Then, without warning, his lights flashed on—not only a vertical barrage, but a horizontal one as well—sweeping the higher points of the entire country around for a distance of twelve or fifteen miles.
We were, at the moment, following the bottom of a narrow gully. Had we been on any of the upper reaches of the plateau we would undoubtedly have been picked out by one of the roving beams of light and destroyed.
We camped where we were, and again for several days I attempted nothing, devoting myself to a thorough exploration of the country about us. The Dark City appeared impregnable. Beams of light from Tao's larger projectors were constantly roaming about the entire plateau that surrounded it, and every higher point of vantage from which one of ours could have reached them must have been struck by their rays a score of times a day.
It will be understood, of course, that any place where we could mount one of the higher powered projectors, a task of several hours at best, and strike the city, must of necessity be also within range of their rays, for theirs were as powerful as ours. Upon observation I felt convinced that should we attempt to mount a projector anywhere on these higher points it would be sought out and destroyed long before we could bring it into action.
That this was Tao's stronghold, and not the Lone City, now became evident. I could readily understand why he had retreated here. Fully four times as many projectors as he had in operation in the Lone City were now in evidence. Those of shorter range, and spreading rays, kept the entire country bathed in steady light for several miles around him, while the larger ones—a hundred of them possibly—roved constantly over the black emptiness beyond.
From our encampment we could advance but little farther. Fortunately, retreat was open to us; and once beyond the circle of steady light, we had no difficulty in moving about in the darkness, even though momentarily we frequently were within range of the single light‑beams, had they chanced to swing upon us.
This was the situation which, even Mercer agreed, appeared hopeless. We explored the brink of the precipice below which lay the sea. It was a sheer drop of many thousand feet. Although a descent might have been made closer to the Dark City, certainly it was not possible at any point we could reach. We sent our girls down, and they reported that from below it appeared probable that access to the ocean was had by the Dark City some miles farther along. They went but a short distance, for Tao's lights were occasionally sweeping about; and more than that, they could make but very short flights, owing to the cold.
To starve Tao out appeared equally as impractical as a direct attack. With our little army we could not surround the city on a circumference of some eighty miles. We might, indeed, have barred the several roads that entered it, but it seemed probable that if Tao wanted to come out he would come, for all we could do to stop him. And yet to starve him out seemed our only possible plan.
"We'll have to send back for reënforcements," I told Mercer, Miela and Anina at one of our many conferences. "An army of several thousand, if we can maintain it up here."
And then, the very next day, Mercer and Anina came forward with their discovery. We had set up our encampment of little black fabric tents in a ravine some six miles outside the city, securely hidden by surrounding cliffs. Above us across the black sky the greenish‑red beams of Tao's light‑rays swept continually to and fro. Miela and I were sitting together disconsolately in our tent, reviewing the situation, when Mercer and Anina burst in. They had been roaming about together, exploring the country, and came in now full of excitement and enthusiasm to tell us what they had found. We two were to accompany them. They would tell us no more than that; and as soon as we had all eaten we started off. It would be a trip of several hours, Mercer said, and would take us around to the other side and partly behind the Dark City.