<div class="htmlview paragraph"><b>THIS paper is prepared in the form of a compendium of the several materials, ferrous and non-ferrous, that are employed in the construction of aircraft engines. The data are arranged in tables giving the specifications and applications for the several metals, with descriptive matter covering the metallurgical reasoning which led to their adoption</b>.</div> <div class="htmlview paragraph"><b>The limitations of the properties of the materials are stated, and suggestions made for changes in design which would permit the application of other materials. The evolution that has taken place in the development and application of metals to meet the demand of increased performance is illustrated</b>.</div>