The provisions of this act shall apply only to counties having a population of 900,000 and upwards and those counties that now have county abstract books and are operating abstract offices: Provided, That upon the petition of not less than 8 per centum of the electors of any county not coming within the provisions of this act according to the vote cast for secretary of state in said county at the last general election presented to the board of supervisors of such county at any regular or special meeting of said board, it shall be the duty of said board to submit to the electors of said county the proposal for said county to own and operate an abstract office and the books, indexes, etc., necessary for the conducting of such abstract office, at the next general election or at a special election called for that purpose: And provided further, That any county in which such proposition shall have been so submitted it shall require a majority vote of the ballots cast on such proposition favoring such proposition before the same shall be adopted: Provided further, That the board of supervisors of any county having a population less than 900,000 may establish and provide for a tract index in said county by a majority vote of the board of supervisors, and no petition signed by electors shall be required to be filed with the board of supervisors to authorize the establishment and maintenance of such tract indexes. All acts or parts of acts whether local or general in conflict with the provisions of this act are hereby repealed.