Mode of computing contents of cask or package.
Section 59
SEC. 59. Mode of computing contents of cask or package.—Every fractional part of a proof liter equal to or greater than a half-liter in a cask or package containing more than one liter shall be taxed as a liter, and any smaller fractional part shall be exempt; but any package of spirits the total contents of which are less than a proof liter shall be taxed as one liter.