That an annual appropriation of fifteen hundred dollars shall be made for the purpose of defraying the expenses of surveying and locating said boundary lines, and for the repairing, resetting and renewing of the monuments that mark the same, which appropriation shall be disbursed, or so much thereof as may be necessary to make effectual the provision of this section, under the supervision of the secretary of internal affairs, who shall in all cases require the presentation of properly verified vouchers and shall cause the same to be filed in the office of the auditor general: Provided, That the said annual appropriation of fifteen hundred dollars shall cease and terminate on the first day of June, 1891.