...making any investigation, or upon official business in any other places than in the city of Washington, shall be allowed and paid on the presentation of itemized vouchers therefor approved by the Commission. Until otherwise provided by law, the Commission may rent suitable offices for its use....

...any investigation or upon any official business in any other places than in the city of Washington, shall be allowed and paid on the presentation of itemized vouchers therefor approved by the chairman of the Commission or by such other member or officer thereof as may be designated by the...

...expenses actually incurred for subsistence, of the members of the board. All expenditures of the board shall be allowed and paid on the presentation of itemized vouchers therefor approved by the chairman. After the creation of such board and for thirty days after such board has made its report...

...arbitration, and as may be provided for by the Congress from time to time. All expenditures of the Board shall be allowed and paid on the presentation of itemized vouchers therefor approved by the chairman. Fourth. The Mediation Board is hereby authorized by its order to assign, or refer, any...

...expenses actually incurred for subsistence, of the members of the board. All expenditures of the board shall be allowed and paid on the presentation of itemized vouchers therefor approved by the chairman. After the creation of such board and for thirty days after such board has made its report...