either hand. There was nothing to be seen but the path in front of us and the trickling, hurrying rivulet of blue phosphorescence. The figures of Cavor and the guiding Selenite marched before me, the sides of their legs and heads that were towards the rivulet were clear and bright blue, their darkened sides, now that the reflection of the tunnel wall no longer lit them, merged indistinguishably in the darkness beyond.
And soon I perceived that we were approaching a declivity of some sort, because the little blue stream dipped suddenly out of sight.
In another moment, as it seemed, we had reached the edge. The shining stream gave one meander of hesitation and then rushed over. It fell to a depth at which the sound of its descent was absolutely lost to us. Far below was a bluish glow, a sort of blue mist—at an infinite distance below. And the darkness the stream dropped out of became utterly void and black, save that a thing like a plank projected from the edge of the cliff and stretched out and faded and vanished altogether. There was a warm air blowing up out of the gulf.
For a moment I and Cavor stood as near the edge as we dared, peering into a blue-
