For the first few days he monopolized me. The emptiness or the bitterness of his life he lightened with fishing, shooting, riding, and walking. He had long since retired from all intercourse with other men. Hitherto his unhappiness, his mechanical studies, his experiments and his flights had sufficed to interest him. Now, however, yielding to his old taste for society, or perhaps simply to the thousand and one charms and attractions of everyday life, which does not long permit us to defy it, he felt the need of a companion and sought one. His daughter he surrounded with an almost passionate affection, yet he did not know how to talk with her as one talks with a child. He recognised this and left her, not without sorrow, to M. Mairieux, who understood both the child’s bursts of confidence and her reserve. I noticed, not without surprise, the respect that Cernay showed his father-in-law, though he exhibited too such embarrassment in the older man’s presence that of his own accord he kept out of his way. I soon believed that I had found the explanation of his character. Out of conjugal loyalty he imposed upon himself each year one month of solitude in this dwelling in the heart of the woods, and little by little the solitude became intolerable to him. Boredom preyed upon him, he turned about in his prison like a tiger in a cage. I supplied him with a diversion. He was faithful to the grief in his heart, to his abiding love. But, then, what can one expect? He did not know how to feast upon his sorrow, how to satiate himself with it. Few people do. Introspection had played but a small part in his life. His days had been consumed by the need of physical activity. Within him a similar fever had devoured that tender affection which was most dear to him, and he was grief-stricken at his helplessness to fan its ashes into flame. Thus I analysed his restlessness. I deceived myself thoroughly, it afterwards appeared; but how could I then have perceived its complex causes? * * * In the course of our walks I noticed the minute and prolonged study that he invariably bestowed upon the sky before we started. He was skilled in interpreting the form and movements of the clouds; those cumuli, lying on the horizon like snow hills, would dissolve in rain; these parasites hanging upon the summits of the mountains heralded a storm. I saw him sniff the air, examining it, one might say, as a hunter studies the depths of the woods and inhales their odour, or a fisherman scrutinises the mysteries of the water. “It is the enemy,” he confided to me one day. “It is invisible and formidable. Before attacking it, we must try to understand it.” I knew that he was thinking of his flying machines, and while we walked on to a neighbouring pond, I questioned him about the origin of his sudden interest in aviation.