BE IT ENACTED by the Senate and House of Representatives of the United States of America in Congress assembled, THATAlexander Vattemare agent of the United States for international exchanges be and he is hereby authorized to frank letters or packages containing books, public documents, maps specimens of the arts or medals sent by him from any foreign country to the United States, or from the United States to any foreign country; and also to receive letters and packages appertaining to international exchanges, free of postage; this privilege to extend to the mail lines of the United States to foreign countries: Provided that such letters or packages shall be endorsed on the envelope, “International Exchange” and shall not exceed three pounds in weight: And it shall be lawful for any Deputy Postmaster to remit the postage on any letter or package not so endorsed and charged with postage directed to said Vattemare if on opening the same, he shall be satisfied that it appertains to international exchanges.