Sir Alfred Ewing exhibited some of the early models used by him in 1890 and subsequent years to demonstrate that the known characteristics of ferromagnetic metals were very completely reproduced by means of groups of pivoted magnets, free to turn on fixed centres, and constrained only by their mutual magnetic forces during the application or variation of an external field. He had been invited to present the models to the National Collection at South Kensington and they were now about to be sent there. The series included models illustrative of his theory of 1890 (Proc. Roy. Soc., vol. xlviii, p. 342) and others of later date which referred to the modified theory communicated to this Society in 1922 (Proc. Roy. Soc. Edin., vol. xlii, p. 97). The models were arranged to show effects of rotation in a constant field, as well as effects of varying a field of constant direction. A feature now shown for the first time, and incorporated in a new model, was to submerge the group of magnets in a liquid, with the effect that the irreversible movements which occurred when the magnets broke away from stable combinations and fell into other stable combinations, were made nearly dead-beat. The fluid in which the magnets were immersed damped out the oscillations, causing the energy dissipated through hysteresis to be quickly absorbed, and facilitated the study of unstable phases in the operation of the model.