Meanwhile, be it remembered, the Rock Island Arsenal was working on 75-millimeter recuperators. It was decided to retain the recuperator department as an active branch of the arsenal. The arsenal was a little ahead of the Singer Company in the development, for it had actually produced an acceptable recuperator before the armistice; and it had 542 others in process in the shop. The arsenal’s production proper was therefore limited to this number, but the incomplete units from Elizabethport were later transferred to Rock Island, and the arsenal eventually completed 555 75-millimeter recuperators before closing down the department. These were pronounced to be in every way the equal of the French product. The War Department provided no arsenal facilities for the production of recuperators for the 155-millimeter guns and howitzers, but centered its entire program for both mechanisms in the Dodge plant at Detroit. After the armistice it was first decided to retain the Dodge factory as a stand-by recuperator plant. All machinery and materials were protected against deterioration, and the plant, under guard, was added to the arsenal system, ranking as a subsidiary to the Rock Island Arsenal. Later the Dodge plant was sold, and nearly half of its machinery was moved to Rock Island. The plan of artillery demobilization and industrial preparedness in this direction is now evident. Watertown Arsenal is the development center for the raw materials of artillery manufacture. Watervliet Arsenal, with its stand-by plants at Rochester and Erie, is the gun-producing center. Rock Island Arsenal is the center for gun carriages and recuperators. One exception to this scheme is to be noted. The war-time producers of the 240-millimeter recuperators were two--the Otis Elevator Company at Chicago and the Watertown Arsenal. The Otis plant, originally having orders for 1,000 recuperators, was ordered to finish 250 of them after the armistice. Thereafter some of its machinery was transferred and stored at the Watertown Arsenal, which thus remains as the manufacturing center for this heavy mechanism.