The officers appointed to hold elections in Dallas County shall each be entitled to twenty-five dollars ($25) and the returning officer, in addition, to fifteen cents ($0.15) a mile in going to the courthouse and returning to the place of holding the election. The several claims shall be paid as preferred claims, out of moneys in the county treasury not otherwise appropriated, on proper proof of service rendered. The county shall be reimbursed for the amount provided under the general law of the state.