The commissioner of the state land office shall, by the direction of the state board of agriculture, sell said lands in quantities of not less than any legal subdivision, according to the original United States survey; and on such sale being made, the commissioner of the state land office shall issue his certificate of sale in the usual form, setting forth the quantity and description of the land sold, the price per acre, the amount paid at the time of purchase, the balance due, with the annual rate of interest, and the time the interest is payable, as is required by law for the payment of interest on contracts for the purchase of primary school lands, and that the purchaser will be entitled to a patent from this state on payment in full of the principal and interest, together with all taxes assessed on such land.