Correspondence and papers concerning proposals and operations to determine, with the assistance of the Royal Observatory, the longitude of Lisbon, Leiden, the Cape Observatory, Gibraltar, places in Australia, New Zealand and Egypt, and Mauritius; and the difference in longitude between Malta and Bombay. The papers include errors of the Greenwich clock; observations of telegraph signals; J.W. Green's abstract of the Greenwich - Lisbon - South American longitudes; the exchange and summary of time signals with Gibraltar; J. Tebbutt's article from 'The Sydney Morning Herald' on the longitude of Sydney; and observations on determining the difference in longitude between Malta and Bombay. The correspondents include T.E.V. Oppolzer, R. Hall, W.H.M. Christie, D. Gill, F.J.O. Evans, J.R. Hind, G.O. Draper, R.C.J. Ellery, N.R. Pogson, A.R. Clarke, J.A.C. Oudemans, J.J. Thomson, O. Heaviside, C.P. Smyth, W. Spottiswoode, W. Harkness, H. James and L. Darwin.