"I know it!" And the Duke's black eyes sparkled with an intensity which had its effect even upon the cynical Warren Jarvis.

"So you think this ghost is dangerous to encounter--that it is the cause of the mysterious deaths and disappearances in the old castle?"

"I do, Mr. Warren!"

Jarvis whistled meditatively. The Duke looked disgusted; this was so absolutely against all rules of his own conduct with women.

"Well, what do you know about _that_?"

Warren was again silent. The Duke was tabulating his own material and preparing his next charge of ammunition.

"_Ghost_ is a broad term, your Excellency. There are fifty-seven varieties of them, just like good pickles. They're equally bad for the digestion. What is your particular conception of this particular ghost?"

The Duke answered impatiently.

"There are certain occult forces in this world, Mr. Warren, that science cannot cla.s.sify or fathom. Some of them are at work in that castle, manifesting their weird powers. A priest might call them demons or fiends--a psychologist might term them, perhaps, returned spirits.... I can't say; but I have been there, and heard their curious warnings and manifestations. There is something definable there, in the periphery of those ancient ruins. A malignant spiritual force lurks within that mediaeval stronghold. While it haunts those musty halls it is madness for any man to expose himself there."

"You could write a good book on it, Duke," observed Jarvis irreverently. "Have you ever seen this ghost?"

"My brother has," interrupted Maria Theresa impetuously. "Twice, to my knowledge, before I left Seguro. So had my father and the others who disappeared from human ken!"

"Good Lord!" and there was a touch of the mock-heroic in the Kentuckian's voice, which escaped his companions.

"According to the family tradition," continued the Princess, "no one has ever seen it three times, and lived to tell the story."

"How do you connect this gentlemanly spook with the treasure, your Excellency?" burst in Jarvis, with a swift look of interrogation which discomfited the n.o.bleman.

"Spook? Treasure? I see no connection. What do you mean?"

"Oh, there is always money when the ghost walks," was the mysterious reply of the American, wasted on the untheatrical Spaniards. "That is the first premise upon which a reliable scientific Ghost Breaker begins his task of investigation."

"I don't know what your experience may have been, Mr. Warren. You are evidently a brave man, but you have yet to encounter a ghost like this supernatural spirit. Things are different in the Old World!"

Warren Jarvis sniffed.

"Huh! Brave? It takes no bravery to fight a coward--that is what the ghost is. It's a coward like every other stealthy, sneaking spirit, afraid to show itself by daylight, in the glare of the sun. I can tell you now that men are not half so afraid of spirits as the spirits are afraid of men. If you face the supernatural, it is more than half beaten to a frazzle, before the fight begins. In my professional career I have learned that ghosts, horse thieves, and peevish wildcats can all be tamed by the same little charm."

The Princess was mystified.

"Charm? What do you mean--a relic?"

The Duke leaned forward, his eyes sparkling with interest.

"What is it?"

"I'd hate to tell you," responded Warren Jarvis. "It's part of my system."

And he forthwith drew out the revolver, caressing it with an unmistakable confidence.

"I had been hoping, Mr. Warren," remarked the Duke, "that you had some subtle method worthy of handling this problem, and justifying the reputation for such work which you say you maintain through America.

You evidently propose to meet the forces of the supernatural with firearms.... I may as well tell you that this specter has been shot at before without the slightest effect."

The Kentuckian smiled gently.

"Quite likely, your Excellency. I have seen rifle-fire that had not the slightest effect on a wildcat for the simple reason that the firing was wilder than the cat!"

The Duke of Alva bestowed a pitying glance upon the weapon and its owner.

"I'm sorry for you, Mr. Warren. You will find that the ghost is more real than the treasure."

The Princess arose indignantly. She interrupted, with feminine betrayal of her own hand.

"But the treasure is real, Carlos. Would I have crossed the ocean for this locket unless I knew?"

Carlos looked at her sharply.

"I know I am right, now, Carlos. With the memorandum which I found inside the old locket, anyone, a total stranger, could walk right up to the very stone that hides it."

There was a meaning tone in Jarvis' voice, as he added: "A pretty dangerous paper to have around--look out that somebody else doesn't get there ahead of you."

The Duke shot back a quick answer to the message between the words: "Yes, it is a dangerous paper--if it leads anyone into the castle."

"Well, despite the danger and the threats of--the ghost--I'd go a long way for the fun of unraveling a good mystery with a little spice of danger thrown in."

The Duke scowled, and then with a peculiar emphasis on his words drew a newspaper from the breast pocket of his coat.

"You needn't have taken such a long trip, Mr. Warren. You are leaving behind you, in New York, a very interesting and unusual mystery. The papers are full of the story to-day.... It will interest you too, cousin. You were stopping at the Manhattan Hotel last night, I believe?"

"Yes," said the girl indifferently; but she and Jarvis exchanged eloquent glances.

The Duke was reading with unusual interest, it seemed to Jarvis.

"Why, no..." he began. "I was so wrapped up in my baggage that I really didn't have the time nor inclination to bother with the scandal of the day. Tell us about it?"

The n.o.bleman began to read:

"'Pistol duel in Manhattan Hotel.... Colonel James Marc.u.m, a wealthy and prominent Kentucky sportsman, nearly met death at an early hour this morning in a revolver battle in his hotel room...'"

He glanced down the column and continued:

"'Even at a late hour the police had no clew to the ident.i.ty of his a.s.sailant, except the remarkable fact that the person is still hiding somewhere in the hotel...'"

The Kentuckian interrupted:

"The villain is probably a long way from the hotel by this time if he knows what's what!"

"But they say he couldn't have gotten out without being seen,"

continued the Duke, still studying the printed column.