most of the men employed at Tom's plant were of a
robust type.

"I done fooled him. I said as how I'd lest brought from town in mah
mule cart some new sauerkraut, an' he could sample it if he liked. So
he went wif me, an' when I got him to de stable I pushed him in and
locked de door!"

"Come on!" cried Tom to his chum. "Rad may be right, after all, and one
of my workmen may be a German spy, though I've tried to weed them all
out.

"However, no matter about that, if he was employed in another shop, he
had no right to go into Number Thirteen. That's a violation of rules.
But if he's in Rad's ramshackle stable he can easily get out."

"No, sah, dat's whut he can't do!" insisted the colored man.

"Why not?" asked Tom.

"'Cause Boomerang's on guard, an' yo'-all knows how dat mule of mine
can use his heels!"

"I know, Rad," went on Tom; "but this fellow will find a way of keeping
out of their way. We must hurry."

"Oh, he's safe enough," declared the colored man. "I done tole Koku to
stan' guard, too! Dat low-down white trash ob a giant is all right fo'
guardin', but he ain't wuff shucks at detectin'!" said Eradicate, with
pardonable pride. "By golly, maybe I's too old t' put on guard, but I
kin detect, all right!"

"If this proves true, I'll begin to believe you can," replied Tom. "Hop
along, Ned!"

Followed by the shuffling and chuckling negro, Tom and Ned went to the
rather insecure stable where the mule Boomerang was kept. That is, the
stable was insecure from the standpoint of a jail. But the sight of the
giant Koku marching up and down in front of the place, armed with a big
club, reassured Tom.

"Is he in there, Koku?" asked the young inventor.

"Yes, Master! He try once come out, but he approach his head very close
my defense weapon and he go back again."

"I should think he would," laughed Ned, as he noted the giant's club.

"Well, Rad, let's have a look at your prisoner. Open the door, Koku,"
commanded Tom.

"Better look out," advised Ned. "He may be armed."

"We'll have to take a chance. Besides, I don't believe he is, or he'd
have fired at Koku. There isn't much to fear with the giant ready for
emergencies. Now we'll see who he is. I can't imagine one of my men
turning traitor."

The door was opened and a rather miserable-looking man shuffled out.
There was a bloody rag on his head, and he seemed to have made more of
an effort to escape than Koku described, for he appeared to have
suffere