The floor, apparently, had been smoothed by human effort, but for the rest, the corridor was, to judge from the evidence, entirely natural for the walls of shiny black rock bore no marks of tools.
At intervals, other passages branched off from the main one we were following, at greater and less angles, but these were much narrower, and had very apparently been hewn in the solid rock. Like the central passage, they were utterly deserted.
"We'll be coming out on the other side, pretty soon," commented Correy after a steady descent of perhaps twenty minutes. "This tunnel must go all the way through. I--what's that?"
We paused and listened. From behind us came a soft, whispering sound, the nature of which we could not determine.
"Sounds like the shuffle of many feet, far behind," suggested Kincaide gravely.
"Or, more likely, the air rushing around the corners of those smaller passages," I suggested. "This is a drafty hole. Or it may be just the combined flarings of all these jets of flame."
"Maybe you're right, sir," nodded Correy. "Anyway, we won't worry about it until we have to. I guess we just keep on going?"
"That seems to be about all there is to do; we should enter one of the big subterranean chambers Fetters mentioned, before long."
As a matter of fact, it was but a minute or two later, that we turned a curve in the corridor and found ourselves looking into a vast open space, the roof supported by huge pillars of black stone, and the floor littered with rocky debris and mining tools thrown down by workmen.
"This is where they take out the temite ore, I imagine," said Kincaide, picking up a loose fragment of rock. He pointed to a smudge of soft, crumbly gray metal, greasy in appearance, showing on the surface of the specimen he had picked up. "That's the stuff, sir, that's causing us all this trouble: nearly pure metallic temite." He dropped the fragment, looking about curiously. "But where," he added, "are the miners?"
"I'm inclined to believe we'll find out before we get back to the _Ertak_," said Correy grimly. "Everything's moved along too sweetly; trouble's just piling up somewhere."
"That remains to be seen," I commented. "Let's move on, and see what's beyond. That looks like a door of some sort, on the far side. Perhaps it will lead us to something more interesting."