law: Indian Post Office Act, 1898 
  7. Power to fix rates of inland postage 
  (1) The Central
  
  Government may, by notification in the Official Gazette, fix the rates of
  
  postage and other sums to be charged in respect of postal articles sent by the
  
  inland post under this Act, and may make rules as to the scale of weights,
  
  terms and conditions subject to which the rates so fixed shall be charged :
  Provided that the highest rate
  
  of postage, when prepaid, shall not exceed the rate set forth for each class of
  
  postal articles in the First Schedule.
  (2) Unless and until
  
  such notification as aforesaid is issued, the rates set forth in the said
  
  Schedule shall be the rates chargeable under this Act.
  (3) The Central
  
  Government may, by notification in the Official Gazette, declare what packets
  
  may be sent by the inland post as book, pattern and sample packets within the
  
  meaning of this Act.