Colonel Wiljohn was a tall, muscular man, with a look of youth in his keen gray eyes despite the lines on his tanned face and his white hair. The type of man that kept young by his intense interest in big things and the future trend of affairs. Jacky, his grandson, was getting aviation in the blood at an early age. The little fellow with his close-clipped hair and wide-open black eyes, must have been only five or thereabouts, yet he could speak familiarly of water-cooled engine, and struts, and spar, and other lingo of aircraft.