In cases where an actual settler may heretofore have purchased the right of a warrantee to a tract of land, north and west of the rivers Ohio and Allegheny, and Conewango creek, whereon he may have made an actual settlement agreeably to the act of April 3, 1792,¹ and where such settler shall apply to the land-office² to patent the same, it shall be the duty of the secretary of the land-office to grant such patent on the usual proof of settlement being made, and a regular chain of title being produced from such warrantee and the arrears of purchase money, (if any there be,) and the usual office fees being first paid: Provided, That nothing contained in the foregoing shall be construed to prevent the commonwealth at any time hereafter from asserting her right in cases of forfeiture under the act of April 3, 1792, where the warrant holders and actual settlers shall fail to embrace the provisions of this act.