with which I am especially familiar. One of the most important and most profitable branches of metal mining is copper mining. I have given figures showing its magnitude in the United States. The bulk of the great production in 1916 and subsequent years was derived from mines that would not have existed as producing and profitable enterprises at all had it not been for improvements in the arts of mining and metallurgy effected within the previous 10 years.
As recently as 1906 so astute and distinguished an authority as J. R. Finlay viewed the Anaconda mines as decadent owing to the impoverishment of their ores, yet since then we have seen them ascend to greater production and profit than ever before. This was due distinctly and entirely to the most brilliant exhibition of mind that has been witnessed in any industry in modern times.
In 1906 the vast deposits of copper ore that are now the source of a major part of the American production, classed generically as the “porphyry” mines, were useless to anybody. They had been known for decades, they were practically free to acquisition by anybody, but their copper contents were too small to be profitably extractable. Some engineers who were then poor men conceived their exploitation by new methods. In order to carry them out they had to tempt investors to supply fabulous sums of money, as much as $10,000,000 for the equipment of a single mine. These investors had to wait years for any return, during which it was uncertain whether they might not lose all the money they had risked, for they were adventuring in an untried field.
These great increases in the national income were
