Sec. 6. That for the purpose of carrying this act into effect it shall be the duty of each of the Executive Departments of the United States to provide for itself and its subordinate officers the necessary envelopes, and in addition to the endorsement designating the Department in which they are to be used, the penalty for the unlawful use shall be stated thereon. Sec. 7. That Senators, Representatives and Delegates in Congress, the Secretary of the Senate and Clerk of the House of Representatives may send and receive through the mail all public documents printed by order of Congress, and the name of each Senator, Representative, Delegate, Secretary of the Senate, and Clerk of the House, shall be written thereon with the proper designation of the office he holds, and the provisions of this section shall apply to each of the persons mentioned therein until the first day of December following the expiration of their terms of office. By this act the use of official stamps upon mail matter _from_ the Departments, bureaus and offices was practically abolished, but official stamps continued to be used by postmasters and other subordinate officers in their mail matter _to_ the Departments or each other on official business. By the 29th Section of the Act of the XLVth Congress, Chapter 180, approved March 3d, 1879, it was enacted that,-- "The provisions of the 5th and 6th Sections of the Act entitled, An Act Establishing Post Routes and for other purposes, approved March 3d, 1877, for the transmission of official mail matter, be and they are hereby extended to all officers of the United States Government, and made applicable to all official mail matter transmitted between any of the officers of the United States, or between any such officer and either of the Executive Departments or officers of the Government, the envelopes of such matter in all cases to bear appropriate endorsements containing the proper designation of the office from which the same is transmitted, with a statement of the penalty for their misuse. And the provisions of said 5th and 6th Sections are hereby likewise extended and made applicable to all official mail matter sent from the Smithsonian Institution. Provided, that this Act shall not extend or apply to pension agents, or other officers who receive a fixed allowance for their services, including expenses for postage." In his report for the fiscal year ending June 30, 1878, D. M. Key, Postmaster General, had already stated that,--