"This comet-control was set on the top of a truncated pyramid in a clearing at the central world's center. It was a great horizontal disk, set parallel to their disk-world, with a pointer that could be moved at will around the disk-dial. The position of the pointer, by means of great projectors to which it was connected, controlled the position of the comet's tail. If the pointer was at the dial's rear the tail would be shot forth from the great coma's rear also, driving it forward through space. If they turned the pointer to the left the tail would shoot from the coma's left, driving the comet to the right. They could thus, by means of the comet-control and the great projectors which controlled the tail's position, drive the comet in any direction at will. The only thing they could not do with it was to reverse the comet-control, to shoot out a new tail opposite to the old one, since the momentum of the old one and the opposite momentum or pressure of the new one would crush and annihilate the coma and its worlds between their great pressures. They could drive the comet to right or left at will, though, which was all that they needed, since now they drove it toward the universe of suns near them. "Onward the giant comet drove to that universe, and soon crashed through it, its suns and worlds being sucked into the gigantic coma and annihilated there, converted instantly into electrical energy which restored the waning coma's glory. So onward through space with renewed power it flashed, through the great void between the galaxies, until ages later when its coma was again waning they drove it toward another universe, crashed through it likewise. And so through the eons, as ever the comet's glory, the coma's power, has waned, they have driven it through another universe, destroying that universe to restore it. On through the limitless void of outer space they have driven it, a cosmic vampire looting the life of universes to restore its own! And now, when the comet's glory has again waned, they have turned it toward our own galaxy, to destroy it as they have done countless others. And within less than a scant half-dozen hours now the comet will have thundered so close to our galaxy that no power in existence can turn it aside!