"He is barely of age, boy," Dr. Cairn said, almost in a whisper. "In another year, he would menace the world. Where are you going?"
He grasped his son's arm as Robert started for the door.
"That man yonder—"
"Diplomacy, Rob!—Guile against guile. Let the man do his work, which he does in all innocence; then follow him. Learn where his studio is situated, and, from that point, proceed to learn—"
"The situation of Ferrara's hiding-place?" cried his son, excitedly. "I understand! Of course; you are right, sir."
"I will leave the inquiry in your hands, Rob. Unfortunately other duties call me."