SECTION 1. No person shall fire or discharge any cannon, gun, fowling piece, pistol or firearms of any description, or fire, explode or set off any squib, cracker or other thing containing powder or other combustible or explosive material, or set off or exhibit any fireworks without within the limits of the city of La Crosse, without having first obtained written permission from the mayor, which permission shall limit the time and fix the place of such firing, and shall be subject to be revoked at any time after the same may have been granted. Any violation of this ordinance shall subject the person or persons so violating the same to a fine of not less than one dollar nor exceeding twenty-five dollars; but this ordinance shall not be construed to prohibit the discharge of fire arms by the chief of police or any of his subordinates or any peace officer when required or made necessary in the performance of any duty imposed by law.