“One of the hangars blown up—dynamite, I guess,” was the reply.

“Accident?”

“No, looks more like malicious spitework. The superintendent and his men are trying to find out.”

Our hero and his comrades could see lanterns moving about over at the row of hangars where the Comet was housed. Another man from the scene was halted by them, and Dave asked quickly:

“Which one of the hangars was blown up?”

“The concrete one—the one the Comet was in.”

Hiram uttered a groan. Dave grew pale with anxiety and distress. Elmer grasped hold of his arm as if the blow had made him reel.

“Dave,” spoke Hiram, in a trembling tone, “they stole our machine back at Washington. They’ve destroyed it, now!”

The young airman did not reply. His lips tightly compressed to hide his emotion, he hurried on. Then they all came to a stop. In dismay they stood staring at a mass of ruins—what was left of the wrecked hangar.

Pieces of concrete blocks littered the ground in all directions. Parts of an airship mechanism showed in the glare of the lanterns. The young aviator felt sick all over. He had known all along what there was to fear. His mind was quickly decided as to the motive and source of the vandal act.