Letters of attorney; recordation; effect as evidence

Every letter of attorney, or other instrument, containing a power to convey lands as agent or attorney for the owner of such lands, and every executory contract for the sale or purchase of lands, only when acknowledged by such owner, may be recorded by the county clerk of any county in which the lands to which such letter, instrument or contract relates, or any part of such lands, may be situated, and when so acknowledged, and the record thereof when recorded, or a transcript of such record duly certified, may be read in evidence in the same manner and with like effect as a conveyance recorded in such county.