served Tom, for he and Jack had been made so much of by the French officers that they felt quite at home, so to speak.
"Ah, messieurs, that is the question," declared Major de Trouville. "First to find the gun, and then to destroy it. The first we can do with some degree of accuracy."
"How?" asked Tom.
The major went to a large map hanging on the wall of the room. It showed the country around Paris and the various lines as they had been moved to and fro along the Western front, according as the Germans advanced or retreated.
"You will observe," said the major, "that by describing an arc, with Paris as the center of the circle, and a radius of about seventy-five miles, you will include a small sector of the German trenches. Roughly speaking this arc will extend from about Hamegicourt to Condé, both within the German lines, I am sorry to say. Now then, somewhere in this arc, or perhaps back of it, the German gun is placed. Anywhere else where it would be possible for such a monster engine of war to be erected, would bring it too close to our batteries.
"So that gives us the comparative location of the gun," went on the French officer. "But the next question is not so easy to settle—
