Meanwhile the work overhead was being completed. They underwent the terrible experience which condemned men must feel on the morning of their last day, when from their cells they hear the preparations: the engine of death that is being set up, or the electric batteries that are being tested. They hear men striving to have everything ready, so that not one propitious chance may remain and so that destiny may be fulfilled. Death had entered the enemy's service and was working hand in hand with him. He was death itself, acting, contriving and fighting against those whom he had resolved to destroy. "Don't leave me," sobbed Coralie, "don't leave me! . . ." "Only for a second or two," he said. "We must be avenged later." "What is the use, Patrice? What can it matter to us?" He had a box containing a few matches. Lighting them one after the other, he led Coralie to the panel with the inscription. "What are you going to do?" she asked. "I will not have our death put down to suicide. I want to do what our parents did before us and to prepare for the future. Some one will read what I am going to write and will avenge us." He took a pencil from his pocket and bent down. There was a free space, right at the bottom of the panel. He wrote: "Patrice Belval and Coralie, his betrothed, die the same death, murdered by Siméon Diodokis, 14 April, 1915." But, as he finished writing, he noticed a few words of the former inscription which he had not yet read, because they were placed outside it, so to speak, and did not appear to form part of it. "One more match," he said. "Did you see? There are some words there, the last, no doubt, that my father wrote." She struck a match. By the flickering light they made out a certain number of misshapen letters, obviously written in a hurry and forming two words: "_Asphyxiated. . . . Oxide. . . ._" The match went out. They rose in silence. Asphyxiated! They understood. That was how their parents had perished and how they themselves would perish. But they did not yet fully realize how the thing would happen. The lack of air would never be great enough to suffocate them in this large room, which contained enough to last them for many days. "Unless," muttered Patrice, "unless the quality of the air can be impaired and therefore . . ." He stopped. Then he went on: "Yes, that's it. I remember."