Papers concerning tides, the Claudian invasion of Britain and the determination of longitudes. There is material on the 'Eclipse of Thales'; a paper by F. Diaz Covarrubios determining the geographical position of Mexico; D. May's observations in the neighbourhood of River Quarra (West Africa); Airy's comments on Lewis' essay on Julius Caesar's invasion; an article in 'The Times' on Caesar's invasion; Airy's paper on the landing of Claudius; C. Merivale's two articles, one on Claudius' landing in Essex, in 'The Essex and West Suffolk Gazette', and the other on Roman Colchester; W.C. Bergin's Great Circle Chart; W. Parkes' work on tides in India; tidal observations at Manosa Point, Karachi Harbour, with calculations of the tide table; and J. Harrison's work on the tides in the Mersey and Irish Sea. The correspondents include, among others, W.H. Smyth, J. Washington, W.F.P. Napier, W.H. Thompson, S. Grimaldi, J.F. Burgoyne, W.P. Wood, H. James and R. Fitzroy.