They did not know the meaning of the military movements they had seen. Indeed, they had not seen military movements in the strict sense of the word. All they knew was that soldiers, first in one uniform, then in another, had passed through their villages, first going north and east, then south and west. They had heard firing, dim and in the distance at first, but coming always nearer. Then the tide of battle had rolled by. That was all they knew.

But to boys who from the beginning of the war had followed every move on the great chessboard of the struggle, these things meant knowledge for which the editors of newspapers would have given fortunes. In Paris they had had a great map, and every day they had shifted the tiny flags that showed where the troops were. They had flags for each of the allies and for the Austrians and Germans at first. Later they had become more particular. They had worked out as well as they could the different armies, even to the army corps, and had marked their flags accordingly. And so this exact knowledge of where troops of particular commands had been, made it possible for them, when there was time for them to go home, to make changes in the positions of the little flags that dotted their map.

When they had finished doing that they looked at one another.

"The French and the English are retreating," said Henri, soberly. "You were right, Frank. They fought on the line of Mons to Charleroi in Belgium, and then they began running away."

"Not exactly that, either," said Frank. "Look here—look at the map, Henri. There is Paris. There is a great army there under General Gallieni. There are enormous fortifications. That is the great base. There is this line with three fortresses—Rheims, La Fere, Laon, with other forts between them. That backed the centre when the French army retired from the border. But there is another army on the left of that line—because, if the Germans get around the left, behind that line of fortresses, they could be surrounded."

"But they could be defended—"

"Yes, as Bazaine defended Metz—until he was starved out," said Frank. He was beginning to be excited. "I think I see what may happen, Harry. The German right is moving out, always—far out, toward the sea. It wants to get around our left, and cut it off. If it gets between our left and Paris, there will be a disaster—another Sedan, perhaps. That is why there is a retreat. It is necessary. We are not ready to fight yet. But wait!"

"Wait! Wait? Is that the thing for French soldiers to do? That is not how Napoleon won his battles! He struck—and he struck first!"

"Never until he was sure of victory."

"But if they keep on retreating, they will be south of here! The Germans can take Amiens, if they like!" exclaimed Harry in much alarm.