15. Each purchaser shall, within two years from the date of his purchase, bring into cultivation not lens than one-tenth of the land purchased by him. Each shall, within four year a from the date of hia pur chase, bring into cultivation not lesi than oue fifth of the land purchased by him, Each purchaser shall, within six years from the date of bis purchase, in addition to the cultivation of one-Sfth of the land, have put substantial improvements of a permanent character on the land to the value of £1 for every acre of such land. , ,.
