"He's looking for us!" exclaimed Mr.Damon with an inward laugh."Bless my watch chain! But it's a good thing we got in ahead of him.Are you sure it was Andy himself?""Sure! I'd know his face anywhere.But I can't understand it.Where has he been? What is he doing? Where is he building his aeroplane? I thought he was out of town.""He may have come back to-night," said Mr.Damon."That's the only one of your questions I can answer.We'll have to wait about the rest, I'm sure he wasn't around the house today, though, for I was working at weeding the flower beds, in my disguise as a tramp, and if he was home I'd have seen him.He must have just come back, and he went out to his shed to get something.Well, we did the best we could.""Indeed we did," agreed Tom, "and I'm ever so much obliged to you, Mr.Damon.""And we'll try again, when we get more clues.Bless my shoelaces! but it's a relief to be able to talk as you like."And forthwith the eccentric man began to call down so many blessings on himself and on his belongings, no less than on his friends, that Tom laughingly warned him that he had better save some for another time.
The two reached home safely, removed their "disguises," and told Mr.Swift of the result of their trip.He agreed with them that there was amystery about Andy's aeroplane which was yet to be solved.
But Tom was glad to find that, at any rate, the craft was not being made in Shopton, and during the next two weeks he devoted all his time to finishing his own machine.Mr.Jackson was a valuable assistant, and Mr.Damon gave what aid he could.
"Well, I think I'll be ready for a trial flight in another week," said Tom one day, as he stepped back to get a view of the almost completed Humming-Bird.
"Shall you want a passenger?" asked Mr.Damon.
"Yes, I wish you would take a chance with me.I could use a bag of sand, not that I mean you are to be compared to that," added Tom quickly, "but I'd rather have a real person, in order to test the balancing apparatus.Yes, we'll make a trial trip together."In the following few days Tom went carefully over the aeroplane, making some slight changes, strengthening it here and there, and testing the motor thoroughly.It seemed to work perfectly.
At length the day of the trial came, and the Humming-Bird was wheeled out of the shed.In spite of the fact that it was practically finished, there yet remained much to do on it.It was not painted or decorated, and looked rather crude.But what Tom wanted to know was how it would fly, what control he had over it, what speed it could make, and how it balanced.For it was, at best, very frail, and the least change in equilibrium might be fatal.
Before taking his place in the operator's seat Tom started the motor, and by means of a spring balance tested the thrust of the propellers.It was satisfactory, though he knew that when the engine had been run for some time, and had warmed up, it would do much better.
"All ready, I guess, Mr.Damon!" he called, and the odd gentleman took his place.Tom got up into his own seat, in front of several wheels and levers by which he operated the craft.
"Start the propeller!" he requested of Mr.Jackson, and soon the motor was spitting fire, while the big, fanlike blades were whirring around like wings of light.The engineer and Eradicate were holding back the Humming-Bird.
"Let her go!" cried Tom as he turned on more gasoline and further advanced the spark of the motor.The roar increased, the propeller looked like a solid circle of wood, and the trim little monoplane moved slowly across the rising ground, increasing its speed every second, until, like some graceful bird, it suddenly rose in the air as Tom tilted the wing tips, and soared splendidly aloft!
