"The fellow was pretty sharp to slip by," Ned observed.

"The stockade is no mean barrier, especially with the rows of
barbed wire at the top," said Mr. Swift.

"Barbed wire! That's it!" exclaimed Tom. It was just here that
Mr. Damon's idea for guarding his prize buff Orpingtons came into
play in Tom's scheme of things. "Barbed wire doesn't seem to keep
out spies," he added slowly. "But believe me, something else
will!"

For Tom to think of a thing was to start action without delay.
Immediately he called a gang from the shops and set them to work
stringing copper wire along the top of the stockade.

He was sure that the man who had set the time bomb in place had
got into the enclosure over the fence. If he tried the same trick
again he was very apt to have the surprise of his life!

Each night when the shops closed and the watchmen went on duty,
a current of electricity was turned into those copper wires
entwined with the barbed wire entanglement at the top of the
stockade that would certainly double up any marauder who sought
to get over the top.

However, no further attempt was made against Tom's peace of
mind and against his invention during the immediate weeks that
followed. The young inventor was so closely engaged in his work
that he scarcely left the house or the confines of the shops.