Paper, 'On the stability of a rotating spheroid of perfect liquid' by G H [George Hartley] Bryan Bryan writes: 'In my communication on “The Waves on a Rotating Liquid Spheroid of Finite Ellipticity” [see Philosophical Transactions A, volume 180], I stated that it did not appear possible to give a complete investigation of the criteria of stability of Maclaurin's spheroid when the liquid forming it is free from all traces of viscosity, and equilibrium is liable to be broken by a disturbance of a perfectly general character.' Annotations in pencil and ink throughout. Subject: Astronomy / Fluid dynamics Received 12 March 1890 / 13 March 1890. Read 27 March 1890. Communicated by George Howard Darwin. A version of this paper was published in volume 47 of the Proceedings of the Royal Society as 'On the stability of a rotating spheroid of perfect liquid'. 1890