"In about thirty hours' time."

The professor's sense of direction was marvelous. Having reclimbed the shed which blocked the entrance to this concealed pit, he made practically a straight line for the place at which we had entered the wood from the road.

"I daresay one would be allowed to see over the house, but perhaps it is as well not to ask," he said. "We can do that later. I'm tired, Wigan; but it was safer not to keep the carriage."

Try as I would, I could get no explanation out of him either that night or next day. He was always as secret as the grave until he had proved his theory, and then he seemed anxious to forget the whole affair, and shrank from publicity. That is how it came about that I obtained credit which I did not deserve.

"We go there again this evening," he said after lunch next day; "so a restful afternoon will suit us."

It was getting dark when we set out, and again Quarles's unerring sense of locality astonished me. He led the way without hesitation. This time he took more precaution not to make a sound when climbing over the shed into the narrow path.

"I think we are first, but great care is necessary," he whispered.

We crept forward and concealed ourselves among the scrub vegetation which grew in that part of the pit which was open to the sky. It was dark, the long shed barely discernible, but the professor was particular about our position.

"We may have to creep a little nearer presently," he whispered. "From here we can do so. Silence, Wigan, and don't be astonished at anything."

The waiting seemed long. Moonlight was presently above us, throwing the cave part of the pit into greater shadow than ever.