My first endeavor was to find a position on top of the cliffs from which the city could be reached with a projector. It was practically the only thing to do. The city could not be approached in front from the valley floor; its entire surface beyond the turn was swept by the light‑rays. Approach from below in the rear was likewise barred.
Had the barrage been not so high our girls might have flown over it and dropped bombs, or we might have sent rockets over it and dropped them into the city. Neither of these projects was practical. The girls could not fly over that barrage. It was too cold in the higher altitudes. Nor could we send rockets over, for rockets sent through the light were exploded before they could reach their mark.
The projectors along the sides of the city were located for the most part a hundred feet or more back from the base of the surrounding cliffs. This allowed them to cut the cliff face at the top. It will be understood then that we could approach the brink of the cliff in many places, but never sufficiently near to be able to direct our rays downward into the city.
These cliffs were exceedingly jagged and broken. They overhung in many places. Great rifts split them; ravines wound their way down, many of these with small, stunted trees growing in them. A descent from the summit to the floor of the valley, had we been unimpeded by the light, would in many places not have been difficult.
During the next week, we succeeded—working in the prevailing gloom—in establishing a projector at the mouth of a ravine which emerged at the cliff face hardly a hundred feet from the valley bottom. This point was below the spreading light‑rays which swept the cliff top above. We mounted the projector without discovery, and, flashing it on suddenly, swept the valley with its rays. An opposing ray from below picked it out almost immediately, and destroyed it, killing two of our men.
The irregularities of the cliffs made several other similar attempts possible. We took advantage of them, and in each case were able to rake the valley with our fire for a moment before our projector was located and destroyed. One, which we were at great pains to protect, was maintained for a somewhat longer period.
I believed we had done an immense amount of damage by these momentarily active projectors, although our enemy gave no sign.
We then tried dropping rockets at the base of the lights in the valley. There were few points at which they could be reached without striking the rays first. But we persisted, sending up a hundred or more. Most were ineffective; a few found their mark, as we could tell by a sudden "hole" in the barrage, which, however, was invariably repaired before we could make it larger.
These activities lasted a week or more. It began, to look as though we had entered upon a lengthy siege. I wondered how long the city's food supply would last if we settled down to starve it out. The thought came to me then that Tao might be almost ready for his second expedition to the earth. Was he indeed merely standing us off in this way so that some day he might depart in his vehicle before our very eyes?
Tao began to adopt our tactics. Without warning one day a projector from a towering eminence near the city flashed down at the river encampment. That we were not entirely destroyed was due to the extreme watchfulness of our guards, who located it immediately with their rays. As it was, we lost nearly a hundred men in the single moment it was in operation.