198 
POLITICAL ECONOMY 
what would be the payment for the marginal 
thing of the class (which, to distinguish it 
from “ differential rent,” can be called a 
“scarcity rent”). Of course, in a sense so- 
called scarcity rent is a payment for differential 
advantages, since persons who possess a rare 
thing enjoy differential advantages over those 
who have not got it and cannot get it. But 
in what follows, for the sake of convenience 
of terminology, I shall use “ differential 
advantage ” with the meaning intended 
when differential rent is distinguished from 
scarcity rent. 
At first, so as to limit the data to which 
attention must be given, we shall deal 
merely with the economic rent of land. 
We shall make a start with the simplest 
conditions conceivable. Let us imagine that 
the same amount of capital and labour is 
applied in cultivating any one acre of land 
in use in a country as any other. The 
fertility of a plot of ground has no influence 
over the degree of its cultivation, we premise ; 
and we assume, further, that the situation of 
a farm is a thing of no importance, and that 
consequently, in the matter of the choice 
of land, it is fertility alone that counts. 
Coming next to detail, let us suppose that the