SEMAINE D ETUDE SUR LE ROLE DE L ANALYSE ECONOMETRIOUE ETC. 
sented by a convergent Taylor series for any value of 8. It is 
worth remarking that in most of the cases which can reasonatly 
be envisaged, the coefficient ¢ remains relatively small, where 
apon the properties of the model are quite similar to those of 
‘he exponential model. 
Amortization of Primary 
Tncor 
333. The relationship between the amortisation function ¢ (6, 
and the usually accepted notion of amortisation raises a number 
of problems to which allusion has already been made (!). It is 
of interest to examine these problems in the light of the results 
which have been obtained. 
1) In the first place, the usual definition considers invest- 
ment as occurring when an already completed investment good 
begins its productive career. By contrast, the act of invest- 
ment is considered in this paper as taking place when the 
primary inputs are furnished. A distinction must therefore be 
made between the amortisation of primary income and the 
amortisation of investment. It further follows that under the 
usual definition, amortisation contains an element of interest as 
well as the depreciation of primary inputs, whereas in the 
present paper, amortisation relates only to the primary input 
content of the investment. 
2) A part of the primary income invested at a given 
instant ¢ emerges in the global producion P* of consumption 
and investment goods at instant (£40). The primary inputs 
which correspond to the latter are thus reintroduced into the 
Allais - pag. 15