I could realize from the heavy breathing of my companion, and the twitchings of the hand which still clutched my wrist, the furious indignation which filled his heart as he saw this vandalism in the very quarter of all others where he could least have expected it. He, the very man who a fortnight before had reverently bent over this unique relic, and who had impressed its antiquity and its sanctity upon us, was now engaged in this outrageous profanation. It was impossible, unthinkable--and yet there, in the white glare of the electric light beneath us, was that dark figure with the bent, grey head, and the twitching elbow. What inhuman hypocrisy, what hateful depth of malice against his successor must underlie these sinister nocturnal labours. It was painful to think of and dreadful to watch. Even I, who had none of the acute feelings of a virtuoso, could not bear to look on and see this deliberate mutilation of so ancient a relic. It was a relief to me when my companion tugged at my sleeve as a signal that I was to follow him as he softly crept out of the room. It was not until we were within his own quarters that he opened his lips, and then I saw by his agitated face how deep was his consternation. "The abominable Goth!" he cried. "Could you have believed it?" "It is amazing." "He is a villain or a lunatic--one or the other. We shall very soon see which. Come with me, Jackson, and we shall get to the bottom of this black business." A door opened out of the passage which was the private entrance from his rooms into the museum. This he opened softly with his key, having first kicked off his shoes, an example which I followed. We crept together through room after room, until the large hall lay before us, with that dark figure still stooping and working at the central case. With an advance as cautious as his own we closed in upon him, but softly as we went we could not take him entirely unawares. We were still a dozen yards from him when he looked round with a start, and uttering a husky cry of terror, ran frantically down the museum. "Simpson! Simpson!" roared Mortimer, and far away down the vista of electric-lighted doors we saw the stiff figure of the old soldier suddenly appear. Professor Andreas saw him also, and stopped running, with a gesture of despair. At the same instant we each laid a hand upon his shoulder. "Yes, yes, gentlemen," he panted, "I will come with you. To your room, Mr. Ward Mortimer, if you please! I feel that I owe you an explanation." My companion's indignation was so great that I could see that he dared not trust himself to reply. We walked on each side of the old Professor, the astonished commissionaire bringing up the rear. When we reached the violated case, Mortimer stopped and examined the breast-plate. Already one of the stones of the lower row had had its setting turned back in the same manner as the others. My friend held it up and glanced furiously at his prisoner.