A proposed simplification of the Parr unit coal formula Illinois State Geological Survey creator Thiessen, Gilbert 1905- Cady, Gilbert H. (Gilbert Haven) 1882- Rees, Orin Wainwright 1898- Reed, Frank Hynes 1890- text ilu Urbana, Illinois Printed by authority of the state of Illinois 1934 monographic eng

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99 p. illus. 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. At head of title: State of Illinois. Department of Registration and Education. Division of the State Geological Survey. Coal Analysis Coal Illinois TP325 .I63 1934 Illinois State Geological Survey. gs 35000001 DLC 790607 20260227111339.0 gs 35000001