The increased consumption of copper is perfectly explained by our knowledge that the last decade has been a period of great electrification and of great expansion in the use of the telephone. Moreover, the automobile manufacturing industry has become a great consumer of copper, about 15 per cent of the consumption in 1922 having been for that purpose. The increased consumption of zinc is explained partially in the same way, for zinc as a constituent of brass is used extensively in connection with copper. However, the use of zinc has not increased in the same ratio as copper owing to diminished consumption of it for the coating of iron and steel, which is building material.
The increased consumption of lead per person is also explained by the electrical and automobile industries, two of the major uses for lead being as casing for electrical cables and the manufacture of electrical storage batteries. Of the latter about five-eighths are now for automobile operation. If we should segregate these uses of lead we should probably find a diminished consumption per person for all other purposes. The consumption of lead for pigment is a complicated study owing to the varying substitution of other pigments, such as those of zinc and barium.
The building materials, including the metals, are used mainly for the production of capital goods or producers’ goods, in brief for goods other than for immediate consumption. To a certain extent some of them are very closely associated with consumers’ goods. Thus, nobody eats, burns or wears iron, but about 5 per cent of the production of steel in 1922 was used for food containers and in the main was consumed in fulfilling that purpose. However, such uses of the
