Purchascrs at c€rtain sales and persons claiming through owner bound by iDstrumetrt executed by owner

Every person who purchases, at a sale for arrears of land reveunc or any other public demand, any land on which is situated a ,monument in respect ol which any instrument has been executed by the owner for the time bcing under section 4 or section 5, and every person claiming any title to a monument from, through or under an owner who executed any such instrumetrt shall be bound by such instrument.