"Hard work! We? Oh, pshaw! You've done most of it, Tom. I only helped here and there."

"Indeed, and you did more than that. If it hadn't been for you, Mr. Damon and Koku we'd never have gotten off as soon as we did. The government is the limit for doing things, sometimes."

"Bless my timetable! but I agree with you," put in Mr. Damon. "But at last we are on the way, in spite of delays."

This conversation took place on board one of Uncle Sam's warships, which the President had designated to take Tom's giant cannon to the Panama Canal.

The big gun had been lashed to the deck of the vessel, and was well protected from the weather. In the hold the parts of the disappearing carriage, which Tom had at last succeeded in having made, were securely stowed. In another part of the warship were the big projectiles, some arranged to be fired as solid shots, and others with a bursting charge. There was also a good supply of the powerful explosive, and Tom had taken extraordinary precautions so that it could not be tampered with. Koku had been detailed as a sort of guard over it, and to relieve him was a trustworthy sergeant of marines.

"If anyone tries to dope that powder now, and spoil my test at Panama," declared Tom, "he'll wish he'd never tried it."

"Especially if Koku gets hold of him," added Ned, grimly.

"But I don't believe there is any danger," went on the young inventor. "I spoke about what had happened, and the ordnance board took extra precautions to see that none but men and officers who could be implicitly trusted had anything to do with this expedition."

"You don't really believe anything like treachery would be attempted; do you, Tom?"

"I don't know what to say. Certainly I can't see why anyone connected with Uncle Sam would want to throw cold water on a plan to fortify the canal, even if an outsider has invented the gun—I mean someone like myself, not connected with the army or navy."