But if it shall appear that the petition has been so signed, the court or judge shall so find, and shall certify such fact to the board of county commissioners of the county or counties in which such district is situated, and said commissioners shall call an election for the election of commissioners of the said drainage district which said call for election shall be in the same form as proclamations for elections now provided by law, and such election shall be held within thirty days after the receipt of the certificate from the district court as provided for herein.