Published online by Cambridge University Press: 21 April 2004
Predicting the tide in four ports, the Admiralty Tide Table (ATT) came out in early 1833. The table was for London and three naval dockyards. The observations at those dockyards, from which the ATT was first made, have recently come to light (Anonymous, 1833). This paper exposes the circumstance of the tables' construction; it is also an analysis of the later part of the observation series. The analysis is a comparison of the difference between observation and contemporary prediction, and to tides synthesised from the modern method. The ATT were only admitted into production after comparisons were made to its competitors. Those comparisons were for London alone and a recent study also concentrates on that one area. This study extends comparison to the remaining three-quarters of the early ATT: to Sheerness, Portsmouth and Plymouth.