The salaries of the members on the part of the United States, of the International Joint Commission, established under the treaty of January 11, 1909, between the United States and Great Britain, relating to boundary waters between the United States and Canada, shall be fixed by the President. Said commission or any member thereof shall have power to administer oaths and to take evidence on oath whenever deemed necessary in any proceeding or inquiry or matter within its jurisdiction under said treaty, and said commission shall be authorized to compel the attendance of witnesses in any proceedings before it or the production of books and papers when necessary by application to the district court of the United States for the district within which such session is held, which court is hereby empowered and directed to make all orders and issue all processes necessary and appropriate for that purpose.