These phials of ours were set each in a metal frame and protected by a guard in such fashion that it would take a heavy blow to break the glass. When not in use, they were kept in strong metal cylinders. Of course, the electric light could be turned on at any instant. There were places where the gallery pitched in a way to make the head swim, many spots in which we had to exercise every caution; a false step might have spelled irrevocable disaster. I wondered how the angel had passed down those difficult places, and many pictures of that mysterious creature, as I wondered, came and went. Well, she had passed down and that without mishap. Where was she now? Indeed, where were we ourselves? Steadily we toiled our downward way. For a long distance, the gallery ran with but slight deviation either to the right or to the left, though the descent was much broken; I mean now was steep and now gentle, now at some angle intermediate. Rhodes thought that we were now moving in an easterly direction; it might have been north, east, south or west for all I knew. Not a trickle of water had we seen, not even a single drop, which I confess caused some unpleasant thoughts to flicker through my mind. [Illustration: The light clung to them like wraiths of fog, to be slowly dissipated, as they advanced, in little streams and eddies behind them.] At five o'clock we were two thousand feet above sea-level; at half past seven, about half a thousand. And we then decided to call it a day. Nor was I at all sorry to do so, even though we might be near some strange, even great discovery, for I was very tired, and sore from the top of my head to the end of my toes. I was in fair trim, and so was Milton Rhodes; but it would take us some time to get used to such work as this. A very gentle current of air, so slight that it required experiment to detect it, was passing down the gallery. The temperature here was 62° Fahrenheit. We had stopped before a cavity in the wall, and, in that little chamber, we passed the night, one holding watch whilst the other slept. My dreams were dreadful, but otherwise the night was as peaceful as any that ever passed over Eden. Neither Rhodes nor I, during that strange, eerie vigil there in the heart of the living rock, heard even the faintest, the most fleeting sound. As the watcher sat there waiting and listening, whilst the minutes slowly passed, he found himself--at any rate, I know that I did--almost wishing that some pulsation would come, so heavy and awful was the stillness of the place. But a sound we were to hear. We had been journeying for about an hour and a half and had just passed below sea-level. In that place Rhodes had left the aneroid. Of a sudden Milton, who was leading the way, halted with a low, sharp interjection for silence. When my look struck him, he was standing in an attitude of the most riveted attention. "There!" he exclaimed. "Did you hear that, Bill?"