It shows how dulled we had become to unfamiliar wonder, or how concentrated our minds had been upon the new problem which had disturbed us, that we had not observed these shifting lights when first our eyes must have beheld them. Now, as we gazed, the left-hand side of the leftward passage glowed with a sudden redness not twenty yards away. The light spread, and spread, along the glassy surface of the wall, until it had almost reached us. It rose up till it neared the gloom of the distant roof, of which the darkness was not pierced but was changed to a dusky red. The steel-gray floor was stained also with a faint reflected redness. The glowing colour showed the lofty passage before us till it curved out of view. “Come,” she said, “while the light lasts,” and I knew that, with the decision made, her mind had recovered all its buoyant serenity. As we left the light, it was already fading, but others showed ahead, and we went on in an ever-changing darkness, seldom far from some luminosity which was sufficient to guide us on a plain and unimpeded way. The colours in the walls were various, not only in their kind, or in their intensity, area, or duration, but they had an appearance of being of varying distance from us, so that we would look at the dark wall, and see the transient motion of some glowing splendour, as it seemed, a mile within it, and then an interval of darkness and then a burst of light and colour, like an open rose, that seemed to be scarcely covered by the surface of the wall that held it. So we went on until, in no great space of time, we came to an opening on the left hand, wide and high as the passage in which we were, and on the same level, but in an absolute blackness. We were of one mind to explore it, for the thought had come to both of us that if we continued to traverse that in which we were, we must return to the point from which we started, should the curve continue. My companion, whose judgment was far more accurate than my own on such points, was definite that we had completed a quarter of the full circle when this side-corridor was reached. So we decided; not doubting that it would be lighted in the same manner, and foreseeing no obstacle. I have little doubt, from our later experiences, that we were right on the first point, as we were certainly wrong on the second, for we found at the first step that we were confronted by the same withstanding force that had obstructed our passage of the sleeping wood, but more instant and urgent in its application, so that we did not attempt to hold our ground, but fell back at the same impulse to consult whether we should again adventure against it.