The detective's swollen muscles, his stiffened limbs, still retained the sensation of being bound; he scarcely realized that his bonds had been removed. Painfully he crawled to his feet, and stood before the doctor, blinking, trying to collect his faculties. On the floor lay a number of broad leather straps, secured to iron rings which had been let into the cement floor.
His first thought was to make a quick rush at his captor, and after overpowering him, secure the snuff box and dash from the place. His eyes must have shown something of his intention, for Hartmann, stepping back a pace, drew his right hand from his pocket. It contained an ugly-looking magazine pistol. "Don't attempt anything rash, Mr. Duvall. It would be useless. Even should you succeed in disposing of me, which I hardly think possible, you could not get away from my man Mayer, who is waiting in the corridor outside. Enough of this nonsense," he went on, scowling. "I mean to be quite frank with you, my friend. I intend to subject you to this device of mine—" he waved his hand toward the opening in the ceiling—"until you disclose the whereabouts of the snuff box. I know it is somewhere near at hand, either here or in Brussels, for your two assistants, whom I have had released, have been hanging about the place all the morning. If the violet rays have no other effect, they will at least prevent you from sleeping, and my experience shows that loss of sleep, if persisted in, will shatter the best set of nerves on earth. You know what the effect is, for six hours. The next time, as I said some little while ago, we shall try ten—and after that, longer periods, until the process becomes continuous. I am giving you these brief respites, at first, because I have not the least wish to drive you mad—all I ask is the snuff box which you took from my messenger Seltz. Give it up, and you can go at your convenience. But I must have it—even if I am obliged to drive you to the limit. I advise you to save yourself much suffering, and give it to me now."
The detective drew back his arm—his fist clenched. The impulse to drive it into Hartmann's face was overpowering. He turned abruptly on his heel, and made no reply.
Hartmann waited for a moment, then seeing that his prisoner was not disposed to answer, went toward the door. "Max," he called, opening it, "bring in the tray." The attendant at once entered with a waiter containing food, which he placed on a box near the door. "Is that all?" he asked. Hartmann nodded and the man withdrew.
"Think the matter over, Mr. Duvall," the doctor remarked, as he stepped across the threshold of the door. "I shall call upon you again, later in the day."
Duvall waited until the door had been closed and locked, and the doctor's footsteps had died away up the iron staircase. He heard them for a moment, on the floor of the room above, then all was quiet.
In a moment the detective had stepped to the large box in the corner, behind which lay, he believed, the discarded opera hat. At a glance, he saw that it was still there. He was about to stoop and pick it up, when a sudden fear swept over him. Suppose he was being watched. The doctor was in the room above. The presence in the room of the beam of light showed clearly that there must be an opening in the ceiling, into the laboratory. For all he knew, Hartmann might be observing his every movement. He stopped in his attempt to pick up the hat, and pretended to be greatly interested in the box and its contents. After making a careful examination of the labels upon it, he strolled carelessly back to the other side of the room, and ate the breakfast which the attendant had left. He supposed it to be breakfast, although he had no realization of the time. In a moment he felt for his watch, and found that it was still in his pocket. When he consulted it, however, he saw at once that it had run down.
After his meal, he began to feel terribly tired and sleepy. At first he fought off the feeling, realizing that his only hope of freedom lay in keeping awake, with all his senses alert. Then he thought of the nerve-racking hours through which he had just passed; the many more which were likely to follow, and decided that he must have rest at any cost. He threw himself upon the floor, his head pillowed upon his arm, and was soon sleeping the deep sleep which follows utter exhaustion.