So under cover of the trees they scaled the fence; then they carefully made their way toward the shop. The windows and door of this were closed, nothing was stirring. Near the door was scattered some rubbish and loose paper. The place had an utterly deserted look.

"Do you think he is there?" asked Pendleton.

"I will know in a few moments," replied the other. "Wait here."

Pendleton expected Ashton-Kirk to continue his cautious approach. But to his surprise the investigator with cool assurance stepped out from behind a tree and advanced toward the outbuilding; when he reached the door he opened it and calmly stepped inside.

The building was in one great room. It had some windows at the side, but the greater part of its illumination came from a huge skylight. As he closed the door behind him, Ashton-Kirk had a vague impression of something huge, made of steel rods and with far-stretching wing-like projections at the sides. But he had no time to give the mechanism even a glance; of greater interest was the small figure which sat at a wide work-table upon which a litter of drawings was scattered.

It was Locke; and as the slight jar of the closing door reached him he lifted his eyes and saw the intruder. If Ashton-Kirk expected any display of fear or other emotion, he was disappointed; upon each of his previous meetings with Locke the latter had shown great trepidation; but now he simply nodded quietly and seemed not at all surprised.

But as Ashton-Kirk made a step toward him, he rose and raised his hand in a gesture that was peremptory and unmistakable. The investigator paused; then Locke pointed to a chair directly before his bench, but some half dozen yards away; and when Ashton-Kirk smilingly seated himself, Locke did likewise.

Then in heavy characters he scrawled upon the back of one of the blue-prints.

"I was expecting a visitor, and fancied that it might be you."

This he held up so that the investigator might read it. Ashton-Kirk nodded. Again the back of a plan came into service and this time the investigator read.