"All but the bow and stern lines."

"You attend to the bow line, and I'll go to the stern," and, going over to the gas generator, Mr. Sharp started it so as to force more vapor into the red aluminum container. This had the effect of rendering the airship more buoyant, and it tugged and strained harder than ever at the ropes.

"Good-by, Tom," called Mr. Swift, reaching up to shake hands with his son. "Drop me a line when you get a chance."

"Oh, Tom, do be careful," implored Mrs. Baggert, her kind face showing her anxiety. "May I kiss you good-by?"

"Of course," answered the young inventor, though the motherly housekeeper had not done this since he was a little chap. She had to stand on a soap box, which Eradicate brought in order to reach Tom's face, and, when she had kissed him she said:

"Oh, I'm so worried! I just know you'll be killed, risking your lives in that terrible airship!"

"Ha! Not a very cheerful view to take, madam," observed Mr. Damon.

"Don't hold that view, I beg of you. Bless my eyelashes, but you'll see us coming home, covered with glory and star dust."

"I'm sure I hope so," answered Mrs. Baggert, laughing a little in spite of herself.

The last ropes were cast off. Good-bys were shouted as the airship shot into the air, and Mr. Sharp started the motor, to warm it up before the propellers were thrown into gear. The twenty cylinders began exploding with a terrific racket, as the m.u.f.fler was open, and Tom, looking down, saw Boomerang awaken with a jump. The mule was so frightened that he started off on a dead run, swinging the rickety, old wagon along behind him.

Eradicate Sampson, who had been feeling his muscle since he discovered what he thought was his marvelous strength, saw what was happening.

"Whoa, dar, Boomerang!" he shouted. Then, as the tailboard of the wagon swung past him, he reached out and grabbed it. Perhaps he thought he could bring the runaway mule up standing, but, if he did, he was grievously disappointed. Boomerang pulled his master along the gravel walk, and kept running in spite of Eradicate's command to "whoa, dar!"

It might have gone hard with him, had not Garret Jackson, the engineer, running in front of Boomerang, caught the animal. Eradicate picked himself up, and gazed sadly at his arms. The navigators of the air could not hear what he said, but what he thought was evident to them.

Then, as Mr. Sharp deadened the explosions of the powerful motor. Tom, looking at a gauge, noted that their height was seven hundred feet.

"High enough!" called Mr. Sharp, and it was time, for Mr. Damon, in spite of his resolution, was getting pale.

The gas was shut off, the propellers thrown into gear, and, with a rush the Red Cloud shot toward the south, pa.s.sing over the Swift homestead, and high above the heads of the crowd that had gathered to witness the start. The eventful voyage of the air had begun.

Chapter 12

Some Startling News

"Well, there they go," remarked Mrs. Baggert to Mr. Swift, as she strained her eyes toward the sky, against the blue of which the airship was now only a large, black ball.

"Yes, and a fine start they made," replied the inventor. "I almost wish I had accompanied them, but I must not stop work on my submarine invention."

"I do hope nothing will happen to them," went on the housekeeper. "I declare, though, I feel just as if something was going to happen."

"Nervousness, pure nervousness," commented Mr. Swift. "Better take a little--er--I suppose catnip tea would be good."

"Catnip tea! The very idea!" exclaimed Mrs. Baggert. "That shows how much you know about nervousness, Mr. Swift," and she seemed a little indignant.

"Ha! Hum! Well, maybe catnip tea wouldn't be just the thing. But don't worry about Tom. I'm sure he can look after himself. As for Mr. Sharp he has made too many ascensions to run into any unnecessary danger."

"Nervous!" went on the housekeeper, who seemed to resent this state being applied to her. "I'm sure I'm not half as nervous as that Mr.

Damon. He gives me the fidgets."

"Of course. Well, I must get back to my work," said the inventor. "Ah, are you hurt, Eradicate?" he went on, as the colored man came back, driving Boomerang, who had been stopped just before reaching the road.

"No, Mistah Swift, I ain't exactly damaged, but mah feelin's am suah hurted."

"How's that?"

"Well, I thought I had growed strong in de night, when I lifted dat airship, but when I went to stop mah mule I couldn't do it. He won't hab no respect fo' me now."

"Oh, I wouldn't let that worry me," commented Mr. Swift, and he explained to Eradicate how it was that he had so easily lifted the end of the buoyant ship, which weighed very little when filled with gas.

The colored man proceeded with his work of whitewashing, the inventor was in his library, puzzling over tables of intricate figures, and Mrs.

Baggert was in the kitchen, sighing occasionally as she thought of Tom, whom she loved almost as a son, high in the air, when two men came up the walk, from the street, and knocked at the side door. Mrs. Baggert, who answered the summons, was somewhat surprised to see Chief of Police Simonson and Constable Higby.

"They probably came to see the airship start," she thought, "but they're too late."

"Ah, good morning, Mrs. Baggert," greeted the chief. "Is Mr. Swift and his son about this morning?"

"Mr. Swift is in his library, but Tom is gone."

"He'll be back though, won't he?" asked Constable Higby quickly--anxiously, Mrs. Baggert thought.

"Oh, yes," she replied. "He and--"

"Just take us to see Mr. Swift," interrupted the chief, with a look of caution at his aide. "We'll explain matters to him."

Wondering what could be the mission of the two officers, Mrs. Baggert led them to the library.

"It's queer," she thought, "that they don't ask something about the airship. I suppose that was what they came for. But maybe it's about the mysterious men who robbed Mr. Swift."

"Ah, gentlemen, what can I do for you?" asked the inventor, as he rose to greet the officials.

"Ahem, Mr. Swift. Ahem--er--that is--well, the fact is, Mr. Swift,"

stammered the chief, "we have come upon a very painful errand."

"What's that?" cried Tom's father. "I haven't been robbed again, have I?'

"There has been a robbery committed," spoke the constable quickly.

"But you are not the victim," interposed the chief.

"I'm glad of that," said Mr. Swift.

"Where is your son, Tom?" asked the head of the Shopton police force, sharply.

"What do you want with him?" inquired the inventor, struck by some strange tone in the other's voice.