Correspondence and papers on magnetic disturbances, alleged new discoveries and theories, and experiments on magnetism. There are calculations for the mean declination of Greenwich, 1849; C. Hansteen's extensive magnetic observations at Christiana (Oslo), and a French paper by him on terrestrial magnetism; E. Sabine's remarks on W. De La Rue's diurnal magnetic theories; an unsigned manuscript on the magnetic disturbances of 24 September 1847 at the Royal Observatory; observations of disturbances to vertical force magnets; the proceedings connected with the magnetical and meteorological conference at Cambridge, June 1845; correspondence on the Toronto and Cambridge magnetic observatories; examples of M. Faraday's iron filing magnetic field experiments; analysis of Kreit's papers on magnetism; 'Colonial magnetic observatories' by E. Sabine; a report in favour of maintaining magnetic and meteorological observatories; electromagnetic pendulums and French cholera statistics in 'Société Universelle'; and a list of papers on terrestrial magnetism. The correspondents include W. De La Rue, A. de Morgan, M. Faraday, J. Phillips, C. Pritchard, W.H. Sykes, J. Tyndall, W. Whewell, C. Wood, J.F.W. Herschel, G.G. Stokes, J. Glaisher, B. Howes, H. Merivale, H.V. Addington, E.C. Herrick, J.G. Galle, W. Sharpey, R. Owen, R. Fitzroy and F.J.O. Evans.