Flying is an art. A pilot may actually fly a small manoeuvrable aeroplane of the present day without knowing much about aerodynamics, just as a musician may draw exquisite music from an instrument without a knowledge of the laws of sound. There is a flying instinct just as there is a musical instinct; an unerring perception of the modes and measures of the art ; a subconscious obedience to laws which are at most but dimly realised. I do not say that a pilot can design a successful aeroplane without a certain knowledge of the fundamental truths of aerodynamics, of the distribution of stresses in a structure, any more than a musician can compose a sonata without a knowledge of the laws of sound, the laws of harmony and counterpoint, the practice of great masters in the traditions of sonata writing ; but I do maintain that he can fly the aeroplane.