Suddenly he released the enormous tension with which he held her. Like a man who has exerted all his strength to some end, the victory won, he loosened his muscles, with a faint sigh of exhaustion. Margaret did not speak, but she knew that something horrible was about to happen. Her heart beat like a prisoned bird, with helpless flutterings, but it seemed too late now to draw back. Her words by a mystic influence had settled something beyond possibility of recall. On the stove was a small bowl of polished brass in which water was kept in order to give a certain moisture to the air. Oliver Haddo put his hand in his pocket and drew out a little silver box. He tapped it, with a smile, as a man taps a snuff-box, and it opened. He took an infinitesimal quantity of a blue powder that it contained and threw it on the water in the brass bowl. Immediately a bright flame sprang up, and Margaret gave a cry of alarm. Oliver looked at her quickly and motioned her to remain still. She saw that the water was on fire. It was burning as brilliantly, as hotly, as if it were common gas; and it burned with the same dry, hoarse roar. Suddenly it was extinguished. She leaned forward and saw that the bowl was empty. The water had been consumed, as though it were straw, and not a drop remained. She passed her hand absently across her forehead. “But water cannot burn,” she muttered to herself. It seemed that Haddo knew what she thought, for he smiled strangely. “Do you know that nothing more destructive can be invented than this blue powder, and I have enough to burn up all the water in Paris? Who dreamt that water might burn like chaff?” He paused, seeming to forget her presence. He looked thoughtfully at the little silver box. “But it can be made only in trivial quantities, at enormous expense and with exceeding labour; it is so volatile that you cannot keep it for three days. I have sometimes thought that with a little ingenuity I might make it more stable, I might so modify it that, like radium, it lost no strength as it burned; and then I should possess the greatest secret that has ever been in the mind of man. For there would be no end of it. It would continue to burn while there was a drop of water on the earth, and the whole world would be consumed. But it would be a frightful thing to have in one’s hands; for once it were cast upon the waters, the doom of all that existed would be sealed beyond repeal.” He took a long breath, and his eyes glittered with a devilish ardour. His voice was hoarse with overwhelming emotion.