100 
POLITICAL ECONOMY 
is that material curtailment of output is less 
to be apprehended in industries functioning 
under increasing returns than in those func 
tioning under decreasing returns, because 
in the former the smaller supply while it 
resulted in higher price would result also in 
the loss of the economies previously reaped 
from producing on a large scale. Yet another 
generalisation may be laid down, namely, 
that if monopolisation is to bring about a 
lower price it is most likely to do so (1) in 
industries in which much of the supply price 
under competition is made up of the expenses 
of securing as customers for particular firms 
persons who, in any event, would buy the 
commodity, and (2) in industries in which 
monopolisation lowers the cost of producing 
proper. 
We pass next to the cases in which dis 
criminative prices, or differential prices, as 
they are sometimes called, are possible. 
It may be said at once that discriminative 
charges cannot be imposed where competition 
is untrammelled, because the existence of these 
charges implies at least some agreement 
among producers. Differential charges are 
of three kinds, namely, persona], trade, and 
local.