Before the corporation disposes of any superfluous lands, it shall, unless the lands are situated within a town, or are lands built upon, or used for building purposes, first offer to sell the same to the person then entitled to the lands (if any) from which the same were originally severed; or if the person refuses to purchase the same, or cannot, after diligent inquiry, be found, then the like offer shall be made to the person, or to the several persons whose lands immediately adjoin the lands so proposed to be sold, such persons being capable of entering into a contract for the purchase of the lands; and when more than one person is entitled to the right of preemption, the offer shall be made to these persons in succession, one after another, in such order as the corporation shall think fit.