Explain the term 'Denoting Duty' under the provisions of the Indian Stamp Act, 1899.

Section 16 of the Indian Stamp Act, 1899, deals with 'Denoting Duty'. The object of this section is to spare parties to an instrument the inconvenience of having to produce (in cases in which the duty payable on an instrument depends upon the duty already paid on another instrument) the original or principal instrument in order to prove that the second instrument has been duly stamped. Section 16 provides that 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 another instrument, the payment of such last-mentioned duty shall, if 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 of Stamps or in such other manner as the rules of the State Government may provide.