Report issued by the U.S. Bureau of Mines on testing done on a variety of American coals collected from 32 coal beds across the country. The carbonizing properties of samples tested at 3 different temperatures are presented. This report includes tables, and graphs.

From Introduction: "Figure 1 shows the location of sources that have been either exploited or seriously considered at one time or another, super-imposed upon a map indicating by small letters the order of consumption of K2O in the leading States; the amount used in these States, together with the percentage of the total consumption of potash used as fertilizer in the United States in 1939, is given in table 1. Figure 2 shows the domestic production and total consumption of potassium salts, in terms of tons of K2O, with the value per unit at the plants, for each year since 1913. Considered together, these two figures tell a significant story."

Report issued by the U.S. Bureau of Mines discussing bituminous coal and lignite seams found in the United States. The thickness of seams from several U.S. states is compared, as well as the mining methods employed. This report includes maps, tables, and illustrations.