There is hereby authorized to be appropriated from time to time, out of any moneys in the Treasury not otherwise appropriated, such sums as may be necessary to carry out the provisions of the convention and of this subchapter, including (1) contributions to the Commission for the United States share of any joint expenses of the Commission agreed by the United States and any of the other contracting governments, and (2) the expenses of the United States Commissioner and his staff, including (a) personal services in the District of Columbia and elsewhere, without regard to the civil-service laws and chapter
51 and subchapter
III of chapter
53 of title
5; (b) travel expenses without regard to subchapter
I of chapter
57 of title
5 and section
5731
(a) of title
5; (c) transportation of things, communication services; (d) rent of offices; (e) printing and binding without regard to section
501 of title
44, and section
5 of title
41; (f) stenographic and other services by contract, if deemed necessary, without regard to section
5 of title
41; (g) supplies and materials; (h) equipment; (i) purchase, hire, operation, maintenance, and repair of aircraft, motor vehicles (including passenger-carrying vehicles), boats, and research vessels.