§ 146. Discriminating duty on merchandise imported in foreign vessels; exception
A discriminating duty of 10 per centum ad valorem, in addition to the duties imposed by law, shall be levied, collected, and paid on all goods, wares, or merchandise which shall be imported in vessels not of the United States; but this discriminating duty shall not apply to goods, wares, or merchandise which shall be imported in vessels not of the United States entitled at the time of such importation by treaty or any act of Congress to be entered in the ports of the United States on payment of the same duties as shall then be payable on goods, wares, and merchandise imported in vessels of the United States, nor to goods, wares, and merchandise imported in a vessel owned by citizens of the United States but not a vessel of the United States if such vessel after entering an American port shall, before leaving the same, be documented under chapter
121 of title
46.