Front-line sector headquarters seemed inexplicably to have escaped whatever fate had overtaken all its posts, but it could only report that they had apparently gone out of existence without warning. American tanks, prowling in the area that had gone dead, announced that no enemy tanks had been seen. G-81, stumbling on a pill-box no more than ten minutes after it had gone silent, offered to investigate. A member of her crew, in a gas-mask, stepped out of the port doorway. Immediately thereafter G-81's wireless reports stopped coming in. * * * * * The situation was clearly shown in the huge tank that had been built to serve as G.H.Q. That tank was seventy feet long, and lay hidden in the mist with a brood of other, smaller tanks clustered near it, from each of which a cable ran to the telephones and instruments of the greater monster. Farther off in the fog, of course, were other tanks, hundreds of them, fighting machines all, silent and motionless now, but infinitely ready to protect the brain of the army. The G.H.Q. maneuver-board showed the battle as no single observer could ever have seen it. A map lay spread out on a monster board, under a pitiless white light. It was a map of the whole battlefield. Tiny sparks crawled here and there under the map, and there were hundreds of little pins with different-colored heads to mark the position of this thing and that. The crawling sparks were the reported positions of American tanks, made visible as positions of moving trains had been made visible for years on the electric charts of railroads in dispatcher's offices. Where the tiny bulbs glowed under the map, there a tank crawled under the fog. As the tank moved, the first bulb went out and another flashed into light. The general watched broodingly as the crawling sparks moved from this place to that place, as varicolored lights flashed up and vanished, as a steady hand reached down to shift tiny pins and place new ones. The general moved rarely, and spoke hardly at all. His whole air was that of a man absorbed in a game of chess--a game on which the fate of a nation depended. He was thus absorbed. The great board, illuminated from above by the glaring bulb, and speckled with little white sparks from below by the tiny bulbs beneath, showed the situation clearly at every instant. The crawling white sparks were his own tanks, each in its present position. Flashing blue sparks noted the last report of enemy tanks. Two staff officers stood behind the general, and each spoke from time to time into a strapped-on telephone transmitter. They were giving routine orders, heading the nearest American patrol-tanks toward the location of the latest reported enemies. * * * * * The general reached out his hand suddenly and marked off an area with his fingers. They were long fingers, and slender ones: an artist's fingers.