That night Tom was uneasy.  Several times he got up, and looked toward the shed where the airship was stored.  He could not rid himself of the idea that the men to whose interest it was that the diamond-making secret remain undiscovered, might attempt to wreck the airship before the start.  Consequently both Eradicate Sampson and Engineer Jackson were on guard.  Tom looked from his window, to the shed where the Red Cloud was housed.  He saw nothing to cause him any uneasiness.

“I guess I’m just nervous,” he mused.  “But, all the same, I’ll be glad when we’ve started.”

They were all up early the next morning, Mr. Damon beginning the day by blessing the sunrise, and many other things that struck his fancy.  The airship was wheeled out of the shed, and Tom gave her a final inspection.

“It’s all right,” he declared.  “All aboard!”

“Now, do be careful,” begged Mr. Swift.  “Don’t take too many chances, Tom.”

“I’ll not.”

The adventurers were in the forward part of the ship, and Tom had taken his place at the wheels and levers in the pilot house.  As he was about to start the motor he looked toward the road, and saw a horse and carriage.  In the vehicle was a girlish figure, at the sight of which Tom blushed and smiled.  He waved his hand.

“I came to wish you good luck!” cried Mary Nestor, for it was she in the carriage.

“Thanks!” cried Tom, leaning from the window of the pilot house.  “It was good of you to get up so early.”

“Oh.  I’m always up early,” she informed him.

“Look out that the motor doesn’t scare your horse,” Tom warned her.

“Old Dobbin doesn’t mind anything,” was her answer.  “I’ll see that he doesn’t run away with me, as long as you’re not on earth to rescue me.  Good-by, Tom!”

“Good-by!” he called, and then he pulled the lever that set in motion the motor, and whirled the great propellers about.  They whizzed around with a roar, and the Red Cloud, shivering and trembling with the vibration, rose in the air like some great bird.

“We’re off for the West and Phantom Mountain!” called Tom to his companions.

As the airship soared upward, Eradicate Sampson ran forward from where he had been standing near his mule Boomerang.  He waved his hands, and shouted something.

“Bless my hatband!  What does he want?” asked Mr. Damon, watching him curiously.

“It sounds as if he were calling to us to come back,” spoke Mr. Parker.

“It’s too late now,” decided Tom.  “Maybe he forgot to tell us good-by,” but, he felt a vague wonder at Eradicate’s odd motions; for the colored man was pointing toward the stern of the airship, as if there was something wrong there.  But the Red Cloud soared on.

CHAPTER IX—­A WARNING BY WIRELESS

Rapidly the airship ascended, and, when it was high over the town of Shopton, Tom headed the craft due west.  Looking down he tried to descry Mary Nestor, in her carriage, but the trees were in the way, their interlocking branches hiding the girl.  Tom did see crowds of other persons, though, thronging the streets of Shopton, for, though the young inventor had made many flights, there was always a novelty about them, that brought out the curious.