Somewhat mystified, Inspector Armadale did as he was bidden, entering the figures up in his note-book while Cecil stood back, evidently equally puzzled by these manœuvres.
“Thanks, that will do nicely,” Sir Clinton assured him when the task had been completed. “Suppose we continue?”
Cecil advanced a few steps. Then a thought seemed to strike him.
“It gets narrower farther on. We’ll have to go on hands and knees, and there won’t be room to pass one another. Perhaps one of you should go first with the torch. There’s nothing in the road.”
Sir Clinton agreed to this.
“I’ll go first, then. You can follow on, Inspector.”
Inspector Armadale looked suspicious at this suggestion.
“He might get away back and shut us in,” he murmured in Sir Clinton’s ear.
The Chief Constable took the simplest way of reassuring the Inspector.
“That’s an ingenious bit of mechanism in the panel, up above,” he said to Cecil. “I had a glance at it as I passed, since it’s all in plain sight. From this side, you’ve only to lift a bar to open it, haven’t you?”