CHAPTER VII

 SUMMARY AND CONCLUSIONS


 In the preceding pages we have attempted to

 analyze the changing relationship between increased levels

 of production and increased needs for copper and iron

 within the United States during the past hundred years.

 During that time, both the volume and the nature of

 production changed so as to place increased reliance

 upon these metals, and while the nature of the relation-

 ship was not direct, the consequences of the changes,

 both in terms of general production and the exhaustion

 of domestic metal deposits was definite. Acquisition

 of large quantities of iron and copper was essential to

 new products and production methods after 1860, and

 economic growth since 1860 generated an increased need

 for iron and copper for use in machines and structures.

 Adequate supplies of these metals could be taken from

 an initially large domestic stock, but as the stock of

 metals in use increased, the known stock of metals in

 the ground diminished.

 In the United States of 1860, both goods

produced and the means of production relied primarily

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