The commissioners of each county of the fourth class are hereby authorized and empowered to employ competent persons, resident freeholders of the county, who shall assist the county commissioners of such counties in the adjustment and revision of assessments; and are further authorized and empowered to employ such clerical and other assistance as may be necessary to enable the commissioners to function properly in their capacity as a board of revision of the assessments and valuations arrived at by such assessments.
The salary of such employees shall be fixed by the salary board in the respective counties, and shall be paid out of the funds of the county in the usual manner.
72 P.S. § 5020-506