"Stolen!" exclaimed Dave, in dismay.
"It startles you?" spoke the manager of the Interstate Aeroplane concern. "So it did us."
"But—"
"You are mystified—unusual occurrence rather. You can follow the track of a stolen automobile. But when it comes to pursuing an airship, you won't find many familiar roads in the clouds."
"How did it happen?" inquired Dave.
"Why, we had tested the machine and it was to have been shipped to you yesterday. The day before, our expert made a very fine and satisfactory demonstration. The tanks were full, everything in perfect shape for another spurt early yesterday morning. During the night some one scaled the fence, evaded the watchman, and broke into the aerodrome."
"It must have been some one familiar with the place here," suggested
Dave.
"We don't know that. It is certain, though, that they knew all about airships."
"Why so?"
"Because from the trail they left we could trace where they ran the machine outside. They gauged its ground run just right. They must have put on the muffler, for the watchman heard no sounds. Then they flew away."