If a vacancy shall occur in the office of the city justice of the peace, the mayor by and with the City council shall forthwith fill any vacancy by appointment for the unexpired term, the person so appointed shall qualify in the same manner as a city justice and shall have and exercise all the powers conferred by law upon a city justice. In case the city justice shall for any reason be unable or disqualified to perform the duties of his office, or shall be absent, the mayor shall appoint some other justice of the peace residing within the county to act as city justice of the peace pro tem, and he shall have the powers and discharge the duties of such city justice during the existence of such disability or absence only in the same manner and to the same extent as the city justice might have done. (Prior code § 9-68)