Correspondence on the tides, including calculations of tides at St Helena, Australia and in the River Shannon. The correspondents include J. Washington, J.D. Forbes, P.H.L. von Boguslawski, F.W. Beechy, F. Beaufort, W. Whewell, T. Colby, A. de Morgan, H. Raper, H.J. Rose, C. Manby, J. Challis, W. Vaughan and T.A. Larcom. There are also two maps of the River Shannon showing long-profile and cross-profiles; plans for tide gauges; a circular for Reed's Tide Tables; calculations of the time of high water, 23 and 24 June 1340; a page extracted from 'The Bombay Times' containing a report of the meeting of the Geographical Society; and a computation of a given formula.