(1)Duties on salt, Federal duties of excise and export duties shall be levied and collected by the Federation, but, if an Act of the Federal Legislature so provides, there shall be paid out of the revenues of the Federation to the Provinces and to the Federated States, if any, to which the Act imposing the duty extends, sums equivalent to the whole or any part of the net proceeds of that duty, and those sums shall be distributed -among the Provinces and those States in accordance with such principles of distribution as may be formulated by the Act.
