Watertown has thus become the producing center for railway artillery of the future. The liquidation of war industry enormously expanded that institution. Before 1917 the government investment in the Watertown Arsenal was less than $4,000,000. After the concentration there of the special-purpose gunmaking machinery acquired by the Government during the war, the arsenal was worth, at a conservative valuation, $20,000,000. CHAPTER XII AMMUNITION AND OTHER ORDNANCE The armistice found in the United States an enormous industry devoted to the production of ammunition for the artillery. Including its powder-making plants and its plants for the production of the raw materials of powder, its scores of shell-making factories, and its loading establishments, this industry overshadowed, in money invested and operatives employed, even the artillery-manufacturing project. The demobilization of this vast enterprise, therefore, afforded the Ordnance Department one of its major problems after the armistice. The production of powders, both high-explosive and propellant, in which about 70,000 persons were engaged at the time of the armistice, was terminated in a remarkably brief time. When the armistice was six weeks old all manufacture of high explosives on war contracts had ceased, and two weeks after that the last of the war-time propellant (smokeless) powder was made. This termination left on the hands of the Ordnance Department a considerable amount of special-purpose machinery which had little or no market value. This machinery was therefore retained and stored at various arsenals, particularly at the Frankford and Picatinny arsenals, the permanent army ammunition production centers. For a while the Old Hickory Powder Plant at Nashville, Tennessee,--its daily capacity of 900,000 pounds of smokeless powder making it the largest powder factory in the world,--was retained as a stand-by plant, but later it was sold. The Nitro (West Virginia) Powder Plant, another government institution nearly as large as Old Hickory, was sold after the armistice, with the result that a new industrial city is developing on its site. The War Department’s enormous ammonium nitrate plant at Perryville, Maryland (ammonium nitrate being used in the manufacture of the widely used war explosive amatol), the equipment of which included several hundred model dwellings, was, after the armistice, turned over to the Public Health Service to be used as a hospital for ex-service men. The three government picric acid plants--at Little Rock, Arkansas, Grand Rapids, Michigan, and Savannah, Georgia--were sold. Briggs & Turivas, Chicago steel manufacturers, bought the plant built by the Government at Senter, Michigan, for the production of tetryl, an explosive used as the charge in boosters in high-explosive shell. The Ordnance Department also closed out and sold the facilities provided at Bound Brook, New Jersey, for the production of tetranitroaniline, another booster charge.