"Good, my friend! And do not fear that a night of anxiety awaits you. Indeed, if I am not mistaken, it will be possible for us all to sleep very soundly, though we may go to bed rather late. But I think we must be prepared not to retire till after two o'clock. I will enter upon my watch at eight--in half an hour. The door shall be left open, as you wish. But I beg that none will approach the east end of the corridor. That is only fair. I will, however, permit Mr. Lennox to station himself on the top of the great staircase, and from time to time he may challenge me. He shall say 'Is all well?' and be sure I shall answer 'All is well.' Could anything be more satisfactory?" Signor Mannetti ate sparingly, then he donned a big, fur, motor-coat and declared himself ready. They thought he had forgotten Prince, but he insisted upon the company of the ancient spaniel. The dog had fed, and he could sleep as well in one place as another. "Fear not," said the Italian. "I shall be considerate to your ancient pet. I do not beg his aid without reason. He is on my side and will help me if he can--infirm though he be. I have made friends with him. Set him at my feet. I will sit here under the electric light and read my Italian papers." Thus once again a solitary occupied the Grey Room and measured his intelligence against the terrible forces therein concealed. Signor Mannetti took leave of them cheerfully at eight o'clock, and while Sir Walter and Mary descended to the library, Henry took up his station at the head of the staircase. The corridor was lighted and the door of the Grey Room left open. But in ten minutes the watcher looked out and cried to Lennox, who sat smoking about thirty-five yards from him. "There is a great draught here," he said. "I will close the door, but leave it ajar that we may salute each other from time to time." The hours crept on and since everybody at Chadlands knew what was happening, few retired to rest. It was understood that some time after midnight Signor Mannetti hoped to declare the result of his experiment.