“If he keeps his appointment, colonel.”

“You have an appointment?”

“Yes, colonel.”

“In this house?”

“To-night.”

“With what object, in heaven’s name!”

Nighthawk hesitated for some moments before replying.

“The fact is, colonel,” he said, “that I inadvertently mentioned my appointment with Swartz without reflecting how singular it must appear to you, unless I gave you some explanation. But I am quite at my ease with you—you are a friend of Colonel Mohun’s—and I will explain, as much of my business as propriety will permit. To be brief, I am anxious to procure a certain document in Swartz’s possession.”

“A certain document?” I said, looking intently at the speaker.

“Exactly, colonel.”