"So that's the Air Scout, is it, Tom?" asked Mr. Damon, as he viewed the machine.
"Yes, that's the girl. 'Air Scout' is as good a name as any, until I see what she'll do."
"It doesn't look different from one of your regular craft of the skies, Tom."
"No, she isn't. The main difference is here," and Tom showed his friend where a peculiar apparatus had been attached to the motor. This was the silencer—the whole secret of the invention, so to speak.
To Mr. Damon it seemed to consist of an amazing collection of pipes, valves, baffle-plates, chambers, cylinders and reducers, which took the hot exhaust gases as they came from the motor and "ate them up," as he expressed it.
"The cylinders, too, and the spark plugs are differently arranged in the motor itself, if you could see them," said Tom to his friend. "But the main work of cutting down the noise is done right here," and he put his hand on the steel case attached to the motor, the case containing the apparatus already briefly described.
"Well, I'm ready when you are, Tom," said Mr. Damon.
"We'll go as soon as it's dark," was the reply. "But first I'll give you a demonstration. Start the motor, Jackson!" Tom called to his chief helper.
Mr. Damon had ridden in aeroplanes before, and had stood near when Tom started them; so he was prepared for a great rush of air as the propellers whirled about, and for deafening explosions from the engine.
The big blades, of new construction, were turned until the gas in the cylinders was sufficiently compressed. Then Jackson stepped back out of danger while Tom threw over the switch.