The request was a strange one, Berrington thought.

Not that he failed to trust Mary Sartoris. In spite of everything, he had faith in her. Whatever she was doing in that queer household, no shadow of shame or disgrace could possibly lie on her.

And yet what could she want that letter for? Again, what was the need to drag Beatrice Darryll into this black business? The more Berrington thought it over, the more puzzled he became. Only one thing was tolerably clear—Sir Charles Darryll had valuable interests somewhere, interests of which he had been in utter ignorance, and which these ruffians had determined to obtain and apply to their own ends.

Still, Berrington hesitated. He did not know what would be for the best. If he declined to write that letter it might be the worse for him and everybody else in the long run; if he did write the letter it might possibly prove harmful to Beatrice. Certainly Carl Sartoris had that end in view. Then there was another thing to take into consideration. Had Inspector Field got safely away?

Berrington could not be absolutely certain, for the reason that there had been no attempt to rescue him which was Field's obvious duty when he escaped. Yet a great many hours had passed and there had been no attempt of the kind.

Very thoughtfully Berrington took paper and pen and ink from the drawer in the table. He was not surprised to see that the paper bore the address "100, Audley Place." So Beatrice was to be lured there for some reason, or other, and Berrington was to be used for the purpose. He threw the pen down and determined that he would do nothing in the matter. He had barely come to this conclusion when the whistle in the tube sounded very faintly. It might have been no more than the wind in the pipe, and yet on the other hand it might have been meant for a cautious message. Berrington crossed over and asked a question in a low voice. Immediately a reply came in the faintest possible whisper.

"It is I who speak," the voice said. "Mary, you know. By accident I have a chance of a few words with you again. My brother thinks that I am in ignorance of everything. He told me that you had left the house and that everybody had gone. At the same time he declined to have the servants back yet, and that aroused my suspicions. You can hear me?"

"My dearest girl, I can hear you perfectly well," Berrington replied. "Where is your brother now? Can you speak freely to me for a time?"

"For a minute or two perhaps, certainly not more. Carl has gone into the conservatory for something; he may be back almost at once. He told me that you had gone. I did not believe it for a minute, so I watched and listened. Then I found out that you were a prisoner here; I found out all about the letter."

"The letter to Beatrice Darryll, you mean?"

"Yes, yes. Don't ask me why they desire to get her here, because I can't tell you,—I don't know. But there is something about Burmah and ruby mines that I fail to understand. It has something to do with Sir Charles Darryll and Miss Violet DeciÉ's father."

"Shall we ever get to the bottom of this business!" Berrington exclaimed. "But why should you particularly want me to write that letter?"

"Because I shall be chosen as the messenger," the girl said eagerly. "There are no servants here; the rest of my brother's friends are busy elsewhere. I gather that the letter is urgent; that being the case, I shall be chosen to take it. You see, I am supposed to know nothing whatever about it. I shall be able to see Miss Darryll myself."

Berrington expressed his appreciation of the suggestion. Perhaps Mary might find herself in a position to do more than that.

"Very well," he said. "Under the circumstances I am to write that letter with the understanding that you are going to convey it to its destination and warn Miss Darryll. But you must do more than that, Mary. It is impossible that I can remain a prisoner here like this. The thing is a daring outrage in the middle of London; it sounds more like a page from a romance than anything else. At all risks, even to the brother by whom you are standing so nobly, you must do this thing for me. After you have seen Miss Darryll you are to go down to Scotland Yard and ask for an interview with Inspector Field. Tell him where I am to be found and——"

"Oh, I cannot, Philip, dearest," came the trembling whisper. "My own brother——"

"Who has been the curse of your life and mine," Berrington said sternly. "What do you suppose you gain by standing by him in this fashion? Sooner or later he must come within grip of the law, and so all your sufferings will be futile. If there was anything to gain by this self-sacrifice I would say nothing. But to spoil your life for a scoundrel like that——"

"Don't say it, Phil," Mary's voice pleaded. "Please don't say it. If you love me as you once seemed to do, have a little patience."

All the anger melted out of Berrington's heart. He had intended to be hard and stern, but that gentle, pleading voice softened him at once. Knowing Mary as he did, he could imagine what her life had been these last three years. Her sense of duty was a mistaken one, perhaps, but it was nobly carried out, all the same. Sooner or later the effort must be lost, and it occurred to Berrington that it would be cruel to hurry the end. Besides, there would be a greater satisfaction to him to feel that he had beaten Sartoris at his own game.

"I love you now as I loved you in the happy years gone by," he said. "Indeed, I love you more, for I know how you have suffered, dearest. Mind you, I am not afraid. I do not regard myself as being in any great danger here—that is not the point. So I will write the letter and you shall deliver it when you please. What is that?"

There was a sudden commotion at the far end of the speaking tube, and something like the sound of wheels. Berrington bent his head eagerly to listen.

"Is there anybody there?" he asked.

"My brother is coming back," Mary said in a voice so faint that Berrington could hardly catch the words. "I must fly. If he knows that I have been here he will have his suspicions. I will speak to you again as soon as possible."

The whistle was clapped to, and the conversation ended. There was nothing for it now but patience. Berrington took the pen and began to write the letter. He wondered if he could possibly warn Beatrice between the lines. There was yet a chance that Mary might not be the messenger.

Berrington racked his brains, but all to no purpose. He must leave the matter to chance, after all. The speaking tube was going again, for the whistle trilled shrilly. Sartoris was at the other end again; he seemed to be on very good terms with himself.

"What about that letter?" he asked. "Have you changed your mind yet? Solitary confinement worked sufficiently on your nerves yet? Not that there's any hurry."

"What shall I gain if I write the letter?" Berrington asked.

"Gain! Why, nothing. The cards are all in my hands, and I play them as I please. 'Yours not to reason why, yours not to make reply,' as Tennyson says. For the present you are a prisoner, and for the present you stay where you are. But one thing for your comfort. The sooner that letter is written and dispatched, the sooner you will be free. We are not taking all these risks for nothing, and our reward is close at hand now, I may tell you. If you don't write that letter I shall have to forge it, and that takes time. Also a longer detention of your handsome person. If you consent to write that letter you will be free in eight and forty hours. Don't address the envelope."

Berrington checked a desire to fling the suggestion back in the speaker's teeth. It angered him to feel that he was in the power of this little cripple, and that events in which he should have taken a hand were proceeding without him. But it was no time for feeling of that kind.

"I admit the defeat of the moment," he said. "I will write that letter at once. But look to yourself when my time comes."

Sartoris laughed scornfully, as he could afford to do. Berrington could hear him humming as he clapped in the whistle, and then silence fell again. The letter was finished and sealed at length, and pushed under the door as Sartoris had directed. A little later and there came the sound of a footstep outside and a gentle scratching on the door panel.

"Is that you, Mary?" Berrington asked, instantly guessing who it was. "Have you come for the letter?"

"Yes, I have," was the whispered reply. "My brother could not manage to get up the stairs. He has one of his very bad attacks to-day. He has not the least idea that I know anything. He said he dropped an unaddressed letter on this landing last night, and he asked me to fetch it. I dare not stay a minute."

"Don't go quite yet," Berrington pleaded. "I have had a brilliant idea. I can't stop to tell you what it is just now. The switch of the electric light has been removed from here. Can you tell me where I can find it?"

"You want more light?" Mary asked. "Well, it is a little dreary in there with only a lamp. The switch was taken off some time ago when the walls were being done, and the electricians forgot to replace it. It is somewhere in the room, for I recollect seeing it. But unless you understand that kind of work——"

"Oh, soldiers understand something of everything," said Berrington cheerfully. "I shall be able to manage, no doubt. I won't detain you any longer."

Mary slipped away, and Berrington commenced to make a careful search of the room. He found what he wanted presently, in a little blue cup on the overmantel, and in a few minutes he had fixed the switch to the wall. As he pressed the little brass stud down, the room was flooded with a brilliant light.

"There's some comfort in being able to see, at any rate," Berrington reflected. "It's ten chances to one that my little scheme does not come off, yet the tenth chance may work in my favour. I'll wait till it gets dark—no use trying it before."

Berrington dozed off in his chair, and soon fell into a profound sleep. When he came to himself again, a clock somewhere was striking the hour of eleven. There was no stream of light through the little round ventilator in the shutter, so that Berrington did not need to be told that the hour was eleven o'clock at night.

"By Jove, what a time I've slept," the soldier muttered. "What's that?"

Loud voices downstairs, voices of men quarrelling. Berrington pulled the whistle out of the tube and listened. Someone had removed the whistle from the other end, or else it had been left out by accident, for the sound came quite clear and distinct.

It was the voice of Sartoris that was speaking, a voice like a snarling dog.

"I tell you you are wrong," Sartoris said. "You tried to fool me, and when we make use of you and get the better of you, then you whine like a cur that is whipped. Don't imagine that you have your poor misguided wife to deal with."

"My wife has nothing to do with the case," the other man said, "so leave her out."

Berrington's heart was beating a little faster as he glued his ear to the tube. He did not want to miss a single word of the conversation.

"This grows interesting," he said softly. "A quarrel between Sartoris and Stephen Richford. Evidently I am going to learn something."