Upon a petition in writing, signed by twenty-five percent (25%) of the qualified electors of the county, such percent to be determined by the total vote cast in such county for the head of the state ticket in the next preceding general election, said petitions being verified by an affidavit, showing that the petitioners are qualified electors of said county, and such petitions being filed with the Governor, the Governor shall, within thirty (30) days, issue his proclamation calling an election to be held in such county not less than sixty (60) nor more than seventy (70) days from the date of his proclamation.
R.L. 1910, § 1518.