§ 78. No person shall fire or discharge, within the city limits, any cannon, gun, fowling piece, pistol or fire-arms of any description, or tire, explode or set off any squib, rocket, cracker, or other thing containing powder or other comlbustible or explosive material, without permission from the mayor or common council. Nor shall any permission be given for the firing of any heavy ordinance, except on the north pier of the Chicago river, at least three hundred feet east of the most eastern warehouse or manufactory thereon.