§ 131. Duties of commissioner. The commissioner of public safety shall have cognizance, jurisdiction, supervision and control of the government, administration, disposition and discipline of the police department, fire department, buildings department and health department, and of the officers and members of said departments, and shall possess and exercise fully and exclusively all powers and perform all duties pertaining to the government, maintenance and direction of said departments, and the apparatus and property thereof and buildings furnished therefor, and shall have the general direction and supervision of the expenditure of all moneys appropriated to said departments. He shall possess such other powers and perform such other duties as may be prescribed by the law or by ordinance of the common council.