Such bonds shall be issued in denominations of one hundred dollars or some multiple thereof, shall be payable to bearer, not later than twenty years from their date, shall bear interest from their date at a rate not exceeding four percent per annum, payable annually or semiannually, such interest payments to be evidenced by annexed coupons, and said bonds shall not be sold for less than ninety-five percent of the face value thereof. Such bonds shall specify the depositary or place where interest and principal payments will be made and shall be signed by the presiding justice of the county commission and attested by the signature of the clerk of the county commission with the seal of his office affixed thereto. The interest coupons may be executed by affixing thereon the facsimile signature of said clerk.