In section 2 the definition of "base date" is added. A date base in relation to valuation roll for a district means the date when the revision of valuation roll for that district comes into force. Section 12 is amended so as to empower the Minister responsible for lands to appoint various base dates for purposes of enabling the Chief Valuer to revise valuation rolls as provided for in section 13. Section 18 is amended so as to provide for certificates, which shall be obtained prior to transactio