Technical paper issued by the Bureau of Mines over progress made for thawing gravel in placer mines. Different thawing tests are presented and discussed. This paper includes tables, photographs, and illustrations.

Technical paper issued by the Bureau of Mines over shaft sinking safety. Safe mechanical equipment and procedures are discussed. This paper includes illustrations.

Technical paper issued by the Bureau of Mines over studies of coal tars. As stated in the introduction, "this paper discusses the uses to which some of the various tars are put and shows briefly the usual methods of working up tar into some of its simple or easily prepared derivatives, for which a market can generally be found" (p. 5). This paper includes tables, illustrations, and photographs.

Report issued by the Bureau of Mines discussing a manual written for individuals who use natural gas in the home. As stated in the introduction, "its purpose is to tell about the supply, production, and distribution of natural gas, so that the necessity for preventing waste will be better understood" (p. 1). This report includes a map, illustrations, and photographs.