SEC. 33. No person or persons shall store or keep at any time within half a mile of the line of buildings of this city, more than thirty pounds of gunpowder; and if at any time hereafter a greater quantity shall be found deposited in the same building, the owner or occupant, as the case may be, of the building in which the same shall be discovered shall be liable to a fine of ten dollars; provided always, that powder deposited in a magazine built for that purpose, according to the act of the legislature of this state, shall not be considered as coming within the provisions of this ordinance; and the chief of police shall inquire and make complaint of all breaches of this section of this ordinance.