OUR MINERAL RESERVES. 
By George Otis Smith. 
INTRODUCTION. 
INVENTORY OE MINERAL RESOURCES. 
The United States is not only the world’s greatest producer of 
mineral wealth, but, so far as estimates of the earth’s treasures have 
shown, it possesses greater reserves of most of the essential min 
erals than any other nation. It is to our national mineral re 
sources that the United States Geological Survey has given special 
attention since its organization in 1879, for the congressional enact 
ment creating the Survey specified as its duties “ the classification 
of the public lands and examination of the geological structure, 
mineral resources, and products of the national domain.” 
Geologic investigations have been made with a view of determining 
the mode of occurrence and the extent of distribution not only of 
those minerals and rocks that possess present value, but also of those 
that have only possible future utility, the nature of which may be 
as yet neither known nor suspected. Thus a geologic map, in so 
far as its scale permits, is a graphic inventory both of the mineral 
resources now used and of those that are untouched because they 
are at present of no value. He is indeed a bold prophet, however, 
who pretends to forecast either the probability or improbability 
°f future usefulness of any raw material. As has been illustrated 
by the radium mineral carnotite, the minéralogie curiosity of one 
decade may become the valuable ore of the next. The principal ore 
of aluminum, bauxite, was not even mentioned in a list of useful 
minerals published by the Geological Survey 25 years ago. 
The Survey’s annual report entitled “Mineral Resources of the 
United States” contains not only statistical statements of production 
and consumption, which constitute an annual census of the mineral 
industry in all its phases, but also a series of comprehensive studies 
of the sources of mineral wealth, with estimates of the reserves to 
be drawn upon for future production. The very nature of many 
mineral resources precludes exact knowledge of the extent of their 
reserves, and the estimates of other reserves must be made roughly 
quantitative. At best, future supply and demand can be only ap 
proximately measured, but the recognition of this limitation has not 
discouraged the collection of all available information concerning 
the country’s mineral resources.