Jimmy and his chums had few opportunities to learn what was done by Captain Dickerson and his associates to get on the trail of the smoke signal traitors. All they heard was that an investigation was being made and that every effort was being bent toward learning whether or not the Bixtons were involved. It would not do to accuse these two wrongly, even though they were of a caliber not greatly desired in the army. They were entitled to be considered innocent until proved guilty, and the private quarrel they had with Jimmy and Roger, because of the instrumentality of the latter in sending Mike Bixton to prison, had nothing to do with the smoke signal issue. As for that personal quarrel, the threats the Bixtons had made against Roger and Jimmy did not greatly worry the two. They felt that they could look out for themselves even against two such bullies and braggarts as were Aleck and Wilbur Bixton. Indeed, there was a time when it seemed as if the paths of the two signal corps men would not again cross those of Roger and Jimmy. For the two latter, with their chums, were sent to a distant sector where the fighting was almost constant. And the chances were much against the four Brothers returning to the lines where the Bixtons were stationed. There was hard fighting--so desperate, in fact, that Jimmy and his chums had little chance to think about anything except how to keep from being killed and how to inflict as heavy a punishment as possible on the enemy. The fighting was in a wooded country where advance was difficult, for the thick underbrush afforded shelter for many machine gun nests, and the Huns seemed to place more dependence on this style of fighting than on any other at this time and place. Day after day the skirmishes, all part of one great battle, waged in and around the forest. The country was rough and hilly, with streams here and there, some of them large enough to be called rivers in the American sense, while others so dignified were but mere creeks. There was not so much of the trench fighting here. The woods afforded almost as good shelter as did holes dug in the earth, but this was not saying much. At times, of course, it became necessary for the Khaki Boys to dig in, but they did not stay long enough in one place to make possible the digging of elaborate and well-protected trenches. All sorts and styles of fighting went on during the week that Jimmy and his friends were in this sector. There was the duel of big guns, the exchange of shots from mortar batteries that fired wicked bombs; there was, of course, constant rifle fire, and many a man lost his life because of some hidden sniper. Aeroplanes were constantly flying to and fro, the Huns endeavoring to locate ammunition dumps or transport trains in the woods, that they might blow up either or both. And the Americans and Allied planes sought to so direct the advance of their fighters as to make it most effective.