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 cut-out.
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 rockets, and there was no way to tell, from the Map, which was which.
Jeffrey shot a look at the chronometer, and Hoshawk saw the atom bombs go through. A few seconds later the glow in Marseilles began to redden, and Hoshawk exulted. The atom bombs had done their work. The Marseilles screen was weakening.
Jeffrey played the keys with fantastic speed. The war would soon be over. Thousands of little red lights began streaking toward Marseilles. At first they exploded in air as they hit the screen, but as the explosive force of the DTN began to drain the screen, those behind began to pour through.
But there was a flash from Philadelphia, and a shock went through Hoshawk. Something was wrong there. Jeffrey hadn't intended that. Forgacs had used atom bombs and had broken through when the screen was down.