Report issued by the Bureau of Mines consisting of bibliographies for petroleum bulletins. The bibliographies for bulletins published between 1919 and 1920 are presented.

Report issued by the Bureau of Mines over studies conducted on types of explosives. Properties, materials, and methods of different explosives are discussed. This report includes tables, and illustrations.

High-compression engines are investigated with the three main objects being elimination of vibration, increase of maximum efficiency, and conservation of this efficiency at the highest possible speeds.

Report consisting of a list of aircraft belonging to different French aircraft companies.

While the reliability of predictions is poor the author still attempts to gauge the future speeds of airplanes.

Three different Marcel Besson airfoils are investigated in terms of maximum lift, maximum fineness, minimum required power, and wing section drag. Comparisons are then made between the three airfoils.

Explanation of soaring flight. Static and dynamic soaring flight. Results of the Rhon contest. Description of the most important gliders. Notes on Soaring Flight Contests in France and England.

The integration is accomplished by the use of the mean camber of the section at particularly selected points. Simple graphical constructions of the zero directions are derived from the results.

One of the most ingenious of the devices intended for use in night landing, especially emergency landing, is a very simple optical instrument known as the Jenkins night altitude indicator. The design and operation of this instrument, which allows a pilot to determine the altitude of the aircraft, is discussed. The author discusses various modifications and improvements that might be made to the instrument.

"The data for the calculation of the air forces acting on the elevators, obtained from previous model experiments are not immediately applicable in practice, as the angle at which the control surfaces meet the air stream is, in general, still unknown. The air stream, when it reaches the elevator has already been deflected by the wings and although the velocity imparted to the air current by the wings is of negligible amount compared with the speed of flight, the air behind the wings has been deflected downwards, so that the elevators work in an airstream which is inclined in a downward direction. The angle at which the air stream meets the elevator surface is, therefore, different from, and, with the usual arrangement of elevators, less than the angle made by the elevator surfaces with the line of flight" (p. 1).

The experimental flights described herein were made with the object of obtaining information regarding the following two questions, which as yet have not been sufficiently elucidated. These are: 1. What effect has altitude upon the formation of the mixture? 2. What alteration takes place, with increasing altitude, in the utilization of the heat contained in the fuel?.

Note presenting an investigation of the Karman vortex street, which is a flow arrangement occurring behind a plate. The equations governing the flow and some of the hypotheses behind it are provided.

"The object of the investigation described in this report was to compare the damping coefficients of an airfoil as calculated from a knowledge of the static characteristics of the section with those obtained experimentally with an oscillation. The damping coefficients as obtained, according to the conventional notation, can be considered either as due to pitching or as due to yawing, the oscillation in these experiments being so arranged that the surfaces oscillate about a vertical axis. This is in reality the case when the influence is yawing about the standard Z-axis, but it can also be considered as a pitching motion when the model is so rigged that its standard Y-axis becomes vertical" (p. 118).

This report describes the theory of calculating the principal stresses in the envelope of a nonrigid airship used by the Bureau of Aeronautics, United States Navy. The principal stresses are due to the gas pressure and the unequal distribution of weight and buoyancy, and the concentrated loads from the car suspension cables. The second part of the report deals with the variations of tensions in the car suspension cables of any type of airship, with special reference to the rigid type, due to the propeller thrust or the inclination of the airship longitudinally.