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huge British aircraft industry that existed at the cessation of hostilities had been built up in an incredibly short time. Unlimited demands were made upon the existing makers, and firms whose experience had been gained in other branches of engineering embarked upon aeroplane construction on a large scale. Engine builders increased their plant and their output, with the result that the 100 aeroplanes per annum which had been the output of this country upon the outbreak of war increased to an output of 30,000 in three years, and at the time of the Armistice machines were being manufactured at the rate of 40,000 per annum. Altogether during the period Great Britain manufactured over 50,000 aeroplanes, most of the engines for which were made in this country. In addition, over 80,000 propellers were manufactured. This is an achievement to be proud of under normal conditions, but under the adverse conditions that prevailed at the time its magnitude is greatly enhanced. Much is expected by some authorities in the future from the dirigible balloon or airship as distinct from the aeroplane. Reference has already been made to the airships of Lebaudy and Santos-Dumont, the latter of which was a tiny ship driven by a 31 horse-power motor-cycle engine. Further experiments were made with this type of craft in France and Germany, the most important vessels constructed in the latter country being those of Count von Zeppelin. A number of Zeppelin airships were constructed prior to 1914, and although several serious mishaps occurred, some of the vessels made comparatively long voyages and carried a number of passengers. The bombing raids of the Zeppelin airships during the war are unhappily fresh in the minds of most people, but from an engineering point of view these performances show that airships had been developed to a high degree. Several airships, usually of the small non-rigid type, were built in this country at various times by or for the Government. The motive power of the airship, like that of the aeroplane, is the petrol motor, and the balloon is inflated usually with hydrogen. The Germans have recently devoted much attention to gliding, the experimental work being reminiscent of that done by Lilienthal and the Wright brothers. Although the practical future of the glider
FUNDACION 1 JUANELO I :|L TURRIANO