"Be careful," warned the aviator. "Do you know what you are saying,
Jack? Who would tamper with my machine?"

"Well, there are many who might have done it," the machinist went
on. "Some of the mechanics you have discharged for not doing their
work properly might have done it. But the fellow I suspect is that
young army officer who got huffy because you wouldn't explain all
about your equalizing gyroscope, or stabilizer."

"Oh--you mean him?" gasped the aviator.

"That's the man," declared Jack. "He went off mad when you turned
him down, and I heard him muttering to himself about 'getting even.'
I'm sure he's the chap to blame for our accident."

"I should dislike to think that of anyone," said Mr. Vardon, slowly.
"But I am sure something was wrong with my aircraft. It had worked
perfectly in other trials, and then it suddenly went back on me.
I should like a chance to examine it."

"We'll try and give you that chance," said Colonel Masterly, who
came up at that moment. "We are to have a drill in building a
pontoon bridge across the river tomorrow, and I will order it thrown
across the stream at the point where your airship went down. Then
we may be able to raise the craft."

"That will be fine!" exclaimed the airship man. "I may even be able
to save part of my craft, to use in demonstration purposes. I may
even be able, to use part of it in building another. It was a fine