Yet the three men were the only human beings in that room. "The voice came from that screen!" cried Patsy, and he leaped toward the old fire-place. He tore away the screen. No one was there. "It was my aunt's voice," said the colonel, calmly. "I consent." "Consent to what?" asked Horace Richmond, entering the room at that moment. The test was explained to him. "Good!" he whispered to Nick. "A fine idea." "Name a piece of jewelry," said the detective to the colonel. "Among all her wonderful collection," replied Colonel Richmond, speaking slowly, "there was no piece of which she was more proud than the gold clasp, studded with diamonds, which you well remember, Horace." "I do," responded Horace. "There is an old tradition about it. A remote ancestor of ours is said to have brought it from the Holy Land at the time of the third crusade." "An ancient family," said Nick. "You have a right to be proud of your ancestry. I accept the article named as the one upon which the test shall be made, provided that you are sure that it is now in the vault." "Perfectly certain," responded the colonel. "I put it there with my own hands. Nobody else was present, except an officer of the company and my daughter. It is utterly impossible that the jewel can have been removed." "I will take that for granted," said Nick. "The conditions of the test are that this piece shall not be found in the vault when we visit it this afternoon, and that it shall be afterward discovered in the possession of Millie Stevens." "Granted," said the colonel; and then in a clear voice, as if he wanted to be sure that there was no misunderstanding in spirit land, he announced the conditions of the test. CHAPTER IX. THE DIAMOND CLASP. They then left the room. Nick dispatched Patsy secretly to the Stevens house. Shortly before noon, Colonel Richmond, Horace, and Nick took a train for the city. At two o'clock they entered the vault of the safe deposit company. It is a long room below the level of the street. The walls are lined with metal drawers, fastened by locks of the most approved pattern. The drawers near the floor are the largest. They are, perhaps, a foot square, as seen when closed. Near the top of the room they are much smaller. A movable metal step-ladder stands ready for the convenience of those who wish to reach the boxes on the upper tiers. The space in the middle of the room is railed off, and there sits a guard day and night. "This is ours," said the colonel, advancing toward one of the larger drawers. "I placed the diamond clasp on the very top of the pile of jewels within. It was in a case of its own." Nick turned to speak to the officer in charge. He questioned him regarding the possibility of any person taking anything from the boxes. He asked especially about the custody of Mrs. Pond's jewels. "Colonel Richmond and Mrs. Pond have the two keys necessary for opening the drawer," said the official.