FOREWORD. 
Mineral resources are coming more and more into prominence as 
the basis upon which modern advance is built. Their adequate 
development is a matter of the first importance, and public opinion 
will be called upon in increasing measure to shape the course of 
advance in this fundamental field. As the general subject is not 
one of popular experience, this series of papers is under preparation 
for the purpose of interpreting in nontechnical language the signifi- 
cant aspects of each resource of mineral origin, in anticipation of a 
growing demand for concise summations of technical knowledge in 
a form adapted to current use. 
The sources of energy underlie the employment of all raw material, 
and this paper on coal, together with those to follow on water-power 
and oil, aim to present a constructive analysis of the fuel situation 
in the United States. 
