In lieu of all existing taxes, every association shall pay to the Treasurer of the United States, in the months of January and July, a duty of one-half of 1 per centum each half year upon the average amount of its notes in circulation.
R.S. § 5214 derived from act June 3, 1864, ch. 106, § 41, 13 Stat. 111, which was part of the National Bank Act. See section 38 of this title.