Vorlesungen über technische Mechanik

IN this volume the vector equation of mass acceleration commonly known as Newton's laws is applied to the “law of areas,” the problems of harmonic and oscillatory motion, the brachistochrone, motion of a rigid body, motion under no forces and motion of a top, vibrations of elastic bodies and equations of motion of hydrodynamics. The use of vector equations throughout and differences of notation and terminology make the treatment a little difficult for an English reader to follow; but it is clear that the author has fully realised the subject of his book to be dynamics, not the integration of differential equations. If exceptions exist, the most noticeable one is in the sections dealing with cycloidal motion, the whole problem of which can be solved, almost without writing down a single equation, by showing the geometric properties of the cycloid in a diagram where the author employs many formulas. Among practical illustrations we notice the reference to Schlick's balancing of marine engines, while the reference to the Kegelbahn or skittle-ground takes our thoughts back to the Fatherland, with its pleasant afternoons spent in admiring the view, drinking beer, and listening to the heavy roll of the balls.Vorlesungen über technische Mechanik.By Dr. August Föppl. Vierter Band, Dynamik. Dritte, stark veränderte Auflage. Pp. viii + 422. (Leipzig: B. G. Teubner, 1909.) Price 10 marks.