“Absolutely; the rear is impossible, bricked-up; and the Avenue itself is a little too conspicuous. The bolts of this door, as far as I can make out, slide into heavy steel cups sunk in solid cement, and are controlled, of course, from inside. Judging from the thickness of these, and the sound of the door, it would take either a pound of soap and nitro-glycerine on the one hand, or five hours of hard drilling with diamond-point drills, on the other, to get through. We’ll say seven hours, altogether, to get into the building. Then comes the safe, or, rather, the vault itself. I had a casual glance at that safe this morning, before I got these duds on—dropped in to purchase an engagement ring, but was altogether too hard to suit. It’s a ten-tonner, I believe, and about as burglar-proof as it can be made. Nothing but a gallon of gun-cotton would make so much as a dent in it. But here again, explosions are not in my line. We’ve got to use these wits of ours. We’ve got to get in that safe, and we’ve got to get through that door! I can’t risk six hours of machine-shop work down there; and I’m still too respectable to drop into safe-cracking.” “Well, the combinations of that sort of vault, you know, aren’t often advertised on the ash-barrels.” “What do you mean?” “I mean we have got to get it by our own wits, as you say.” “The janitor, old Campbell, leaves the building about ten-fifteen every night. He’s also a sort of day-watchman, I find. He’s a pretty intelligent and trusty old fellow, absolutely unapproachable from our standpoint. Another thing, too, the place is webbed with Holmes’ burglar-alarm apparatus. It would take another hour or so to get the right wires cut off and bridged. I hate to feel squeamish at this stage of the game—but that Ottenheimer safe does look uninviting!” Frances walked up and down, with the little watch-case receiver and its handkerchief still crowning her heavy mass of dark hair, like a coronet, and the green wires trailing behind her, like the outline of a bridal-veil. She was thinking quickly and desperately. Suddenly she stopped in the midst of her pacing, and looked hard at Durkin. “I’ve found it,” she said, in a feverish half-whisper. “We’ve got to do it!” Durkin looked at her gloomily, still struggling with his own line of fruitless thought. “Here, Jim, quick, take this and listen!” She placed the receiver close to his ear as she spoke. “Now, that’s Ottenheimer himself at the ’phone. Can you catch his voice distinctly? Well, do you notice what kind of voice it is—its timbre, I mean? A plaintive-toned, guttural, suave, mean, cringing sort of voice! Listen hard. He may not be at the ’phone again today. Is he still talking?” “Yes, the old scoundrel. There, he’s finished!” “What was it about?” “Just kicking to some one down in Maiden Lane, because Judge Hazel, of the District Court, has overruled the board of appraisers and imposed a ten per cent. _ad valorem_ duty on natural pearls coming in.”