Effect of existing agreements between landholder and tenants.

All engagements entered into between the landholder and his tenants, except such as are hereinafter mentioned, shall be binding upon the Collector, during attachment, but all such engagements made collusively with a view to defeat or delay the effect of the attachment, and all leases of land at a rate lower than the usual rates of assessment, and not made bona fide for the purpose of erecting factories or buildings, or of bringing waste land into cultivation, and all engagements made subsequently to attachment, shall be null and void against the Collector, if he shall so declare: subject, however, to the right of the parties to such agreement, to bring a suit against the Collector in the ordinary tribunals to establish the same; and all charges or incumbrances upon such land shall be postponed to the payment of the public revenue.