Mr. Fentolin pointed to the little pile of books upon the table, the deep easy-chair, the green-shaded lamps, the decanter of wine. He had insisted upon a visit, however brief, to the library.

"It is a student's appeal which I make to you, Mr. Hamel," he said, with a whimsical smile. "Here we are in my study, with the door closed, secure against interruption, a bright fire in the grate, a bowling and ever-increasing wind outside. Let us go together over the ground of your last wonderful expedition over the Andes. You will find that I am not altogether ignorant of your profession, or of those very interesting geological problems which you spoke of in connection with that marvellous railway scheme. We will discuss them side by side as sybarites, hang ourselves around with cigarette smoke, drink wine, and presently coffee. It is necessary, is it not, for many reasons, that we become better acquainted? You realise that, I am sure, and you will not persist in returning to your selfish solitude."

Hamel's eyes were fixed a little longingly upon some of the volumes with which the table was covered.

"You must not think me ungrateful or churlish, Mr. Fentolin," he begged. "I have a habit of keeping promises which I make to myself, and to-night I have made myself a promise that I will be back at the Tower by ten o'clock."

"You are obdurate?" Mr. Fentolin asked softly.

"I am afraid I am."

Mr. Fentolin busied himself with the handle of his chair.

"Tell me," he insisted, "is there any other person save yourself to whom you have given this mysterious promise?"

"No one," Hamel replied promptly.

"I am a person very sensitive to atmosphere," Mr. Fentolin continued slowly. "Since the unfortunate visit of this man Dunster, I seem to have been conscious of a certain suspicion, a little cloud of suspicion under which I seem to live and move, even among the members of my own household. My sister-in-law is nervous and hysterical; Gerald has been sullen and disobedient; Esther has avoided me. And now - well, I find even your attitude a little difficult to understand. What does it mean, Mr. Hamel?"

Hamel shook his head.

"I am not in the confidence of the different members of your family," he answered. "So far as I, personally, am concerned -"

"It pleases me sometimes," Mr. Fentolin interrupted, "to interfere to some extent in the affairs of the outside world. If I do so, that is my business. I do it for my own amusement. It is at no time a serious position which I take up. Have I by any chance, Mr. Hamel, become an object of suspicion to you?"

"There are matters in which you are concerned," Hamel admitted, "which I do not understand, but I see no purpose in discussing them."

Mr. Fentolin wheeled his chair round in a semicircle. He was now between the door and Hamel.

"Weaker mortals than I, Mr. Hamel," he said calmly, "have wielded before now the powers of life and death. From my chair I can make the lightnings bite. Science has done away with the triumph of muscularity. Even as we are here together at this moment, Mr. Hamel, if we should disagree, it is I who am the preordained victor."

Hamel saw the glitter in his hand. This was so end, then, of all doubt! He remained silent.

"Suspicions which are, in a sense, absurd," Mr. Fentolin continued, "have grown until I find them obtrusive and obnoxious. What have I to do with Mr. John P. Dunster? I sent him out from my house. If he is lost or ill, the affair is not mine. Yet one by one those around me are falling away. I told you an hour ago that Gerald was at Brancaster. It is a lie. He has left this house, but no soul in it knows his destination."

Hamel started.

"You mean that he has run away?"

Mr. Fentolin nodded.

"All that I can surmise is that he has followed Dunster," he proceeded. "He has an idea that in some way I robbed or injured the man. He has broken the bond of relationship between us. He has broken his solemn vow. He has run a grave and terrible risk."

"What of Miss Esther?" Hamel asked quickly.

"I have sent her away," Mr. Fentolin replied, "until we come to a clear understanding, you and I. You seem to be a harmless enough person, Mr. Hamel but appearances are sometimes deceptive. It has been suggested to me that you are a spy."

"By whom?" Hamel demanded.

"By those in whom I trust," Mr. Fentolin told him sternly. "You are a friend of Reginald Kinsley. You met him in Norwich the other day - secretly. Kinsley's chief is a member of the Government. He is one of those who will find eternal obloquy if The Hague Conference comes to a successful termination. For some strange reason, I am supposed to have robbed or harmed the one man in the world whose message might bring to nought that Conference. Are you here to watch me, Mr. Hamel? Are you one of those who believe that I am either in the pay of a foreign country, or that my harmless efforts to interest myself in great things are efforts inimical to this country; that I am, in short, a traitor?"

"You must admit that many of your actions are incomprehensible," Hamel replied slowly. "There are things here which I do not understand - which certainly require explanation."

"Still, why do you make them your business? "Mr. Fentolin persisted. "If indeed the course which I steer is a harmless one," he continued, with a strange new glitter in his eyes, "then you are an impertinent stranger to whom my doors cannot any longer be open. If you have taken advantage of my hospitality to spy upon me and my actions, if indeed you have a mission here, then you can carry it with you down into hell!"

"I understand that you are threatening me?" Hamel murmured.

Mr. Fentolin smiled.

"Scarcely that, my young friend. I am not quite the obvious sort of villain who flourishes revolvers and lures his victims into secret chambers. These words to you are simply words of warning. I am not like other men, neither am I used to being crossed. When I am crossed, I am dangerous. Leave here, if you will, in safety, and mind your own affairs; but if you show one particle of curiosity as to mine, if you interfere in matters which concern me and me only, remember that you are encircled by powers which are entirely ruthless, absolutely omnipotent. You can walk back to the Tower to-night and remember that there isn't a step you take which might not be your last if I willed it, and never a soul the wiser. There's a very hungry little mother here who takes her victims and holds them tight. You can hear her calling to you now. Listen!"

He held up his finger. The tide had turned, and through the half-open window came the low thunder of the waves.

"You decline to share my evening," Mr. Fentolin concluded. "Let it be so. Go your own way, Hamel, only take care that your way does not cross mine."

He backed his chair slowly and pressed the bell. Hamel felt himself dismissed. He passed out into the hall. The door of the drawing-room stood open, and he heard the sound of Mrs, Fentolin's thin voice singing some little French song. He hesitated and then stepped in. With one hand she beckoned him to her, continuing to play all the time. He stepped over to her side.

"I come to make my adieux," he whispered, with a glance towards the door.

"You are leaving, then?" she asked quickly.

He nodded.

"Mr. Fentolin is in a strange humour," she went on, a moment later, after she had struck the final chords of her song. "There are things going on around us which no one can understand. I think that one of his schemes has miscarried; he has gone too far. He suspects you; I cannot tell you why or how. If only you would go away!"

"What about Esther?" he asked quietly.

"You must leave her," she cried, with a little catch in her throat. "Gerald has broken away. Esther and I must carry still the burden."

She motioned him to go. He touched her fingers for a moment.

"Mrs, Fentolin," he said, "I have been a good many years making up my mind. Now that I have done so, I do not think that any one will keep Esther from me."

She looked at him a little pitifully, a little wistfully. Then, with a shrug of the shoulders, she turned round to the piano and recommenced to play. Hamel took his coat and hat from a servant who was waiting in the hail and passed out into the night.

He walked briskly until he reached the Tower. The wind had risen, but there was still enough light to help him on his way. The little building was in complete darkness. He opened the door and stepped into the sitting-room, lit the lamp, and, holding it over his head, went down the passage and into the kitchen. Then he gave a start. The lamp nearly slipped from his fingers. Kneeling on the stone floor, in very much the same attitude as he had found her earlier in the day, Hannah Cox was crouching patiently by the door which led into the boathouse, her face expressionless, her ear turned towards the crack. She was still listening.