"Because it's high tide twice a day--approximately every twelve hours. I looked up a tide-table in the hall out there and found it was high at one eleven this morning and low at seven thirty-five--just about an hour turned when I had my swim, the water-line then about twelve feet short of the marks of the boat. It'll be high again about one forty-eight this afternoon--at least noon before water begins to wash over those marks." He puffed voluminously. "If there was any shenanigan afoot last night, a couple of thick-heads footed it--that is, if they cared whether they left any clues or not." Constrained to fill in his expectant pause, she made shift with a "How very odd!" that was a triumph of naturalness. "Isn't it?" he agreed. "Now what do you make of it?" "Nothing," she replied truthfully, for she was entirely at a loss to fit this new development into the adventures of Lyttleton and the lighted window--and make sense of it. "I can't imagine--" "What I want to know is this," Trego propounded cunningly: "had Lyttleton anything to do with it?" She had prepared for that question, had settled her answer beforehand; even with any real reason to suspect Lyttleton of complicity in something underhand, she would not have betrayed him to this man--if to anybody. "I'm sure I can't say." "Well--it's funny, anyhow. Guess we better not say anything about it. After all, it's no concern of ours." She couldn't refrain from the question: "But why should you think he--?" "Well, what _was_ he doing all that time--?" He checked and stammered with embarrassment. "I beg your pardon!" "You needn't. He wasn't--with me--all that time." The situation grown intolerable, Sally got up suddenly and without a word of excuse took her scarlet cheeks out of the dining-room and back to her bedchamber. On the dot of their standing appointment she found Mrs. Gosnold unconsciously, perhaps, but none the less strikingly posed in the golden glow of her boudoir window for the portrait of a lady of quality on fatigue duty--very much at her ease in a lavender-silk morning gown and stretched out in a _chaise longue_, a tray with fruit, coffee and rolls on her left dividing attention with a sheaf of morning notes on the other side and the portable writing-case on her knees. Acknowledging Sally's appearance with a pleasant if slightly abstracted smile, she murmured: "Oh, is it you, Miss Manwaring? Sit down, please. Half a minute . . ."