On the distinction between ground rent and the rental value of the land plus building (improvements), professional valuation officers and estate agents currently examine both the physical state of a property and its location, taking account of market prices for similar or comparable properties. Where a parcel of land is currently vacant they can likewise infer its market value, both from the prices of similarly located vacant sites and by comparing the whole value of similar houses in different locations. As they say in Spanish: "Quien puede mas puede menos": he who can do more can do less. A valuation officer can (and does) calculate the site value more easily than the value of the building. Adjacent buildings are often much more heterogeneous than the value of adjacent land. Hence cadastral (land) valuations could be done more frequently and less expensively if site values alone were required for purposes of revenue-raising -- and with far fewer disincentive effects than with taxes on improvements. And as Adam Smith (Bk.I, ch.VI) also wrote: "As soon as the land of any country has all become private property, the landlords, like all other men, love to reap where they never sowed." Roger Sandilands