law: Indian Stamp Act, 1899 
  16. Denoting duty 
  Where the duty with which an instrument is chargeable, or its
  
  exemption from duty, depends in any manner upon the duty actually paid in
  
  respect of both the instruments, be denoted upon such first mentioned
  
  instrument by application is made in writing to the Collector for that purpose,
  
  and on production of both the instruments, be denoted upon such first mentioned
  
  instrument by endorsement under the hand of the Collector or in such other
  
  manner (if any) as the 6[State Government] may by rule prescribe.