"Place yourself before the door, Nugent, that nobody may be able to look through the key-hole," whispered John, "for you know that I do not trust Conrad. And you, Hormayr, watch the secret door."

The two gentlemen hastened noiselessly to obey. The archduke cast a searching glance around the walls, as if afraid that even the silken hangings might contain somewhere an opening for the eyes of a spy, or serve as a cover to an ear of Dionysius.

"Something of importance must have occurred," whispered John; "otherwise the empress would not have ventured to send me a direct message. I did not lend her a book, and you know we agreed with the ladies of our party to communicate direct news to each other only in cases of pressing necessity. Let us see now what it is."

He hastily tore open the sealed package and drew from it a small prayer-book bound in black velvet. While he was turning over the leaves with a smile, a small piece of paper fluttered from between the gilt-edged leaves and dropped to the floor.

"That is it," said John, smiling, picking up the paper, and fixing his eyes on it. "There is nothing on it," he then exclaimed, contemplating both sides of the paper. "There is not a word on it. It is only a book-mark, that is all. But, perhaps, something is written in the book, or there may be another paper."

"No, your imperial highness," whispered Nugent, stepping back a few paces from the door. "The Princess Lichtenstein whispered to me yesterday, at the court concert, that she had obtained an excellent way of sending a written message to her friends and allies, and that, if we received a piece of white paper from the ladies of our party, we had better preserve it and read it afterward near the fireplace."

"Ah, sympathetic ink," exclaimed John; "well, we will see."

He hastily approached the fireplace, where a bright fire was burning, and held the piece of paper close to the flames. Immediately a number of black dots and lines appeared on the paper; these dots and lines assumed gradually the shape of finely-written words.

The archduke followed with rapt attention every line, every letter that appeared on the white paper, and now he read as follows:

"The French ambassador has requested the emperor to grant him an audience at eleven o'clock this morning. A courier from Metternich in Paris has arrived, and, I believe, brought important news. The decisive hour is at hand. Hasten to the emperor; leave nothing undone to prevail on him to take a bold stand. Send somebody to the Archduke Charles; request him to repair likewise to the emperor and influence him in the same direction. I have paved the way for you. I hope the French ambassador will, in spite of himself, be our ally, and by his defiant and arrogant bearing, attain for us the object which we have hitherto been unable to accomplish by our persuasion and our arguments. Make haste! Burn this paper."