Contributions to the study of coal: A proposed simplification of the Parr unit coal formula,
Contributions to the study of coal: A proposed simplification of the Parr unit coal formula,
by Gilbert Thiessen. Ash-to-mineral matter correction in coal analyses, by Gilbert Thiessen. Unit coal as a basis of coal standardization as applied to Illinois coals, by G. H. Cady and O. W. Rees. Studies of the graphical method of calculating pure coal calorific value, by Gilbert Thiessen and Frank H. Reed.
- Urbana, Illinois, Printed by authority of the state of Illinois, 1934.
- 99 p. illus.
- Its Report of investigations no. 32 .
- Illinois State Geological Survey. Report of investigations no. 32. .
At head of title: State of Illinois. Department of Registration and Education. Division of the State Geological Survey.
gs 35000001
Coal--Analysis.
Coal--Illinois.
TP325 / .I63 1934
At head of title: State of Illinois. Department of Registration and Education. Division of the State Geological Survey.
gs 35000001
Coal--Analysis.
Coal--Illinois.
TP325 / .I63 1934