Meanwhile the plotters were gradually getting at the secrets of construction, and they were in the midst of this work when one of them saw the aeroplane. Rightly guessing what it portended, they left hurriedly, still leaving the hapless men bound, and started the tank on what they thought would be her last trip.
"But you saved her, Tom!" cried Ned. "You saved her with the wireless."
And word was sent back to Shopton by the same means to tell Mr. Swift, Mr. Damon, and the others that Tom and his tank were safe. And then, a little later, when the bound men had recovered the use of their cramped limbs, the tank was backed away from the ledge and started on her homeward way, Tom and Ned preceding her in the Hawk.
Without further incident, save a slight break which was soon repaired, Tank A soon reached her harbor again, and a double guard was posted about the shop.
"And they won"t get much more chance to steal her secrets," said Tom that night, when the stories had been told.
"Why?" asked Ned.
"We start to dismantle her at once," Tom answered, "and she goes to England to be reproduced for France."
"If only those plotters haven"t stolen the secrets," mused Ned.
But if they had they got little good of them. For shortly afterward government secret service agents rounded up the chief members of the gang, including Simpson and Blakeson. They, with Schwen, were sent to an internment camp for the period of the war, and enough information was obtained from them to disclose all the workings of the plot.
"It was just like lots of other stunts the German spies tried to put over on the good old U.S.A.," said Tom to Ned, the day after the dismantled tank was shipped to Great Britain. "In some way the spies found out what I was making, and then they got hold of Blakeson and Grinder. Those fellows, who so nearly queered me in the big tunnel game promised to make a tank that would beat those the British at first put out, and they took some German money in advance for doing it.
"When they found they couldn"t make good, the German spies agreed to help them get possession of my secrets. They worked hard enough at it, too, but, thanks to you, Ned, and to Eradicate, who gave us the tip on Schwen, we beat "em out."
"And so it"s all over, Tom?"
"Yes, practically all over. I"ve given all my interests in the tank to Uncle Sam. It was the only way I could do my bit, at this time. But I"ve something else up my sleeve."
And those of you who care to learn what the young inventor next did may do so by reading the next volume of this series.
It was about a week after Tank A, as she was still officially called, had been shipped in sections that Ned Newton called at Tom"s home. He found his chum, with a flower in his b.u.t.tonhole, about to leave in his small runabout.
"Oh, excuse me!" exclaimed Ned. "This is Wednesday night. I might have known. Give Mary my regards."
"I will," promised Tom, with a smile.