17. A copy of, or an extract from, any public archives or any private document or manuscript deposited in the National Archives purporting to be duly certified as true and authenticated by the Director or any other officer authorised by him in writing for the purpose and having impressed thereon the official seal of the National Archives, shall be admissible in evidence in any proceeding in any Court in like manner and to the like extent as the original document or manuscript would have been admissible.