Arithmetic. —The principles and processes of arithmetic applied to whole numbers and vulgar and decimal fractions. The metric system. Approximations to a specified degree of accuracy. Contracted methods of multiplication and division of decimals. Ratio and proportion. Percentage. Averages. Practical applications of arithmetic. Algebra.—Symbolical expressions. Equations of the first or second degree (and problems leading thereto). Square root. Graphs of simple rational integral algebraic functions. Arithmetic and harmonic progression. Geometric progression. Theory of indices. Logarithms. Theory and use of the slide rule. Binomial theorem for a positive integral index. Geometry.— The subjects covered by Euclid I.-IV. with simple deductions, including easy loci and the areas of triangles and parallelograms of which the bases and altitudes are given commensurable lengths. (Euclid proofs will not be insisted upon.) Trigonometry.—Up to and including the solution of triangles, together with the practical solutions of triangles and applications, and numerical examples involving the use of logarithmic and other tables.

The design and construction of light hulls and floats suitable for flying boats and seaplanes is a very highly specialised branch of shipbuilding. This being the case, all matters pertaining to same Should be in the hands of naval architects. At a recent lecture before this Society, Commander Hunsaker, of the United States Navy, stated that British aircraft designers followed the naval architect's methods more than in any other country; he thought this was natural as he gave us the credit of being the first maritime power of the world. This may be perfectly true with regard to airships, but I cannot endorse his opinion that the majority of flying boats built in this country show the impress of the trained hand of a naval architect. I do not imply that the American boats are superior to ours, as for instance, a large American boat with twin engines built in the United States, which we used for the North Sea patrol, was by no means typical of good boat-building ; there were no less than four consecutive planks butted—not even scarfed—on the same timber, which had a siding of 5/8in., the line of butts being in line with the step where the boat was naturally weakest.

The efficiency of all internal combustion engines is influenced to a large degree by the density of the charge prior to ignition. In the stationary engine operating at normal ground density, the variation in compression pressure throughout the range of working conditions is so small as to have no appreciable effect upon engine performance. In the aero engine, however, the conditions obtaining in flight are such as to produce wide variation in the suction pressure and therefore in the compression pressure due to changes in atmospheric density.

Table I has been prepared to show the variation in air pressure, temperature and density with height, the figures given representing the mean conditions obtaining in the south of England.