11.—(1) Where any corrosive or explosive substance is found in or on any premises, the occupier of the premises shall be deemed to be in possession of that substance unless he shall prove that some other person was in possession thereof, or that he had no knowledge or reasonable means of knowledge that that substance was in or on the premises and that he had taken all reasonable precautions against that substance being kept in or on the premises.
(2) In any prosecution under section 3 or 5, it shall be presumed until the contrary is proved that any substance was intended to be used for the purpose of causing hurt if —
(a)
the quantity of the substance found exceeded the quantity reasonably required to be kept by the accused for ordinary use and consumption in his household or establishment and, in the case of a person carrying on business, exceeded the quantity reasonably required to be kept in the ordinary course of that business;
(b)
the substance was kept concealed or in a place other than that in which it might reasonably be expected to be kept for domestic purposes or, in the case of a person carrying on business, for business purposes; or
(c)
the substance was kept in a container other than a container of a kind in which the substance is ordinarily kept for domestic purposes or, in the case of a person carrying on business, for business purposes.