"She's a success!" exulted Tom to himself."She's a success, but she isn't perfect yet," he added."I've got to make the muffler bigger and put in more baffle-plates.Then I think I can turn the trick."He swung the machine out over the open country, and then, when they were up at a height and sailing along easily, he called back to Mr.Damon in the seat behind him:
"How do you like it?"
"Great!" exclaimed the eccentric man."Bless my postage stamp, but it's great! Why, there's hardly a sound, Tom, and I can hear you quite easily.""And I can hear you," added Tom."I don't believe, down below there," and he nodded toward the earth, though Mr.Damon could not see this, as the airship, save for a tiny light over the instrument board, was in darkness, "they know that we're flying over their heads.""I agree with you," was the answer."Tom, my boy, I believe you've solved the trick! You have produced a silent aeroplane, and now it's up to the government to make use of it.""I'm not quite ready for that yet," replied the young inventor."I haveseveral improvements to make.But, when they are finished, I'll let Uncle Sam know what I have.Then it's up to him.""And you must be careful, Tom, that some of your rivals don't hear of your success and get it away from you," warned Mr.Damon, as Tom guided the Air Scout along the aerial way--an unlighted and limitless path in the silent darkness.
"Oh, they'll have to get up pretty early in the morning to do that!" boasted Tom, and afterward he was to recall those words with a bit of chagrin.
On and on they sailed, and as Tom increased the speed of the motor, and noted how silently it ran, he began to have high hopes that he had builded better than he knew.For even with the motor running at almost full speed there was not noise enough to hinder talk between himself and Mr.Damon.
Of course there was some little sound.Even the most perfect electric motor has a sort of hum which can be detected when one is close to it.But at a little distance a great dynamo in operation appears to be silence itself.
"I can go this one better, though," said Tom as he sailed along in the night."I see where I've made a few mistakes in the baffle plate of the silencer.I'll correct that and--"As he spoke the machine gave a lurch, and the motor, instead of remaining silent, began to cough and splutter as in the former days.
"Bless my rubber boots, Tom! what's the matter?" cried Mr.Damon."Something's gone wrong," Tom answered, barely able to hear andmake himself heard above the sudden noise."I'll have to shut off the power and glide down.We can make a landing in this big field," for just then the moon came out from behind a cloud, and Tom saw, below them, a great meadow, not far from the home of Mary Nestor.He had often landed in this same place.
"Something has broken in the muffler, I think, letting out some of the exhaust," he said to Mr.Damon, for, now that the motor was shut off, Tom could speak in his ordinary tones."I'll soon have it fixed, or, if I can't, we can go back in the old style-- with the machine making as much racket as it pleases."So Tom guided the machine down.It went silently now, of course, making, with the motor shut off, no more sound than a falling leaf.Down to the soft, springy turf in the green meadow Tom guided the machine.As it came to a stop, and he and Mr.Damon got out, there was borne to their ears a wild cry:
"Help! Help!"
