“No, apparently not. My room adjoins and I am sure I would have awakened if anyone had tried to open the door. Perhaps the intruder knew where I slept and avoided that part of the house.”

Madge moved thoughtfully about the laboratory examining articles which had been misplaced. In spite of the disorder, the thief had left behind no clue to his identity.

“Anne, you haven’t mentioned the formula to anyone save Mr. Brownell, have you?” she asked suddenly.

“Why, no. That is, except to Clyde Wendell. I asked him if he had any idea what could have become of it and he said he knew nothing about it. You don’t think the person who came here last night was after the formula?”

“Perhaps not. It merely occurred to me.” Madge lapsed into thoughtful silence. “I can’t think of anyone save Mr. Brownell who would want to lay hands on that missing paper,” she added, after a moment, “and I’m sure he never left the house last night. But just as I was going to bed, I do recall hearing a motor boat out on the lake and it sounded as though it might be heading toward Stewart Island.”

“Jake Curtis has one, Madge!”

“I thought of that right away but what reason would he have for coming here?”

“It’s beyond me. All I know is that my silverware is gone. You don’t suppose someone—Jake for instance, is trying to frighten me away from here?”

“That’s a possibility,” Madge conceded. “Jake is bent on getting this property by one means or another. Still, your theory doesn’t entirely satisfy me.”

From the laboratory the girls went to Mr. Fairaday’s bedroom. After a brief search which revealed no clues, they examined the other upstairs rooms and then returned to the first floor. The identity of the prowler remained a mystery.