RESOURCES FOR THE FUTURE, INC. 



1755 Massachusetts Avenue, N.W., Washington, D.C. 20036 



Board of Directors: 



William S. Paley, Chairman, Robert O. Anderson, Harrison Brown, 



Erwin D. Canham, Edward J. Cleary, Joseph L. Fisher, Luther H. Foster, 



Charles J. Hitch, Hugh L. Keenleyside, Edward S. Mason, Frank Pace, Jr., 



Laurance S. Rockefeller, Stanley H. Ruttenberg, Lauren K. Soth, 



John W. Vanderwilt, P. F. Watzek. 



Honorary Directors: Horace M. Albright, Reuben G. Gustavson, 



Otto H. Liebers, Leslie A. Miller. 



President: Joseph L. Fisher 



Vice President: Michael F. Brewer 



Secretary-Treasurer: John E. Herbert 



Resources for the Future is a non-profit corporation for research and 

 education in the development, conservation, and use of natural resources. 

 It was established in 1952 with the cooperation of the Ford Foundation and 

 its activities since then have been financed by grants from that Foundation. 

 Part of the work of Resources for the Future is carried out by its resident 

 staff, part supported by grants to universities and other non-profit 

 organizations. Unless otherwise stated, interpretations and conclusions in 

 RFF publications are those of the authors; the organization takes responsibility 

 for the selection of significant subjects for study, the competence of the 

 researchers, and their freedom of inquiry. 



Director of RFF publications, Henry Jarrett; editor. Vera W. Dodds; 

 associate editor, Nora E. Roots. 



Copyright © 1958 by The Johns Hopkins Press, Baltimore, Maryland 21218 



All rights reserved 



Manufactured in the United States of America 



Originally published, 1958 

 Second printing, 1961 

 Third printing, 1966 

 Fourth printing, 1968 



