“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 Harveyized, 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?

No, I could see that even in his cursory examination of the door he had gained a pretty good knowledge of the location of the bolts imbedded in the steel.  One after another he was cutting clear through and severing them, as if with a super-human knife.

What was going on on the other side of the door, I wondered.  I could scarcely imagine the consternation of the gamblers caught in their own trap.

With a quick motion Kennedy turned off the acetylene and oxygen.  The last bolt had been severed.  A gentle push of the hand, and he swung the once impregnable door on its delicately poised hinges as easily as if he had merely said, “Open Sesame.”  The robbers’ cave yawned before us.

We made a rush up the stairs.  Kennedy was first, O’Connor next, and myself scarcely a step behind, with the rest of O’Connor’s men at our heels.

I think we were all prepared for some sort of gun-play, for the crooks were desperate characters, and I myself was surprised to encounter nothing but physical force, which was quickly overcome.

In the now disordered richness of the rooms, waving his “John Doe” warrant in one hand and his pistol in the other, O’Connor shouted:  “You’re all under arrest, gentlemen.  If you resist further it will go hard with you.”

Crowded now in one end of the room in speechless amazement was the late gay party of gamblers, including Senator Danfield himself.  They had reckoned on toying with any chance but this.  The pale white face of DeLong among them was like a spectre, as he stood staring blankly about and still insanely twisting the roulette wheel before him.