"Just a little farther over this way, Ned. That's better. Now mark it there, and we'll have it clamped down."

"But can you get enough elevation here, Tom?"

"Oh, yes, I think so. Besides, I've added a few more inches to the lift of the disappearing carriage, and it will send the gun so much farther in the air. I think this will do. Where is Koku?"

"Here I be, Master."

"Just get hold of that small derrick, Koku, and lift up one of the projectiles. I want to see if they come in the right place for the breech before I set the hoisting apparatus permanently."

The giant was soon engaged in winding up the rope of an improvised hoist that stood about in the position the permanent one was to go. From the interior of the barbette, which was, in effect, a bomb-proof structure, there was lifted one of the big projectiles destined to be hurled from Tom Swift's giant cannon.

"Yes, I think that will do," decided the young inventor, as he watched Koku. "Now, Mr. Damon, if you will kindly oversee this part of the work, I'll see if we can't get that motor in better shape. It didn't work worth a cent this morning."

"Bless my rubber coat, Tom, I'll do all I can to help you!" declared the odd man.

"Massa Tom! Massa Tom!" called Eradicate.

"Yes, Rad. What is it?"

"Heah am dem chicken sandwiches, an' some hot coffee fo' yo' all. I done knowed yo' alt wouldn't hab no time t' stop fo' dinnah, so I done made yo' all up a snack."

"That's mighty good of you, Rad," spoke Tom, with a laugh. "I was getting pretty hungry; but I didn't want to stop until I had things moving in better shape. Come on, Ned, let's knock off for a few minutes and take a bite. You, too, Mr. Damon."

As they sat about the place where the gun was being mounted, munching sandwiches and drinking the coffee which the aged colored man had so thoughtfully provided, Eradicate said, with a chuckle:

"By gar! Dey can't git erlong wifout dish yeah coon, arter all! Ha! ha! Dat cocoanut giant he mighty good when it comes t' fastening big guns down so dey won't blow away, but when it comes t' eatin' dey has t' depend on ole Eradicate! Ha! ha! I'se got dat cocoanut giant beat all right!"

"He sure is jealous of Koku," remarked Ned, as Tom and Mr. Damon smiled at the colored man.

"He certainly hit me in the right spot," declared Tom, as he reached for another sandwich.

They had landed from the warship several days before, and from then on there had been hard work and plenty of it. Tom was here, there and everywhere, directing matters so that his gun would be favorably placed.

Some preliminary work had been done before they arrived in the way of preparing a place to mount the gun, and this work was now proceeding. The officers of the ordnance department were in actual charge, but they always deferred to Tom, since he had most at stake.

"It will be some days before you can actually fire your gun; will it not?" asked Ned of his chum, as they finished the lunch, and prepared to resume work.

"Yes--a week at least, I expect. It is taking longer to set up the carriage than I thought. But it will be an improvement over the solid one we formerly used. That was fine, Rad," he concluded as the colored man went back to the shack of which he had taken possession for himself and his cooking operations. It adjoined the quarters to which Tom, Ned, Mr. Damon and Koku had been assigned.

"Golly! I ain't so old yit but what I knows de stuff Massa Tom laiks!" exclaimed the colored man, moving off with a chuckle.

Tom, though he had many suspicions about the cut cables that had nearly been the cause of his gun sliding into the sea, had learned nothing definite--nor had Ned.

The German officer, with his body servant, who seldom spoke, had landed at Colon, and was proceeding to make himself at home with the officers and men who were building the canal. Occasionally he paid a visit to Tom and Ned, where they were engaged about the big gun. He always seemed pleasant, and interested in their labors, asking many question, but that was all, and our hero began to feel that perhaps he was wrong in his suspicions.

As for Ned, he veered uncertainly from one suspicion to another. At one time he declared that von Brunderger and General Waller were in a conspiracy to upset Tom's plans. Again he would accuse the German alone, until Tom laughingly bade him attend more to work and less to theories.

Slowly the work progressed. The gun was mounted after much labor, and then arrangements began to be made for the test. A series of shots were to be fired out to sea, and the proper precautions were to be taken to prevent any ships from being struck.

"Though if you intend to send a projectile thirty miles," said one of the officers, "I'm afraid there may be some danger, after all. Are you sure you have a range of thirty miles, Mr. Swift?"

"I have," answered Tom, calmly, "and with the increased elevation that I am able to get here, it may exceed that."

The officer said nothing, but he looked at Tom in what our hero thought was a peculiar manner.

A few days before the date set for the test one of the sentinels, who had been detailed to keep curiosity-seekers away from the giant cannon, approached Tom and said:

"There is a gentleman asking to see you, Mr. Swift."

"Who is it?" asked Tom, laying aside a pressure gauge he intended attaching to the gun.

"He says his name is Peterson--Alec Peterson. Do you want to see him?"

"Yes, let him come up," directed the young inventor. "Do you hear that, Ned?" he called. "Our fortune-hunting friend is here."

"Maybe he's found that lost opal mine," suggested Ned.

"I hope he has, for dad's sake," went on Tom. "Hello, Mr. Peterson!" he called, as he noticed the old prospector coming along. "Have you had any luck?"

"I heard you were down here," said the many not answering the question directly, "and as I had to run over from my island for some supplies I thought I'd stop and see you. How are you?" and he shook hands.

"Fine!" answered Tom. "Have you found the lost mine yet?"

Alec Peterson paused a moment. Then he said slowly:

"No, Tom, I haven't succeeded in locating the mine yet. But I-- I expect to any day now!" he added, hastily.