“It came into my mind, Louisa; I didn’t put it there, and it refuses to be dislodged. But what if Alec be not really dead? What if the report that he was killed by that explosion was based on some error to which we have not the key? You remember the letter, written in an evidently disguised hand, which was found on my study table together with the key of the strong room?” Lady Pell nodded assent. “Who but Alec would have been in the position to point out the fact that the child—his child—who had died in infancy, was not a boy, but a girl? Who but Alec—my Alec—would have cared to press a kiss on an old man’s brow?” “There is certainly some feasibility in what you say,” remarked her ladyship; “but if Alec were still alive he would surely have made the fact known to you long before now.” “You forget that he was a banished man—that it was a condition of the agreement between us that he should never set foot in England till he had my permission to do so. Heaven knows, permission would have been given long ago, because long ago all his early faults and follies were condoned and forgiven, had the faintest suspicion that he was still among the living ever found lodgment in my mind!” “Even granting your assumption that Alec is still alive (and with all my heart I pray he may be), by what possible motive could he be influenced in coming back to the Chase and allowing himself to be seen by several people under the guise of the family spectre?” “Ah, now you ask me a question which it is impossible to answer with any degree of certitude. Perhaps it had somehow come to his ears that I had adopted an impostor as my heir. In any case, I care not what may have been the motive which brought him back, if only it were he whose arms I felt about me three short hours ago. I am alone in the world, Louisa, alone and old. I have just been made the victim of a most shameful fraud, and if only, by some miracle, my eldest-born could be restored to me, I should feel that the remnant of my days had indeed been blessed to me far beyond my deserts!” “Have you thought of any plan yet by which your theory can be tested and the mystery of the Grey Monk elucidated?” “Not yet—not yet. But I generally lie awake for several hours in the course of the night, and I shall have time to turn the matter over in my mind before morning.” That evening Sir Gilbert did not make his appearance in the drawing-room, but retired at an earlier hour than usual, to fall asleep almost immediately, but only to awake at the end of three hours and remain so till daybreak. During that wakeful period he formulated a certain theory in his mind which he determined to put to the proof immediately after breakfast. The theory thus worked out by him, briefly stated, was to the following purport: