Paper, 'On Jacobi's figure of equilibrium for a rotating mass of fluid' by G H [George Howard] Darwin Darwin writes: 'I am not aware that any numerical values have ever been determined for the axes of the ellipsoids, which are figures of equilibrium of a rotating mass of fluid. In the following paper the problem is treated from the point of view necessary for reducing the formulæ to a condition for computation, and a table of numerical results is added.' Annotations in pencil and ink throughout. Includes one page of geometrical diagrams and corresponding prints. Subject: Physics / Astronomy Received 12 October 1886 / 1 November 1886. Read 25 November 1886. A version of this paper was published in volume 41 of the Proceedings of the Royal Society as 'On Jacobi's figure of equilibrium for a rotating mass of fluid'. 1886