COMPARATIVE ADVANTAGE AND PROTECTION 189

without effect, in others was followed by great industrial development.
 The explanation of the differences is again to be found in
the fact that the combination and interplay of human and physical
causes, while serving to bring about in some directions a comparative
 advantage in the United States, yet proved by no means
equally effective in each and every phase of the industry.
In two quite different parts of the iron and steel manufacture
American producers have shown themselves able to produce
cheaply, to command the home market, to export. These are on
the one hand the heavy industry — crude iron and steel, beams,
plates, rails, structural material; and, on the other hand, the
making of tools and machines.
In the heavy industry, the richness of the natural resources
explains much. The extraordinary coal deposits of the Pittsburgh
region, and the no less extraordinary deposits of iron ore on Lake
Superior, were the foundations for a burst of development unprecedented
 in history. But there was much more than this physical
advantage. The coal and the ore were a thousand miles apart, and
gave opportunity for long distance transportation — a species
of industry in which, as I have already remarked, the Americans
have achieved unique successes. It is not to be doubted that
here, as in other achievements of transportation, a contributing
factor has been the existence over the entire continent of absolute
and permanent free trade. But still other human elements
counted. Large-scale operations, mass production, elaborate plant,
labor-saving devices thru standardization of products and of
processes — these have been characteristic of American engineering
 and management. With these, partly as cause and partly
as effect, have come the great industrial combinations, both
vertical and horizontal, until the industrial unit in the iron trade
has exceeded the wildest dreams of the preceding century. The
familiar story need not be again rehearsed. Nothing brings into
sharper relief the plain fact that here American industry has
triumphed ; and this not merely because of the bounty of nature,
but in large part because of the peculiarly effective application
of man’s faculties.