8. From and after the service of notice of any certificate under section 7 upon a certificate-debtor,- (a) any private transfer or delivery of any of his immovable property situated in the district in which the certificate is filed, or of any interest in any such property, shall be void against any claim enforceable in execution of the certificate; and (b) the amount due from time to time in respect of the certificate shall be a charge upon the immovable property of the certificate-debtor, wherever situated, to which every other charge created subsequently to the service of the said notice shall be postponed.