The board of county commissioners is authorized to sell any unused town lots or parcels of ground not needed for courthouse or jail purposes of any county to the highest bidder for cash, in the manner hereinafter provided. Before any such sale shall be made the board of county commissioners, in regular or special session, shall adopt a resolution declaring that said real estate is not needed for courthouse or jail purposes of the county; said resolution to be published with other proceedings of said board and a copy of said resolution shall be certified by the county clerk to the judge of the district court of such county, and said judge shall appoint three disinterested freeholders of said county to appraise said real estate, said appraisement to be returned by said appraisers to the board of county commissioners.