receptacle.

"No use taking any chances," he remarked. "I've had too
much trouble with people trying to get inside information
about dad's and my patents. Now, Koku, I'll go and see this
man."

The buildings composing the plant of Tom Swift and his
father at Shopton were enclosed by a high, board fence, and
at one of the entrances was a sort of gate-house, where some
one was always on guard. Only those who could give a good
account of themselves, workmen in the plant, or those known
to the sentinel were admitted.

It happened that the colored man, Eradicate, was on guard
at the gates this day when the stranger asked to see Tom.
Koku, working on the airship engine not far away, saw the
stranger. Hearing the man say he was in a hurry and noting
the slow progress of the aged Eradicate, who was troubled
with rheumatism, the giant took matters into his own hands.

Tom Swift entered the gate-house and saw, seated in a
chair, a man who was impatiently tapping the floor with his
thick-soled shoe.

"Looks like a detective or a policeman in disguise,"
thought Tom, for, almost invariably, members of this
profession wear very thick-soled shoes. Opposite the
stranger sat Eradicate, a much-injured look on his honest,
black face.