United States Statutes at Large/Volume 3/15th Congress/2nd Session/Resolution 2
II. Resolution authorizing the transmission of certain documents free of postage.
Documents transmitted by the President, or heads of Departments, and printed, may be franked by members of Congress, &c.Resolved, by the Senate and House of Representatives of the United States of America in Congress assembled, That the members of Congress, the delegates from territories, the Secretary of the Senate, and the clerk of the House of Representatives, be, and they are hereby authorized to transmit, free of postage, to any post-office within the United States or the territories thereof, any documents which have been, or may be, communicated to either House of Congress, during the present session, by the President of the United States, or either of the heads of departments, and printed for the use of Congress.
Approved, December 5, 1818.