne,” said Dick, rather horrified at Anne’s question. But she really meant it. Mr. Luffy was so absent-minded that she could quite well picture him wandering off and not being able to find his way back.

He smiled at her. “No,” he said. “I know my way about here all right — I know every stream and path and — er — volcano!”

Anne giggled. The others stared at Mr. Luffy, wondering what in the world he meant, but neither he nor Anne told them. They said good-bye and set off.

“It’s heavenly walking to-day,” said Anne. “Shall we follow a path if we find one or not?”

“Might as well,” said Julian. “It’ll be a bit tiring scrambling through heather all the day.”

So when they did unexpectedly come across a path they followed it. “It’s just a shepherd’s path, I expect,” said Dick. “I bet it’s a lonely job, looking after sheep up on these desolate heathery hills.”

They went on for some way, enjoying the stretches of bright heather, the lizards that darted quickly away from their feet and the hosts of butterflies of all kinds that hovered and fluttered. Anne loved the little blue ones best and made up her mind to ask Mr. Luffy what all their names were.

They had their lunch on a hill-top overlooking a vast stretch of heather, with grey-white blobs in it here and there — the sheep that wandered everywhere.

And, in the very middle of the meal, Anne heard the same rumbling she had heard before — and then, not far off, out spouted some white smoke from the ground. George went quite pale. Timmy leapt to his feet, growling and barking, his tail down. The boys roared with laughter.

“It’s all right, Anne and George. It’s only the trains underground here. We knew they ran under the moors and we thought we’d see what you did when you first heard them rumbling, and saw the smoke.”

“I’m not a bit frightened,” said Anne, and the boys looked at her, astonished. It was George who was the scared one! Usually it was quite the other way round.

George got back her colour and laughed. She called Timmy. “It’s all right, Tim. Come here. You know what trains are, don’t you?”

The children discussed the trains. It really did seem queer to think of trains in those hollowed-out tunnels down below the moors — with people in them, reading their newspapers and talking — down in tunnels where the sun never shone at all.