3. Insertion of new section 29 Ain the principal enactment

The following new scction is hereby inserted immediately after section 29 of the principal cnactment and shall have effect as section 29a of that enactment :-

“Presumption.

29a. In any prosecution for an offence referred to in section 27 it shall be presumed, unless the contrary is proved, that such poisonous, explosive or stupefying substance (including dynamite) or other noxious or harmful material or substance was uscd, carried or possessed for any of the purposes referred to in section 27." .