Abstract. The 100th anniversary of the Liverpool Tidal Institute (LTI) was
celebrated during 2019. One aspect of tidal science for which the LTI
acquired a worldwide reputation was the development and use of tide
prediction machines (TPMs). The TPM was invented in the late 19th
century, but most of them were made in the first half of the 20th
century, up until the time that the advent of digital computers consigned
them to museums. This paper describes the basic principles of a TPM, reviews
how many were constructed around the world and discusses the method devised
by Arthur Doodson at the LTI for the determination of harmonic tidal
constants from tide gauge data. These constants were required in order to
set up the TPMs for predicting the heights and times of the tides. Although
only 3 of the 30-odd TPMs constructed were employed in operational tidal
prediction at the LTI, Doodson was responsible for the design and oversight
of the manufacture of several others. The paper demonstrates how the UK, and
the LTI and Doodson in particular, played a central role in this area of
tidal science.