In its centre the floor of iron, or whatever it may have been, rose, the fraction of an inch at first, but afterwards more sharply, and this at a spot where the groove had a somewhat steep downward dip which appeared to extend onwards I know not how far.

Following along this central rise for a great way, nearly a mile, I should think, we observed that it became ever more pronounced, till at length it ended in a razor-edge cliff which stretched up higher than we could see, even by the light of the electrical discharges.  Standing against the edge of this cliff, we perceived that at a distance from it there were now two grooves of about equal width.  One of these ran away into the darkness on our right as we faced the sharp edge, and at an ever-widening angle, while the other, at a similar angle, ran into the darkness to the left of the knife of cliff.  That was all.

No, there were two more notable things.  Neither of the grooves now lay within hundreds of yards of the cliff, perhaps a quarter of a mile, for be it remembered we had followed the rising rock between them.  To put it quite clearly, it was exactly as though one line of rails had separated into two lines of rails, as often enough they do, and an observer standing on high ground between could see them both vanishing into tunnels to the right and left, but far apart.

The second notable thing was that the right-hand groove, where first we saw it at the point of separation, was not polished like the left-hand groove, although at some time or other it seemed to have been subjected to the pressure of the same terrific weight which cut its fellow out of the bed of rock or iron, as the sharp wheels of a heavily laden wagon sink ruts into a roadway.

“What does it all mean, Lord Oro?” I asked when he had led us back to the spot where the one groove began to be two grooves, that is, a mile or so away from the razor-edged cliff.

“This, Humphrey,” he answered.  “That which travels along yonder road, when it reaches this spot on which we stand, follows the left-hand path which is made bright with its passage.  Yet, could a giant at that moment of its touching this exact spot on which I lay my hand, thrust it with sufficient strength, it would leave the left-hand road and take the right-hand road.”

“And if it did, what then; Lord Oro?”

“Then within an hour or so, when it had travelled far enough upon its way, the balance of the earth would be changed, and great things would happen in the world above, as once they happened in bygone days.  Now do you understand, Humphrey?”

“Good Heavens!  Yes, I understand now,” I answered.  “But fortunately there is no such giant.”

Oro broke into a mocking laugh and his grey old face lit up with a fiendish exultation, as he cried: