Under the rug it went, and across to the window. She looked out. A fire escape pa.s.sed the window. It was open. She saw the little wire cross through the woodwork to the outside brick construction and down the wall. Softly she clambered down the fire-escape until she could peer through the window on the floor below.

There at a desk, in the private office of the "Mercantile" a.s.sociation, sat the man who had been hugging her predecessor at Trubus'

switchboard, the man who had exchanged the curious looks with the philanthropist. Talking to him was the man who had taken her sister away from the candy store the day before!

Hurriedly she climbed back up the fire escape into the window, out through the door of the private office, closing it behind her.

She telephoned Bobbie at the station house. Fortunately he was there.

She gave him her address, and before he could express his surprise begged him to hurry to the doorway of the building and wait for her.

He promised.

Mary kept her nerves as quiet as she could, praying that the man Sawyer would not leave before she could follow him with Bobbie. In a few minutes one of the girls from the stenography room came out. Seeing that she was the new girl the young woman spoke: "Do you want me to relieve you while you go to lunch. I'm not going out to-day. I'm so glad to see anyone here but that fresh Miss Emerson that it will be a pleasure."

"Thank you. I do want to go now," said Mary nervously. She hurriedly donned her hat and rushed down to the street. Bobbie was waiting for her, as he had lost not a minute.

They waited behind the big door column for several minutes. Suddenly a man came swinging through the portal. It was Sawyer.

Bobbie remembered him instantly, while Mary gripped his arm until she pinched it.

"We'll follow him," said Burke, for the girl had already told of the dictagraph conversation.

Follow him they did. Up one street and down another. At last the man led them over into Burke's own precinct. He ascended the iron steps of an old-fashioned house which had once been a splendid mansion in generations gone by.

"Ah, that's where Lorna is hidden, as sure as you're standing here, Mary. From what he said no harm has come to her yet. Hurry with me to the station house, and we'll have the reserves go through that house in a jiffy."

It took not more than ten minutes for the police to surround the house.

But disappointment was their only reward. Somehow or other the rascals had received a tip of premonition of trouble; perhaps Shepard was suspicious of his princ.i.p.als, and wished to move the girl out of their reach.

The house was empty, except for a few pieces of furniture.

"Look!" cried Mary, as she went through the rooms with Bob. "There is a handkerchief. She s.n.a.t.c.hed it up. It was one of her own, with the initials "M. B." in a monogram.

"Lorna has been here," she exclaimed. "I remember handing her that very handkerchief when we were in the store yesterday."

"What's to be done now?" thought Bobbie. "We had better go up to your father and tell him what we know--it is not as bad as it might have been."

"Precious little comfort," sighed Mary, exhausted beyond tears.

They reached the desolate home, and Bob broke the news to the old man.

As Mary poured forth her story of the discovery in Trubus' office, her father's face lighted with renewed hope.

To their surprise he laughed, softly, and then spoke:

"Mary, my child, my long hours of study and labor on my own invention have not been in vain. My dictagraph-recorder--this very model here, which I have just completed shall be put to its first great test to save my own daughter. Heaven could reward me in no more wonderful manner than to let it help in the rescue of little Lorna--why did I not think of it sooner?"

"What shall we do, father?" breathlessly cried Mary.

"Can I help, Mr. Barton?"

"Describe the arrangement of the offices."

Mary rapidly limned the plan of the headquarters of the Purity League.

Her father nodded and his lips moved as he repeated her words in a whisper.

"I have it now. You must put the instrument under the telephone switchboard table," he directed. "Pile up a waste-basket, or something that is handy to keep it out of view. I have already adjusted enough fresh cylinders to record at least one hour of conversation. This machine is run by an automatic spring, which you must wind like a clock. Here I will wind it myself to have all in readiness."

He rolled his chair swiftly to his work table, and turned the little crank, continuing his plan of attack.

"Now, take the long wire, and run it through the door of the private office up close to the desk. Attach this disc to the dictagraph receiver. It is so small, and the wiring so fine that it will not be noticed if it is done correctly. Here, Burke. I will do it now to this loose dictagraph receiver. Watch me."

The old man worked swiftly.

Burke scrutinized each move, and nodded in understanding.

"Be careful to cover the wire along the floor with a rug--he must never be allowed to see that, you know. After you have all this prepared, Mary, you must start the mechanism going, and then get the reproduction of the conversation as it comes on the dictagraph."

"All right, father--but how shall we get it there without Mr. Trubus knowing about it? He is very watchful of that room."

Barton patted Bobbie's broad shoulder, with a confident smile.

"I think Officer 4434 can devise a way for that. He has had harder tasks and won out. Now, hurry down with the machine. It is a bit heavy. You had better take it in a taxicab. You will spend all your money on taxicabs, my boy, I am afraid."

"Well, sir, a little money now isn't important enough to worry about if it means happiness for the future--for us all."

Mary's face reddened, and she dropped her eyes. There was an understanding between the three which needed no words for explanation.

So it is that the sweetest love creeps into its final nestling place.

"G.o.d bless you, my boy. I'm an old man and none too good, but I shall pray for your success."

"Good bye," said Bobbie, as he and Mary left with the mechanism.

Bobbie stopped the taxicab which carried them half a block east of the office building which was their goal.

"Mary, I will take this machine up on the floor above Trubus' office, and hide it in the hall. Then you go to your place in the office and I will manage a way to draw Mr. Trubus out in a hurry. We will work together after that, and spread the electric trap for him."

Mary went direct to the office, where she found Trubus storming about angrily.

"What do you mean by staying nearly two hours out at luncheon time?" he cried. "I am very busy and I want you to be here on duty regularly, even if my wife did foolishly intercede in your behalf, young woman."

"I am sorry--I became ill, and was delayed. I will not be late with you again, sir."

The president of the Purity League retired to his sanctum, slightly mollified. Mary had not been at her post long when a messenger came in with a telegram.

"Mr. Trubus!" he said, shoving the envelope at her.

She signed his book, and knocked at the door. There was a little delay, and the worthy man opened it impatiently. "I do not want to be interrupted, I am going over my accounts."

She handed him the telegram, and he tore it open hastily.