They stepped down. “That’s right, Daventry—that’s where you saw them—and I’ve one in my pocket as well—that I took from the ink-bowl.” He started to walk round the rockery—his eyes searching everywhere—keenly alert but apparently anxious as well. “I can do with half a dozen of these pieces of paving,” he called over his shoulder to Peter. “Half a dozen of the smaller pieces—the size that I could pick up pretty comfortably—get them for me, will you—you’ll probably find the kind I want round the top of the garden.” Peter made his second undignified scramble to the summit of the rockery. He quickly collected a few and tossed them one by one down to Anthony below. He watched the latter pick them up and in turn examine them with the greatest care. Peter noticed that he paid particular attention to the underneath part of each piece that he looked at. Then he shook his head doubtfully as though dissatisfied with the turn that events were taking. Picking the rocky pieces up again, he subjected them to a further examination. “You command the back of the house from where you’re standing, Daventry——or at any rate part of it—is there anybody about?” Peter looked across—and then back over the stretch of grass that ran to the doors of the library, and saw no one. “Not a soul,” he called with cheerful assurance. “Good man,” said Anthony, “I’m rather keen that we shouldn’t be observed at this particular moment.” Then an idea seemed to strike him suddenly. With his eyes on the path of the rock garden he began to walk around—keeping the fountain in the center. He had almost completed the entire circle when he came to an abrupt stop. “Quick, Daventry—come down here.” Peter picked his way down. “Look at the side of this path—the side nearest the pool—does anything suggest itself to you?” Peter adjusted his thinking-cap. He gazed carefully at the side that Anthony indicated—there was a slight declivity where the path made its natural shelving towards the pool. The meaning of what he saw was instantaneously obvious to the most elementary powers of observation. There was the impression of a stone—but there was no stone near anything like the shape delineated in the soft soil. Anthony rubbed his hands. Peter knew the gesture to signify pleasure and success. “I see what you mean,” said the latter, “there’s a piece of paving missing!” Anthony looked all round. Then came to a decision. “Daventry,” he said, “I’m going to ask you to do me a favor. Somewhere in that pool lies the missing stone—you know its shape.” He bent down and inspected the impression at the side of the path. “It’s roughly the shape of a magnum of champagne—about fourteen inches in length and at its widest part—the part corresponding to the bottom of the bottle—about half that size.” “What do you want me to do?” inquired Peter. Anthony grinned. “I want you to go paddling.”