MINING INDUSTRIES 
R7 
one time this country, at another time that one, has special effec- 
tiveness, absolute or comparative, for copper, silver, tin, coal, iron. 
de facto situation appears in the matter of comparative costs and 
comparative advantages, and international trade is shaped accord- 
ingly. Whether the trade is likely to continue for a given country 
n the same lines in the future as in the past or present, we haveno 
eans even of guessing. In the case of agricultural products we 
ay expect, on grounds of general reasoning, that a change in 
emand or in supply will lead to certain permanent alterations in 
he positions and advantages of the several trading countries. But 
we can hardly apply such theorizing to the products of mines. We 
have simply to accept the situation as it happens to develop at the 
given time and place