carefully!
They contain explosives and ammunition for the machine gun!"

If there had been hurry and bustle before, there was ten times as much
now. The professor gave one look at the place where Taggert had been
concealed. The man had worked off his bonds and escaped while his
captors were in the airship's cabin.

Soon there was a queer hissing noise from the engine room of the
_Monarch_. The gas bag began to distend.

"She's fillin', Perfessor!" cried Washington.

"We must tie her down," muttered the old man. "Otherwise she will rise
and take the shed with her. I say, Washington!"

"Yes, Perfessor."

"We must get some one to help us open the shed roof to let the ship rise
out. We can't do it alone."

"Guess it's a extraunordinary contract," agreed the negro.

"Then you go out and see if any one is in sight. Try to hire them for
the work, but don't tell them about the ship. They can work up on the
roof. I will see to the gas machine while you are away. Hurry now!"

The colored man went out. In the meanwhile the professor and the two
boys continued to load up the _Monarch_. They had nearly everything that
the inventor intended to take along piled in its proper place, when
footsteps were heard outside. Then the noise of some persons on the roof
was audible. In a few minutes Washington came in.

"I found three men," explained the negro. "One is dat old hunter as
helped us before, Andy Sudds. He was goin' huntin' but he said he'd help
take the roof off fer a dollar. De oder two is does farm hands, Tom
Smith an' Bill Jones. Dey was goin' down to do post-office, but dey said
dey'd help fer fifty cents apiece. All three is up on de roof now."

"Good!" exclaimed the professor. "It's lucky I had the roof made in
sections when I built this shed. Now it can be taken off in a hurry.
Come on, boys! There are some more things that must go in the ship!"

Thus urged, Mark and Jack worked with a will. Washington helped, and
then went up on the roof to aid the three emergency toilers. By this
time several sections of the covering to the shed had been taken off and
the place was quite light.

All the while the gas machine in the ship continued to generate the
vapor. It flowed into the cigar-shaped bag through two rubber tubes. As
the bag distended more and more, the _Monarch_ tugged and pulled at the
anchoring ropes on the floor of the shed, as if anxious to be away.

The boys worked with a will. The last articles were pl