mised Ned, with a laugh.

The two chums found that every precaution had been taken in regard to
the projectiles and powder. Koku was on guard, the giant regarding the
boxes of explosive with a calm but determined eye. It would not be well
for any unauthorized hand to tamper with them.

"Am dere anyt'ing I kin do fo' yo'-all, Massa Tom?" inquired Eradicate,
as the young inventor and Ned prepared to go on deck again. The aged
colored man had insisted on coming as a sort of personal bodyguard to
Tom, and the latter had not the heart to refuse him. Eradicate was
desperately jealous of the giant.

"Huh!" Eradicate had said, "anybody kin sit an' look at a lot ob dem
powder boxes; but 'tain't everybody what kin wait on Massa Tom. I kin,
an' I'se gwine t' do it." And so he had.

It was planned to proceed directly to Colon, the eastern terminus of
the canal, from New York, stopping at Santiago to transact some
government business there. The big gun was to be mounted on a barbette
near the Gatun locks, pointing out to sea, and the trial shots would be
fired over the water.

Eventually the gun would be so mounted as to swing in a circle, so as
to command the land as well as the water; and, in fact, if the
government decided to adopt Tom's giant cannon as the official
protective arm of the canal, they would all be so mounted. For, of
course, it might be possible for land as well as sea forces to attack
and try to capture the big ditch.

The first few days of the voyage were pleasant enough. The weather was
fine, and Tom was kept busy explaining to many of the officers aboard
the ship the principles of his gun, powder and projectiles. Members of
the ordnance board, who had been detailed to witness the test, were
also much interested as Tom modestly described his work on the giant
cannon.

At Santiago de Cuba, when Tom and Ned were standing near the gangway,
watching the officers returning from shore leave, for the ship was to
proceed soon, after a two days' stay, the young inventor started as he
noticed a military man walking aboard.

"Look, Ned!" he exclaimed, in a low voice.

"Where?"

"At that man--an officer in civilian dress, I should judge--haven't you
seen him before?"

"I have, Tom. Now, where was it? I seem to remember his face; and yet
he wasn't dressed like this the last time I saw him."

"I guess not, Ned. He had on a uniform then."

"By jinks! I have it. That German officer--von Brunderger! That's he!"