"The screen will be ready in two," answered F-2.
The cloudiness was solidifying, and now strangely it wavered, and thinned, as it spread out across, and like a growing canopy, it arched over them. In two minutes it was a solid, black dome that reached over them and curved down to the ground about them.
Beyond it, nothing was visible. Within, only the screens glowed still, wired through the screen.
The beams appeared, and swiftly they drew closer. They struck, and as Trest and Roal looked, the dome quivered, and bellied inward under them.
F-2 was busy. A new machine was appearing under his lightning force-beams. In moments more it was complete, and sending a strange violet beam upwards toward the roof.
Outside more of the green beams were concentrating on this one point of resistance. More—more—
The violet beam spread across the canopy of blackness, supporting it against the pressing, driving rays of pale green.
Then the gathering fleet was driven off, just as it seemed that that hopeless, futile curtain must break, and admit a flood of destroying rays. Great ray projectors on the ground drove their terrible energies through the enemy curtains of blankness, as light illumines and disperses darkness.
And then, when the fleet retired, on all Earth, the only life was under that dark shroud!