A table is presented which includes data for calculating the index of efficiency. The author uses this data to conclude that seaplanes cannot be considered inferior to terrestrial airplanes.

The author discusses various aspects of landing aircraft such as the actual process of touchdown and the problems associated with the tail skid touching the ground before the landing gear.

A simplified formula for calculating wing spars is presented.

The author presents a comparison and combination of the numerical and geometrical determinations of the maximum M, when calculating the maximum bay moment.

"It is profitable to examine the organization and equipment of the German airship stations. The stations best adapted for serving as the basis of this study were chiefly constructed by the German Navy, during the war, for exclusively military purposes and do not therefore entirely satisfy the conditions of exploitation required for a civilian air service. The requisite modifications for satisfying the latter conditions may nevertheless be readily determined according to circumstances" (p. 1).

This report presents experiments and calculations for the purpose of determining the landing gear requirements upon the water. Moving pictures are given which furnish data and also may give both the magnitude and direction of the forces acting. Different classes of seaplanes are examined and proposals for calculation instructions are given.

It was a conclusion of this detailed study of the practicality of using airships for carrying passengers that, although slow, airships are capable of carrying useful loads over long distances. However, it is noted that there is a certain limit to the advantages of large cubature. Beyond a certain point, the maximum altitude of the airship goes on decreasing, in spite of the fact that the range of action in the horizontal plane and the useful load go on increasing. The possibility of rapid climb is an essential factor of security in aerial navigation in the case of storms, as is velocity.

Now, in existing wind tunnels, using a horsepower of 100 to 300, the models are generally made to a 1/10 scale and the speed is appreciably lower than the speeds currently attained by airplanes. The Reynolds number realized is thus 15 to 25 times smaller than that reached by airplanes in free flight, while the ratio of speed to the velocity of sound is between a third and three quarters of the true ratio. The necessary increases in either the diameter of the wind tunnel or the velocity of the airstream are too costly.

Technical paper issued by the Bureau of Mines over the development of gas masks designed for fighting fires. The characteristics of the different types of masks in development are presented. This paper includes tables, illustrations, and photographs.

The author presents a comparison and combination of the numerical and geometrical determinations of the maximum M, when calculating the maximum bay moment.