No executioner at his switch in the little room behind an electric chair of our day could ever have shuddered as Alan now must be shuddering. But he held himself firm when once we were in the ship's cabin. The controls, with a white-faced young pilot seated at them, were near us. There were several other men in the cabin, with observation instruments; and at a bank of mirrors, receivers and audiphones three operators held us in close communication with the city authorities. Our commander moved quietly about; seldom speaking; but intent upon every detail. Sixty minutes! Five of them were already gone when--with the world-power dead at the Trinight Hour--we hastily stripped our mechanism of its insulation and rose from the landing-stage. The gigantic city loomed into the sky before us. The night was still overcast. We climbed steeply, then levelled, and presently we were over the city roof; a thousand feet over it perhaps; and beneath us it spread in the darkness like a great rolling expanse of soiled canvas. We had not heard Nanette's voice again. Precautions were taken against the eavesdropping. What Turber personally may have learned of our plans we never knew. Nothing probably, until near the end. He had no warning that the world-power was to be shut off. The battle everywhere in the city was undiminished in its fury. It was raging down there now. Our mirrors, here in the cabin, occasionally shadowed it, but there was no other sign. * * * * * Turber had carried our tower Space. San was gone with the tower--with orders from Lea to swing slowly past at intervals. The Turberites, finding the tower was gone, left a guard there and swept on--fighting our troops northward. The Hoboken power-house still was surrounded, but holding out. The attack there seemed momentarily to have slackened as Turber concentrated on his northern drive. There was still no fighting on the roof. Our lines had withdrawn northward as the Turber mobs swept north through the city. Most of this roof area seemed deserted. We could make out occasionally the dark forms of the Turberites patrolling this captured area. We crossed over the Turber wall. The roof from this height was very little different of aspect. Our projector had not yet flashed. All our lights were carefully hooded. But we thought that by now some Turber ship would have come up to assail us. There had been occasional Turber patrol ships here all day, but none were here now. I thought that the harbor with its lacework of causeways and islands must be beneath this area of the roof. It was difficult for me to estimate. Far off, ahead to the right where the roof ended beyond Staten Island, I could see the banks of lights that marked the great Turber wall inclosing this end of his rural territory. There was no ship in sight. I murmured: "When do we turn it on, Alan?" "Soon. When we get near where Turber houses the aero." "Yes, but where is that? I don't know where we are."