Correspondence on various mathematical theories and calculations, mainly pure, but some applied, and miscellaneous papers on scientific matters. The correspondents include, among others, J.C. Adams, A.R. Clarke, F. Galton, E.J. Mills, E.J. Routh, B. Stewart and G.G. Stokes. The material includes two printed papers by M.F. Folie, in French, one translated as 'second note on the extension of the idea of an harmonic ratio', the other translated as 'On the evolution, or fundamental new propositions on the theory of the cone and surfaces of the second degree, and its extension with the curves and superior surfaces'; graphs and correspondence by G.G. Stokes on the harmonic analyser; a brochure on a spiral slide rule; a pamphlet by N.G. Wilkins titled 'Rules for effecting certain operations in division in a neat and expeditious manner'; a paper from the Association for the Improvement of Geometrical Teaching, with a 'Draft Syllabus of Solid Geometry'; papers on pure mathematics by J.C. Adams and B. Stewart; a page on keyboards extracted from 'Nature'; a printed 'Address to the Anthropological Department of the British Association' by F. Galton; printed papers on psychological phenomena; and a paper titled 'Un Rien', giving a theory of the evolution of the Earth.