Material relating primarily to Airy's paper on Julius Caesar's invasion of Britain and his path through South-East England. Airy asserted that Caesar landed at Pevensey, but this was challenged in a paper by F.B. Martin, which stated that he landed near Ramsgate. There is considerable correspondence on this topic, with a nautical chart of the Dover Straits; a map of the Goodwin Sands; and the 'Proceedings of the Society of Antiquities'. Other subjects covered include the geography of the Exodus; the velocity of galvanic currents; firing gunpowder by electrical current; the geology of India; C. Lyell on the Blackheath pebble-bed and the geology of London; optics and poor vision; tidal observations by A.B. Beechy of the Severn, English Channel and North Sea; W. Denison's observations of the tides around Tasmania; and maps of Maestricht (1748), the East Indies (1748) and Africa, and a plan of Calcutta (1834). The correspondents include F.N.M. Moigno, C.V. Walker, E. Guest, W. Cubitt, F. Beaufort, J. Francis, W.H. Smyth, E. Sabine, J.F.W. Herschel, W.D. Cooper, A.J. Dunkin, C. Austin, J. Britton, J.C. Hare, M.F.C.D. Corbaux, G.S. Butler, T. Jones, J.N. Smyth, B. Woodcroft, W. Hopkins, W. Whewell, W. Swan and C. Pritchard.