They sat down relievedly again, while the fog-gas made all the earth invisible behind a pall of grayness, a grayness from which the noises of battle came. In the tank that was headquarters, the air of strain was pronounced. The maneuver-board showed the situation as close to desperation, now. The reserve-tank positions had been switched on the board, dim orange glows, massed in curiously precise blocks. And little squares of green showed there that the supply and machine-shop tanks were massed. They were moving slowly across the maneuver-board. But the principal change lay in the front-line indications. The red glows that showed where tank battles were in progress formed an irregularly curved line, now. There were twenty or more such isolated battles in progress, varying from single combats between single tanks to greater conflicts where twenty to thirty tanks to a side were engaged. And the positions of those conflicts were changing constantly, and invariably the American tanks were being pushed back. * * * * * The two staff officers behind the general were nearly silent. There were few sparks crawling within the American lines now. Nearly every one had been diverted into the front-line battles. The two men watched the board with feverish intensity, watching the red glows moving back, and back.... The chief of staff was shaking like a leaf, watching the American line stretched, and stretched.... The general looked at him with a twisted smile. "I know my opponent," he said suddenly. "I had lunch with him once in Vienna. We were attending a disarmament conference." He seemed to be amused at the ironic statement. "We talked war and battles, of course. And he showed me, drawing on the tablecloth, the tactical scheme that should have been used at Cambrai, back in 1917. It was a singularly perfect plan. It was a beautiful one." "General," burst out one of the two staff officers behind him. "I need twenty tanks from the reserves." "Take them," said the general. He went on, addressing his chief of staff. "It was an utterly flawless plan. I talked to other men. We were all pretty busy estimating each other there, we soldiers. We discussed each other with some freedom, I may say. And I formed the opinion that the man who is in command of the enemy is an artist: a soldier with the spirit of an amateur. He's a very skilful fencer, by the way. Doesn't that suggest anything?" The chief of staff had his eyes glued to the board. "That is a feint, sir. A strong feint, yes, but he has his force concentrated in the dead area."