I found it too hot to drink, but I filled a tin cup which my knapsack held, and waited for it to cool, till my thirst overcame me.
It had a bitter and unpleasant taste, but I was in too great a need to be cautious. While I cooled a second cup at greater leisure I looked round and discovered that I had reached the place I was seeking.
I saw, on my left, the entrance to a long straight tunnel sloping gently downward. This entrance was reached by a terraced drop in the opal roadway. The tunnel had a floor of yellow sand, which was divided by a narrow conduit down which an overflow from the heated tank ran smoothly, and very swiftly, owing to the slope at which it flowed. The sides of the tunnel were of a smooth grey material, not concave but flat, converging upwards, till they almost met at the top, but not quite, there being a slit of perhaps two inches dividing them, through which a certain amount of light entered the tunnel.
It had a sinister appearance, and as I sat for a time regarding it, I considered what I might possibly have to fear if I should endeavour to penetrate it.
The purpose of the great lake of heated water behind me appeared to be evident. It must be the source from which the great expanse of ordered growth was irrigated, and perhaps fed. The stream that came through the tunnel might be a mere overflow, which was drained off into the sea, or it might be used for the filling of subterranean pipes lower down the slope. In either case, it did not greatly concern me—or so I thought, not foreseeing how greatly I should need its help in the coming peril.
The yellow sand on either side supplied a sufficient space on which to walk upright beneath the shelving walls.
It was dimly lit from above, and obscured by the steam which rose from the water, but I could see that it ran straight on for a long distance. Actually, it was a length of about twelve miles, as I learnt afterwards.
It appeared that, being entered, it would offer no exit until I reached the further end, however far it might be.
But there was no appearance of any possible danger, and I knew that it was the way which I had been directed to take. The only warning I had received was to traverse it as rapidly as possible, and it certainly did not appear to be an inviting avenue in which to linger.
Perhaps it was the fact that I must emerge from it on the threshold of a new experience, the nature of which I could only guess very dimly, that made me rest so long, even when I waked from the sleep I needed, before I entered the passage, but I remember that I did it with a great reluctance, and started at a pace which, though it might not be equal to the light swift running of my instructress, was sufficient to take me a long way forward in safety.
After a time, I noticed that my feet were becoming warm, and realised that the sand must be heated, though not so much so as the soil on which I had walked previously. I did not think it to be sufficiently so to constitute a serious danger, or discomfort, but I considered that it might be a different matter to a foot protected only by its own fur, and, supposing that I had found the explanation of the warning, and that it did not affect me, and being somewhat short of breath from the long spurt I had taken, I slackened to a quieter walk—and as my right foot came down, a pink streak shot out of the sand a few inches from it, and smacked against my ankle, with a sound like a whip lash. I jumped, with a cry of horror, or at least I tried to jump, and came down on my hands, for the grip held, and I was powerless to break it. The pink worm did not twine round my foot, but lay up the side, holding on, leech-like, by power of suction. It was trying to drag the foot into the sand, but, for the moment, that was beyond its power. Wrenching desperately, I tried to get loose the axe, for which I had expected no use, and which was slung on my back, under the knapsack, for convenience as I ran. When I got it clear I realised that I could not strike hard against my own ankle, and to an attempt at cutting, my assailant showed the resilient rubber-like quality which seemed common to several of the forms of life with which I was becoming familiar. With a despairing effort I strained my foot a few inches from the ground, and drove a hard blow beneath it, at which the severed worm fell writhing on the sand.
But now there were two others round my left foot, and their united strength was too great for me to lift it to enable me to deal with them in the same way. I gave up the axe, and hacked them free with the clasp knife. Then I saw that the ground behind me, and for several yards in front, showed similar worms that had pushed up through the sand, and waved and felt around for the origin of the vibrations which had disturbed them.
No doubt they had been rising behind me all the time, but I had passed over the ground so quickly that I had always been in advance of my danger, and unaware that it threatened me.
I suppose that the roots of the plants without—if plants they could be called—grew under the wall
