“And your three thousand pounds!” muttered the Chief Constable, aside to Blick. “Well, Mr. Spindler,” he said aloud, “I can assure you that no scientific papers of the sort you refer to were found on Mr. Guy Markenmore’s dead body—we have everything that was found. But just tell me—that formula of yours? Supposing it fell into the hands of anybody who knew what it was—what it was all about, I mean—would it be of use?” “Of use?” vociferated Spindler. “I should just think it would! Why, of course, it tells exactly how to manufacture this particular dye!” “Then—it would be worth anybody’s while to steal it?” asked the Chief Constable. “Worth anybody’s while?” exclaimed Spindler. “Goodness gracious me!—don’t I tell you Markenmore was giving three thousand pounds for it?” “Just for the papers?” “The secret is on the paper—a paper—an ordinary sheet of note-paper! There were, of course, some other papers—memoranda. But if _the_ paper falls into the hands of—of anybody—why, of course, my secret’s lost! Are you sure it wasn’t on Markenmore’s body?—just a sheet?—it would look like a prescription.” They saw by that time why Mr. Eustace Spindler had called. It was not to give information, but to get news. And they had none to give him. “There were no papers of that sort on Markenmore,” said Blick. “But—they may be at his office in London, or at his private residence. We’ll do what we can for you, Mr. Spindler, and as soon as possible.” But when Spindler had gone, highly concerned, and dissatisfied, Blick turned to the Chief Constable and shook his head. “We know from what Lansbury told us that Guy Markenmore had the papers this chap speaks of on him that night at the Sceptre!” he observed. “He must have had, because it was about them and the secret and the price that the discussion was. Probably he had the formula and Professor What’s-his-name’s opinion on it. In that case he’d have them when he left the Sceptre—put them all together with the three thousand pounds’ worth of bank-notes. And whoever murdered him got ’em—with the notes!” “There’s another alternative,” remarked the Chief Constable. “He no doubt had the notes on him. But he may have handed over the formula and opinion to one of his fellow-purchasers.” “Not to Lansbury,” declared Blick. “He’d have told us.” “There was a third man,” said the Chief Constable, meaningly. “Von Eckhardstein.” Blick took two or three paces about the room, thinking. “I wish we could follow that up!” he exclaimed suddenly. “That fellow’s disappeared, and we’ve done nothing whatever to trace him. How do we know, after all, in spite of his being the wealthy man he’s reputed to be, that for purposes of his own he didn’t shoot Guy Markenmore and appropriate the money and the formula?”