Correspondence concerning meetings, membership and reports of the Terrestrial Magnetism Sub-committee of the International Union of Geodesy and Geophysics. The correspondents include Professor S. Chapman, Dr J.A. Fleming, A.H. Goldie, Captain Heck, M. Maurain, Dr G.S. Ljungdahl, Dr T.W. Warmell, Professor F.J.M. Stratton, Professor E.V. Appleton, Dr J. Bartels, F.J. Whipple, J.G. Jeans and Professor Eve. The papers include a report of the Magnetic Chairs Sub-committee, with comments; resolutions adopted for discussion in Washington magnetic observatories in the U.S.A.; correspondence with Dr Ljungdahl concerning the basis for the future work of the committee; correspondence concerning T.W. Wormell's work on atmospheric electricity; correspondence concerning the British National Report on Terrestrial Magnetism; and correspondence with the Meteorological Office at the Air Ministry concerning the classification of papers on magnetism.