Гидродинамика

186 ON TNE MOTION OF A RIGID BODY is investigated by the aid of Poiseuille's theory of laminar tubes and the solution is verified by means of an apparatus construc ­ ted by the auhtor (Fig. 20). Concluding his work Prof. Joukowsky makes several remarks ( § 38) regarding the motion of a free body in the interior of which is confined a viscous liquid. Prof. Joukowsky proves that if some initial velocities are imparted both to the body containing a cavity filled with a vis ­ cous liquid and t o the liquid, t he motion of the system t ends t o an ultimate state in which one of the principal axes of inertia of the masses considered has t he direction of the prin­ cipal moment of the initial momenta, and the whole system will rotate about this axis with a certain constant angular velo­ city a s one invariable body. This result is of great importance in cosmogony.