“What happened then?” asked Ned.

“Oh, Koku forgot that he had so much muscle, and he kept on pumping air into the bicycle wheel tires until he burst one.  Go easy this time, Koku.”

“I will, Mr. Tom,” and the giant took the air pump.

“Is he going along?” asked Ned, as he looked to see that all the guy wires and stays were tight.

“I guess so,” replied Tom.  “He makes good ballast.  I wish Mr. Damon was here.  If everything goes right we may take a run over, and surprise him.”

In a little while the noiseless airship was ready for the start.  Tom, Ned and Koku climbed in, and took their positions.

“Good luck!” Mr. Swift called after them.  Tom waved his hand to his father, and the next moment his craft shot into the air.  Up and up it went, the great propeller blades beating the air, but, save for a soft whirr, such as would be made by the wings of a bird, there was absolutely no sound.

“Hurrah!” cried Tom.  “She works!  I’ve got a noiseless airship at last!”

“Say, don’t yell at a fellow so,” begged Ned, for Tom had been close to his chum when he made his exulting remark.

“Yell!  I wasn’t yelling,” replied Tom.  “Oh, I see what happened.  I’m so used to speaking loud on the other airships, that make such a racket, that I didn’t realize how quiet it was aboard the new Falcon.  No wonder I nearly made you deaf, Ned.  I’ll be careful after this,” and Tom lowered his voice to ordinary tones.  In fact it was as quiet aboard his new craft, as if he and Ned had been walking in some grass-grown country lane.

“She certainly is a success,” agreed Ned.  “You could creep up on some other airship now, and those aboard would never know you were coming.”

“I’ve been planning this for a long time,” went on our hero, as he shifted the steering gear, and sent the craft around in a long, sweeping curve.  “Now for Waterford and Mr. Damon.”

They were soon above the town where the odd man lived, and Tom, picking out Mr. Damon’s house, situated as it was in the midst of extensive grounds, headed for it.

“There he is, walking through the garden,” exclaimed Ned, pointing to their friend down below.  “He hasn’t heard us, as he would have done if we had come in any other machine.”

“That’s so!” exclaimed Tom.  “I’m going to give him a sensation.  I’ll fly right over his head, and he won’t know it until he sees us.  I’ll come up from behind.”

A moment later he put this little trick into execution.  Along swept the airship, until, with a rush, it passed right over Mr. Damon’s head.  He never heard it. and was not aware of what was happening until he saw the shadow it cast.  Then, jumping aside, as if he thought something was about to fall on him, he cried: 

“Bless my mosquito netting!  What in the world—­”

Then he saw Tom and Ned in the airship, which came gently to earth a few yards further on.