N.Y. Second Class Cities Law § 134: Constitution of police and fire departments

§ 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.