388 ILLINOIS STATE ACADEMY OF SCIENCE 



by-products oven also makes available for utilization vast 

 quantities of by-products. 



I have tried in this small way to discuss a slight por- 

 tion of the most important resource which nature has 

 left us. It is ours to use, not to abuse; to consume, not 

 waste. Let us accept it as our treasure, use it as our 

 friend and ally, and in turn pass it on to those who are to 

 follow us with as little impairment as possible. 



REFERENCES. 



1. Shaw, E. W., and Savage, T. E., U. S. G. S. Folio, No. 185, p. 7. 



2. DeWolf, F. W., 111. State Geol. Survey, Bui. No. 14. Yearbook 1908, 



p. 189. 



3. Lesher, C. E., U. S. G. S. Mineral Resources of the United States, 



1918, Part 2, Nonmetals p. 748. 



DeWolf, F. W., 111. State Geol. Survey, Bui. 33, 1916, pp. 38, 39. 



4. Lesher, C. E., U, S. G. S. Mineral Resources of the United States, 



1918, Part 2, Nonmetals, p. 708. 



5. Ibid. pp. 747, 748. 



6. Ovitz, F. K., Dept. of Interior, Bui. 138, "Coking of Illinois Coals," 



p. 21. 



7. Ibid, p. 38. 



