A FURTHER contribution to the study of the effect of storage on the properties of bituminous coals has been issued from the Engineering Experimental Station, University of Illinois (Bull. 97). Prof. S. W. Parr, who has been associated with Wheeler, Barker, and Kressman in a series of experiments started in 1910, summarises the conclusions arrived at, and records further investigations; more particularly of interest are those on the action of pyrites and the tests of weathered coals under boilers. The general conclusions that freshly mined coal has a large absorptive capacity for oxygen, the degree being dependent on the character of the coal; that the rate of absorption depends upon fineness of division and temperature; that such oxidation leads to slight increase of temperature, and if not radiated more rapidly than generated the action accelerates to a dangerous point (180° F. is named), have for some time been recognised as the main causes of spontaneous ignition. Parr concludes that the well-recognised loss of thermal value on storage is more apparent than real, being largely due to increase of weight due to oxygen absorption.