All lands and all estates or interests in lands, within the state of Washington, which were conveyed or attempted to be conveyed to, or acquired or attempted to be acquired by, any alien or aliens, prior to the date of the adoption of this act, are hereby confirmed to the respective persons at present owning or claiming to own the title thereto derived by, through or under any such alien ownership or attempted ownership, to the extent that title was vested in or conveyed by said alien or aliens: PROVIDED, That nothing in this section shall be construed to affect, adversely or otherwise, any title to any such lands, or to any interest or estate therein, held or claimed by any private person or corporation adversely to the title hereby confirmed.