immense bag of oiled silk. It was shaped like a cigar, big in the middle
and tapering at both ends. The bag was enclosed in a net of ropes which
extended down to the lower part of the airship.

This lower part, as the boys could see, was just like a steam launch in
shape, only much lighter in weight. It had a sharp bow, and a blunt
stern. From the stern there extended a large propeller, the blades being
made from sheets of aluminum.

The main part of the ship proper, or the part suspended from the gas
bag, was covered by a closed and roofed cabin about forty feet long, ten
feet wide, and extending five feet above the gunwale of the ship. The
cabin had four windows on each side, a companionway fore and aft, and a
sort of look-out or conning tower forward, which, the professor
explained, was the place for the steersman.

"Because this ship can be steered wherever you want to go," he said,
pointing to the big rudder that was hung aft, an opening in it allowing
the screw or propeller to revolve.

The boys were lost in admiration of the wonderful airship. They were
consumed with curiosity as to how the machinery worked, and they thought
no more of their knocks and bruises than as if a mosquito had bitten
them. The professor watched their faces with delight. He loved boys and
mechanical apparatus.

"Now we will enter the _Monarch_," he said. "Turn on the lights,
Washington."

There was a click, and the cabin of the airship was flooded with a soft