a heavy fine, or the military prison at Fort
Leavenworth.--I say, Owens, how did the colonel find it out?"

"Do you suppose he tells his secrets to us privates?" asked Bob in
reply.

"We spoke to somebody who was not worthy of the confidence we placed in
him," continued Bristow. "The thing never could have become known
unless one of our own number had proved treacherous. But we can easily
find out who he is. There are just thirty of us, and if there are only
twenty-nine arrested, the missing man is the guilty one. When I find out
who he is, I shall take particular pains to see that the next battle he
gets into is his last."

This threat was uttered in a very low tone of voice, for Bristow and his
captor had by this time reached the place where the lieutenant had
stationed himself to receive his men when they came in with their
prisoners. Bob reported, "Your orders have been obeyed, sir," and took
his stand close behind his officer.

"I counted only twenty-six," said Bristow when the sergeant-major came
up and announced the complete success of the undertaking. "There must be
four traitors among us."

"Have you counted in the horse-guards?" asked Bob. "There they are on
the top of that ridge."

No, Bristow had not counted them in, for he did not know until that
minute that they had been arrested. He was very much astonished when he
learned that every one of his party had been secured, and could not for
the life of him imagine how the colonel had found out about it; for that
he knew _all_ about it was evident from the manner in which the arrests
had been effected.

Having sent one of his men back to order up the horses, the lieutenant
formed his captives in line, threw a guard around them and marched them
into the fort. Halting them on the parade, he went in to report to the
colonel, and when he came out again he put every one of them into the
guard-house; after which Bob and his companions went to the quarters and
tumbled into their bunks.

Great was the astonishment among the soldiers the next morning when it
became known that the expedition, which they supposed had gone out in
search of the hostiles, had returned to the fort and captured thirty
armed men, and that the work had been done so quietly that the sentry at
the gate never knew anything about it until it was all over. Of course
they were quite at a loss to determine who it was that told the colonel
about it; and the general impression seemed to be that