Hitherto, definite specifications have always been made for fuel oils and they have been classified as more or less good or non-utilizable. The present aim, however, is to build Diesel engines capable of using even the poorest liquid fuels and especially the waste products of the oil industry, without special chemical or physical preparation.

A historical sketch of duralumin is presented, especially in regards to its manufacture by various countries. The properties of duralumin are discussed and strength characteristics listed. Increasing the hardness of duralumin by tempering is discussed as well as the uses of the metal.

The following experiments on the air flow behind bodies were made for the purpose of assisting in the explanation of the phenomena connected with air resistance. The first two series of experiments dealt with the phenomena behind a cylinder. The third series of experiments was carried out behind a streamlined strut.

This paper relates some of the problems commercial aircraft companies have in attracting larger numbers of paying customers. The author discusses some remedies such as changing the public perception of flying as dangerous.

Report presenting an exploration of the concept that the ratio between the volume and the surface area also exerts an influence on other secondary characteristics of airships.

The purpose of this paper is to summarize the present status of the problem of mooring airships. Mooring with one, two and even three cables are all discussed.

"In opposition to the advantage of larger dimensions, there is one disadvantage, namely, the weight of the structure increases more rapidly than the buoyancy. It is not possible, however, to determine a general law. In order to formulate one having the merit of simplicity, we will divide the structure into two parts: one subject to tensile and compressive stresses, varying directly as the ascensional or lifting forces; the other subject to varying stresses of the surface areas" (p. 1).

Similarities in the study of aviation accidents in different countries are made as well as statistics on the causes of those accidents.

"It is obviously interesting to know the names of those who were the first contributors to aeronautical science. Therefore, without claiming to give a complete history, I present in this article a summary list of names in chronological order relating to the history of experiments on the resistance of the air and its application to aeronautics" (p. 1).

The object of this work has been to construct an apparatus for obtaining oscillogram of voltages and currents which are variable with respect to time and of the frequency which is constantly met in radio.

Engine conditions such as pressure characteristics, temperatures, and mechanical fatigue enable the employment of a criterion of general fatigue which simultaneously takes account of both mechanical and thermal conditions, for the sake of comparing any projected engine with engines of the same type already in use.

This airship was built by the Zeppelin Airship Company at Friedrichshafen in 1923-4, for the United States Navy, as the reparations service of the German Government in fulfillment of the treaty of peace. A description of the design, components, flight characteristics, blueprints, and photographs are provided.

The causes of the destruction of the Dixmude are discussed and some conclusions are drawn. The author believes a gasoline fire instead of a lightning strike was probably responsible, but the public believes otherwise.

"The recent development of technical science demands maximum reliability of functioning, together with maximum utilization of construction materials. For this purpose we must know what stresses are produced during functioning. One cause of great stresses are mechanical vibrations and this report describes a method of using an oscilloscope to measure the stresses of rapidly changing phenomena" (p. 1).

"The development of aeronautic instruments. Vibrations, rapid changes of the conditions of flight and of atmospheric conditions, influence of the air stream all call for particular design and construction of the individual instruments. This is shown by certain examples of individual instruments and of various classes of instruments for measuring pressure, change of altitude, temperature, velocity, inclination and turning or combinations of these" (p. 1).

"The crisis which troubles the world market for liquid fuel in general and for carburants in particular is doubtless one of the most serious ever experienced by modern industry. It is a national crisis of economic and political independence for countries like Italy and France. The solutions suggested for meeting the lack of liquid fuel may be summed up under two general headings: the economical use of the petroleum now available; creation of petroleum substitutes from natural sources within the country" (p. 1).

"The Commissariat of Aviation deems it expedient to issue a few rules of a general character which should be followed by constructors in designing aircraft, into the manufacture of which metal enters to a considerable extent. The materials covered include: aluminum, duralumin, soft steel, high-resistance steel, in sheets, tubing, and shaped elements" (p. 1).

"The air is known to be charged with electricity (chiefly positive) with reference to the earth, so that its potential increases with the altitude and the difference in potential between two points in the same vertical line, divided by the distance between them, gives a value called the "potential gradient," which may vary greatly with the altitude, the nature of the ground and the atmospheric conditions" (p. 1).

"The behavior of a liquid or gaseous medium, in which a solid body can move freely under the action of a force of constant magnitude and direction, is yet little known. Only in connection with a few special problems, which belong in this field, have experiments been tried and these chiefly concern technically important cases. The behavior of the simplest shaped bodies has as yet been scarcely investigated at all" (p. 1).

The laboratory instruments, which we often constructed with makeshift means, gave encouraging results and showed that they could satisfactorily meet the required conditions. By limiting ourselves to the employment of hot wires of 0.05 mm (0.002 in.) diameter, we obtained instruments which faithfully followed all the wind fluctuations of over 0.1 second and even much more rapid variations without any very great error.

This report recounts some of the successful experiments conducted in England and Germany on slotted wings and ailerons. Wind tunnel test results are given and examples of aircraft constructed with these new wing components are described.

"If the low-powered airplane is to be used advantageously by private individuals, the most important consideration is a smaller fuel consumption and, hence, a lower engine power. From experiments with gliders, it appears entirely possible, by utilizing ascending winds (on the weather side of mountains and those generated by the heat of the sun) and by employing engine flight intermittently, as required to fly long distances over land" (p. 1).

The contest for engines of great endurance had entries of 13 types by the following firms: Breguet, Farman, Fiat, Hispano-Suiza, Lorraine-Dietrich, Panhard-Levassor, Peugeot, Renault, and Salmson.

This article presents the difficulties and triumphs of the airship Dixmude in its long distance flight over North Africa as described by one of the occupants.