SEC. 7½. Any county may frame a charter for its own government consistent with and subject to the Constitution (or, having framed such a charter, may frame a new one), and relating to matters authorized by provisions of the Constitution, by causing a board of fifteen freeholders, who have been for at least five years qualified electors thereof to be elected by the qualified electors of said county at a general or special election. Said board of freeholders may be so elected in pursuance of an ordinance adopted by the vote of three fifths of all the members of the board of supervisors of such county, declaring that the public interest requires the election of such board for the purpose of preparing and proposing a charter for said county, or in pursuance of a petition of qualified electors of said county as hereinafter provided. Such petition, signed by fifteen per centum of the qualified electors of said county, computed upon the total number of votes cast therein for all candidates for Governor at the last preceding general election at which a Governor was elected, praying for the election of a board of fifteen freeholders to prepare and propose a charter for said county, may be filed in the office of the county clerk. It shall be the duty of said county clerk, within twenty days after the filing of said petition, to examine the same, and to ascertain from the record of the registration of electors of the county, whether said petition is signed by the requisite number of qualified electors. If required by said clerk, the board of supervisors shall authorize him to employ persons specially to assist him in the work of examining such petition, and shall provide for their compensation. Upon the completion of such examination, said clerk shall forthwith attach to said petition his certificate, properly dated, showing the result thereof, and if, by said certificate, it shall appear that said petition is signed by the requisite number of qualified electors, said clerk shall immediately present said petition to the board of supervisors, if it be in session, otherwise at its next regular meeting after the date of such certificate. Upon the adoption of such ordinance, or the presentation of such petition, said board of supervisors shall order the holding of a special election for the purpose of electing such board of freeholders, which said special election shall be held not less than twenty days nor more than sixty days after the adoption of the ordinance aforesaid or the presentation of said petition to said board of supervisors; _provided_, that if a general election shall occur in said county not less than twenty days nor more than sixty days after the adoption of the ordinance aforesaid, or such presentation of said petition to said board of supervisors, said board of freeholders may be elected at such general election. Candidates for election as members of said board of freeholders shall be nominated by petition, substantially in