The whirling of shafts

The paper is an attempt to explain the phenomenon of whirling by proving that it is essentially a case of vibration, and obeys the laws of vibration, especially those relating to the phase change between the disturbing force and the resulting displacement. Whilst acknowledging that the critical speed of whirling is usually calculated by the same expressions as those which give the natural time of vibration, it is maintained that the identity of the two phenomena is not sufficiently recognized. To prove this, the case of the spring-controlled governor is cited, which, according to the ordinary treatment of whirling¿equating the centrifugal and the elastic restoring forces¿should come in again above a certain speed. A description is given of experimental verifications of the theories put forward.