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