The officers of said City shall be a Mayor, and two councilmen from each ward, who shall be freeholders of said City; a Clerk, Assessor, Treasurer, Marshal, Health Officer, Street Commissioner, City Solicitor, and such other officers as the Council shall by ordinance provide. The Mayor, Clerk and Assessor shall be elected by the qualified voters of said City, and the councilmen from each ward by the qualified voters thereof; the other officers named, and such other officers as may be provided for by ordinances of the Council, shall be appointed by the Council. No person shall be eligible to any City office unless he is a taxpayer of the City and a qualified voter; nor unless he has resided therein for at least six months next preceding his election or appointment.