SEMAINE D'ÉTUDE SUR LE ROLE DE L'ANALYSE ECONOMETRIQUE ETC. 501 
We might say that there is also another stock in the system, 
at the beginning of the period we are considering, namely po- 
pulation. This stock, however, for economic purposes, is not 
relevant as such, i.e. as a stock (except in a slave society, 
which is outside our interests). Its economic relevance is con- 
nected only with the flows it calls into being. 
Let us come, therefore, to consider these flows. As in the 
previous case, all the members of the community are grouped in 
a final sector #. This final sector provides the labour services 
to all productive processes and owns the stocks of capital. 
Moreover, it exerts the demand for all the final goods, which 
are now of two types — consumption goods and investment 
goods. 
The flows of consumption goods, as before, come from 
‘n — 1) consumption goods sectors. In addition to these, we 
have now a whole series of flows of investment goods, which 
will be denoted with the suffix k. As a first step to the more 
general formulation of section 7, we shall assume that capital 
is required only for the production of consumption goods, while 
capital goods can be produced exclusively from labour. Since 
the unit of measure of capital is different for each consumption 
good sector, the process for the production of capital goods 
must itself be expanded into (# - 1) sectors. Our system the- 
reby acquires (z - 1) new variables: Xp,o Xi,» oor Xi,» cach 
of which represents the production of capital for the correspond- 
ing consumption goods sector. This production of capital goods 
s devoted partly to new investment (expressed by demand 
coefficients in the final sector: a, ; ns Ayn, @ ,) and partly 
‘0 replacement of worn-out capacity (expressed by replacement 
coefficients : Ak,1> 4,2 +++» @p,_,n-1)- Hence the whole struc- 
cure of physical flows can be represented by the following 
system of equations, which takes the place of (II): 
10] Pasinetti - pag. 21