54 STAT.] 76TH CONG. , 3D SESS.-CH. 395-JUNE 18, 1940 Survey and subsequently repaid to the appropriation from which advanced; During the fiscal year 1941, upon the request of the Secretary of the Interior, the Secretary of War or the Secretary of the Navy is authorized to furnish aerial photographs required for mapping projects, insofar as the furnishing of such photographs will be economical to the Federal Government and does not conflict with military or naval operations or the other parts of the regular training program of the Army, Navy, and Marine Corps flying services, and the Secretary of the Interior is authorized to reimburse the War or Navy Department for the cost of making the photographs, such cost to be confined to the actual cost of gasoline, oil, film, paper, chemicals, and the labor performed in developing the photographic negatives and the printing of copies of photographs, and the per diem expenses of the personnel authorized by law, together with such incidental expenses as care and minor repairs to plane and transportation of personnel to and from projects, and the War Department or the Navy Department, on request of the Department of the Interior, is authorized to furnish copies to any State, county, or municipal agency cooperating with the Federal Government in the mapping project for which the photographs were taken. In the event that the Director of the Geological Survey deems it advantageous to the Government, the Geological Survey is authorized to contract with civilian aerial photographic concerns for the furnishing of such photographs or for the furnishing of topographic maps made from such photographs; Appropriations herein made, and funds transferred thereto, shall be available for payment of the costs of packing, crating, and trans- portation (including drayage) of personal effects of employees upon permanent change of station, under regulations to be prescribed by the Secretary of the Interior; In all, salaries and expenses, United States Geological Survey, $3,586,910. BUREAU OF MINES 441 Aerial photographs for mapping projects. Copies. Contracts with ci- vilian concerns. Transportation of personal effects of em- ployees. Total. SALARIES AND GENERAL EXPENSES Salaries and general expenses: For general expenses, including pay of the Director and necessary assistants, clerks, and other employees, in the office in the District of Columbia and in the field, and every other expense requisite for and incident to the general work of the Bureau in the District of Columbia and in the field, to be expended under the direction of the Secretary of the Interior, $64,000, of which amount not to exceed $51,440 may be expended for personal services in the District of Columbia; Operating mine rescue cars and stations and investigation of mine accidents: For the investigation and improvement of mine-rescue and first-aid methods and appliances and the teaching of mine safety, rescue, and first-aid methods; investigations as to the causes of mine explosions, causes of falls of roof and coal, methods of mining, espe- cially in relation to the safety of miners, the appliances best adapted to prevent accidents, the possible improvement of conditions under which mining operations are carried on, the use of explosives and electricity, the prevention of accidents, statistical studies and reports relating to mine accidents, and other inquiries and technologic inves- tigations pertinent to the mining industry; the exchange in part payment for operation, maintenance, and repair of mine-rescue trucks; the construction of temporary structures and the repair, maintenance, and operation of mine-rescue cars and the Government- owned mine-rescue stations and appurtenances thereto; personal Salaries and general expenses. Operating mine res- cue cars, etc., and in- vestlgation of mine accidents.