Louis Hamblin, in all probability, although she had not dreamed of such a thing until that moment.

"It is very strange that I should not have recognized Mrs. Montague, in spite of the white hair and the spotted lace vail," she murmured, thoughtfully. But after reflecting and recalling the fact that even the woman's eyebrows had been whitened and the whole expression of the face changed by pencil lines, to simulate wrinkles and furrows, and then covered with a thickly spotted vail, she did not wonder so much.

She was amazed and appalled by these discoveries, and trembling with excitement, she resolved to learn more, if possible.

She lifted the lid of the hat-box, at one end of the tray, and there lay the very bonnet and vail that the woman had worn in St. Louis, and also the wig of white hair.

"What a wretched creature!" she exclaimed, in a horrified tone. Then wondering if Ray might not have come, while she had been there, she flew back to the window in the other room to look for him.

Yes, his carriage was standing before the door, and he would soon find means to release her, she thought.

But moment after moment went by, and no one came, while the continuous murmur of voices in the room below made her wonder what was going on there.

Presently, however, her attention was attracted to a man who was sauntering slowly along the opposite sidewalk, and she was sure she had seen him somewhere before, although, just at first, she could not place him.

"Why!" she exclaimed, after studying his face and figure a moment, "it is Mr. Rider. Can it be possible that he suspects anything of the mystery concealed in this house? At any rate, he is just the man that is needed here at this time."

She tapped lightly on the pane to attract his attention.

He stopped, glanced up, and instantly recognized Mona, nodding and lifting his hat to indicate that he did so.

She beckoned him to cross the street, and then cautiously raised the window. He was beneath it in a moment.

"Come in, Mr. Rider, and come directly up stairs to me," she said, in a low tone. "I have been locked in this room, and I have made an important discovery which you ought to know immediately."

He nodded again, his keen eyes full of fire, turned, ascended the steps, and pulled the bell.

Mary sighed heavily as she bent her weary steps, for the fifth time, up the bas.e.m.e.nt stairs to answer his imperative summons.

"Is your mistress at home?" Mr. Rider inquired, in a quick, business-like tone.

"Yes, sir; but she is engaged with callers," the girl replied.

"So much the better," returned the detective; then, bending a stern look on her, he continued: "I am an officer; I have business in this house; you are to let me in and say nothing to any one. Do you understand?"

Mary grew pale at this, and fell back a step or two from the door, frightened at the term "officer."

Mr. Rider took instant advantage of the situation and stepped within the hall.

"Don't dare to mention that I am here until I give you leave," he commanded, authoritatively, and then ran nimbly and quietly up stairs.

It was the work of but a moment to find the room where Mona was confined, turn the key, and enter.

"What does this mean, Miss Richards?" he asked, regarding her curiously.

"How do you happen to be locked up like a naughty child?"

"I will explain that to you by and by; but first let me show you these."

She uncovered the box which contained the crescents and cross, and held the gleaming diamonds before his astonished eyes.

The man was so utterly confounded by the unexpected sight that for a moment he gazed at them with a look of wonder on his face.

"Zounds! where did you get them?" he cried, breathlessly.

Mona briefly explained regarding the accident to the table, which had resulted in her discovering the secret compartment with its treasures.

"Clever! clever!" the man muttered, as his eyes fastened upon the table and he comprehended the truth. "Well, well, young lady, you've done a fine stroke of business this day, and no mistake! These are the real articles, no paste or sham to fool me this time," he added, as he lifted the crescents from the box. "But--when--Mrs. Richmond Montague!--who'd have thought it?"

"This isn't all, Mr. Rider," Mona continued, in a whisper, for she feared Mrs. Montague might catch the sound of their voices.

"What! more discoveries!" the man exclaimed, all alert again, as he shut the box and slipped it into his pocket.

"Yes, step this way, if you please," and leading him to the door of Mrs.

Montague's chamber, she pointed at the costume lying upon the bed.

The quick eyes took it all in at a glance, and his face lighted with a swift flash of triumph.

"The Bently affair--the Vanderbeck swindle--the Palmer robbery! Clever!

clever!" he muttered, as he seized the costume, shook out its folds, discovered the thick layers of padding about the waist and hips, and eyed it with intense satisfaction. Then he revealed two rows of firm, white teeth in a broad smile, as he s.n.a.t.c.hed up and twirled that dainty red wig upon his hand, examining it with a critical and admiring eye.

"And this, also," continued Mona, going to the trunk and lifting from it the tailor-made costume of gray ladies' cloth.

"Aha! ha!" chuckled Mr. Rider. "Really, Miss Richards, if you were only a man we might make a right smart detective of you. This is the very dress we have been wanting, and here is the rent. Have you still the fragment that you showed me in St. Louis?"

"Yes, it is here in my purse," Mona answered, drawing it from her pocket, and, taking the piece of cloth from it, she handed it to him.

"Here, too, is the gray wig worn by Mrs. Walton," she went on, as she lifted the lid of the hat-box and revealed its contents.

"Yes; true enough! and I'll wager that this trunk contains some other disguises which we should recognize," he responded. "But," he added, "we have enough for our purpose just now, and we will defer further examination until later. Now, Miss Richards, I am going down stairs to confront that woman with this stolen property. You follow me, but remain in the hall until I give you a signal, then come forward with these disguises. Have you any idea who is below calling on her ladyship?" he asked, in conclusion.

"No; but I am very sure that Mr. Raymond Palmer is somewhere in the house, for he was to call for me, and his carriage is at the door."

"I am glad to know that," the man cried, "and now I will make quick work of this business."

He turned and left the room with a quick step, and going directly below entered the drawing-room, just as Mrs. Montague was rudely taunting Ray about Mona.

The young girl gathered up the various articles of clothing and followed him, and we know what occurred after that.

CHAPTER XX.

MRS. MONTAGUE EXPLAINS.

It would be difficult to describe the abject distress of the wretched woman, whose career of duplicity and crime had been so unexpectedly revealed and cut short.