  Roger, in the dark, hearing the echoes of that crash, felt fright that nearly swept him into unreasoning panic. Not quite, though! With every effort of will he held his muscles steady when he wanted to run. Clear faculties would be all he had left to pit against an adversary certainly more than simply vindictive. The unknown was almost as brilliant in mind as was his cousin, Grover. Grover? Why he would have thought out that one and only way in. Roger, forcing himself to be calm, realized at once how his extra protection had been turned against him. He had wired to the telescope. Some one, climbing the candy factory fire escape, looking down from the roof of that building, could, by the angle of view, have seen him attach that wire, peering down past the bulk of the telescope. Thus charged, all the miscreant had to do was to lay a wire or rod or any metallic carrier, from the candy factory drains or rainspouts across to the skylight. By pushing it into contact with the heavy charge in the telescope, a short-circuit could be established that would blow even the main-line fuses. Thus, and in no other way, could the devices have been rendered impotent, the locks be only held by wires which a powerful implement in hands so adroit could easily sever. Even the alarms would not work. They had undoubtedly operated at the instant of the break, and in time a Falcon patrol agent and anyone who called police from home, would help him. But until then!—— He must, Roger knew, be his own protector. At ten Grover would arrive, using a pre-arranged signal. Not for an hour would he come. “Self-preservation is the first law of Nature,” Roger’s mind in a whimsical flash reminded him. Instead of throwing his faculties into a turmoil, the imminent danger calmed him. That much Grover had made him learn. By opening a way in, the miscreant had, for Roger, made clear a way out. He was, then, in no vital trap. He could afford to drive back panic, to think carefully what to do. If the whole building had been short-circuited, the telescope was no longer charged. He had climbed it. Climb it he could again. His problem, though, was to trap his unknown adversary if he could. With no electrical help he must think out a plan. It must be clever, Roger knew. His menace was from a man as brainy as was his cousin. And that, Roger felt, was a compliment to a very unjustified person. He thought he knew what the crash had been. Something deliberately upset in the cellar, to scare him. It had come about as long after the flash as would have been consumed in rising to the roof on a rope, scuttling down the fire escape, opening the cellar coal chute, and climbing down. He estimated the time that had since elapsed. The adversary had by now gotten up the cellar stairway and would be on the ground floor. Would he come further or try to lure Roger down, the solitary youth wondered. He must let that become apparent by what his keen ears would detect. He discarded all but attentive listening, making his mind focus on some plan to trap his adversary. What his mind had, with seeming whimsicality, obtruded during his moment of terror, came back to Roger. “Law of Nature.” seemed to prod at his thoughts. What law of Nature? How would it help? Almost as though some inner monitor was going to save him, a mental visualization of the laboratory seemed to become clear to his mind. He saw the ceilings, with the slim pipes that ran here and there to openings; and he connected the vision with the fact that their fire-protective apparatus had not functioned, when the alarm had been set off. The tanks of heavy gas, under pressure, were still charged. “Gravity!” Roger’s mind grasped at an idea, “that’s the Law of Nature I am trying to think up.” As if he had received a key to a tantalizing problem, Roger solved his course of procedure in a flash. In his mind he ran over their stock of chemicals. Hydrocyanic acid, a stinging, powerful combination of cyanogen and hydrogen; and hydrochloric acid—and many more. One of these, akin to a tear gas, would do. But he was cautious, and in spite of the pressing uncertainty he paused to be sure he would not take for his plan anything that could, in combination with the fire-smothering gas, cause an explosion. Almost at once he had the solution. Sulphuretted hydrogen—the common, refined gas that comes in the city mains from gas plants to stoves and gas jets—that would not explode in combination with the heavy gas in the compression-tank system! He wanted a gas that would stupefy: but he needed to be sure that it would lie, close to the floor. The gas in the fire-prevention apparatus was such a heavy gas that on being liberated, under pressure, it would settle rapidly, diffusing and spreading, as if it could be likened to a cloud, surcharged with moisture, settled on the earth, enfolding it like a blanket. There, in the upper room, was the means of releasing the city gas, which, Roger knew, would stupefy of its own constituents—even kill, in time. He did not intend to give it that much time! He merely had the desire to put his assailant into a state where he could not leave. Either the intruder was hesitating because of Roger’s silence or he was very quiet in his actions. Roger, equally quiet, was extremely active. He had unlaced and had slipped off his shoes at once. On stocking feet he tiptoed to the large gas outlet set into the wall for use with Bunsen burners or gas heaters used in experiments where a regulated heat was needed. This he opened, full, by turning the valve one half a revolution. Darting swiftly away from its low, humming release of a heavy flow, he ran quietly across to the thermostat on the wall, connected into the fire alarm and release system. Under it was a manual lever, one to be operated by hand, in any emergency where the thermometer failed. Swiftly Roger threw this on, and with his handkerchief tied over his nostrils and back of his head, for already he smelled the gas of the opened outlets, he swarmed up the telescope. The house-lighting gas, he knew, would be held down, running to the lower floor down the stairway, and the amount released would be enough to stupefy quite soon. Even if the adversary climbed the stairs, he would be in a bath of the sleep-inducing sulphuretted hydrogen. With his arms and legs helping him rise, Roger clambered up the inclined metal barrel of the telescope. At the top, above the flow of smother-gas to kill fires, he paused, listening. Not a sound. To the roof he clambered, and sat on the coaming of their skylight, looking down, waiting a few moments in case the other tried to come up. Below him all was silence. |
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