Max considered the plan carefully. "I can't say it does," he admitted after a minute survey. "Give me a lead."
"That dotted line," said Win, pointing to it with Max's pencil, "according to Colonel Lisle, marks the path down to the cottages on the shore, only the path curves more now than it did when the plan was first made. Don't you think it strange that it was the only path put on the plans? Even the state driveway isn't indicated."
"That, I suppose, wasn't made then."
"But surely," persisted Win, "there was some driveway to the main road. Why should this especial path be marked? It couldn't have been the most important, even at that time."
"That does seem true," replied Max thoughtfully.
[Illustration: WIN'S PLAN OF THE MANOR CELLARS.]
"Now look at the point where the dotted line comes to the house," Win went on, tracing its course as he spoke. "This is the very oldest vault of all, under the library, you know. On the plan, its northern wall is continued flush by the northern side of the addition made later, and this dotted line runs parallel to it, but—it runs inside the foundations."
"So it does," Max agreed. "But isn't that due to clumsy drawing? There's an axiom, you know, about it being impossible for two bodies to occupy the same space. Two lines couldn't occupy the same location on a plan."
"Yes," said Win, "but if this is a path, what is it doing inside the house?"
There followed a second of silence and then Max gave a low whistle.
"I'm on," he announced. "Clever reasoning, Win."