We were trespassers in a private park. To our right was a large house, only partially seen through its screen of trees, but it was evidently mellow with age. To our left, toward what was evidently the extremity of the park, was hilly ground, which had been allowed to run wild.
"That is our way," he said. "We'll use what cover we can."
We plunged into the wood again, and were soon in the wilderness, forcing our way, sometimes with considerable difficulty, through the undergrowth. Once or twice the professor gave me a warning gesture, but he did not speak. He had evidently some definite goal, and I was conscious of excitement as I followed him.
For an hour or more he turned this way and that, exploring every little ravine he could discover, grunting his disappointment each time he failed to find what he was looking for.
"I said I wasn't certain," he whispered when our path had led us into a damp hollow which looked as if it had not been visited by man for centuries. "My theory seems—and yet this is such a likely place. There must be a way."
He was going forward again. The hollow was surrounded by perpendicular walls of sand and chalk; it was a pit, in fact, which Nature had filled with vegetation. The way we had come seemed the only way into it.
"Ah! this looks promising," Quarles said suddenly.
In a corner of the wall, or, to be more precise, filling up a rent in it, was a shed, roughly built, but with a door secured by a very business-like lock.
"I think the shed is climbable," said Quarles. "Let's get on the roof. I am not so young as I was, so help me up."