As he spoke there reached our ears the first, far-off murmurs of a dreadful music. I cannot describe it in words because that is impossible, but it was something like to the buzz of a thousand humming-tops such as are loved by children because of their weird song. “Back to the wall!” cried Oro triumphantly. “The time is short!” So back we went, Oro pausing a while behind and overtaking us with long, determined strides. Yva led us, gliding at my side and, as I thought, now and again glanced at my face with a look that was half anxious and half pitiful. Also twice she stooped and patted Tommy. We reached the wall, though not quite at the spot whence we had started to examine the grooved roads. At least I think this was so, since now for the first time I observed a kind of little window in its rocky face. It stood about five feet from its floor level, and was perhaps ten inches square, not more. In short, except for its shape it resembled a ship’s porthole rather than a window. Its substance appeared to be talc, or some such material, and inches thick, yet through it, after Oro had cast aside some sort of covering, came a glare like that of a search-light. In fact it was a search-light so far as concerned one of its purposes. By this window or porthole lay a pile of cloaks, also four objects which looked like Zulu battle shields cut in some unknown metal or material. Very deftly, very quietly, Yva lifted these cloaks and wrapped one of them about each of us, and while she was thus employed I noticed that they were of a substance very similar to that of the gown she wore, which I have described, but harder. Next she gave one of the metal-like shields to each of us, bidding us hold them in front of our bodies and heads, and only to look through certain slits in them in which were eyepieces that appeared to be of the same horny stuff as the searchlight window. Further, she commanded us to stand in a row with our backs against the rock wall, at certain spots which she indicated with great precision, and whatever we saw or heard on no account to move. So there we stood, Bickley next to me, and beyond him Bastin. Then Yva took the fourth shield, as I noted a much larger one than ours, and placed herself between me and the search-light or porthole. On the other side of this was Oro who had no shield.