The Riddle of the Yellow Zuri

by Harry Stephen Keeler

  Carson leaned forward. “Mr. van Twillingham, you may have had a good many offers today — and probably from cranks galore — but I am certain that in the man-trap invented by Cary Desmond, my future brother-in-law, is about the closest thing you can ever get to a device which is both a practical safe and a trap at the same time. Incidentally I am here to tell you that not only are we prepared to deliver over to your consideration the idea itself as well as the working model, but that we are in a position, strange to say, where we can actually demonstrate the trap before your eyes.”

  “To demonstrate!” ejaculated Reggie. “Why — why — you don’t mean — Why say — that’s a sporting proposition — but who’s the goat? One man came here today with a scheme for having a dynamite bomb underneath a safe with a trigger that explodes it when anyone sets foot on the ledge in front of it. Think of having a blooming thing like that around the house, eh, what? My own shotgun idea was defective enough, for a decent flashlight would probably have shown up the threads I had stretched over the floor, and a cracksman could have stepped over them. Another man — but — well, my friend, nobody has offered yet to demonstrate their invention.” He was all attention.

  “Mr. van Twillingham,” said Carson earnestly, “if you were to examine the newspaper files of the past few days you would come across a certain fantastic story which describes a much-wanted Indian snake which is locked up in a little safe out on St. Giles Lane in this city. The reporter who wrote that story drew very copiously upon his imagination, for in itself that snake is not valuable nor is it wanted by any Indian priests. What the facts are is that the markings of the snake are the sole key to the location of a stolen twenty thousand dollar Federal Reserve Bank gold note, for they were used by an illiterate Missouri hill-girl to mark the position of an envelope in which she hid it.” As rapidly as possible Carson sketched in the story of Jake Jennings, Lola Higgs Jennings and Casper Wolff, sticking to the skeleton of the story only and passing over its elements in quick succession.

  “Now,” he said in conclusion, “it was absolutely necessary for those crooks to get their hands on that snake for a minute, or just the fraction of a minute, in order to find out where the blotter containing that stolen twenty thousand dollar bill went to. The further details of this entire yarn I will not use up your time nor mine narrating today. Suffice to say that this crooked St. Paul lawyer of whom I spoke tried to play a hand, and nearly won out. What he did was to engage a woman handcuff expert known on the stage as Madame Mercedes, but whose right name is Kate Barwick, to go with him to the house last night and look things over. As a result it is all arranged between them that she is to come to this St. Giles Lane house tonight, drill a hole so many inches below and to one side of the combination, and then release the mechanism with a wire by some method known to her only.”

  “I take it,” commented van Twillingham, now much interested, “that the trip last night to the house was to determine the exact make of the safe?”

  “Exactly,” said Carson. “The make is a fairly common one among the old-fashioned strongboxes — Amos Todd and Sons, Type B-18, date 1864. This was the necessary data which had to be secured. Tonight operations are to be slightly different. The St. Paul lawyer is supposed to be hidden in an old building-materials shack across the street from this cottage, and this Kate Barwick is to come direct to the house after an interchange of flash signals between them assuring her that the coast is clear. What is most reprehensible about it is that the woman blindly thinks she is aiding a good cause — a legal cause — and even refuses to take money for her work.” With which remark Carson went into slightly more detail about that phase of the matter.

  “But, my dear fellow,” said van Twillingham, after Carson had finished, stroking his chin troubledly, “while I’ve no objection to killing a blooming cracksman that enters my house to steal my valuables, I — I can’t kill a woman, you know. Really I can’t.” He paused. “And — and you haven’t even explained this man-trap yet.”

  “No,” returned Carson, “we can’t very well kill a woman, but I have schemed out a method by which we can see the action of this safe and still not despatch any living being. For one thing looms up above everything else: she is the victim of an adroit lie herself, and we can’t for that reason alone murder her in cold blood.” He paused. “And now for a description of Mr. Cary Desmond’s man-trap.”

  CHAPTER XIX

  INFORMATION FROM AN M.D.

  CARSON crossed his legs and leaned back in the comfortable over-stuffed armchair. Then he spoke.

  “Mr. van Twillingham, I don’t know whether you know much about hydrocyanic acid gas, but it is probably the quickest poison known on this earth. One whiff of the pure gas means instant death. Scheele, the great Swedish chemist who discovered it and experimented to some extent with it, fell dead on the floor of his laboratory after inhaling some from a retort he had accidentally broken. If a man inhales this gas, he dies. The Germans would have used this gas in the war — in fact they attempted to use it — but it was found that when fired in shells from cannon, the terrific concussion and intense heat broke down the deadly molecule into harmless molecules. Hydrocyanic acid gas, in other words, must remain quiescent and at normal temperatures to remain hydrocyanic acid gas — it cannot be transported around and subjected to high and low extremes of heat and cold.

  “It is,” continued Carson, “on the principle of hydrocyanic acid gas that the Cary Desmond Man-Trap has been devised by its young inventor. The idea is simple — yet if you search the patent offices at Washington you will not find anything even remotely touching upon the idea or its application — and in treating with you as one gentleman treats with another by openly discussing and elaborating a secret — I am divulging an idea which at present is known only to one girl and two men, the latter two being Mr. Cary Desmond and myself with whom he consulted.

  “Now the Cary Desmond safe, of which there is one working model,” Carson went on, “is nothing more nor less than a hollow safe, the inside and outside shells of which are about a half-inch thick. You might look upon it to a certain extent as two safes, one within the other, the inner one held equidistant from the outer one by the fact that the frame of the opening into which the door swings is common to the inner and outer shells. That is to say, they are held together at the front of the safe, and have a common door — the safe door itself which tapers inward by a series of steps, its large outer face completing the face of the outer shell, its small inner face completing the inside receptacle when the door is to and locked.” Carson paused. “Is it quite clear to you, Mr. van Twillingham?”

  “Oh yes,” the multi-millionaire replied slowly. “I get the arrangement perfectly. But I want to hear more about it. Pretty difficult thing to cast, wasn’t it?”

  “Yes,” replied Carson. “Mr. Cary Desmond, who had had some training along those lines when a boy, cast it himself in a small foundry at night with only myself to assist him. In order to obtain the hollow space running around the five sides of the safe, it was necessary to use what is known as a baked sand core. One of the odd problems we faced was the getting of the core out after the casting was finished. Through a certain aperture that leads from the outside to the hollow interior of this device, we had to inject water with a hand syringe, at first just a few drops, later a great deal, washing out the sand core bit by bit. It required several days to fully clean out the hollow space. But this is purely one of the technical problems connected with casting difficult objects, and I will not bore you with any more of them. Suffice to say that we obtained a perfect casting, its outer dimensions taken directly from the old Amos Todd and Sons, Type B-18, 1864 safe in Mr. Cary Desmond’s home.

  “Now the aperture through which the sand core, which makes the hollow part of the safe, was washed out,” continued Carson, “was no other than one of the four legs. Three of the legs, in other words, are solid, but the fourth is hollow and threaded inside to take an iron pipe running upward through the floor. Th
at hollow leg, as you have already perceived mentally, leads directly to the space between the inner and outer shells of this hollow safe.” The younger man paused.

  Reggie van Twillingham was not thick-headed by any means. “I get the construction perfectly,” he commented, “and I am beginning to see the idea back of it. But a question about the safe door itself. Is this door solid? Or is it hollow too? If it is hollow, I take it that it too is connected with the space between the metal shells that comprise the double safe. But how?”

  Carson smiled. “That is a good question, Mr. van Twillingham, and involves one of the unique points of the mechanism. The thick safe door is, as you surmise, hollow, and its interior is connected up to the hollow space between the inner and outer safe by two strong, tough, corded flexible rubber tubes, each with threaded steel nipples on either end, and each running through one of the two heavy nickel-plated hinges on which the door swings. Which means, of course, that the hinges are hollow. As for the rubber tubes, they give with ease and perfect safety a swing of 90 degrees to the door.”

  “I get it,” van Twillingham nodded slowly. “Go ahead.”

  “A hole has been drilled in the inner floor of the safe,” went on Carson, “and a small brass valve has been soldered there. An exhaust pump can be attached to this valve, and with the pipe leading from the hollow leg closed entirely by a special hand-valve of its own, the entire hollow space between the inner and outer shells — including the front door as well — can be made a vacuum. When this is done, the intention of the inventor is that for absolute safety against leakage the air valve projecting upward inside of the safe is to be completely sealed up and over with lead.” He paused. “But now let us revert once more to that hollow leg of which I spoke, and which in itself is nothing more than a pipe. This ornamental leg appears to terminate on the rug or carpet upon which the safe stands, but the pipe screwed into it goes directly through a hole in that carpet or rug, down through the floor and the ceiling beneath it, and into a chamber — say — in the basement of the building where the safe is in use. In this chamber, attached directly to the pipe leading to the safe, is a tank of Hydrocyanic Acid gas — death! — at a very high pressure of no less than sixty or eighty pounds per square inch. The hand-valve which connects and disconnects this tank of gas to the apparatus in the room upstairs can be operated electrically by a small motor geared to the handle of it. A long tube of mercury at least fifteen feet in height should be connected also to the tank of hydrocyanic acid gas, so arranged — it is a very simple matter to do this — that when the pressure in the tank drops by — say — one pound, the mercury falls, operates an electrical connection, and the motor which runs the hand-valve cuts off the tank entirely from the apparatus.

  “Now let us outline,” Carson went on, warming up to his subject, “just how we would prepare this entire mechanism, and how it would operate if a cracksman attempted to attack it. The first thing we would do, of course, would be to make a vacuum of the hollow interior of both safe and safe door, sealing up with lead the tiny aperture through which we induced that vacuum. Then by connecting to the system with our motor downstairs the tank of hydrocyanic acid gas, screwed and sealed to the pipe running upstairs, the hollow interior of our safe and of our safe door will fill instantly with hydrocyanic acid gas at a pressure of from sixty to eighty pounds per square inch, depending upon the pressure in the tank. And thus matters will remain. We may at any time swing open the door of the safe, deposit articles in or withdraw articles from the inside receptacle itself, because we have an air-tight system and we are on the outside of that system.

  “Now what results if a cracksman tries to open such a system? Where can he attack it? Can he blow it apart with nitro-glycerine? No, for the rush of gas that would come out would annihilate him and his brother yeggs completely. Can he blow off the door alone? No, for the severance of the hinges will also sever the rubber pipes inside them, and again he will be fatally caught by the rush of gas. For the same reason he can’t cut a section out of the safe by means of an oxy-hydrogen jet. Now suppose he tries to drill a hole somewhere in the safe? I can show you from the blue prints of that object that no matter where a hole is drilled it must pierce that interior chamber containing the high-pressure gas. There is no way in through the back, the sides, the top or the bottom. How about the front of it, around the door? There is no point there. How about the door instead? It is hollow. How about its edge? Well, it tapers inward in a series of fine steps. No matter how close to the edge of the door a hole is drilled, it must pierce the hollow interior either of the tapered door or of the tapered recess which receives the door. How about drilling in the hinge, for example? Again fatal, for the hinge is part of the whole system. So all this means that no matter where a hole may be drilled a blast of hydrocyanic acid gas at eighty pounds per inch pressure will shoot forth with such velocity that a cracksman could not even hold it back with the point of his drill. He would be a dead man before he even backed away from the safe. Consult Reese, James, any of the toxicologists and see for yourself how deadly hydrocyanic acid gas is.”

  “And how,” asked van Twillingham, with a slight smile on his lips, “do we pick up the dead cracksman without joining him in his profound slumber?”

  “That is the reason for the fifteen or twenty foot tube of mercury down in the chamber containing the gas tank,” answered Carson without any hesitation. “As soon as the gas has jetted forth from the safe for the space of a minute, the pressure in the entire system drops; the mercury in the tube drops also, it makes its electrical connection, the small motor attached to the valve of the tank cuts that tank off entirely, and at the same time — in view of the fact that you are a rich man and a little elaborateness and expense mean nothing to you — a couple of powerful fan motors set in round windows at the top of your library automatically start to draw all the atmosphere of the room to the outside. Within five minutes the room is cleared of the vapor, its air changed, and a steady circulation of fresh ozone maintained from the inside to the outside.” Carson made a gesture with his hands. “You cannot secure a one hundred per cent sure man-trap, Mr. van Twillingham,” he added, “unless you go to some trouble, and then at best it will only be 99.99 sure. I hope you’ll agree on that.”

  “I concede the fact,” returned van Twillingham. He sat back in his chair, his eyes closed. He seemed to be reflecting deeply. Thus he sat for a long two minutes. Finally he opened his eyes. “You have an idea there, I’m forced to admit, that is more ingenious than any I have had put up to me today. As you say, a little expense more or less in rigging it up means nothing to me. It seems, so far as I can see, ninety-nine per cent sure anyway. From your description of it I fail to see how a cracksman, unless protected by a special made-to-order gas mask, can touch it in any way whatever without fatal results to him.” He paused, thinking.

  “And cracksmen,” put in Carson, “haven’t yet begun to wear gas masks, and won’t dream of so doing until the first of their brotherhood gets carried out dead from a job like this. However — as to that possibility. If you will consult the April bulletin of the American Chemical Society, Mr. van Twillingham, you will see the full formulæ of two new war gases against which no sort of gas mask ever invented or projected has any efficacy. If you really think there exists such an ultra-modern cracksman as you have described — then it’s up to you to consider having either of these two other fatal gases made up for you by a chemical company.”

  “Well — we’ll let that pass for the present,” said van Twillingham. “It seems to me that your hydrocyanic acid gas is lethal enough. At least for the average cracksman. Anyway, we’ll just go ahead with the discussion on that presumption.” He mused a moment. “Hm, the more I think of your idea, the more it looms up like the real thing. As near perfect as any man-trap I’ve heard described today. For there’s nothing really perfect in the universe, as you say. And it does seem as though I’ve got to award the prize to somebody, or I’m undone in this town for the res
t of my days. Jove, I do believe that you come closer to justifying my awarding that prize than anybody. Although — ” He pondered again. “No guns, no dynamite, no guards — and yet the safe is impervious to the yegg.” He gritted his white even teeth. “And by the great pewter spoon I’d like to kill off a half dozen of ‘em before I’m done. But I ask only one — just one little yegg in my trap. Just one!” He paused. “One question: Suppose part of the contents of this closed system leak out either into the inner safe or into the room. Will the owner have to go ‘round perpetually with a gas mask on, or is there some way that he can be warned of this leakage?”

  “There is,” returned Carson quickly. “Mind you, the casting is perfect and there can be no leakage into the interior of the safe. Likewise the shaft of the unlocking mechanism, which is turned by the combination dial when properly manipulated, passes through a bushing cast as an integral part of the inner and outer shells and connecting those two shells; in view of the air-tight perfection of this bushing, there can be no leakage out through the combination dials. And with a perfectly joined up and sealed up system of piping I do not see that you need in the least fear the matter of leakage to the outside, but there is nevertheless a method by which you could be warned of this if you feared it. Suppose you should decide on hydrocyanic acid gas as the lethal agent. Then a small glass window in the door of the room where you decide to keep your safe, with a bit of blotting paper pasted to it and connected by a wick with a vial of ferrous chloro-sulphate will show blue if there is a trace of one in ten thousand parts of gas in the atmosphere of that room. This dilution cannot be fatal. The test window, for that or any other fatal gas, involves a little more detail, but as we have agreed you can’t have a 99.99 per cent efficacious man-trap unless you go to some trouble!”

  Reggie van Twillingham fell into a deep revery. “How do you intend to demonstrate this thing,” he asked at length, “without killing this Barwick woman?”