That the auditor general is authorized to appoint, from time to time, as necessity may require, one or more expert accountants to examine the accounts of county officers, and of institutions receiving state aid in whole or in part. The compensation to be first fixed by the accounting officers of the commonwealth before any appointment shall be made, which compensation, with the necessary expenses incurred in the work, shall be paid by filing proper voucher on the warrants drawn by the auditor general on the state treasurer, and payable out of moneys in the state treasury not otherwise appropriated: Provided, however, That the payments for the services of the said expert accountants shall not exceed the sum of one thousand five hundred dollars in any one fiscal year.
72 P.S. § 4366