M. S. Reidy, Tides of History: Ocean Science and Her Majesty’s Navy. University of Chicago Press, Chicago, 2008

Reviewed by Duncan Redford
Leverhulme Early Career Research Fellow
Centre for Maritime Historical Studies
University of Exeter

Tides of History is a fascinating book, both a scientific history and a maritime one that demonstrates the close links between these two areas of historical investigation as it charts the development of scientific enquiries and methods into tides. In today’s information age of good charts, data and satellite navigation it is easy to forget the difficulties, dangers and risk that mariners once faced. While the development of accurate charts and the ability to calculate a position while out of sight of land has attracted attention, the problems caused by tides have escaped serious study until Michael Reidy’s excellent work.

It might be thought that something as mundane for today’s world as tidal theory would make dry reading; such a view would be wrong. Reidy writes in an accessible and readable style, and the story he lays out is one of great interest, as he charts the formation of ‘tideology’ notably by concentrating on the efforts of William Whewell and his associates in the first half of the nineteenth century, before showing how from its foundations in tidal theory the maritime sciences moved outwards to encompass a multitude of phenomena such as mapping the magnetic variation of the earth’s oceans – a task just as important to safe and accurate navigation as Whewell’s work on tides, or Harrison’s chronometer and the measurement of longitude the previous century.

It is hard, sitting in a warm office or in a comfortable chair, to understand the importance of the advances made in the marine sciences during the nineteenth century – perhaps a few good tales of maritime misfortunate complete with the Victorian melodrama might make the process of understanding how vital this work was to the mariner. Tidal science when combined with accurate charts, an accurate log of speed and distance run, a good compass (made even more accurate in by the 1830s with the understanding of magnetic variation), the ability to calculate latitude and longitude made navigation more precise and safer tool for the mariner. Once the ground work of understanding tides had been achieved, understanding tidal streams – their speed and direction soon followed – then dead reckoning (course and speed only) could be replaced with the more accurate estimated position (course, speed and the influence of the tidal stream during the period) as the mainstay of the navigator’s art particularly in coastal waters where the effect of tides was most felt. Only the ability to see through the night, fog and driving rain could do more to improve the safety of navigation, and this would have to wait for the development of navigation radar in the 1950s.

Reidy is right to emphasise the level of support the early investigators and scientists of tidal theory received from the British Admiralty. What Reidy does not do, however, is go into detail as to why the Navy felt the marine sciences were of such importance during the late 1830s and 1840s. Yes, there was genuine interest from some officers about the use of science to improve understand of the natural world such as Beaufort, who as the Hydrographer had great influence over what research the Navy got involve with. Yes, the advances in understanding tides made navigation safer, but why was the Navy interested in tidal theory in that particular period? Was there more to the issue than just safe navigation and the increasing trade of Britain’s merchant marine? It is therefore important to consider strategy and naval policy with regard to the Royal Navy’s relationship with scientists and laymen who were involved in formulating tidal theory.

For many years the Navy had been vexed by the problem of what to do if an enemy refused to do the decent thing and leave its harbours and fortified anchorages behind and sail out to be beaten by the Royal Navy’s squadrons. The answer was to be able to seek out the enemy in harbour – steam and shell firing guns had made this more practicable, while understanding tides made it safer. At the same time, steam and the French development of Cherbourg as a major naval arsenal had undermined Britain’s traditional strategy of being able to command the English Channel with a Western Squadron up-wind of the main French base and Brest. The Royal Navy’s answer to these problems was to develop a coastal attack strategy in the 1840s that would neutralise the French threat at Cherbourg and which saw use in the Baltic during the Crimean War against the Russians. As Andrew Lambert has pointed out, the Royal Navy put a great deal of hydrographical effort into accurately charting and understanding the waters off Cherbourg in the 1804s and perhaps we should see the more general enthusiasm for the marine sciences in this period as an aspect of this coastal attack strategy.

Tides of History is a well written and engaging book. It is warmly recommended for all those interested in the development of the Royal Navy and Merchant Marine during the nineteenth century.