Clause 15

A certificate purporting to be signed by a Government chemist and purporting to relate to any chemical compound specified in the Schedule shall be admitted in evidence, in any proceedings for an offence under this Act, on its production by the prosecution without proof of signature and, until the contrary is proved, that certificate shall be prima facie evidence of all matters contained therein:Provided that the certificate shall not be accepted as evidence for the prosecution unless a copy thereof had been served on the accused not less than 7 days before the hearing.