Correspondence on geodesy with related papers. The correspondents include H. James, W. De La Rue, C. Pritchard, B.A. Gould, O. Struve, F.A.T. Winnecke, C.F. Varley, W.G. Armstrong, J.T. Chance, W. Smyth, A.R. Clarke, R.L.J. Ellery, J.J.V. Littrow, A. d'Abbadie and C.V. Walker. There is material concerning experiments to find the Earth's density; a paper on a geological survey of Britain; drawings of two portable transit instruments and a zenith sector; departmental orders for a trigonometrical survey of India; a sketch map of India; pendulum observations in India; a report on the survey; investigations into Indian geodesy; the determination of the longitude of Valentia (Valencia) and a monument in commemoration of this determination; connections of the British triangulation with Europe; a plan of a telescope housing and a print of the 'Standing Room'; and papers on geodesy in France and the direction of gravity.