Only one exception was made. During the war the Wright-Martin Aircraft Corporation developed a plant in Long Island City for the production of Hispano-Suiza engines. This plant was purchased by the War Department and is being retained as a stand-by plant under the name of the United States Aëronautical Engine Plant. The future of this establishment, however, is uncertain. Although it ruthlessly dispensed with the war manufacturing facilities, the Air Service retained in the demobilization a considerable part of the physical plant created for it during the war. Of the twenty-six flying fields used in the training of the war aviators, six have been retained as flying fields. These are the Bolling, Langley, Mather, and Kelly flying fields and the Carlstrom and March pilot training fields. The present equipment also includes three balloon schools, three balloon fields, one mechanics school (Chanute Field), one observation school, various stations for the defense of our island possessions and for the patrol of the Mexican border, nineteen supply, storage, and repair depots, and various other stations. The storage of reserve supplies retained by the Air Service afforded some interesting problems, since nearly every class of supplies required special treatment in storage. Engines, for instance, were thoroughly covered inside and out with a heavy rust-preventing grease compound before being stored away in dry, cool concrete warehouses. Reserve balloons were dusted with talc, rolled carefully so as to put as little weight as possible on creases and folds, enclosed in sealed rubber envelopes, packed in wooden chests, which were then sealed up so as to be practically waterproof and air-tight, and then stacked in dry rooms in which air at a medium temperature circulates constantly among the chests. Even so, no long life for the balloons is expected. Wing fabric, both cotton and linen, was unbolted, rolled upon cardboard tubes, wrapped in paper, and suspended on racks in rooms heated in winter. Aviators’ fur and woolen clothing was stored in fly-proof and moth-proof tar-paper-lined rooms, the floors of which were thickly covered with naphthaline. Fabric was stripped from airplane wings before storage in order to permit the free ventilation of the wood; glued joints were given an extra coat of varnish; all metal parts were painted with red lead or white lead; and the wings were stored in racks designed to keep their edges straight. Thousands of propellers were stored at the aviation supply depot at Middletown, Pennsylvania, in a room in which moisture sprayers maintain a constant humidity and a thermostat a constant temperature.