Busby’s wife had appeared at the laboratory door.

Margate swung round like a flash, with his ghastly face showing plainly how near Nick had come to the truth. He started up, crying harshly:

“Why are you here, Nancy? What do you want? Leave us to send these infernal sleuths to perdition.”

Nancy Busby did not fear him.

“I’m here with a reason,” she retorted. “There’s a man at the front door to see you.[Pg 40]

“See me?” cried Margate, staring. “What man?”

“He says his name is Peterson, and as how he’s got a message for you.”

Nick Carter’s face did not change by so much as a shadow.

“Peterson!” Margate spoke, with a gasp. “Don’t be alarmed, mates. He’s the house butler. He must have seen me coming here, or this way. Wait while I see what he wants.”

“He will not keep you waiting long,” thought Nick, with grim satisfaction.