The logs were taken out of the fireplace, and as soon as the smoke cleared the young men gave the inside of the chimney a thorough going over. They could see the blue sky away up above. The opening was large, but far too small for any human being to enter down it. The mortar between the bricks seemed for the most part undisturbed. Breitmann made the first discovery of any importance. Just above his height, standing in the chimney itself, he saw a single brick projecting beyond its mates. He reached up, and shook it. It was loose. He wrenched it out, and came back into the light. "See! Nothing less than a chisel could have cut the mortar that way. Miss Killigrew is right." He went back, and with the aid of the tongs poked into the cavity. The wall of bricks was four deep, yet the tongs went through. This business had been done from the other side. "Well!" exclaimed the admiral, for once at loss for a proper phrase. "You see, father? I was right. Now, what can it mean? Who is digging out the bricks, and for what purpose? And how, with the alarms all over the house, to account for the footprints in the flour?" "It is quite likely that something is hidden in the chimney, and some one knows that it is worth hunting for. This chimney is the original, I should judge." Fitzgerald addressed this observation to the admiral. "Never been touched during my time or my father's. But we can soon find out. I'll have a man up here. If there is anything in the chimney that ought not to be there, he'll dig it out, and save our midnight visitor any further trouble." "Why not wait a little while?" Fitzgerald ventured. "With Breitmann and me in the house, we might trap the man." "A good scheme!" "He comes from the outside, somewhere; from the cellar, probably. Let us try the cellar." Breitmann urged this with a gesture of his hands. "There'll be sport," said Fitzgerald. The coffee was cold in the little cups when they returned to it. The cellar, as far as any one could learn, was free from any signs of recent invasion. It was puzzling. "And the servants?" Breitmann intimated. "They have been in the family for years." The admiral shook his head convincedly. "I ask your pardon, my dear. My ears are not so keen as might be. I'm an old blockhead to think that you were having an attack of ghosts. But we'll solve the riddle shortly, and then we shan't have any trouble with our alarm bells," with a significant glance at Fitzgerald. "Well, Mr. Breitmann, suppose we take a look at the work? Laura, you show Mr. Fitzgerald the gardens. The view from the terrace is excellent."