From what has been said it will be seen that the factory continued, as it began, in close relations with the army. It had been founded, under army auspices, at an important inland military centre, and it was not so well adapted, by its history or situation, to serve the navy. The results obtained by research at the National Physical Laboratory, and by experiment at the factory, furthered the science of aviation, and were open to all. But when flight began, a united national air force was not thought of by any one, or was thought of only in dreams. Meantime the new invention offered to the navy, no less than to the army, new opportunities of increasing the power of its own weapon. The problems of the navy were not the problems of the army, and a certain self-protective jealousy made the two forces keep apart, so that each might develop unhampered by alien control. The navy trusted more to private firms, and less to the factory. It was a difference of tendency rather than a clean-cut difference of policy. Both army and navy made use of the results obtained at the laboratory and the factory. The army employed many private makers for the supply of machines and engines, and the navy, in the course of the war, ordered a very large number of that most famous of factory machines--the B.E. 2c. But the navy stood as far aloof from the factory as possible, and looked mainly to private firms not only for the supply of machines and engines, but for much of its experimental work. Several of the firms who devoted themselves to the needs of naval aviation did excellent service as pioneers. The most distinguished of these was the firm of the Short brothers--that is, of Messrs. Oswald, Eustace, and Horace Short. The impulse of their work was scientific, not commercial. As early as 1897 Mr. Eustace Short was an amateur balloonist, and his younger brother Oswald, at the age of fifteen, began to accompany him on his voyages. In a public library they came across that celebrated record of balloon voyages, _Travels in the Air_, by James Glaisher, and made up their minds to construct a balloon of their own. Success led them on step by step; in 1905 they contracted to supply captive war balloons for the Government of India, and in 1906 they became the club engineers of the newly formed Royal Aero Club. The reported successes of the Wright brothers in America shifted the interest of the club, and of the club engineers, from balloons to flying machines; in 1908 they built their first glider--a complete miniature Wright machine, without the power plant--for the Hon. C. S. Rolls. At about this time they were joined by the eldest of the three brothers, Mr. Horace Short, an accomplished man of science and a lover of adventure; from this time onward the firm of the Short brothers never looked back. From sketches made by Mr. Horace Short, they built six biplanes to the order of the Wrights. They constructed, in 1909, the aeroplane on which Mr. J. T. C.