Moving steadily along they quickly found themselves getting among crowds of civilians and soldiers who filled the streets of the little old Belgian town, now a ruined place. “What are they all staring up at, I wonder?” remarked Amos. “It must be some of those rash pilots driving German Taubes are circling around again, trying to locate hidden batteries of the Allies. Oh! Jack, look there, that’s a Zeppelin I do believe.” Jack had already decided this for himself. Away up among the fleecy clouds of the early morning they could see what looked like a bulky cigar-shaped object that was speeding along its course. It was too high for any anti-air craft gun to hope to reach it. Possibly Allied birdmen would presently be sent aloft to try and engage the enemy, or failing that chase him off. All at once there arose a shout that was taken up by a thousand excited voices. The entire crowd started to sway and break. Men dashed for any sort of shelter that came most convenient. Others threw themselves flat upon their faces, believing in their sudden panic they would be in far less danger if they hugged the ground closely. Jack had himself detected some object falling from aloft. It might have been a cast-off sandbag, but in these perilous war times one must expect something more destructive than this. He too would have followed the example of those close by and dropped flat, only that he saw the falling object was bound to miss the spot where he and his chum stood by a big margin. In fact, it would drop outside the town, as the hostile airship was at too high an altitude for the marksman to aim with any reasonable certainty of success. Instantly there came a terrific boom. Jack and Amos felt the ground tremble under them with the concussion, and they did not need to be told it had been a most destructive bomb that had been dropped from the swiftly moving Zeppelin. [Illustration: Instantly there came a terrific boom.--_Page 249._] Almost immediately afterwards came a second shock, with the same quiver of the racked earth following the explosion. When even a third made the atmosphere seem to be surcharged with thunder Amos sank to his knees and pulled at the legs of his companion. “Drop down, Jack,” he called, almost frantically. “How do we know but what the very next bomb will be close by? We don’t want to be torn into fragments if we can help it, do we?” “It’s all over, I reckon, by now,” Jack assured him. “The Zeppelin seems to have passed well over us; and besides there’s a whole flock of Allied aeroplanes rising like birds to give chase. This wreck of a town has had another close call, I take it. Those bombs were terrible ones, and must have been meant for a purpose.” “What do you think the Germans were after? I don’t suppose now they knew for a minute Jack Maxfield and Amos Turner had come to town?” Of course Jack understood that his chum was only saying this in a spirit of sport.