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,
