It came with a vertical spray of light rising from the ice wall which encircled the city. Spreading light beams rising from points a hundred feet apart along the wall. The beams spread fan-shape, so that within fifty feet above their source they met and merged into a thin sheet of effulgence rising into the sky. Tarrano's barrage. It seemed then that beyond suicidal sorties of the kind we had just repulsed, Tarrano was planning to stand purely on the defensive. It was our own plan to surround the city with our towers; even those on the further side would be within range of our power house; and with the city thus beleaguered, we would attack the wall from every side at once. We tested now this barrage Tarrano had thrown up. Sprays of its insulated area came down to protect the wall in front; and protected also the triangular spaces between the sources of the main beams. Tentatively one of our towers approached within range; but our rays only beat into the barrage with the hiss of molten metal plunged into water, and with a burst of interference sparks. Even at a horizontal thousand feet we could do nothing. Then we tried altitude. Our projectors, mounted individually on small platforms automatically controlled to fly without human pilot, went up and we strove to get them over the barrage. At five thousand feet one went over safely. But the electronic bomb it dropped into the city was an easy mark for Tarrano's watchful defense rays. He exploded it harmlessly when it was still high above him. After the next time of sleep we invested the city. Our towers were set in a ring about it, two thousand feet from the wall. They were mobile units, ready to sail forward or back or upward at any moment. Georg stayed in command of the instrument room. It was never placed, but sailed continuously in slow circular flight around the city above our line. The power house remained in its place, with our largest projector mounted on the cliff beside it in order to frustrate any further attacks. They were solemn moments as we broke our encampment. The girls, far more agile in the air than men, were lightly dressed, with the supporting mechanism strapped to them. The heating units enveloped them in an invisible cloak of warm air. To their left arms a strapped cylinder gave off a fan-shape area of insulation--an almost invisible shield of protective barrage some five feet long. It showed as a faint glow of light; and in flight their left arms could swing it like a shield to protect their bodies. They had telephonic ear-pieces available; a tiny mirror fastened to their chests to face them, upon which Georg or Geno-Rhaalton could project images; a mouthpiece for talking to Georg; and a belt of offensive weapons, useful within a range of five hundred feet but no further.