ciently 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