With trembling hands Gemma grasped it, as Nenci had done on the night when she had watched, and with a quick wrench tried to turn it back. It would not move! Next second, however, she twisted it in the opposite direction. As she did so there was a harsh grating sound, as of steel cutting into stone, a crack, as though some strong spring had snapped; and then all knew that the mechanism of the devilish invention had been disordered, and the frightful catastrophe thereby averted. She bent down, opening Nenci's bag, and took therefrom a second bust, exclaiming-- "He tricked us cleverly. Fortunately, however, I detected the difference in the markings of that green stone, or ere this we might each one of us have been dead." Then, placing the two busts side by side, she pointed out the difference in the vein of the malachite which had attracted her attention, and thus caused her to make the astounding declaration which had held them petrified. "You've saved us!" the Gobbo cried, addressing her. "These men must not escape," Gemma cried determinedly. "They shall not! Our lives have been endangered by their villainous treachery, and they shall not evade punishment." CHAPTER THIRTY. "I BEAR WITNESS!" Next morning Gemma stood at the window of her bedroom, looking down upon Northumberland Avenue. She had breakfasted unusually early, and had chosen a dark-green dress trimmed with narrow astrachan--one of her Paris-made gowns which she knew fitted her perfectly and suited her complexion. She had stood before the long mirror in the wardrobe for some minutes, and, with a pride that may always be forgiven in a woman, regarded herself with satisfaction. They knew how to make a woman look her best in the Rue de la Paix. The recollection of the previous night was, in the light of morning, horrifying. After leaving Sussex Square, she had stopped her cab at the telegraph office opposite Charing Cross Station, the office being open day and night, and had sent a long and urgent message to Rome explaining the situation. Already a reply reposed in the pocket of her gown, but it was unsatisfactory. The private secretary had wired back that the Marquis was away at his high-up, antique castle of Montelupo, "the Mountain of the Wolf," between Empoli and Signa, in Tuscany. She therefore knew that many hours must elapse ere her cipher message was delivered to him. Even his reply could not reach her for four hours or so after it had been despatched from Empoli. But after sending the message to Rome, she had also sent one to Armytage at Aldworth Court, and was now awaiting his arrival.