LONDON. Mathematical Society, January 10.—Prof. W. Burnside, president, in the chair.—An exhibition of models of fourdimensional figures was made by Mrs. A. Stott. The models are sections by three-dimensional flat spaces of the six regular hypersolids of a flat space of four dimensions. The sections are in general polyhedra; and corresponding faces of different polyhedra, forming a series of sections of the same regular hypersolid, are coloured identically in order to show the relations between the different sections. Other models show the grouping about a point of the regular hypersolids which have the space-filling property.