254 (5) such reserve of supplies as is needed to enable the Army to perform its mission. This section does not authorize the design or development of any prototype aircraft intended primarily for commercial use. §4532. Factories and arsenals: manufacture at; abolition of (a) The Secretary of the Army shall have supplies needed for the Department of the Army made in factories or arsenals owned by the United States, so far as those factories or arsenals can make those supplies on an economical basis. (b) The Secretary may abolish any United States arsenal that he considers unnecessary. §4533. Army ration Under the direction of the Secretary of the Army, any branch, office, or officer designated by him shall buy the components of the Army ration and items directed by the President to be issued in place thereof. § 4534. Subsistence supplies; contract stipulations; place of delivery on inspection Each contract for subsistence supplies for the Army that is made on public notice must provide for complete delivery, on inspection, at a specified place. §4535. Exceptional subsistence supplies: purchase without advertising Exceptional articles of subsistence supplies that are for members of the Army, and for which they are to pay regardless of condition upon arrival, may, under regulations to be prescribed by the Secretary of the Army, be bought on the open market without advertising. §4536. Equipment: post bakeries, schools, kitchens, and mess halls Money necessary for the following items for the use of enlisted members of the Army may be spent from appropriations for regular supplies: (1) Equipment for post bakeries. (2) Furniture, textbooks, paper, and equipment for post schools. (3) Tableware and mess furniture for kitchens and mess halls. § 4537. Military surveys and maps: assistance of United States mapping agencies The Secretary of the Army may obtain the assistance of the United States Geological Survey, the Coast and Greodetic Survey, and other mapping agencies of the United States in— (1) making topographic and other surveys; (2) obtaining extra topographic data; (S) making maps needed for military purposes; (4) research and development of surveying by aerial photography; and (5) developing methods of field reproduction.