buildings with their valuable contents.

"You mean some one purposely put that bomb in the red shed,
Tom?"

"That's exactly what I mean. Some enemy, who wanted to do me an
injury, planned this thing deliberately. He filled this steel
shell with chemicals which, of themselves, after a certain time,
would send out a hot tongue of flame through this hole," and Tom
pointed to the opening in the round steel shell.

"He knew the fire would be practically unquenchable by ordinary
means, and he counted on its soon eating its way into the carbide
and other explosives. Only it didn't."

"Why, Tom!" cried Ned. "It was just like one of those alarm-
clock dynamite bombs--set to go off at a certain time."

"Exactly," Tom said, "only this was more delicate, and, if it
had worked properly, there wouldn't have been a vestige left to
give us a clue. But the fire, thanks to the ballast sand in the
dirigible, was put out in time. The fuse burned itself out, but I
can tell by the smell that chemicals were in it. That's all,
Koku," he went on to the giant who had stood waiting, not
understanding all the talk between Tom and Ned. "I'll take care
of this now."

"Bad man put it there?" asked the giant, who at least
comprehended that something was wrong.