economic change that occurred. The simple statement of

income or wealth figures, no matter how couched with

qualifications, cannot serve to reflect adequately the

scope of economic "progress."35

 Nor can the increased importance of metals to

the economy be discerned easily from figures showing

increased rates of metals production and consumption.

The effects of increased metals use were pervasive; every

conceivable productive process, whether concerned with

manufacturing, agriculture, transportation, communications,

or services, was affected by the application of power

and machinery. In turn, mechanization and mass pro-

duction generated an increased dependence upon metals

and an increased metals demand, and while economic

progress in terms of quality was astonishing, changes in

quantity were astonishing as well.

 Mechanization virtually revolutionized the

agricultural industry.37 Output per worker increased


 35Changing volume of production as shown by
employment, income, and physical output figures is shown
in Appendix A.
 36
 6Figures for copper, iron, and steel production
are included in Appendix B, as are figures showing
apparent consumption of those metals.
 37
 7Whether the change was revolutionary or
evolutionary is a matter of definition. But agricultural
production and productivity increased very rapidly between
1860 and 1880; thereafter the rate of growth declined until
1940, after which a new revolution in the way of fertilizers,
insecticides, hybrid seeds took place. Cf. Wayne D.
Rasmussen, "The Impact of Technological Change on American
Agriculture, 1862-1962," Journal of Economic History, XXII
(December, 1962), 578-91.