MONOPOLY 
101 
Local discrimination is practised when a 
thing is sold for one price in one locality, 
and another price in another locality. Inter 
national discriminations are common, and 
even intra-national discriminations are to be 
found. In the case of the latter the difference 
between the two prices cannot be more than 
the cost of carriage from the one place to 
the other if the thing can be transported 
after being sold ; as, for example, gas, 
electricity, and transportation itself cannot. 
In the case of international discriminations, 
however, where tariffs protect the home 
market, the difference between the two prices 
may amount to as much as cost of carriage 
and the import duty on re-entry. 
A trade discrimination means charging 
more for a thing when it is used for one 
purpose, that is in one trade, than when 
it is used for another purpose, that is in 
another trade. Generally trade discrimination 
is not feasible because of the difficulty of 
discovering to what use the purchaser intends 
putting the commodity ; but there remain 
some important instances in which differential 
charges of this kind are not only possible but 
have become the common rule. The best 
example is to be found in railway freight 
rates. The railways sell transportation and