Jean Krebs crystallized Georges Guynemer's vocation. He developed and specialized his taste for mechanics, separating it from vague abstractions and guiding it towards material realities and the wider experiences these procure. He deserves to be mentioned in any biography of Guynemer, and before passing on, it is proper that his premature loss should be cited and deplored. Highly esteemed as an aviator during the war, he made the best use of his substantial and reliable faculties in the work of observation. Airplane chasing did not attract him, but he knew how to use his eyes. He was killed in a landing accident at a time almost coincident with the disappearance of Guynemer. One of his escadrille mates described him thus: "With remarkable intelligence, and a perfectly even disposition, his chiefs valued him for his sang-froid, his quick eye, his exact knowledge of the services he was able to perform. Every time a mission was intrusted to him, everybody was sure that he would accomplish it, no matter what conditions he had to meet. He often had to face enemy airplanes better armed than his own, and in the course of a flight had been wounded in the thigh by an exploding shell. Nevertheless he had continued to fly, only returning considerably later when his task was done. His death has left a great void in this escadrille. Men like him are difficult to replace...." Thus the immoderate Guynemer had for his first friend a comrade who knew exactly his own limits. Guynemer could save Jean Krebs from his excess of literal honesty by showing him the enchantment of his own ecstasies, but Jean Krebs furnished the motor for Guynemer's ambitious young wings. Without the technical lessons of Jean Krebs, could Guynemer later have got into the aviation field at Pau, and won so easily his diploma as pilot? Would he have applied himself so closely to the study of his tools and the perfecting of his machine? The war was to make them both aviators, and both of them fell from the sky, one in the fullness of glory, the other almost obscure. When they talked together on school outings, or as they walked along beside the walls of Stanislas, had they ever foreseen this destiny? Certainly not Jean Krebs, with his positive spirit; he only saw ahead the Ecole polytechnique, and thought of nothing but preparation for that. But Guynemer? In his very precious notes, Abbe Chesnais shows us the boy constructing a little airplane of cloth, the motor of which was a bundle of elastics. "At the next recreation hour, he went up to the dormitory, opened a window, launched his machine, and presided over its evolutions above the heads of his comrades." But these were only the games of an ingenious collegian. The worthy priest, who was division prefect, and watched the boy with a profound knowledge of psychology, never received any confidence from him regarding his vocation.