PREFACE The chief feature which distinguislies this volume from other American textbooks on the saine subject is that the Principle of AIoments is used coilsistently throughout in place of the usual calculus processes. By basing the vork 011 this priaciple it has been founcl practicable to give a simple and obvious treatment of Inally topics for which the calculus is usually thought to be indispensable, such as the calculation of moments of inertia, the deflection of beams, the buckling of columns, and the strength of t h i k cylinders. Experience has sho vn conclusively that the average engineering graduate, and even the practicillg engineer, is deficient in the al ilityt o apply the Priilciple of nioinents readily, but when thus used as the central and coiirdinatiilg principle, it must necessarily make an indelible irnpressioil on the mind of the student and go far toward remedying this deficiency. The mechanics of materials is of such fundamental importance in all branches of technology that it is important to begirl its study as early in the course as possible. Heretofore it has been necessary to defer it - - awaiting the cornpletioli of the calculus - until junior year, when the curriculum is already cro vded with technical subjects requiring its application. This text makes it possible for the course to parallel or eve11 to precede the calculus. In addition, it makes the subject available for trade or architectural schools where 110 calculus is taught. Although siinple and ol vious, the treatment is adequate, and its simplicity in no way limits its range or generality. The text is supplemented by a variety of engineering applications, giving practical illformation as well as a mastery of the principles involved.