When morning came Tom and his friends had matters running almost as smoothly as before their capture.

The prisoners had no chance to escape, and, indeed, they seemed to have been broken in spirit.  La Foy was no longer the insolent, mocking Frenchman that he had been, and the two chief foreign engineers seemed to have lost some of their reason when the lightning struck them.

“But it was a mighty lucky and narrow escape for us,” said Ned, as he and Tom sat in the pilot-house the second day of the return trip.

“That’s right,” agreed his chum.

Once again they were above the earth, and, desiring to get rid as soon as possible of the presence of the spies, a landing was made near New York City, and the government authorities communicated with.  Captain Warner and Lieutenant Marbury took charge of the prisoners, with some Secret Service men, and the foreigners were soon safely locked up.

“And now what are you going to do, Tom?” asked Ned, when, once more, they had the airship to themselves.

“I’m going back to Shopton, fix up the gas bag, and give her another government trial,” was the answer.

And, in due time, this was done.  Tom added some improvements to the aircraft, making it better than ever, and when she was given the test required by the government, she was an unqualified success, and the rights to the Mars were purchased for a large sum.  In sailing, and in the matter of guns and bombs, Tom’s craft answered every test.

“So you see I was right, after all, Dad,” the young inventor said, when informed that he had succeeded.  “We can shoot off even bigger guns than I thought from the deck of the Mars.”

“Yes, Tom,” replied the aged inventor, “I admit I was wrong.”

Tom’s aerial warship was even a bigger success than he had dared to hope.  Once the government men fully understood how to run it, in which Tom played a prominent part in giving instructions, they put the Mars to a severe test.  She was taken out over the ocean, and her guns trained on an obsolete battleship.  Her bombs and projectiles blew the craft to pieces.

“The Mars will be the naval terror of the seas in any future war,” predicted Captain Warner.

The Secret Service men succeeded in unearthing all the details of the plot against Tom.  His life, at times, had been in danger, but at the last minute the man detailed to harm him lost his nerve.

It was Tom’s enemies who had set on fire the red shed, and who later tried to destroy the ship by putting a corrosive acid in one of the propellers.  That plot, though, was not wholly successful.  Then came the time when one of the spies hid on board, and dropped the copper bar on the motor, short-circuiting it.  But for the storage-battery that scheme might have wrought fearful damage.  The spy who had stowed himself away on the craft escaped at night by the connivance of one of Tom’s corrupt employees.