"I know something about motors," replied Matt, "but not the first thing about air-ships."
As near as Matt could judge, they were proceeding at a speed of something like thirty miles an hour. He speeded up the engine a little and was surprised at the smoothness with which it worked. The propeller hummed in a low, husky drone that was quite different from the song of the cylinders.
He moved the steering lever backward a couple of notches. Immediately the rudder was tilted and the Hawk began to climb upward.
"Stop that!" yelled Brady. "We're high enough. What are you trying to do?"
"Learning the machine," answered Matt, and threw the lever forward.
The front end of the gas-bag tipped downward, and the air-ship slid toward the earth with a suddenness that almost threw Brady over the rail.
"That'll do you!" he whooped. "Get her on a level again, and be quick about it. You can handle the machine, all right, and I don't want you to do anything but what you're told."
"All right," said Matt quietly.
For five minutes longer they continued to swim onward through the air. A long string of lights shot across the gloomy landscape below them, and a whistle came upward from the earth with startling distinctness.
"There goes a train, whistlin' fer Lake Station," remarked Pete.