728 PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 28 nifies that the value of the services rendered by capital goods is the total of the amortization of all capital goods and the interest on their global value. Thus, in the present theory, the value of a privately owned and used motor car is not counted in income Rec at the mo- ment of sale to its owner. This value appears in the form of income only in the form of the services rendered by the car over time. The definitions usually adopted, by contrast, include the value of an automobile in R’; at the moment of sale. There is no difficulty in specifying the correction to be made to Rc to derive Rg, at least as a first approximation. The adjustment consists of subtracting investment in con- sumer durables Ic from consumed income R”c as it is normally calculated, and adding back the amortisation of consumer durables Ac and the interest {Cy chargeable against the capital represented by existing consumer durables Co (1). Thus Re=R"- Ic + Ac +ICo , Now, from the definition of amortization d Ce Ac=le- =1lc- Pc Ce !) Relation (116-2) above. 11] Allais - pag. 32