Out of the tanks stout tubes led, with stopcocks and gages at the top.From a case under his arm Kennedy produced a curious arrangement like a huge hook, with a curved neck and a sharp beak.Really it consisted of two metal tubes which ran into a sort of cylinder, or mixing chamber, above the nozzle, while parallel to them ran a third separate tube with a second nozzle of its own.Quickly he joined the ends of the tubes from the tanks to the metal hook, the oxygen-tank being joined to two of the tubes of the hook, and the second tank being joined to the other.With a match he touched the nozzle gingerly.Instantly a hissing, spitting noise followed, and an intense blinding needle of flame.
"Now for the oxy-acetylene blowpipe," cried Kennedy as he advanced toward the steel door."We'll make short work of this."Almost as he said it, the steel beneath the blowpipe became incandescent.
Just to test it, he cut off the head of a three-quarter-inch steel rivet--taking about a quarter of a minute to do it.It was evident, though, that that would not weaken the door appreciably, even if the rivets were all driven through.Still they gave a starting-point for the flame of the high-pressure acetylene torch.
It was a brilliant sight.The terrific heat from the first nozzle caused the metal to glow under the torch as if in an open-hearth furnace.From the second nozzle issued a stream of oxygen under which the hot metal of the door was completely consumed.The force of the blast as the compressed oxygen and acetylene were expelled carried a fine spray of the disintegrated metal visibly before it.And yet it was not a big hole that it made--scarcely an eighth of an inch wide, but clear and sharp as if a buzz-saw were eating its way through a three-inch plank of white pine.
With tense muscles Kennedy held this terrific engine of destruction and moved it as easily as if it had been a mere pencil of light.He was easily the calmest of us all as we crowded about him at a respectful distance.
"Acetylene, as you may know," he hastily explained, never pausing for a moment in his work, "is composed of carbon and hydrogen.As it burns at the end of the nozzle it is broken into carbon and hydrogen--the carbon gives the high temperature, and the hydrogen forms a cone that protects the end of the blowpipe from being itself burnt up.""But isn't it dangerous?" I asked, amazed at the skill with which he handled the blowpipe.
"Not particularly--when you know how to do it.In that tank is a porous asbestos packing saturated with acetone, under pressure.
Thus I can carry acetylene safely, for it is dissolved, and the possibility of explosion is minimised.This mixing chamber by which I am holding the torch, where the oxygen and acetylene mix, is also designed in such a way as to prevent a flash-back.The best thing about this style of blowpipe is the ease with which it can be transported and the curious uses--like the present--to which it can be put."He paused a moment to test the door.All was silence on the other side.The door itself was as firm as ever.
"Huh!" exclaimed one of the detectives behind me, "these new-fangled things ain't all they're cracked up to be.Now if Iwas runnin' this show, I'd dynamite that door to kingdom come.""And wreck the house and kill a few people," I returned, hotly resenting the criticism of Kennedy.Kennedy affected not to hear.
"When I shut off the oxygen in this second jet," he resumed as if nothing had been said, "you see the torch merely heats the steel.
I can get a heat of approximately sixty-three hundred degrees Fahrenheit, and the flame will exert a pressure of fifty pounds to the square inch.""Wonderful!" exclaimed O'Connor, who had not heard the remark of his subordinate and was watching with undisguised admiration.
"Kennedy, how did you ever think of such a thing?""Why, it's used for welding, you know," answered Craig as he continued to work calmly in the growing excitement: "I first saw it in actual use in mending a cracked cylinder in an automobile.
The cylinder was repaired without being taken out at all.I've seen it weld new teeth and build up old worn teeth on gearing, as good as new."He paused to let us see the terrifically heated metal under the flame.
"You remember when we were talking on the drive about the raid, O'Connor? A car-load of scrap-iron went by on the railroad below us.They use this blowpipe to cut it up, frequently.That's what gave me the idea.See.I turn on the oxygen now in this second nozzle.The blowpipe is no longer an instrument for joining metals together, but for cutting them asunder.The steel burns just as you, perhaps, have seen a watch-spring burn in a jar of oxygen.Steel, hard or soft, tempered, annealed, chrome, or Harveyised, it all burns just as fast and just as easily.And it's cheap too.This raid may cost a couple of dollars, as far as the blowpipe is concerned--quite a difference from the thousands of dollars' loss that would follow an attempt to blow the door in."The last remark was directed quietly at the doubting detective.
He had nothing to say.We stood in awe-struck amazement as the torch slowly, inexorably, traced a thin line along the edge of the door.
Minute after minute sped by, as the line burned by the blowpipe cut straight from top to bottom.It seemed hours to me.Was Kennedy going to slit the whole door and let it fall in with a crash?
