The county treasurer is authorized to sell such notes upon the order and under the direction of the county commission and shall cause notice to be published in first class counties for ten days in at least two daily papers of general circulation published in the county, or in third and fourth class counties for two weeks in two weekly papers of general circulation published in the county; that sealed proposals for the purchase of all or any part of said notes will be received at his office, and that the same will be opened by him in the presence of the county commission on the day and hour mentioned in the notice. Said treasurer shall, under the direction of the commission, reject any or all bids that the commission may not deem satisfactory as to price or otherwise, and in case of rejection, he may again advertise and sell said notes in the same manner. Or, if the commission so order, the county treasurer may sell the said notes or any part thereof at not less than their face value, at private sale without advertisement, and report the same to the commission at the next term thereafter.