The roof was low in places and the boys bumped their heads till they got used to looking out for a sudden dip in the roof. They trailed on, with only the light of Barney’s torch. The tunnel smelt dank and musty, and Roger hoped the air was good enough. If it was bad they might faint and fall down! ‘Just as well we left Di behind to raise the alarm if we don’t get back,’ he thought. The tunnel took a sharp bend, and ran downwards instead of level. The boys went on steadily. They all wished they had warm coats on, for they felt very chilly indeed. Suddenly Barney stopped and pointed with his torch to something. A tree-root had penetrated through the roof of the tunnel and hung down in front of them! It looked very strange. ‘We’re under the trees now,’ said Barney in a whisper. ‘We shall soon leave the wood behind and come to the stream. I bet the tunnel takes a big dip under that, to get away from the damp river-bed!’ It did.
