Dean Rawson was there to watch the next attempt. Again Riley's roaring bass rolled out the count, but this time the call stopped at fifty-two-seven. The jangling bell told that the carrier had touched.
"Divil a bit do I understand this," Riley was calling. "We're right at the point where we dropped through into the clear. Right at the roof of the big cave—fifty-two-seven, it says—and no lower do we go. The bottom of the hole is plugged!"
awson made no reply. He was scowling while he stared speculatively at the mouth of the twenty-inch bore—a vertical tunnel that led from the drilling floor down, down to some inner vault. "Molten gold," he was thinking. "It melted a cylinder of the new Krieger alloy—melted it when its melting point is way higher than that of any rock that we've hit. And now the bore is closed...."
He was trying vainly to project his mental vision through those miles of hard rock to see what manner of mystery this was into which he had probed. He shook his head slowly in baffled speculation, then spoke sharply.
"Drill it out!" he ordered. "We're into a hot spot sure enough, though I can't just figure out the how of it. But we'll tame it, Smithy. Send down the drill. Clean it out. Then we'll poke around down there and get the answer to all this."
Five days were needed to send down the big drill with a new drill-head replacing the other too fouled with gold for any use. The tubular sections, a hundred feet in length, were hooked together and lowered one by one. Each joint meant the coupling of the air-pipe as well. Air, mixed with water from the outer jacket, must come foaming up through the central core to bring the powdered rock to the surface.
Five days, then one hour of boring, and another five days to pull out the drill before Rawson could hope for his answer. But he found it in the severed shaft of the great drill where the head had been melted completely off. The big stem that would have resisted all but electric furnace heat, and been cut through like a tallow candle in the blast of an oxy-acetylene flame.