the county clerk of said county, petitioning the board of supervisors thereof to submit any proposed amendment or amendments to the charter of such county, which amendment or amendments shall be set forth in full in such petition, to the qualified electors thereof, such petition shall forthwith be examined and certified by the county clerk, and if signed by the requisite number of qualified electors of such county, shall be presented to the said board of supervisors, by the said county clerk, as hereinbefore provided for petitions for the election of boards of freeholders. Upon the presentation of said petition to said board of supervisors, said board must submit the amendment or amendments set forth therein to the qualified electors of said county at a general or special election held not less than thirty days nor more than sixty days after the publication or posting of such proposed amendment or amendments in the same manner as hereinbefore provided in the case of the submission of any proposed amendment or amendments to such charter, proposed and submitted by the board of supervisors. In submitting any such charter, or amendments thereto, any alternative article or proposition may be presented for the choice of the electors, and may be voted on separately without prejudice to others. Every special election held under the provisions of this section, for the election of boards of freeholders or for the submission of proposed charters, or any amendment or amendments thereto, shall be called by the board of supervisors, by ordinance, which shall specify the purpose and time of such election and shall establish the election precincts and designate the polling places therein, and the names of the election officers for each such precinct. Such ordinance, prior to such election, shall be published five times in a daily newspaper, or twice in a weekly newspaper, if there be no such daily newspaper, printed, published and circulated in said county; _provided_, that if no such daily or weekly newspaper be printed or published in such county, then a copy of such ordinances shall be posted by the county clerk in three public places in such county and in or near the entrance to at least one public schoolhouse in each school district therein. In all other respects, every such election shall be held and conducted, the returns thereof canvassed and the result thereof declared by the board of supervisors in the same manner as provided by law for general elections. Whenever boards of freeholders shall be elected, or any such proposed charter, or amendment or amendments thereto, submitted, at a general election, the general laws applicable to the election of county officers and the submission of propositions to the vote of electors, shall be followed in so far as the same may be applicable thereto.