"George Weston refused to go with you, Mr. Weston, and Mr. Hatch, to the ghost party, as you called it, because he said he was going to a ball in Providence that night. He did not go to Providence; I learned that from your correspondent there, Mr. Hatch; so George Weston might, possibly, have gone to the ghost party after all.
"After I looked over the situation down there it occurred to me that the most feasible way for a person, who wished to avoid being seen in the village, as the perpetrator of the ghost did, was to go to and from the place at night in a motor-boat. He could easily run in the dark and land at the foot of the cliff, and no soul in the village would be any the wiser. Did George Weston have a motor-boat? Yes, an electric, which runs almost silently.
"From this point the entire matter was comparatively simple. I _knew_--the pure logic of it told me--how the ghost was made to appear and disappear; one look at the house inside convinced me beyond all doubt. I knew the motive for the ghost--a search for the jewels. I knew, or thought I knew, the name of the man who was seeking the jewels; the man who had fullest knowledge and fullest opportunity, the man whose brain was clever enough to devise the scheme. Then, the next step to prove what I knew. The first thing to do was to find the jewels."
"Find the jewels?" Weston repeated, with a slight smile.
"Here they are," said The Thinking Machine, quietly.
And there, before the astonished eyes of the broker, he drew out the gems which had been lost for fifty years. Mr. Weston was not amazed; he was petrified with astonishment and sat staring at the glittering heap in silence. Finally he recovered his voice.
"How did you do it?" he demanded. "Where?"
"I used my brain, that's all," was the reply. "I went into the old house seeking them where the owner, under all conditions, would have been most likely to hide them, and there I found them."
"But--but----" stammered the broker.
"The man who hid these jewels hid them only temporarily, or at least that was his purpose," said The Thinking Machine, irritably. "Naturally he would not hide them in the woodwork of the house, because that might burn; he did not bury them in the cellar, because that has been carefully searched. Now, in that house there is nothing except woodwork and chimneys above the cellar. Yet he hid them in the house, proven by the fact that the man he killed was killed in the house, and that the outside ground, covered with snow, showed two sets of tracks into the house and none out. Therefore he did hide them in the cellar. Where? In the stonework. There was no other place.