It must not be imagined that as soon as the Wrights had constructed a glider fitted with this clever system of controlling mechanism they could fly when and where they liked. They had to practise for two or three years before they were satisfied with the results of their experiments: neglecting no detail, profiting by their failures, and moving logically from step to step. They never attempted an experiment rashly: there was always a reason for what they did. In fact, their success was due to systematic progress, achieved by wonderful perseverance. But now, for a short time, we must leave the pioneer work of the Wright brothers, and turn to the invention of the petrol engine as applied to the motor car, an invention which was destined to have far-reaching results on the science of aviation. CHAPTER XX. The Internal-combustion Engine We have several times remarked upon the great handicap placed upon the pioneers of aviation by the absence of a light but powerful motor engine. The invention of the internal-combustion engine may be said to have revolutionized the science of flying; had it appeared a century ago, there is no reason to doubt that Sir George Cayley would have produced an aeroplane giving as good results as the machines which have appeared during the last five or six years. The motor engine and the aeroplane are inseparably connected; one is as necessary to the other as clay is to the potter's wheel, or coal to the blast-furnace. This being the case, it is well that we trace briefly the development of the engine during the last quarter of a century. The original mechanical genius of the motoring industry was Gottlieb Daimler, the founder of the immense Daimler Motor Works of Coventry. Perhaps nothing in the world of industry has made more rapid strides during the last twenty years than automobilism. In 1900 our road traction was carried on by means of horses; now, especially in the large cities, it is already more than half mechanical, and at the present rate of progress it bids fair to be soon entirely horseless. About the year 1885 Daimler was experimenting with models of a small motor engine, and the following year he fitted one of his most successful models to a light wagonette. The results were so satisfactory, that in 1888 he took out a patent for an internal-combustion engine--as the motor engine is technically called--and the principle on which this engine was worked aroused great enthusiasm on the Continent.