"Eleven hundred and fifty!" cried Ned.
"Good! That'll do it. She'll give more after she's been running a while. We'll go up."
Ned scrambled to his seat, and Tom followed. He had an arrangement so that he could slip loose the retaining rope from his perch whenever he was ready.
Waiting until the motor had run another minute, the young inventor pulled the rope that released them. Over the smooth starting ground that formed a part of the Swift homestead darted the aeroplane. Faster and faster she moved, Ned gripping the sides of his seat.
"Here we go!" cried Tom, and the next instant they shot up into the air.
Ned Newton had ridden many times with his chum Tom, and the sensation of gliding through the upper regions was not new to him. But this time there was something different. The propellers seemed to take hold of the air with a firmer grip. There was more power, and certainly the speed was terrific.
"We're going fast!" yelled Ned into Tom's ear.
"That's right," agreed the young inventor. "She'll beat anything but my Sky Racer, and she'd do that if she was the same size." Tom referred to a very small aeroplane he had made some time before. It was like some big bird, and very swift.
Up and onward went the remodeled airship, faster and faster, until, when several miles had been covered, Ned realized that the young inventor had achieved another triumph.
"It's great, Tom! Great!" he yelled.