Section 14-19-105 - Payment of installments(a) When any installment shall become due to the contractor according to contract, the county court shall make an order that it be paid out of the county treasury.(b) No such order shall be made, except on the certificate of the commissioner of public buildings, that due proportion of the work has been completed and executed according to contract.Rev. Stat., ch. 36, §§ 16, 17; C. & M. Dig., §§ 1941, 1942; Pope's Dig., §§ 2463, 2464; A.S.A. 1947, §§ 17-913, 17-914.