120 
POLITICAL ECONOMY 
express indirectly the cost of production of 
rides when rapidity of circulation is taken into 
account. Just as the price of a cab is deter 
mined by such influences, so is the price of a 
piece of money. If the money commodity be 
gold and the unit be an ounce, the demand for 
ounces of gold in relation to the marginal cost 
of production per ounce of different quantities 
of gold settles the value of gold money ; but 
this demand and supply, so long as we confine 
our attention to the monetary uses of gold, 
is derived from the demand for exchanging 
power on the one hand, and the supply of 
exchanging power associated with different 
amounts of gold money on the other hand. 
Next, we must take into account the fact 
that gold is not demanded merely for money 
but also for uses in the arts. The recognition 
of this fact brings with it few complexities. 
It simply involves noting that the demand 
for gold is a composite demand, and that to 
get the complete demand we must add to the 
demand for gold as money the demand for 
gold in the arts. Gold is by no means peculiar 
in being the object of a composite demand. 
Probably most demands are composite. Wood, 
for example, is demanded for buildings, 
furniture, boats, and numerous other things ; 
and the demand for wood is made up of the