my father was greatly excited over
something, and that he called in my stepmother and she was excited,
too. I was not told what it was about."

"Well, to drop him, do you know a man named John Watkins, of Bryport?"

"Watkins? Yes, I do. He once called on my father, about the same time
that Mr. Styles called last."

"Do you know why he called?"

"I do not. I thought it was about a patent. I learned that Mr.
Watkins worked for the United States government and I thought it was
for the patent office."

"Then that is all, Miss Langmore." The detective arose and held out
his hand. "Now take good care of yourself and do not worry. Matters
are bound to come out right in the end."

"But how can they be better for me?" Margaret's face took on its
worried look again. "They have proved that I am guilty."

"You are not guilty," said Adam Adams firmly and looking her squarely
in the eyes. "You are not guilty. I say so, and I know. Do not
worry. Rest quietly, and soon everything shall be made plain to you."
And then before she could answer he was gone. She sank back among the
pillows, closed her eyes and heaved a sigh.

"It cannot be!" she murmured. "It is too late! I am guilty! I am
guilty!"

CHAPTER XXII

AN UNDERGROUND MYSTERY

Late that afternoon a burly negro, plainly dressed and wearing a slouch
hat, made his way along the river road in the direction of the old
mill. He kept as much as possible in the shade of the bushes and trees
and when close to the mill sank low in the tall grass, that he might
not be seen by anyone who was passing.

The negro was Adam Adams and his disguise was perfection itself. The
detective was heavily armed and carried in his pockets several things
which were unusual to him.

He waited around the old mill until the sun went down and the stars
began to come out one by one. No one was in sight, but this did not
ruffle him. He was ready to play a waiting game and take whatever was
to come, even at the risk of his life.

Presently he heard a whistle at a distance. Then a man appeared whom
he rightfully took to be the fellow called Bart. This individual
passed up and down the road near the mill and also came down to the
water's edge, to gaze at the footpath on the other side of the river.
The man had the mastiff Queen with him and the dog came within a
hundred feet of where Adam Adams was in hiding. Quickly the detective
pulled a large atomizer from his pocke