Section 5. And be it further enacted by the authority aforesaid, That the power of the corporation of the said city shall be vested in the said select and common councils, who shall, in common councils assembled, have full power and authority to make, ordain, constitute and establish such and so many laws, ordinances, regulations and constitutions (provided the same shall not be repugnant to the laws and constitution of the United States or of this commonwealth) as shall be necessary or convenient for the government and welfare of the said city, and the same to enforce, put in use and execution, by constables and other proper officers (whom they shall have the power to appoint,) and at their pleasure to revoke, alter and make anew, as occasion may require, and shall have, hold and enjoy, in addition to the powers now vested in the borough of Pittsburg, which are hereby transferred to and vested in the said councils, all the powers and authorities now vested by law in the select and common councils of the city of Philadelphia.