Section 2. And be it further enacted by the authority aforesaid, That it shall be the duty of all holders of unseated lands to file his, her or their title or claim with the commissioners of the proper county, within one year from and after the passing of this act, or within one year after he, she or they shall become possessed of the title or claim to such lands, and, on failure thereof, it shall be the duty of the county commissioners whenever such lands shall come to their knowledge, to assess on said lands four times the amount of tax that such lands would have been liable to had they not been secreted, and to enforce the collection thereof in the same manner that taxes due on unseated lands are or may be assessed and collected: Provided always, That nothing in this act contained shall be construed as giving any greater validity to unexecuted land-warrants than they are now entitled to, nor to the detriment of persons under legal disabilities: Provided, Such person or persons comply with the foregoing requisitions within the time or times limited respectively after such disabilty shall be removed.