It is not yet twenty years since man first flew, but into that twenty years have been compressed a century or so of progress, while, in the two decades that preceded it, was compressed still more. We have only to recall and recount the work of four men: Lilienthal, Langley, Pilcher, and Clement Ader to see the immense stride that was made between the time when Penaud pulled a trigger for the last time and the Wright Brothers first left the earth. Into those two decades was compressed the investigation that meant knowledge of the qualities of the air, together with the development of the one prime mover that rendered flight a possibility--the internal combustion engine. The coming and progress of this latter is a thing apart, to be detailed separately; for the present we are concerned with the evolution of the driven plane, and with it the evolution of that daring being, the flying man. The two are inseparable, for the men gave themselves to their art; the story of Lilienthal's life and death is the story of his work; the story of Pilcher's work is that of his life and death. Considering the flying man as he appeared in the war period, there entered into his composition a new element--patriotism--which brought about a modification of the type, or, perhaps, made it appear that certain men belonged to the type who in reality were commonplace mortals, animated, under normal conditions, by normal motives, but driven by the stress of the time to take rank with the last expression of human energy, the flying type. However that may be, what may be termed the mathematising of aeronautics has rendered the type itself evanescent; your pilot of to-day knows his craft, once he is trained, much in the manner that a driver of a motor-lorry knows his vehicle; design has been systematised, capabilities have been tabulated; camber, dihedral angle, aspect ratio, engine power, and plane surface, are business items of drawing office and machine shop; there is room for enterprise, for genius, and for skill; once and again there is room for daring, as in the first Atlantic flight. Yet that again was a thing of mathematical calculation and petrol storage, allied to a certain stark courage which may be found even in landsmen. For the ventures into the unknown, the limit of daring, the work for work's sake, with the almost certainty that the final reward was death, we must look back to the age of the giants, the age when flying was not a business, but romance. VII. LILIENTHAL AND PILCHER