AbstractWith a view to obtaining a more trustworthy record of tidal movements, it was decided by the Public Works Department of the Hong Kong Government that a second permanent tide gauge was desirable in order to provide a check on results obtained from the existing gauge situated in Victoria Harbour. The reliability of the results obtained from the existing gauge was subject to some doubt due to the abnormal conditions prevailing in the Harbour—a rather narrow and shallow channel in which extensive reclamation works have taken place. A site for the new tide gauge was thus chosen well away from the harbour, on the coast of Lan Tao Island, and a gauge of the automatic recording type was duly installed on the Chi Ma Wan Prison Pier in February, 1960.