“Why so many twists and turnings when it was so simple to go out by the gate?” I could not restrain myself from exclaiming.

Mme. Edith looked at me reproachfully and I regretted having even seemed to have taken part against her in any way.

“And this is stranger yet!” said the Prince. “Day before yesterday, the ‘hangman of the sea’ came to bid me adieu, saying that he was going to leave the country, and I am sure that he took the train for Venice, his native city, at five o’clock in the afternoon. How then could he have conveyed your uncle in his boat late that night? In the first place, he was not in this part of the world; in the second, he had sold his boat. He told me so, adding that he would never return to this country.”

There was a dead silence and Prince Galitch continued:

“All this is of little importance—provided that your uncle, Madame, recovers speedily from his injuries and, again,” he added with another smile, more charming than those which had preceded it—“if you will aid me in regaining a poor piece of flint which has disappeared from the grotto and of which I will give you the description. It is a sharp piece of flint, twenty-five centimeters long and shaped at one end to the form of a dagger—in brief, the oldest dagger of the human race. I value it greatly and, perhaps you may be able to learn, Madame, through your uncle, Bob, what has become of it.”

Mme. Edith at once gave her promise to the Prince, with a certain air of haughtiness which pleased me greatly, that she would do everything possible to obtain for him news of so precious an object. The Prince bowed low and left us. When we had finished returning his parting salutes, we saw M. Arthur Rance before us. He must have heard the conversation for he seemed very thoughtful. He had his ivory-headed cane in his hand, and was whistling, according to his habit. And he looked at Mme. Edith with an expression so strange that she appeared somewhat exasperated.

“I know exactly what you are thinking, sir!” she said. “It does not astonish me in the least. And you may keep on thinking so, if it amuses you, for aught I care.”

And she stepped nearer Rouletabille, smiling nervously.

“At all events,” she exclaimed. “You can never explain to me how, when he was outside the Square Tower, he could have hidden behind that panel.”

“Madame,” said Rouletabille, slowly and impressively, looking at the young woman as though he were trying to hypnotize her, “have patience and have courage. If God is with me, before night I shall explain to you all that you wish to know.”