“The posts look like supports. Actually, they are dummies. They can be driven sideways, in opposite directions.
“When that has been done; you will observe that the section of the wall is actually a large door. Behind it is a secret vault — an old, unused compartment of the cellar.”
He handed the pad to the big man.
“Take it,” said Harkness. “That’s what you want.”
“Yeah?” The man laughed. “Is that the only place?”
“Positively,” replied Harkness. “I designed the wall for Theodore Galvin. It was the only special work that he had done in the old house.
“He brought in two men at night to do the work. They didn’t know the location of the house. He brought them in an automobile and sent them away in the same manner.”
The big man studied Harkness. He looked at the plan. There was something in his manner that made Harkness feel the man was satisfied. Yet he made no move to leave.
While Harkness was still wondering, the telephone rang. The big man pounced upon the instrument.
“Hello,” he said. “O.K. It’s in the old house. Yeah. Down the cellar stairs.” He referred to the plan. “Passageway and two posts at the end. Dummies. Hammer them outward. O.K.”