law: Indian Post Office Act, 1898 
  17. Postage stamps to be deemed to be stamps for the
  
  purpose of revenue
   13  [(1)] Postage stamps
  
  provided under section 16 shall be deemed to be stamps issued by Government for
  
  the purpose of revenue within the meaning of the Indian Penal Code, and,
  
  subject to the other provisions of this Act, shall be used for the prepayment
  
  of postage or other sums chargeable under this Act in respect of postal
  
  articles, except where the Central Government directs that prepayment shall be
  
  made in some other way.
   14  [(2) Where the Central
  
  Government has directed that prepayment of postage or other sums chargeable
  
  under this Act in respect of postal articles may be made by prepaying the value
  
  denoted by the impressions of stamping machines issued under its authority, the
  
  impression of any such machine shall likewise be deemed to be a stamp issued by
  
  Government for the purpose of revenue, within the meaning of the Indian Penal
  
  Code.]