trunk-line, long-distance, and leased-line telephone service at or con- necting any post, camp, cantonment, depot, arsenal, headquarters, hospital, aviation station, or other office or station of the Army, Exceptions. excepting the local telephone service for the various bureaus of the War Department in the District of Columbia, and toll messages pertaining Rental of lines, etc. to the office of the Secretary of War; electric time service; the rental of commercial telegraph lines and equipment, and their operation at or connecting any post, camp, cantonment, depot, arsenal, headquar- ters, hospital, aviatlon station, or other office or station of the Army, including payment for official individual telegraph messages trans- Electrical installa- mitted over commercial lines; electrical installations and maintenance tios. thereof at military posts, cantonments, camps, and stations of the Army, fire controf and direction apparatus, and materiel for Field civiian employees. Artillery; salaries of civilian employees, including those necessary as instructors at vocational schools; supplies, general repairs, reserve supplies, and other expenses connected with the collecting and trans- mitting of information for the Army by telegraph or otherwise; Experimental in- experimental investigation, research, purchase, and development, or vetiation, etc. improvements in apparatus, and maintenance of signaling and acces- sories thereto, including machines, instruments, and other equipment for laboratory and repair purposes; lease, alteration, and repair of such buildings required for storing or guarding Signal Corps sup- plies, equipment, and personnel when not otherwise provided for, including the land therefor, the introduction of water, electric light and power, sewerage, grading, roads and walks, and other equipment Aircraft warning required; for all expenses incident to the preparation of plans, and servicesystems. construction, purchase, installation, equipment, maintenance, repair, and operation of aircraft warning service systems, and their acces- sories, including purchase of lands and rights-of-way, acquisition of leaseholds and other interests therein, and temporary use thereof, Payments under $49,690,649, of which not to exceed $1,160,000 shall be available for payments under contracts for the procurement of aircraft-communi- cation equipment and ground radio and telephone facilities under 53 Stat. 94. the authorization contained in the Supplemental Military Appropria- contracts author- tion Act, 1940, and in addition, the Chief Signal Officer, when authorized by the Secretary of War, may enter into contracts prior to July 1, 1941, to an amount not in excess of $1,700,000 for the procurement of Signal Corps equipment. Post, pp. 602 , 873, 968. Post, pp. 602, 603, 873, 968, 970. Instruction, etc., ex- pense Aircraft operation, etc. Photographic sup- plies. Helium ga. Pod. p . 443. AIR CORPS AIR CORPS, ARMY For creating, maintaining, and operating at established flying schools and balloon schools courses of instruction for officers, stu- dents, and enlisted men, including cost of equipment and supplies necessary for instruction, purchase of tools, equipment, materials, machines, textbooks, books of reference, scientific and professional papers, instruments, and materials for theoretical and practical instruction; for maintenance, repair, storage, and operation of air- ships, war balloons, and other aerial machines, including instruments, materials, gas plants, hangars, and repair shops, and appliances of every sort and description necessary for the operation, construction, or equipment of all types of aircraft, and all necessary spare parts and equipment connected therewith and the establishment of landing and takeoff runways; for purchase of supplies for securing, develop- ing, printing, and reproducing photographs in connection with aerial photography; improvement, equipment, maintenance, and operation of plants for testing and experimental work, and procuring and 364 PUBLIC LAWS--CH. 343-JUNE 13, 1940 [54 STAT.