§ 134. Constitution of police and fire departments. The police and
fire departments shall, as to their membership and component parts,
remain as now constituted until the same shall be changed by action of
the common council. The common council has power at all times by
ordinance to determine the number of officers and members of each of
said departments and the classes and grades into which they shall be
divided, except that it shall not have the power to diminish the number
of the members of either of said departments as now fixed. The number of
officers or members of either of said departments shall not be increased
without the approval of the board of estimate and apportionment. The
common council may pass ordinances not inconsistent with law for the
government of the police and fire departments, and regulating the powers
and duties of their officers and members. The commissioner shall
appoint, as vacancies in said department occur, all officers and members
thereof, and classify and apportion them into grades to conform to such
ordinances.