aid Oscar.

"Can you not come to my home to-morrow?"

"I fear I will not have time."

"We must practice those signals. I will not ask you to visit me across
the river. I have the privilege of receiving company at the rooms of a
friend of mine in this city. If we could meet there some time to-morrow
morning, you might bring one or two of your friends with you and we will
practice the signals together."

"All right, it is not a bad idea."

"Then I will take a walk in Washington Parade ground to-morrow at about
eleven o'clock, and you shall meet me and I will lead you to my friend's
room, and then and there we will complete all our arrangements. Yes,
yes, I will save my brother and earn the money to start him out on an
honest course."

"Your affection for your brother appears to be very great."

"It is. I idolize him."

"Then at eleven o'clock to-morrow we are to meet by chance."

"Yes."

Our hero and the siren separated. She said she was to meet her brother
who was to accompany her to her home. The siren passed out ahead of our
hero after a merry good-night. When Oscar came forth he had wrought a
change. He stepped down to the curb and glanced. He saw a little chalk
mark. It would have looked to an ordinary observer like a mere
accidental scrape of chalk. To Oscar it spoke volumes, and he knew that
his faithful strategist had succeeded in falling to a trail; and he knew
that he would soon be on the trail like a sleuthhound following its
prey. The detective started forward. At the first street corner he drew
a little mask lantern and flashed its light around quickly and deftly,
and there again under its glare he beheld a tiny chalk mark.

"Right," he muttered as he read his sign and moved on; and so he
proceeded until he arrived at a certain corner, when he came to a halt;
and a few moments later a messenger boy came up close to him and said in
a low tone:

"She met her man."

"Well?"

"They went in that house across the street."

"Great Scott!" ejaculated Oscar, "are you sure, Cad?"

"Yes."

"The woman and how many men?"

"One man only."

"And that man?"

"Was Girard."

"Sis, you can call up our aids and have them ready."

"We can snake them into the house."

"It's lucky; yes, it's lucky, Cad, and yet, it's risky."

"Why?"

"Credo may be in with them."

"But he knows you hold his life as it were in your hands, and----"

"Well?"

"He knows if you have trailed these fellows down so cl