atients are in trouble. The use of adequate
geologic advice in the planning stages is about as little advanced in
some localities as the practice of preventive medicine.

The work of the economic geologist may not be ended by the finding and
development of the ore; for the moment this is accomplished, he should
again consider the economic phases of the problem--the grade of his ore,
its probable amount, and other features, in relation to the general
economic setting. In his enthusiasm for physical results, he may be
carried into expenditures not justified by the economic factors in the
problem. Some one else may and usually does look out for the economic
elements, but the prudent geologist will at least see to it that someone
is on the job.

FOOTNOTES:

[37] Smith, George Otis, and others, The classification of the public
lands: _Bull. 537, U.S. Geol. Survey_, 1913.

[38] Schlumberger, C., _Study of underground electrical prospecting_:
Translated from the French by Sherwin F. Kelly, Paris, 1920.

Bergstrom, Gunnar, and Bergholm, Carl, "Teknisk Tidskrift, Kemi och
Bergvetenskap," 1918, Book 12.

[39] Hoover, Herbert C., _Principles of mining_: McGraw-Hill Book Co.,
New York, 1909, p. 32.

[40] Leith, C. K., Use of geology in iron ore exploration: _Econ.
Geol._, vol. 7, 1912, pp. 662-675.

[41] Van Hise, C. R., and Leith, C. K., Geology of the Lake Superior
region: _Mon. 52, U.S. Geol. Survey_, 1911.

CHAPTER XV

VALUATION AND TAXATION OF MINERAL RESOURCES

POPULAR CONCEPTION OF MINERAL VALUATION

The total returns from mining may not in the aggregate be far above the
expenditure for exploration, development, and extraction; yet the total
mineral wealth of the United States, on the basis of earning power and
aside from the industries based on it, cannot be far from sixty billions
of dollars, and this wealth has virtually come into existence since the
1849 gold rush to California. The mining industry supports a large
population. These facts are the solid basis for the widespread popular
interest in mineral investment--and mineral speculation. But there are
other reasons for this interest,--the gambler's chance for quick
returns, the "lure of gold," the possibility of "getting something for
nothing," the mushroom nature of certain branches of the industry, the
element of mystery related to nature's secrets, and the conception of
minerals as bonanzas with ready-made value, merely awaiting discovery
an