This report presents the results of wind tunnel tests conducted to determine the aerodynamic characteristics of airship models. Eight Goodyear-Zeppelin airship models were tested in the original closed-throat tunnel. After the tunnel was rebuilt with an open throat a new model was tested, and one of the Goodyear-Zeppelin models was retested. The results indicate that much may be done to determine the drag of airships from evaluations of the pressure and skin-frictional drags on models tested at large Reynolds number.

This report describes test made in the Variable Density Wind Tunnel of the NACA to determine the possibility of controlling the boundary layer on the upper surface of an airfoil by use of the low pressure existing near the leading edge. The low pressure was used to induce flow through slots in the upper surface of the wing. The tests showed that the angle of attack for maximum lift was increased at the expense of a reduction in the maximum lift coefficient and an increase in the drag coefficient.

Report compiled by the U.S. Bureau of Mines including statistics on fatalities in coal mines located in the United States as well as data regarding the various operations (e.g., number of miners employed and average production). The information is organized into tables for comparison and the text draws some overall conclusions in the summary.

Report issued by the U.S. Bureau of Mines covering accidents that happened in metal mines located in the United States including statistics for injuries, fatalities, kinds and causes of accidents, and operational data, such as number of mine workers and shifts worked.

Report published by the U.S. Bureau of Mines which is a compilation of accidents in quarries located in the United States with data regarding the number and kinds of accidents as well as information about the mining operations (e.g., number of men employed, kinds of quarries, amount of work performed, etc.).

Report issued by the U.S. Bureau of Mines on the coal mine related deaths during the month of April, 1931. The number of fatalities and the causes are presented. This report includes tables and graphs.

Report issued by the U.S. Bureau of Mines on the coal mine related deaths during December, 1930. The number of fatalities and the causes are presented. This report includes tables.

Report issued by the U.S. Bureau of Mines on the coal mine related deaths during the month of February, 1931. The number of fatalities and the causes of each are presented. This report includes tables.

Report issued by the U.S. Bureau of Mines on the coal mine related deaths during the month of January, 1931. The number of fatalities and their causes are presented. This report includes tables.

Report issued by the U.S. Bureau of Mines on the coal mine related deaths that occurred during the month of June, 1931. The number of fatalities and the causes of each are presented. This report includes tables and a graph.

Report issued by the U.S. Bureau of Mines on the coal mine related deaths that occurred during the month of March, 1931. The number of fatalities and their causes are listed. This report includes tables.

Report issued by the U.S. Bureau of Mines on the coal mine related deaths that occurred during the month of May, 1931. The number of fatalities and their causes are presented. This report includes tables and graphs.

Report issued by the U.S. Bureau of Mines on the fatalities of coal miners in November, 1930. The common causes of death, and the location of the mines that the fatalities occurred in are listed. This report includes tables.

From Summary: "This paper presents the results of tests of six commonly used airfoils: the CYH, the N-22, the C-72, the Boeing 106, and the Gottingen 398. The lifts, drags, and pitching moments of the airfoils were measured through a large range of positive and negative angles of attack. The tests were made in the variable density wind tunnel of the National Advisory Committee for Aeronautics at a large Boeing 106, and the Gottingen 398 airfoils, the negative maximum lift coefficients were found to be approximately half the positive; but for the M-6 and the CYH, which have less effective values were, respectively, 0.8 and 0.6 of the positive values."

From Summary: "This report contains the lift, drag, and moment characteristics of tapered Clark Y, Gottingen 393, and USA 45 airfoils as obtained from tests made in the Variable Density Wind Tunnel of the NACA. The results are given at both low and high Reynolds Numbers to show scale effect and to provide data for use in airplane design."

"This is a resume of the work of the Bureau of Standards on a cotton parachute cloth for use as a substitute for silk in the event of an emergency curtailing the supply. Cotton yarn of high strength in proportion to its weight and otherwise specially suitable for parachute cloth was developed. Cloth woven from this yarn in the bureau mill was equal or superior to parachute silk in strength and tear resistance, met the requirements with respect to air permeability, and weighed only a few tenths of an ounce per square yard more than the silk cloth" (p. 1).

This investigation has a double object: 1) the calculation of the general characteristics of certain wings with progressively varying sections; 2) the determination of data furnishing, in certain cases, some information on the actual distribution of the external forces acting on a wing. We shall try to show certain advantages belonging to the few wing types of variable section which we shall study and that, even if the general aerodynamic coefficients of these wings are not often clearly superior to those of certain wings of uniform section, the wings of variable section nevertheless have certain advantages over those of uniform section in the distribution of the attainable stresses.

Report containing tables detailing cost of mining accidents in Washington state in comparison with other states.

Summary of the species of mammals native to New Mexico, including a map of the life zones, descriptions of the physiographic features, and lists of characteristic zone-marking plants, birds, mammals.

"This report presents the results of an investigation to determine the effect of boundary layer control on the lift and drag of an airfoil. Boundary layer control was accomplished by means of a backward-opening slot in the upper surface of the hollow airfoil. Air was caused to flow through this slot by a pressure which was maintained inside the airfoil by a blower. Various slot locations, slot openings, and wing pressures were used" (p. 3).

From introduction: The fossil plants described in the present report were collected at the north end of Grand Coulee during the summer of 1927 by Messrs. T. A. Bonser, F. A. Roberts, and Walter Bruce, of Spokane, and F. W. McCann, of Coulee City. The locality is in the big bend of the Columbia River near the northern boundary of Grant County, Wash., about 85 miles west of the plant-bearing Latah sediments around Spokane. The outcrop in Grand Coulee is about the same distance east of the crest of the Cascade Mountains, about 100 miles northeast of the plant beds at Ellensburg, which are of approximately the same age, and some 200 miles west of beds in Idaho yielding a similar flora and assigned to the Payette formation by Knowlton and others.

Report issued by the U.S. Bureau of Mines on the effects of different operating conditions on high-pressure natural gas pipelines. Analysis of past and current studies on natural gas transmission are presented. This report includes tables, graphs, and an illustration.

From Content and Arrangement of Report: "For the convenience of the reader the bulletin has been divided into two parts. Part I describes the investigation and summarizes the most important results. Part II gives the detailed data of the best of the washing tests by each process."

This report covers a series of tests on thin flat elastic strips restrained at two parallel edges and subjected to shear by conversely directed stresses. Theoretical treatments, particularly those of Lilly, Southwell and Skan, and Timoshenko are briefly outlined. The problem to be solved by these tests was to find out whether, and to what extent the conditions and assumptions upon which the calculations are based are complied with in the tests.