"Oh, it's something on the same order, designed to help batter down the German lines," Tom answered. "I haven't quite made up my mind what to call it yet. But let's get home. I want to see that my tank is safe.

The absence of the plotters from the factory makes me suspicious."

On the way back Tom told more of the details of the attack.

"But we'll forget about it all, now you're out," remarked Ned.

"And the sooner we get home, the better," added Tom. "Can't you get a little more speed out of this machine?" he asked.

"Well, it isn't the Hawk," replied Ned, "but we'll see what we can do,"

and he made the runabout fairly fly.

Mrs. Baggert was the first to greet Tom as they arrived at his home.

She did not seem as surprised as either Tom, Ned or Mr. Damon expected her to be.

"Well, I'm glad you're all right," she said. "And it's a good thing you sent that note, for your father was so excited and worried I was getting apprehensive about him."

"What note?" asked Tom, while a queer look came into his face.

"Why, the one you sent saying you were detained on business and would probably not be home for a week, and to have Koku and the men bring the tank to you."

"Bring the tank! A note from me!" exclaimed Tom. "The plotters again!

And they've got the tank!"

He ran to the big shop followed by the others. Throwing open the doors, they went inside. A glance sufficed to disclose the worst.

The place where the great tank had stood was empty.

"Gone!" gasped Tom.

Chapter XXIV

Camouflaged

Two utterances Tom Swift made when the fact of the disappearance of the tank became known to him were characteristic of the young inventor. The first was:

"How did they get it away?"

And the second was:

"Come on, let's get after 'em!"

Then, for a few moments, no one said anything. Tom, Ned, and Mr. Damon, with Mrs. Baggert in the background, stood looking at the great empty machine shop.

"Well, they got her," went on Tom, with a sigh. "I was afraid of this as soon as they left me alone at the factory."

"Is anything wrong?" faltered the housekeeper. "Didn't you send for the tank, Tom?"

"No, Mrs. Baggert, I didn't," Tom answered.

"But I don't understand," the housekeeper said. "A man came with a note from you, Tom, and in it you said to have him take the tank, with Koku and the men who know how to run it. We were so glad to hear from you, and know that you were all right, that we didn't think of anything else, your father and I. So he went out and saw that the tank got off all right. Koku was glad, for it's the first chance he'd had to ride in it."

"Who was the man who brought the note?" asked Tom, and he was striving to be calm. "To think of poor old dad playing right into the hands of the plotters!" he added, in an aside to Ned.

"Well, I don't know who the man was," said Mrs. Baggert. "He seemed all right, and of course having a note from you--"

"Who has that note now?" asked Tom quickly.

"Your father."

"Come on," and Tom led the way back to the house. "I'll have a look at that doc.u.ment, which of course I never wrote, and then we'll get after the plotters and the tank."

"She ought to be easy to trace," observed Mr. Damon. "Bless my fountain pen, but she ought to be easy to trace! She will leave a track like a giant boa constrictor crawling along."

"Yes, I guess we can trace her, all right," a.s.sented Tom Swift; "but the point is, will there be anything left of her? What's what I'm afraid of now."

Mr. Swift was still excited, but his worry had subsided as soon as he knew Tom was safe.

"The whole thing is a forgery, but fairly well done," Tom said, as he looked at the paper his father gave him--a brief note stating that Tom was well, but detained on business, and that the tank was to be brought to him, just where the bearer of the note would indicate. Koku, the giant, and several of the machinists, who knew how to operate the big machine, were to go with it, the note said.

"That made me sure everything was all right," said Mr. Swift. "I knew, of course, Tom, that plotters might try to get hold of your war secret, but I didn't see how they could if Koku and some of your own men were in possession."

"They couldn't--as long as they remained in possession," Tom said. "But that's the trouble. I'm afraid they haven't. What has probably happened is that under the direction of this man, who brought the forged note from me, Koku and the others took the tank where he directed them, thinking to meet me. Then, reaching the place where the rest of the plotters were concealed, they overpowered Koku and the others and took possession of the machine."

"They'd have trouble with Koku," suggested Ned.

"Yes, but even a giant can't fight too big a crowd, especially if he is taken by surprise, and that's probably what happened," remarked Tom.

"Now the question is where is the tank, and how can we get her back?

Every minute counts. If those German spies and their helpers remain in possession long, they'll find out enough of my secrets to enable them to duplicate the machine, and especially some of the most exclusive features. We've got to get after 'em!"

"They imitated your writing pretty well, Tom," Observed Ned, as he looked at the forged note.

"Yes; that's why they took all my papers away from me--to get specimens of my handwriting. I half suspected that, but I didn't quite figure out what their game was. Well, we know the worst now, and that's better than working in the dark. Now I'm going to have a bath and get into some decent clothes, and we'll see what we can do."

"Count on me, Tom!" exclaimed Ned. "I'll go the limit with you!"

"I knew you would, old man!"

"And me, too!" cried Mr. Damon. "Bless my open fireplace, but I'll send word to my wife that I'm not coming home to-night, and we can start the first thing in the morning, Tom."

"Yes; there isn't much use in going now, as it will soon be dark."

"How are you going to trace the tank, Tom?" asked Ned, when his chum had bathed and gotten into fresh clothes.

"I'm going to tour the country around here in an auto. The tank can make ten miles an hour, but that's nothing to what an auto can do. And we oughtn't to have much trouble in tracing her. No one whose house she pa.s.sed would forget her in a hurry."