The termination of this industry was guided almost solely by industrial conditions. With most signaling supplies it was impracticable to build up large war reserves. There is perhaps no branch of modern mechanical development to which applied science pays more attention than it does to perfecting the means of communication. Progress is rapid, and therefore any large reserves of supplies set aside by the Signal Corps were likely to become obsolete and without value after a few years. Moreover, although the war industry of the Signal Corps scored its greatest production records with such common things as telephone and telegraph instruments and wire, all this equipment was of special design unknown in ordinary commercial use and therefore without value to it. Consequently there was not the usual good business reason to continue production under the well-advanced signal corps contracts--namely, that a greater cash recovery could be obtained from the sale of finished products than from the junk sale of semi-finished materials. Finally, many of the signal corps supplies--and this applies particularly to radio--were heavily protected by valid patents. These patents the Government made free with during the war, but the existence of the patents virtually precluded the Government from selling its excess radio equipment after the war. For these and other reasons the signal corps war business was terminated at precisely the rate at which the manufacturing equipment and its operatives could be diverted to other work. Unlike the Ordnance Department and the Air Service, the Signal Corps was not organized before the armistice by manufacturing districts, but conducted all its business from the central office in Washington. The Washington headquarters, however, maintained intimate contact with the contractors through its so-called flying squadron, an organization of officers who visited the war factories, inspected their work, and coöperated with the producers in the solution of their shop problems. This same organization after the armistice conducted the field work of the industrial liquidation, acting under the direction of the Signal Corps Board of Contract Termination, which, in turn, was subsidiary to the War Department Claims Board.