As the passage turned again Sir Clinton halted.

“I’d like to have a look at these walls,” he said.

Cecil turned back and threw the light of the torch over the sides and roof of the tunnel.

“It’s very old masonry,” he pointed out.

Sir Clinton nodded.

“This is a bit of old Ravensthorpe, I suppose?”

“It’s older than the modern parts of the building,” Cecil agreed. He seemed to have overcome his ill-humour and to be making the best of things.

“Let’s push on, then,” Sir Clinton suggested. “I’ve seen all I wanted to see, thanks.”

As they proceeded, the tunnel walls drew nearer together and the roof grew lower. Before long the passage was barely large enough to let them walk along it without brushing the stones on either side.

“Wait a moment,” Sir Clinton suggested, as they reached a fresh turning. “Inspector, would you mind making a rough measurement of the dimensions here?”