152 
POLITICAL ECONOMY 
trade cannot be opened between any two 
countries unless there is a difference between 
the comparative values of transportable 
things in each of them. I speak of com 
parative values instead of comparative costs 
so as to include the trade in things which are 
not, or cannot be, produced in one or more 
of the trading countries. By comparative 
values is meant the ratios of values in the 
two countries. Let us suppose there are two 
countries only and two commodities only, 
and for the sake of simplicity of exposition let 
us assume that both countries use the same 
kind of money, and that there is no cost of 
carriage. Then, if the countries are England 
and Germany, and the commodities are timber 
and steel, and these commodities fetch res 
pectively 20s. a ton and 40s. a ton in England, 
and 25s. a ton and 50s. a ton in Germany, a 
permanent trade cannot arise because in both 
countries steel is just twice as expensive as 
timber. Trade of a kind would appear in which 
England would export both steel and timber 
and import money, but this trade would 
come to an end as soon as the level of prices 
was the same in both countries, timber and 
steel realising respectively in both England 
and Germany, 22s. and 44s., let us suppose. 
Of course as money left Germany for England