"No, I--I can't come with you," the unknown said. "I'm sorry, but you will have to shift for yourselves. I'll give you the best directions I can to enable you to reach your own lines, but you'll have to go alone."
"We'll try," said Bob. "But we wish to thank you, and we don't know--"
"Oh, it was all in the day's work," interrupted the officer, "Any one who came along would have done just as I did to help you."
"Not anyone, sir," asserted Franz, in a low voice. "A German wouldn't have chopped us out."
"Well--er--perhaps not," said the officer. "But it was in my line of duty and I did it. I don't want to be thanked for doing my duty."
"But we insist on thanking you, sir!" exclaimed Jimmy with a smile. "If it hadn't been for you we'd be dead in there now--it was impossible for us to free ourselves!"
"Well, you may call me Captain Frank Dickerson," said the officer slowly. And he appeared to hesitate over the words.
"Then allow me, in the names of my companions, to thank you from the bottoms of our hearts!" exclaimed Jimmy, rising and saluting. The captain returned the salute. He stood for a minute looking Jimmy straight in the eyes, and the lad said afterward that the officer seemed to be searching out the sergeant's very soul. Then Captain Dickerson said:
"I must leave you now. You will find a little package of food at the end of the mill flume. I'll leave you this canteen so you may carry water with you on your journey toward your own lines. Your way lies there," and he pointed to the south. "Good-bye--and good luck! I hope you may get through, but--"
Then, turning abruptly he strode off between two high grassy hummocks, and was soon lost to sight in the smoke and haze.
For a moment the khaki boys stood, motionless, and then Jimmy, looking around on the circle of his companions, exclaimed:
"I should say so!" agreed Bob. "Talk about the man in the iron mask--this beats it!"
"Why doesn't he come with us, toward the American lines?" asked Roger. "Why does he want to go over where the Huns are? This gets me. It looks as if he was----"
He did not finish the sentence. But his chums knew what he had started to say. Only it seemed a terrible suspicion to which to give voice, against the man who had saved their lives. Still, with all that, the khaki boys could not help thinking in their hearts that there was something wrong.