330 PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 28 
oroduction process. Some portion of them will reappear at 
‘nstant (£46 +0’) in the global production of that instant. The 
primary inputs which correspond to the durable goods element 
of this production again enter the production circuit, and so on. 
There 1s therefore a close relationship between the amorti- 
sation schedule of primary income (08) and the amortisation 
schedule for durable goods from the time they emerge from 
‘he production process and are themselves put into operation 
to produce further new production of consumption goods. 
Clearly, of course, the amortisation schedule for primary in- 
come is not identical to the durable goods schedule. 
The supply of reproducible capital at a given moment is 
composed of three elements: 
a) Inventories (stocks and work in progress); 
b) Equipment (machines, lorries, motor cars, washing mach- 
ines, etc.); 
c) Structural assets (factories. houses. roads. etc.). 
No item of primary income arising at any given moment 
can emerge in subsequent consumption unless it has been 
Incorporated during the interval either in inventories (stocks 
and work in progress) or in equipment or structural invest- 
ment. There is thus a close relationship between the amorti- 
sation function of primary income ©(0) and the structure of 
eproducible capital. 
Finally, since inputs of labour constitute a part of primary 
Income there is also a close link between the amortisation func- 
lion of primary income ¢(8) and the composition of the labor 
force which corresponds at any given moment to the allocation 
of the amounts of labour available as between the different 
phases of the production process. In particular, as has been 
noted earlier, the invariance of the function (0) over time 
11] Allais - pag. 134