And with light hearts they set out, glad to walk, since it gave them a chance to stretch the legs that had been cramped for so many hours in the bottom of the boat. Plainly there had been a great change in the character of the battle over night. The heavy thunder of the guns was greatly reduced in volume, though they should still have been able to hear it. And it was unmistakably coming from further north. It must be that the Germans were retreating. But they walked for three hours before they knew for certain that they were right. They did not meet the cuirassiers of whom they had heard. Instead a cloud of dust that they saw for two miles before men emerged beneath it turned out to be a column of French infantry. They were in their Boy Scout uniforms, and the men who first saw them at the side of the road cheered them. Soon a captain came up to them. "Eh bien, mes enfants!" he said. "What do you do here? Where do you come from!" They told him Amiens, and he laughed. "And it is there, precisely, that we are going!" he laughed. "The Germans are out by now and our men were in there an hour ago!" Frank and Henri cried out in delight at the news. "May we go with you?" asked Frank. "We would like to go back as soon as possible." "As to that you must ask the colonel. He will decide--and, see, here he comes now in his automobile! I will report to him that you are here." But there was no need, for the officer who sat in the car was Colonel Menier himself, and at the sight of them he laughed aloud. "Ah, my brave ones!" he cried. "So you are here! Ride with me! Did the Germans drive you from Amiens? I shall drive you back!" They obeyed that order with delight. They sprang to their places in the car. "Now tell me everything!" said Colonel Menier. "How it is that you left Amiens and how you came here?" He leaned over first, however, and spoke to his driver, and the car shot forward, leaving the troops far behind. And then they began the story, each telling the part of it that he knew best. At the story of how the German officer had recognized Henri and caused his arrest, he clenched his hand angrily. "They make war even on boys!" he said, bitterly. "A brave enemy recognizes the heroism of his foes. If I had been in that man's place I should have forgotten my own defeat and praised those who had caused it!" Then came the story of Frank's discovery of the hidden vault and the boat, and of their voyage down the Somme and their lucky escape. "Milles tonnerres!" he cried. "A thousand million thunders! That was well done! Through all the German sentries! Eh, well, I have a surprise for you when you reach Amiens with me, I think. Mind, I make no promises! Only wait!"