"Hi, Perfessor! Shall I shut off de gas?" Washington suddenly cried.
"For a while," was the inventor's reply. "We are high enough now. Then oil up the engines and dynamos, they need it. You boys can help," he said to Mark and Jack. "I must see to my instruments and find whether everything is working right."
The two boys were delighted to have a chance in the engine room. Under Washington's direction, the colored man showing quite a knowledge of the apparatus, they oiled the various bearings until everything was running smoothly.
Until now they had no time to realize what an experience they were going through. Things had happened so quickly that it was hard to realize they were sailing through the air in a wonderful ship, probably the most successful navigator of the upper regions ever invented.
It was not until Jack looked over the edge of the airship from the engine room window that he felt what a trip up among the clouds meant. Below the earth was spread out like a good-sized map, with little threads of silver for rivers, patches of green for big fields, and narrow gray ribbons where there were roads.
"It's wonderful!" he cried to Mark.
"And to think we were chased out of town yesterday by a constable," spoke his companion. "This is a great change. I'd like to see him catch us now."
"Dis prolonguated elevation into de airy space ob de zeneth am extremely discommodatiousness to a pusson what ain't used to it," remarked Washington with a broad grin as he oiled a whirring motor.
"Yes—er—I guess it is," admitted Mark.
"Are your teeth all fast after that effort?" asked Jack with a laugh.