"Quite correct, Mr. Nightingale; but what are you driving at?"

"All in good time, my dear. You leave the house safe, and you are sure you shut the street-door tight?"

"I'll take my oath of it."

"It may come to that; I don't want to scare you, but it may come to that. When you come back with the supper-beer you find the street-door open?"

"But I don't."

"Excuse me, you do; it's necessary."

"Oh!"

"And I'll tell you why. When you come home you find Wigg and me here, don't you?"

"Yes."

"You've heard how we got in, but it's a fact that we had no business here unless we was called in. We must have been called in by somebody, and whoever it was must have had a reason for inviting us. Is that sound, Wigg?"