"Marco, have you the box in front of you? . . . Is there anything particular about it? . . . Ebony inlaid with ivory. . . . Yes, I know the sort of thing. . . . Japanese, from the Faubourg Saint-Antoine. . . . No mark? . . . Ah, a little round label, with a blue border and a number! . . . Yes, a shop-mark . . . no importance. And is the bottom of the box thick? . . . Not very thick. . . . Bother! No false bottom, then? . . . Look here, Marco: just examine the ivory inlay on the outside . . . or, rather, no, the lid." He reveled with delight. "The lid! That's it, Marco! Kesselbach blinked his eyes just now. . . . We're burning! . . . Ah, Kesselbach, old chap, didn't you see me squinting at you? You silly fellow!" And, to Marco, "Well, what do you see? . . . A looking-glass inside the lid? . . . Does it slide? . . . Is it on hinges? . . . No! . . . Well, then, break it. . . . Yes, yes, I tell you to break it. . . . That glass serves no purpose there . . . it's been added since!" He lost patience. "Mind your own business, idiot! . . . Do as I say! . . ." He must have heard the noise which Marco made at the other end of the wire in breaking the glass, for he shouted, in triumph. "Didn't I tell you, Mr. Kesselbach, that we should find something? . . . Hullo! Have you done it? . . . Well? . . . A letter? Victory! All the diamonds in the Cape and old man Kesselbach's secret into the bargain!" He took down the second receiver, carefully put the two discs to his ears and continued: "Read it to me, Marco, read it to me slowly. . . . The envelope first. . . . Good. . . . Now, repeat." He himself repeated, "'Copy of the letter contained in the black morocco case.' And next? Tear the envelope, Marco. . . . Have I your permission, Mr. Kesselbach? It's not very good form, but, however . . . Go on, Marco, Mr. Kesselbach gives you leave. . . . Done it? . . . Well, then, read it out." He listened and, with a chuckle: "The deuce! That's not quite as clear as a pikestaff! Listen. I'll repeat: a plain sheet of paper folded in four, the folds apparently quite fresh. . . . Good. . . . At the top of the page, on the right, these words: 'Five feet nine, left little finger cut.' And so on. . . . Yes, that's the description of Master Pierre Leduc. In Kesselbach's handwriting, I suppose? . . . Good. . . . And, in the middle of the page, this word in printed capitals: 'APOON.' Marco, my lad, leave the paper as it is and don't touch the box or the diamonds. I shall have done with our friend here in ten minutes and I shall be with you in twenty. . . . Oh, by the way, did you send back the motor for me? Capital! So long!" He replaced the instrument, went into the lobby and into the bedroom, made sure that the secretary and the manservant had not unloosed their bonds and, on the other hand, that they were in no danger of being choked by their gags. Then he returned to his chief prisoner. He wore a determined and relentless look: