there were busy times in the shed next to the seaside
cottage. So busy, in fact, were Tom and Mr. Sharp, that
they only found opportunity for one trip in the airship, and
that was to get some supplies from the shops at home.

"Well," remarked Mr. Swift one night, at the close of a
hard day's work, "another week will see our craft completed.
Then we will put it in the water and see how it floats, and
whether it submerges as I hope it does. But come on, Tom. I
want to lock up. I'm very tired to-night."

"All right, dad," answered the young inventor coming from
the darkened rear of the shop. "I just want to--"

Ne paused suddenly, and appeared to be listening. Then he
moved softly back to where he had come from.

"What's the matter?" asked his father in a whisper.
"What's up, Tom?"

The lad did not answer Mr. Swift, with a worried look on
his face, followed his son. Mr. Sharp stood in the door of
the shop.

"I thought I heard some one moving around back here," went
on Tom quietly.

"Some one in this shop!" exclaimed the aged inventor
excitedly. "Some one trying to steal my ideas again! Mr.
Sharp, come here! Bring that rifle! We'll teach these