“No, I don’t. And I don’t know which is the right way, so we’ll have to hope for the best. We’ll try to walk in a straight line, and perhaps we’ll leave this fog behind.”

But they did not, Either the mist had spread out over a wide area, or, as the children began to suspect, it was moving with them. They made very slow progress; every few paces they would stop and listen, but there was only the silence of the mist, and that was as unnerving as the sound of something moving would have been. Also, it was impossible to see for more than a couple of yards in any direction, and they were frightened of falling into a hidden shaft, or even the quarry, for they had lost all sense of direction by now.

The path seemed to have vanished: but, in fact, they had crossed it some minutes earlier without knowing. As they approached, the mist had gathered thickly about their feet. hiding the ground until the path was behind them.

After quarter of an hour Colin and Susan were shivering uncontrollably as the dampness ate into their bones. Every so often the trunk of a pine tree would loom out of the mist, so that it seemed as though they were walking through a pillared hall that had no beginning, and no end.

“We must be moving in circles, Colin. Let’s change direction instead of trying to keep in a straight line.”

“We couldn’t be more lost than we are at present, so we may as well try it.”

They could not believe their luck. Within half a minute they came upon an oak, and beyond that another. The fog was as dense as ever, but they knew that they were breaking fresh ground, and that was encouraging.

“Oh, I wish Cadellin would come,” said Susan.

“That’s an idea! Let’s shout for help: he may hear us.”

“But well give our position away.”

“I don’t think that matters any more. Let’s try, anyway.”