Once or twice the chopper had to stoop down, in order to breathe the purer and cooler air near the ground, and the boys were put to the same expedient.
And then, suddenly, there came a crashing, splintering sound. There was an exclamation from the officer, and, as he leaped back he cried:
"There she goes, boys! The way is as clear as I can make it! Come on out, and lively, too!"
The Khaki Boys lost no time in obeying. Leaping and scrambling as best they could over the heaps of brick, stone and splintered wood, they emerged through the hole cut for them by the officer. He had chopped through the one beam that held all the others, or most of the others in place, and the crisscross structure had collapsed, allowing the boys to escape.
"Come on! Come on!" cried Jimmy. "Everybody out!"
And they leaped out only just in time, for as Bob, the last to make his way to safety, cleared the jagged barrier, a burst of flames and smoke swept into what had been the boys' prison.
Now they stood on the green grass, in the open, with the burning ruins of the mill at their backs. And confronting them, still holding the axe, and panting from his terrific exertions, was the strange officer.
And as the young soldiers looked at him they wondered, more than ever, who he was.