Left alone in the turret-room, Edgar Caswall carefully locked the door and hung a handkerchief over the keyhole.  Next, he inspected the windows, and saw that they were not overlooked from any angle of the main building.  Then he carefully examined the trunk, going over it with a magnifying glass.  He found it intact: the steel bands were flawless; the whole trunk was compact.  After sitting opposite to it for some time, and the shades of evening beginning to melt into darkness, he gave up the task and went to his bedroom, after locking the door of the turret-room behind him and taking away the key.

He woke in the morning at daylight, and resumed his patient but unavailing study of the metal trunk.  This he continued during the whole day with the same result—humiliating disappointment, which overwrought his nerves and made his head ache.  The result of the long strain was seen later in the afternoon, when he sat locked within the turret-room before the still baffling trunk, distrait, listless and yet agitated, sunk in a settled gloom.  As the dusk was falling he told the steward to send him two men, strong ones.  These he ordered to take the trunk to his bedroom.  In that room he then sat on into the night, without pausing even to take any food.  His mind was in a whirl, a fever of excitement.  The result was that when, late in the night, he locked himself in his room his brain was full of odd fancies; he was on the high road to mental disturbance.  He lay down on his bed in the dark, still brooding over the mystery of the closed trunk.

Gradually he yielded to the influences of silence and darkness.  After lying there quietly for some time, his mind became active again.  But this time there were round him no disturbing influences; his brain was active and able to work freely and to deal with memory.  A thousand forgotten—or only half-known—incidents, fragments of conversations or theories long ago guessed at and long forgotten, crowded on his mind.  He seemed to hear again around him the legions of whirring wings to which he had been so lately accustomed.  Even to himself he knew that that was an effort of imagination founded on imperfect memory.  But he was content that imagination should work, for out of it might come some solution of the mystery which surrounded him.  And in this frame of mind, sleep made another and more successful essay.  This time he enjoyed peaceful slumber, restful alike to his wearied body and his overwrought brain.

In his sleep he arose, and, as if in obedience to some influence beyond and greater than himself, lifted the great trunk and set it on a strong table at one side of the room, from which he had previously removed a quantity of books.  To do this, he had to use an amount of strength which was, he knew, far beyond him in his normal state.  As it was, it seemed easy enough; everything yielded before his touch.  Then he became conscious that somehow—how, he never could remember—the chest was open.  He unlocked his door, and, taking the chest on his shoulder, carried it up to the turret-room, the door of which also he unlocked.  Even at the time he was amazed at his own strength, and wondered whence it had come.  His mind, lost in conjecture, was too far off to realise more immediate things.  He knew that the chest was enormously heavy.  He seemed, in a sort of vision which lit up the absolute blackness around, to see the two sturdy servant men staggering under its great weight.  He locked himself again in the turret-room, and laid the opened chest on a table, and in the darkness began to unpack it, laying out the contents, which were mainly of metal and glass—great pieces in strange forms—on another table.  He was conscious of being still asleep, and of acting rather in obedience to some unseen and unknown command than in accordance with any reasonable plan, to be followed by results which he understood.  This phase completed, he proceeded to arrange in order the component parts of some large instruments, formed mostly of glass.  His fingers seemed to have acquired a new and exquisite subtlety and even a volition of their own.  Then weariness of brain came upon him; his head sank down on his breast, and little by little everything became wrapped in gloom.

He awoke in the early morning in his bedroom, and looked around him, now clea............