4Without prejudice to section 15 of this Act, no article shall be used for trade as a cubic measure of ballast other than a receptacle (which may, if so desired, form part of a vehicle) which conforms with such requirements as to form, capacity, calibration and other matters as may be prescribed ; and any person who uses for trade, or has in his possession for use for trade, as a cubic measure of ballast any article other than such a receptacle shall be guilty of an offence.