Feeling very happy all by herself, Anne walked on and on. She came at last to a big mound of a hill-top. The little stream began there, half-way up the mound. It came gurgling out of the heathery hillside, edged with moss, and made its chattering way far down the hill.

“So that’s where you begin, is it?” said Anne. She flung herself down on the heather, hot with her climb. It was nice there, with the sun on her face, and the sound of the trickling water nearby.

She lay listening to the humming bees and the water. And then she heard another sound. She took no notice of it at all at first.

Then she sat up, frightened. “The noise is underground! Deep, deep underground! It rumbles and roars. Oh, what is going to happen? Is there going to be an earthquake?”

The rumbling seemed to come nearer and nearer. Anne didn’t even dare to get up and run. She sat there and trembled.

Then there came an unearthly shriek, and not far off a most astonishing thing happened. A great cloud of white smoke came right out of the ground and hung in the air before the wind blew it away. Anne was simply horrified. It was so sudden, so very unexpected on this quiet hillside. The rumbling noise went on for a while and then gradually faded away.

Anne leapt to her feet in a panic. She fled down the hill, screaming loudly: “It’s a volcano! Help! Help! I’ve been sitting on a volcano. It’s going to burst, it’s sending out smoke. Help, help, it’s a VOLCANO!”

She tore down the hillside, caught her foot on a tuft of heather and went rolling over and over, sobbing. She came to rest at last, and then heard an anxious voice calling:

“Who’s that? What’s the matter?”

It was Mr. Luffy’s voice. Anne screamed to him in relief. “Mr. Luffy! Come and save me! There’s a volcano here!”

There was such terror in her voice that Mr. Luffy came racing to her at once. He sat down beside the trembling girl and put his arm round her. “Whatever’s the matter?” he said. “What’s frightened you?”

Anne told him again. “Up there — do you see? That’s a volcano, Mr. Luffy. It rumbled and rumbled and then it shot up clouds of smoke. Oh quick, before it sends out red hot cinders!”

“Now, now!” said Mr. Luffy, and to Anne’s surprise and relief he actually laughed. “Do you mean to tell me you don’t know what that was?”

“No, I don’t,” said Anne.

“Well,” said Mr. Luffy, “under this big moor run two or three long tunnels to take trains from one valley to another. Didn’t you know? They make the rumbling noise you heard, and the sudden smoke you saw was the smoke sent up by a train below. There are big vent-holes here and there in the moor for the smoke to escape from.”