Payments to the permanent school fund upon contracts, or loans of another nature, shall be made to the treasurer of the county upon a certificate from the auditor showing the amount due. [R60, §1986; C73, §1867; C97, §2853; C24, 27, 31, 35, 39, § 4496; C46, 50, 54, 58, 62, 66, 71, 73, 75, 77, 79, 81, §302.29 ] 83 Acts, ch 185, §20, 62 C93, §257B.29