"Then why did he not care to give up his interest to his brother?" asked Moore. "That is as yet a mystery. But, as he was a great business man, it is supposed by some that he saw opportunities to convert the vast grounds into town lots, and sell at a great advance some day when Mona should boom, as the town will sooner or later, owing to its natural advantages. He told many, however, that it was merely a sentiment with him, the place having belonged in Colonial times to the family. Be that as it may, however, he finally sold, and never would buy it back again, even after the mystery had made it practically valueless. "His brother offered to sell it back for next to nothing, but Winthrop only laughed, and refused. This conduct seemed to dispose of the supposition that he was in any way responsible for the occurrences there which had such a depressing effect in the value of the property." "Then, if mixed up, he had a deeper motive," said I. "Yes--if he has really been involved in the mystery at all. You must remember, however," said Oakes, "that his story may be true. Having disposed of his share of the property, he may have seen no reason for bothering with it again, at least until it was clear of the depressing occurrences which had lowered its value from half a million to practically nothing." "Goodness! What were these mysteries?" said Moore, with a feigned shudder. "Evidently, they are unpopular." Oakes proceeded slowly. "They consist of a series of assaults on those who have occupied the house, and they are conducted in such a way that detection has been impossible. "One evening Mrs. Mark was heard to shriek in her bedroom, and when found by her husband was insane from fright. In her ravings she spoke of a terrible thing choking her, and of a swishing sound. She never regained her reason, and is now in an insane asylum. Alienists at first thought that she had an experience common to those going mad--that she had been subject to a delusion. But evidences were against this, as she had in no way shown any signs of mental trouble before. While she was being cared for at the Mansion, the two nurses in charge had similar experiences. They reported hearing a tread on the stairs one night and of seeing a figure disappear into the dining-room. One stated up and down that it was a woman. "The patient was removed from the place. Then Mr. Odell Mark received such a scare one night that he packed up and left the Mansion for good. He was assaulted by an invisible party from behind, and only escaped after a severe struggle. Whoever, or whatever, assaulted him disappeared in an instant, and he swore that he heard the closing of a door somewhere downstairs. "Everything was done to keep the truth quiet, but of course it leaked out and the place has been regarded as haunted ever since. The servants left, save a few of the oldest, who live away from the Mansion under a separate roof, and have never seen anything unusual."