They were more than astonished at what they saw. They had no idea that the rough shed held such a perfect piece of machinery. Up near the roof of the place, which was quite high, there swayed an 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 glow of incandescent lamps. "Come on!" called Mr. Henderson, leading the way. The boys followed, marveling at the wonders on every side. They found the cabin of the strange craft divided into three parts. First came a sort of parlor, with a table and seats arranged on the sides. In the front part of this was a passage leading to the conning tower, or the place for the steersman. Behind the parlor came the sleeping quarters and dining room combined. The bunks were arranged to fold against the wall, and a table in the centre could be shut up when not in use and hoisted to the ceiling, giving plenty of space. Next came the engine room, and as they entered it the boys could hardly restrain from giving cheers of delight. It was almost filled with machinery, and occupied a little more than half of the whole boat, being twenty-two by ten feet in size.