The wealth which consists merely of a right or credit on the part of A. with a corresponding duty or debt on the part of B., is not considered by the political economist. He deals with the things which are the subjects of the right or of the credit, not with the claims or the liabilities which may affect them. In fact, the credit amounts merely to this, that B. has in his hands a part of the property of A. I have said that my definition of wealth differs from that which has been adopted by many of my predecessors. Some political economists extend the term to all the objects of human desire; others restrict it to what they have called material products; and others to the things which cannot be acquired or produced without labour. The objections to the first definition are obvious. If wealth be the subject of Political Economy, and wealth include all that man desires, Political Economy, whether a science or an art, is the science or the art which treats of human happiness--a subject, as I have already remarked, too extensive to be included in a single treatise. The second, that which confines wealth to material objects, is more plausible. It includes all visible wealth, it includes all wealth which is capable of direct and complete sale. The things which it excludes are mere objects of the intellect. They may be shared, but cannot be completely transferred, since the proprietor, though he may impart them, cannot divest himself of them; they may produce permanent effects, but perish themselves with the individual mind of which they are qualities. But as they obey, in other respects, the same laws as material wealth, are obtained by the same means, and owe their value to the same causes, I think their exclusion a fatal objection to a definition of wealth. The definition which confines wealth to the things which cannot be acquired or produced without labour, differs little from mine, which confines it to things limited in supply. Whatever must be obtained by labour is necessarily limited in supply, the supply of labour itself being limited; and, on the other hand, there are, in fact, scarcely any, if there be any, commodities limited in supply and capable of transfer, which can be obtained without some labour. So that wealth is always found subject to both these incidents. Nor does value appear to depend on either incident exclusively. A quarter of corn from the best, and one from the worst land, of equal goodness, sell in the same market at the same price, though one may have cost three times as much labour as the other. The pictures of Hans Hemling are far more limited in supply than those of Raffaelle, and yet they sell for much less.