David’s hour of anguish only began when he was locked into his cell for the night. Lights are not allowed in the cells. A prisoner detained on arrest used to be subjected to rules devised for malefactors, unless he brought a special exemption signed by the public prosecutor. The jailer certainly might allow David to sit by his fire, but the prisoner must go back to his cell at locking-up time. Poor David learned the horrors of prison life by experience, the rough coarseness of the treatment revolted him. Yet a revulsion, familiar to those who live by thought, passed over him. He detached himself from his loneliness, and found a way of escape in a poet’s waking dream. At last the unhappy man’s thoughts turned to his own affairs. The stimulating influence of a prison upon conscience and self-scrutiny is immense. David asked himself whether he had done his duty as the head of a family. What despairing grief his wife must feel at this moment! Why had he not done as Marion had said, and earned money enough to pursue his investigations at leisure? “How can I stay in Angoulême after such a disgrace? And when I come out of prison, what will become of us? Where shall we go?” Doubts as to his process began to occur to him, and he passed through an agony which none save inventors can understand. Going from doubt to doubt, David began to see his real position more clearly; and to himself he said, as the Cointets had said to old Séchard, as Petit-Claud had just said to Eve, “Suppose that all should go well, what does it amount to in practice? The first thing to be done is to take out a patent, and money is needed for that--and experiments must be tried on a large scale in a paper-mill, which means that the discovery must pass into other hands. Oh! Petit-Claud was right!” A very vivid light sometimes dawns in the darkest prison. “Pshaw!” said David; “I shall see Petit-Claud to-morrow no doubt,” and he turned and slept on the filthy mattress covered with coarse brown sacking. So when Eve unconsciously played into the hands of the enemy that morning, she found her husband more than ready to listen to proposals. She put her arms about him and kissed him, and sat down on the edge of the bed (for there was but one chair of the poorest and commonest kind in the cell). Her eyes fell on the unsightly pail in a corner, and over the walls covered with inscriptions left by David’s predecessors, and tears filled the eyes that were red with weeping. She had sobbed long and very bitterly, but the sight of her husband in a felon’s cell drew fresh tears. “And the desire of fame may lead one to this!” she cried. “Oh! my angel, give up your career. Let us walk together along the beaten track; we will not try to make haste to be rich, David.... I need very little to be very happy, especially now, after all that we have been through .... And if you only knew--the disgrace of arrest is not the worst.... Look.”