Forgacs was beginning a drive on Philadelphia, the site of the power plant. Jeffrey was watching for an opening to Marseilles, vulnerable for the same reason.

Jeffrey kept firing rockets, but his mutant mind would be racing ahead, calculating with infinite precision the times of discharge and times of arrival.

It was apparent by now that Forgacs’ most powerful defenses were centered around Marseilles, because Forgacs was not using them. This meant he was not taking a chance on opening the Marseilles sector of the screen.

Jeffrey calculated the probable interchange of batteries for some sixty moves ahead, Hoshawk knew, then he began to fire the Philadelphia batteries at intervals.

The firing rose in intensity, and Jeffrey’s faster-than-light fingers played the great keyboard like a master organ. A bell sounded and his right foot threw on the western screen with its automatic cutout.

And all the time Jeffrey fired his big Philadelphia batteries at intervals with a definite rhythm⁠—five, three, and six seconds.

He shot to the right and manipulated a bank of keys and was back in the center almost instantaneously.

He did not pause in his rocket salvos, but in three minutes and eight seconds his first salvo of one-ton atom bombs would reach the Marseilles screen. If he had calculated correctly, the Marseilles screen would be open for an instant just as the atom bombs reached it. He didn’t think Forgacs could resist the temptation to blast Philadelphia with his Marseilles batteries.

Presently a thousand red lights winked up from the screen at Marseilles. But Forgacs overlooked the atom bombs. They were slower than the