He listened for the booming of the guns and tried to figure out from the sound just where the contending armies were facing each other. Sometimes they grew louder and fiercer, and at other times seemed to recede, as the tide of battle ebbed and flowed.  But there was rarely any lull in the ominous thunder, and Tom knew that the fiercest kind of fighting was going on.  He thought of Frank and Bart and Billy, who he felt sure were in the very thick of it, and he grew desperate at the thought that he was not at their side, facing the same dangers, and, as he hoped, sharing in the same victories.