TO DISCOVER A STABLE STANDARD 18% 
With the franc, on the contrary, the only method of 
determining its value is by comparison with the objects 
which are valued by it, or with the mass of such objects, 
by ascertaining average prices. And if this average varies 
from one period to another, there is nothing to prove 2 
priori that such variations are attributable to causes in- 
herent in the commodities. A change in the ratio between 
the factor commodity and the factor money may be attri- 
butable to the latter. 
Nevertheless it is still true that money as a standard of 
values enables variations in the exchange ratio between it 
and commodities as between one period and another to be 
measured, even if it has caused them, and to this extent it 
may be said to be an accurate standard of values. And so 
the difficulty arises not so much from its inadequacy as an in- 
strument of measure as from a general tendency to consider a 
priori that a sum cf money at a given period must be equivalent 
to the same sum of money at another period, and to make con- 
tracts on this basis without taking into consideration those very 
indications which are given by money itself as a standard of 
values showirg how such calculations ought to be corrected. 
This habit is no doubt due to the fact that usually price 
changes are slow and small over any period which affects a 
contract. It is probably also due to the fact that such 
variations in the average exchange ratio between the mone- 
tary unit and commodities over a given period have only 
recently been registered, and that the method of registra- 
tion is still somewhat imperfect. As money is used, not 
only as an instrument of exchange and as a common 
measure of value, but also in some sort as an “accumu- 
lator” of values, it is evidently convenient, in carrying out 
transactions in successive stages over a period of time, to 
agree that a given sum of money shall always retain the 
same purchasing power. This can be done in normal 
times without any serious inconvenience ; but it becomes 
quite impossible when exceptional events such as a general 
fall in production, excessive note issues or exchange crises 
make the purchasing power of money exceedingly variable. 
liable owing to the fact that the substance of which it is made does not 
entirely escape the effect of variations in temperature,