Father Brown seemed quite unconscious of this cloud of witnesses, but followed Parkinson with an idly attentive eye till he took himself and his absurd spear into the farther room of Bruno. Then he abandoned himself to such abstract meditations as always amused him—calculating the angles of the mirrors, the angles of each refraction, the angle at which each must fit into the wall ... when he heard a strong but strangled cry.
He sprang to his feet and stood rigidly listening. At the same instant Sir Wilson Seymour burst back into the room, white as ivory. "Who's that man in the passage?" he cried. "Where's that dagger of mine?"
Before Father Brown could turn in his heavy boots Seymour was plunging about the room looking for the weapon. And before he could possibly find that weapon or any
