A General Theorem in Kinematics

Abstract

PROF. MINCHIN has been anticipated in his discovery of the theorem on uniplanar motion given in NATURE, vol. xxiii. p. 62. It was published some six years ago by Prof. W. Schell of the Polytechnikum, Carlsruhe, in the Zeitschrift für Mathematik und Physik, xix. 3. The paper containing it is entitled “Ueber den Beschleunigung zustand des ebenen unveranderlichen, in der Ebene beweglichen Systems,” and commences at p. 185. The two parts of the theorem will be found in leaded type at pp. 190 and 192. The paper (which is an admirable specimen of clear writing) is purely kinematical, and treats only of motion in plano. The dynamical consequences pointed out by Prof. Minchin are accordingly not to be found in it nor the analogous theorem for the general motion of a rigid body obtained by Prof. Wolstenholme. The following quaternion proof of the latter theorem may interest some of your readers.