national banks with the American Reserve Bank, as aforesaid, shall
reach the sum of five hundred million dollars all the bonds now
deposited by national banks to secure Government deposits shall be
returned to the respective banks to which they belong; and from and
after that date any national bank holding a Government deposit shall
pay interest thereon to the Treasurer of the United States at the
rate of 2 per centum per annum, and the said interest so received
shall be paid into the division of reserve fund in the Treasury, and
United States notes of an equal amount shall be retired, canceled, and
destroyed and gold certificates issued therefor. The said interest
shall be payable as follows: 1 per centum on the tenth days of January
and July of each year on the average balance during the preceding six
months.