Circular presenting a description of the light airplane SM-1, which was designed by W. S. Shackleton and Lee Murray. Information regarding the design and flight characteristics and some photographs of the airplane are provided.

Circular presenting a description of the Avro Trainer airplane, which is primarily intended for pilots in training and is designed to be easy to use, including large, comfortable cockpits, good view, effective windshields, and wide track. Details of the design, flight characteristics, drawings, and photographs are provided.

"A quantitative criterion of merit has been needed to assist airplane designers to incorporate satisfactory spinning characteristics into new designs. An approximate empirical criterion, based on the projected side area and the mass distribution of the airplane, has been formulated in a recent British report. In the present paper, the British results have been analyzed and applied to American designs. A simpler design criterion based solely on the type and the dimensions of the tail, has been developed: it is useful in a rapid estimation of whether a new design is likely to comply with the minimum requirements for safety in spinning" (p. 1).

Circular describing the Dewoitine D 33 commercial airplane, which is a low-wing cantilever monoplane. Details of the wing, fuel tanks, fuselage, landing gear, controls, engine, characteristics, drawings, and photographs are provided.

Circular presenting a description of the Baynes Bee, which is a light two-seat high-wing monoplane. Details of its unique qualities, design, components, flying qualities, drawings, and photographs are provided.

Circular presenting a description of the Bernard 82, which is a scaled-up version of the 80 G.R.; they have similar designs but the 82 has greater span and wing area, deeper chord, higher fuselage, and a thicker wing for the bombs. A description of some flight tests and characteristics is also provided.

Report issued by the U.S. Bureau of Mines on the exploration of the Oklahoma City oil field for natural gas reserves. This report includes tables, maps, and illustrations.

Report issued by the U.S. Bureau of Mines on the different types of gases that are present in coal. Theories behind why these gases occur in coal are presented. This report includes tables and graphs.

Report issued by the U.S. Bureau of Mines on the improvements made on permissible electric mine lamps. The types of electric lamps approved for use, and their characteristics are presented. This report includes tables.

Report issued by the U.S. Bureau of Mines on the pegmatite deposits found near Tinton, South Dakota. The properties, and geology of the deposits are presented. This report includes tables, and maps.

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 migration of gas injected into reservoir sands. The movements, speed, and direction of the gas are studied. This report includes tables, graphs, and illustrations.

Report of the annual conference on weights and measures, hosted by the U.S. National Bureau of Standards in Washington D.C. It includes conference proceedings, a list of attendees, information about committees and officers, and other reports or commentaries discussed at the meetings.

Report of the annual conference on weights and measures, hosted by the U.S. National Bureau of Standards in Washington D.C. It includes conference proceedings, a list of attendees, information about committees and officers, and other reports or commentaries discussed at the meetings.

Report of the annual conference on weights and measures, hosted by the U.S. National Bureau of Standards in Washington D.C. It includes conference proceedings, a list of attendees, information about committees and officers, and other reports or commentaries discussed at the meetings.

Report of the annual conference on weights and measures, hosted by the U.S. National Bureau of Standards in Washington D.C. It includes conference proceedings, a list of attendees, information about committees and officers, and other reports or commentaries discussed at the meetings.

"This investigation was conducted to study the practicability of employing heat as a means of preventing the formation of ice on airplane wings. The report relates essentially to technical problems regarding the extraction of heat from the exhaust gases and its proper distribution over the exposed surfaces. In this connection a separate study has been made to determine the variation of the coefficient of heat transmission along the chord of a Clark Y airfoil. Experiments on ice prevention both in the laboratory and in flight show conclusively that it is necessary to heat only the front portion of the wing surface to effect complete prevention" (p. 3).

This investigation attempts to surpass the boundaries of pure mathematical interest in that it possesses as an example, a flow investigation in a multiply-connected region. Then the results appear to be carried out by means of an appropriate conformal representation of the region around two chosen closed curves. Thus we have the basis of an exact plane theory of the biplane.

This report details the methods of construction employed by the Gloster Company in their fabrication of metal aircraft parts. Ribs, spars, wings, and metal treatments to prevent oxidation are all discussed.

From Summary: "A theory is developed for the airfoil of finite span at supersonic speed analogous to the Prandtl airfoil theory of 1918-1919 for incompressible flow. In addition to the profile and induced drags, account must be taken at supersonic flow of still another drag, namely, the wave drag, which is independent of the wing aspect ratio. Both wave and induced drags are proportional to the square of the lift and depend on the Mach number, that is, the ratio of flight to sound speed. In general, in the case of supersonic flow, the drag-lift ratio is considerably less favorable than is the case for incompressible flow."

The theory of landing impact is briefly stated and the applicability of a previously suggested formula is extended. Theoretical considerations regarding impact measurements on models and actual seaplanes are followed by a brief description of the instruments used in actual flight tests. The report contains a description of the strength conditions and deals exhaustively with force measurements on the float gear of an "HE 9a" with flat-bottom and with V-bottom floats. The experimental data are given and compared with the theoretical results.

This report presents the results and a recounting of the new technological developments that were developed for the 11th Rhon Soaring Contest.

The appearance of expressed discontinuity layers in the free atmosphere, where a warm air mass flows over a cold mass without perceptible intermingling forms the basis of the present report. In these experiments an air stream is to be blown between a water-cooled and a vapor-heated plate. According to what preceded it is anticipated that the exchange will be enhanced.

"At the suggestion of Professor Betz, the following device was tested with the object of reducing the autorotational speed of airplane wings. The model of a normal wing with the Gottigen profile 420, 1 meter span and 0.2 meter chord was provided with a pair of symmetrical slots on the suction side, connected with each other inside the wing. The arrangement of the testing equipment and models are given and the effect of the slots can be seen in the experimental curves that are included" (p. 1).