“The code on that paper.”
The old man laughed. “This is not a code,” he declared.
“Not a code? What—”
“It is a map,” said Zachary Mitchell, quietly. “A map of New York streets, with your uncle’s house as the starting point.
“Look” — Bob leaned forward, intently as Mitchell explained — “and observe those double lines. Your uncle’s house faces south. You go one square east, then one south.
“Connect the next symbol. Another square south, another east. Connect the next — one more east. Then a single square on a diagonal street, running southeast—”
Bob clutched the paper as the old lawyer paused. Here was the clew — the map of New York streets that led to a spot some eleven squares away from the old mansion where Theodore Galvin had lived.
“But what then?” he questioned. “Where will the hiding place be?”
“I have read the instructions in the envelope,” declared Mitchell, calmly, now convinced that Bob was fully entitled to all information. “It gives a number and describes a room, telling how the key can be used. That makes it obvious.
“At the end of your trail you will, in all probability, come to one of the many buildings which your uncle erected.”