The Secretary of the Interior is authorized to acquire, by purchase or otherwise, after July 1, 1932, an area of land not to exceed three thousand acres, at an average cost of not more than $10 per acre, with the improvements thereon, situated on the east and south of said preserve as described in section 674a of this title, within sections 10, 11, 12, 13, 14, 15, 22, 23, and 24, township 152 north, range 65 west, fifth principal meridian, said lands, upon acquisition by the United States, to become a part of the White Horse Hill National Game Preserve.