Purchasers at certain sales and persons claiming through owner bound by instrument executed by owner.

Every person who purchases at a sale, for arrears of land revenue or any other public demand, any land on which is situated a monument, in respect of which an instrument has been executed by the owner for the time being under section 5 or section 6, and every person claiming any right, title or interest to or in a monument from, through or under an owner who executed any such instrument, shall be bound by such instrument.