An additional executive department in the government of cities of the second class may be created by ordinance to the known as the Department of City Development, which shall be in charge of a City Development Commission, consisting of five (5) residents of the city, to be appointed by the mayor, subject to the approval of council, one of whom shall be designated to serve from his appointment until January first, one thousand nine hundred and twenty-eight; one from his appointment until January first, one thousand nine hundred and twenty-nine; one from his appointment until January first, one thousand nine hundred and thirty; one from his appointment until January first, one thousand nine hundred and thirty-one, and one from his appointment until January first, one thousand nine hundred and thirty-two.

Their respective successors shall be appointed on the expiration of their respective terms, to serve for five years.

An appointment to fill a casual vacancy shall be only for the unexpired portion of the term.

Three of the members shall be a quorum. They may make regulations for their own organization and procedure, consistent with the laws of this Commonwealth and the ordinances of the city. They shall serve without compensation and make, annually, to the mayor a report of their transactions and recommendations. They may employ such persons and employés as may be necessary, whose salary, together with the necessary expense of the commission, shall be provided for, in the discretion of council, by the proper appropriations and ordinances.