zinc, lead and phosphates are produced in the United States in large
quantities. Indeed, we have ample supplies of practically all of the
minerals of importance to industry, except platinum, tin, and nickel.

58. AGRICULTURE.--Until very recently, at least, agriculture has been
by far our most important industry. Of the two billion acres
comprising continental United States, approximately half are under
cultivation. In most sections of the country the quality of the soil
is good, and rainfall is ample. We have long led the world in the
value of farm crops grown. Our production of wheat, corn, oats,
barley, rye, and dairy products totals an enormous figure. The steady
enclosure of lands formerly used for grazing stock is restricting our
production of food animals, but we are still important as a producer
of meats. Most of the world's tobacco is grown in this country. The
world's supply of cotton is derived mainly from southern United
States. Finally, our soil is of such variety, and our climate so
diversified, that the danger of a general crop failure is slight. A
loss in one part of the country is almost certain to be offset by good
crops in another.

59. MANUFACTURING.--In colonial times American manufactures were
subjected to more or less restraint by Great Britain, but after the
Revolution these industries entered upon a period of free and rapid
development. Modern machinery was introduced rapidly after 1800, large
scale production was developed, transportation was fostered, and
larger and larger markets were supplied with the products of American
manufacturers. Particularly since the Civil War has the importance of
our manufactures increased. This increase has been due chiefly to the
large scale production of foodstuffs, including meats and flour;
textiles; iron and steel products; shoes; chemicals; and agricultural