"That is certainly surprising news, and the telling of it will please the colonel," said the officer. The boys were now introduced to Lieutenant Martin, who occupied the seat of observer in the other machine. Together the five ascended the hill and reported to the colonel commanding the batteries on the crest. The captain and lieutenant entered the commandant's office, while the boys remained outside with the officers. In a few moments an orderly appeared and notified the boys that the commandant required their presence. As they entered the door the commandant met them with a pleasant smile. "I am glad to hear about you from the captain. Why didn't you tell me you were friends of the captain here and of Colonel Winston at the camp?" asked the commandant. "Well, I suppose we had too much else to think about, sir," replied Alfred. "It is very interesting," continued the commandant. "But we must proceed to business. These boys made a remarkable discovery yesterday; I am about to make a test of the information we gained through them, and we need your eyes to help us out." "No wonder the boys were entitled to decorations!" said the captain, looking at the boys with ill-concealed admiration. "Decorations?" almost shouted the commander. "Where are they?" he asked the boys. "Why, we have them in our pockets," said Ralph, amused at the allusion to them. Alfred drew out his and dangled it. The officers laughed heartily, as the commandant said: "Well, most men would have had them on show all the time." "Our engineers have made these charts for your guidance," continued the commandant. "We have peppered that section, marked 29, for the past week, but the big guns they have somewhere in that section are just as lively as ever. This sketch shows the bench marks that the boys discovered yesterday on the side of the hill. Our observation of it seemed to confirm the theory of the boys that these arrows pointed to the hidden batteries. We want your aid to ascertain whether or not they are really there, and if you will commence your observation over that section, the guns will begin as soon as we receive your signals." The preliminaries having been all arranged, and the signals understood so that there would be no errors, the captain and lieutenant at once proceeded down the hill. Fifteen minutes thereafter the two machines began to circle overhead, and, having reached the predetermined height, began the flight southeast to reach the depression to the left of the hill behind the German lines. The two machines soon found themselves antagonized by several enemy ships, but still the flights were made back and forth. With field glasses it could plainly be seen that there was a fight on hand, which increased their anxiety more and more as two more German machines came up from the north. "That begins to look a little serious for our boys," said Ralph, walking back and forth nervously.