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TIDES A Scientific History

By David Edgar Cartwright

Cambridge University Press, 1999

xii + 292 pages. Price £40

ISBN 0 521 62145 3

 

The book has a preface, acknowledgements, 15 chapters, 6 appendices and 2 indices. It is interspersed with a large number of tables, figures and photographs each of which being cited. Monograph and periodical citation is footnoted in situ and listed at the end of each chapter. A collated bibliography would have been useful. This story of the development of tidal theory is very well written by one uniquely qualified to speak on the subject. The author, a natural scientist and mathematician, began his life’s work in UK oceanography but gave a year to the Scripps Institute. When he retired as director of the Institute of Oceanographic Science in 1987 he gave another whole year to America, this time with NASA. Planning the TOPEX/POSEIDON project for both the US and France continues to occupy him.

 

Interestingly it was an American, Rollin Harris, who had written the only, then, full history of tidal theory a century ago. Clearly there has been some need for such an augmentation of the literature for Margaret Deacon’s Scientists and the Sea 1650-1900, which was recently re-edited, has already sold out in paperback. Horace Lamb’s celebrated treatise Hydrodynamics, which he first published in 1879, continues to find a place in modern bookshops in its 6th edition.

 

The review conveys the growth of ideas. Schools of expertise in different countries have led certain aspects of the field at different times. A recurrent theme of how the latest state of the art was always considered to be definitive is explored. The antiquity of tidal history is pushed back to 2,000 BC. It is remarkable how men of antiquity bothered to note upon such a small phenomenon and its relationship to the heavens. The erratic pace of advances being followed by lulls is shown. The scientific exposition of Giraldus Cambrensis is made possible by the profound knowledge of the author. Modern analysis shows how Newton on the Gulf of Tonquin tides is the first citation of interference between two wave trains. Via Harris, we have repeated one of the few statements that the so-called Coriolis effect had been indicated earlier by Mclaurin. The cerebral place of Newton is noted, but it was the mundane activity of the Astronomer Royal, passing by boat upon the tideway to and from his workplace, who observed difference between prediction and actuality. So in this respect the divining that it was as late as Bernoulli in 1740, that any advance in tidal prediction beyond the pre-medieval rule of thumb method was made, is important. On the other hand, perhaps the assertion of Maskelyene being the last astronomer to get his feet wet may not be so definitive if one considers Edmund Neison.

 

It was gratifying to learn that the original Liverpool tide observations of 1774-1792 have recently been re-discovered. These form an early set of good quality data establishing Liverpool’s special place in the science. Single years of predictions derived from this data were then sold for one shilling!

 

By Chapter 7 and only one quarter in to the book Cartwright gets into his stride as the basis of the field of geophysical fluid dynamics develops. The author is very useful in offering English translation of much French work. Laplace exposes the coriolis acceleration (fv-fu). Clearly Dr Cartwright finds a greater utility in Laplace than Formidable Young. However the empirical analysis of Laplace was used for predictions of French tides until mid 20C and the amplitude of Brest is still used for minor ports today. The mathematics is set out clearly, requiring an ordinary understanding of calculus. An assiduous historian could ignore much of the maths and get a lot of satisfaction out of just the text. Curiously an assumption is made throughout the book, that the reader grasps the very difficult and complex subject which is an understanding of what drives the tides.

 

To William Thomson, Baron Kelvin of Largs, is given the accolade grandfather of geophysics. That is despite the dissertation of David Kushner on ‘Sir George Darwin and a British School of Geophysics’ in 1993. Sir Richard Strachey had written imploringly to Thomson as the high priest of tides in 1883. The value of being able to read French is shown in obtaining the accurate, earlier citation for Delauney, and his famous statement on the tide causing lunar acceleration, than other writers.

 

The first two appendixes form glossaries but the monograph includes many definitions and explanations of terms throughout. Not least of which being ‘Kelvin Wave’. Nowadays ‘computer’ means a machine but forty years ago it meant a person; particularly regarding tidal reductions this had great relevance from Mid-Victorian to mid present century. Other stringently oceanographic terms as ‘shelf-break’ are strewn throughout the text and require the reader to conjure up a meaning.

 

The concluding chapters lead into altimitry and this is really the crucial value of the work. For here is an accessible collated version of modern tidal work to the very end of the twentieth century. Few people could have written these chapters. The launch into orbit and decay after 57 days of Sputnik 1 in 1957 enabled western scientists to understand gravity more. The major cause of a tidal variation in the gravity field as sensed at satellite height is the earth tide. By 1974 it was realised that the orbital perturbations are significantly affected by the oceanic tide as well as by the earth tide.  Thereby the astonishing fact emerged, that important geophysical parameters that had been sought for more than a century in terms of frictional drag on the sea-bed, could be directly deduced from the variations in a satellite’s orbit. The Hebridean tides first described by Sir Robert Moray in 1665 received explanation. The first ocean amphidromic system was indicated in 1968. But all was not plain sailing for the ‘Working Group on deep-sea Tides’ bust up in 1975. The retro reflector placed on Moon’s surface by the man who left his footprints behind in 1969 enabled the direct measurement of Moon’s mean movement from Earth at 3.8 cm per year. Increased satellite use enabled the old problem, initiated by Whewell and Harris in the 19C, of defining the tides was almost completely solved to a few centimetres of accuracy. By the US Navy’s 1985 Geosat all the empirical harmonic constituents were defined and every amphidrome was detected.

 

Lord Kelvin and the Age of the Earth controversy can not be divorced from the furore created upon publication of ‘Origin of Species. Kelvin and the later Darwin opened up more than just geophysics with their solutions and finally here, the questions are brought up to date. The accumulation in recent years of historical records of eclipse phenomena, translated from Eastern languages, and identifiable daily growth rates in coral in 1963; led to good measures of length of day and number of days per year during past epochs. All of which lead to lower estimates of dissipation – tidal friction. The author concludes with stating what motivated him to write: that most of the original mainstream problems of tides are now part of the history of science. This book is essential for students of tidal history but more than desired reading for the history of geophysics, oceanography and astronomy.

 

PAUL HUGHES

Airmyn, Yorkshire

The Mariner's Mirror 85 (2) May 1999 pp249-250 Back

 

 

A STUDY OF CHANGES IN HIGH WATER LEVELS AND TIDES AT LIVERPOOL DURING THE LAST TWO HUNDRED AND THIRTY YEARS WITH SOME HISTORICAL BACKGROUND

By PHILIP L. WOODWORTH

Proudman Oceanographic Laboratory Report Number 56, Birkenhead , 1999

ii + 62 pages + 9ff., 22 figures.

Copies available from the Proudman Oceanographic Laboratory

 

The Liverpool tidal record is one of the world’s longest. This report describes the changes in the tide and sea level that can be detected from that data, and attempts to show how important the archive is to students of climate change. Inadvertently there are profuse historical references of datum’s that can be extrapolated for use over a wider area than Merseyside. I know of no other similar study.

 

The work is a report whose main body is 46 pages of text, with chapter headings in bold, so that a contents list and index are omitted, then follow five reference pages. Annex 1 is a synopsis of the most remarkable Life of William Hutchinson. Annex 2 is a Comparison of Historical and Recent Measurements of the Geodetic Levelling at Liverpool, which serves as a model for elsewhere. An integral part is the two end tables, the captions and figures.

 

The 230 years’ high water height and time record has been near continuous. Dr Woodworth sets out to describe where the old records were made in relation to the modern townscape; this is difficult work at the waters edge and he has searched early engineering archives. This effort is paid off because the datum is later shifted horizontally and the errors involved are considered, followed by the tidal data being referred to the national mapping. These principally historical sections conclude with interesting biographical notes of the early tide recorders. It is the diligence of these men, combined with chance preservation, upon which the report is constructed.

 

The first Liverpool Dock masters are considered in relationship to the dock engineering. Notably, Captain William Hutchinson had been shipwrecked on a barren coast. He and his crew drew lots for who was to be sacrificed to feed the remainder. Hutchinson drew the short straw - but was saved when a ship providently appeared. Fortunately, Hutchinson was then appointed Dock master in 1759 and begun to record Liverpool tides, those that survive date from 1768. The start might have been meeting James Ferguson FRS, an astronomer, in 1763 – Thomas Slade had begun a national tide survey in only 1761. The luck really lies in both Ferguson and Hutchinson being members of The Lyceum Library, which was where the tidal records were deposited.

 

Hutchinson ’s recordings had a temporary use, which was that George Holden took them for analysis and from them made tidal predictions. So good were these tide tables that Liverpool pilots were compelled, upon pain of a £5 fine, to be not without them. J. W. Lubbock saw the virtue of these records and had them analysed during 1833-5 by his computer J. F. Dessiou for astronomical coefficients. Woodworth rightly places much emphasis upon this early series because it is these, which need to have ascertained how they were made. Not least, of which is to determine Hutchinson ’s times of High Water: What Clock Did He Use?

 

After Hutchinson ’s data, more sets are included in the consideration and from these it has been possible to extract changes in time and height of high water. The earlier data set provided the conclusion of no change in amplitude, later estimates are of a 3.5% increase; but the whole data suggests a lag in the arrival time of high water of from 6 to 17 minutes. Crucially it became vital to discover if historically Liverpool , rather than Greenwich , mean time had been used, this search appears to be ongoing. Woodworth asserts, “This is the first time to our knowledge that the evidence for tidal changes in the mid-nineteenth century has been presented quantitatively.”

 

A crucial element of the report is the survey of Geodetic Levellings and Checks on Datum Relationships. In order to understand the relationships between the heights of various benchmarks in the area, particularly with regard to their long-term stability, the Institute carried out a new set of levelling during 1996-8. This led directly to what the report is about - the secular trends in water level, which are raises of 1 and 2 mm per year. The significance of the change is assessed as being local and not caused by the deep ocean, leading to potential interest from an engineering standpoint.

 

The records studied were brought about purely by port existence and few were made simply for research. However, the Liverpool record is an excellent example of ‘data archaeology’. The long-term changes in sea level are studied for natural and man-made causes. The context of this study is set against other long European series such as Amsterdam and Stockholm . The report verifies other findings of acceleration of European mean sea level.

 

The reason why these old records were begun, made and kept is an integral part of the report and reinforces the study’s worth. Those reasons at first appear a scientific world apart from the present use, they return to what we now call oceanography and geophysics - but which early moderns would have called scientific and practical applications. Philip Woodworth promises that a search at other locations ‘would repay the efforts involved’. This report is a must for historians of oceanography; it is a model for the astronomer, altimetrist and civil engineer of how a long tidal record is used.

 

PAUL HUGHES

Airmyn, Yorkshire

The Mariner's Mirror 86 (3) August 2000 pp378-379 Back

 

 

 

The Flux and Reflux of Science: The Study of the Tides and the Organization of Early Victorian Science.

Michael S. Reidy.

Minnesota , D.Phil. dissertation 2000.

pp iv+427, including 11 figures.

 

This much needed dissertation answers one important question left by previous general commentators. This is what exactly was wrong with the London tide predictions of 1829. They had merely used a wrong ingredient and setting it right unveiled a massive study for a number of nineteenth century intellectuals and field workers. The first part of the title is a reworking of that used from Grosseteste and Bacon onwards; the second part has to be taken in a more general sense because Victoria became Queen in 1837 whereas these six chapters concern 1829 to 1835. In 1829 predicting tides was generally by the rule of thumb method, Liverpool was one of the few places in the world boasting anything like a tolerable accuracy. That is accuracy greater than that of a sundial in time. However all such prognostication methods remained highly secret although it is probable that use was being made of the Nautical Almanac, available since 1767, increasingly superior and ever more affordable timepieces and perhaps some trickle down of the equations and notions of Bernoulli. By 1835 the proper and systematic study of the tides was being developed across the world,

 

The way that Reidy sets out in his introduction, the whole story that he is to develop, makes plain that he wrote the introduction after the story. In doing so the introduction forms anexcellent synopsis of his work. This dissertation analyses how and why one aspect of oceanic science, the study of tides, became a pertinent and prominent research topic in the 1830’s. The precursive investigations of Cannon, Miller and Dettelbach set the scene of Humboldtian science being done by mathematical practitioners. An accurate understanding of this Humboldtian initiative requires one to look further back in time. Humboldtian science included ‘the physics of the earth, and its biology, from a geographic view, to discover mathematical quantities’. This activity, the move from the internal laboratory to the external, whole earth laboratory defines Victorian science; but since Cannon’s definition certain incongruities have surfaced. Humboldtian science demanded simultaneous observations over wide areas of Earth, over long time periods, to produce laws explaining the connection between the physical and biological realms. Empire expansion allowed scientists to ask, for the first time, questions that demanded observations on a world-wide scale. Dettelbach had suggested that Humboldtian science was first natural history, its collection and classification and secondly physical science, measurement, instrumentation and error estimation. This dissertation is a history of why tidal theory became important when it did and how the advances in tidal theory were accomplished. It is a history of the organisation, funding and pursuit of science that particularly takes into account the field workers.

 

Understanding the history of tidal science begins with the seventeenth century origins then moves to problems uncovered in the eighteenth. Newton ’s fundamental explanation did not account for the irregularity found in Europe and then later, in the rest of the world. Conversely the institutional mechanisms necessary for tidal solutions had yet to be created. A few cases of shipwreck are cited as motivation for more accurate tide tables but this facet is thin and could be extended or stressed. Tide tables have a scientific function in that they test theory, tidal study being utterly empirical. Reidy shows that the nineteenth century workers achieved success over their predecessors because of their Humboldtian processes. A number of rule of thumb formulations in the seventeenth century are described without an assessment of their accuracy. By 1778 explicit instructions were published for anyone to determine the method from first principles. Reports published in the Philosophical Transactions expressed how deficient Newtonian theory was in explaining aberrant tidal activity. This caused a decline in faith in Newton ’s theory as it failed to account for observed data. Despite publication in French, Daniel Bernoulli after 1740 had made known that luni-solar distance was related to tidal height and lunar meridian passage to time, this was probably incorporated in the Liverpool tide tables of 1770. These were the most superior known for accuracy, testified by their renown and by the reliance that officials placed in them. However, because of their contemporary pecuniary importance their method of construction remained unknown.

 

Despite the Board of Longitude being inundated with tidal data and requests for payment for theories to be divulged it was the more proletarian Society for the Diffusion of Useful Knowledge with its British Almanac of 1829 that came to be the catalyst for systematic tidal study and analysis. The success of the Mechanics Institute movement was in publishing for the working class, for the education in science of artisans and craftsmen themselves. The virtue of the SDUK was the combination that it was open to all and yet it also attracted people of talent and industry, including fellows of the Royal Society. SDUK was a society for the diffusion rather than the production of knowledge; they published over a wide range of subjects and included a treatise on navigation. Their British Almanac was an immediate success and they were promoting it heavily by its second edition. The Nautical Almanac had declined in accuracy in recent years and did not include tides; the BA and Companion did include them. They also included method, common rules for finding the time of High Water at any place. This was the ancient method first espoused more than a millennium previous, but it was now clearly and simply expressed. Joseph Foss Dessiou had undertaken the Labour of calculating the tides; he worked upon previously published tables which in turn had been influenced by Bernoulli. Unfortunately Bernoulli had only published the ‘vulgar establishment’ for London rather than the ‘corrected establishment’. This then meant a reduction in the value and utility of the BA and caused the SDUK to seek a theoretical understanding of the tides. Beaufort, a society member, considered that practical treatises should be reviewed by theoretically inclined members and vice versa. The SDUK turned to their logarithmic compiler to perfect the error in their tide table, John W. Lubbock. Lubbock had particularly studied the mathematics of Laplace and he was personally interested in physical astronomy, of which tidal problems are a part. He set to work out the tide from scratch, and begun to gather observational data. By November 1829 the ‘corrected establishment’ of London had been properly calculated after Dessiou’s prodigious work. Importantly the BA for 1830, the following year, told how HW London had been obtained. The tide tables of 1829 & 1830 were nothing more than the rule of thumb timed with clocks rather than sundials or the moon itself. From 1830 Lubbock directed Dessiou to incorporate elements of parallax and declination but still had recourse to empiricism. The then Astronomical Society requested Lubbock that he availed the Nautical Almanac of both his heights and times but heights were not added to the BA until 1832. Despite error, by 1832, there were attestations to the tables’ usefulness marking their accuracy.

 

The Hydrographic Office had been formed only in 1795 and it was hungry for accurate determination of sea level, prediction of local vertical oscillation and of Oceanic horizontal streaming. Reidy shows that the study, begun by Lubbock , was made into an enduring one because of a number of factors coming together to sustain the initiative into a full Humboldtian pursuit. The post-Napoleonic peace brought strategic changes, and these combined with technological changes to make the Admiralty actually seek relations with the scientific community of the Royal Society. It was the Society’s philosophical decline and stocking by Navy men which was exactly what made the RS influential with the government. Another medium doing more than merely allowing the study to continue was the British Association for the Advancement of Science, the peripatetic character of its very nature, combined with its willingness to pay for the data to be processed, fuelled the initiative. This institution increasingly came to take tidal study as its own, appearing first on the scene in 1831. From 1815 Britain considerably extended its ‘peaceful’ naval operations further out across the globes’ surface and its policing role was also extended into survey work, facilitated by the peace releasing ships from war purpose to being available for scientific work. The advent of iron hulls and power driven vessels made ships not only deeper in the water necessitating more survey work but it also made their investment the greater and thus required better protection by better survey work – and knowledge of the science of the sea. Between the years 1828 and 1831 science became formally instituted within the Admiralty framework, and by 1830 the government had a scientific budget of £1,000. This dissertation shows with what vigour the RS was pursuing tidal science throughout the early 1830’s.

 

In a strategically important place, such as Dover , there had historically been a continuous military need of tidal knowledge. Tides can not be divorced from surveying, of both land and sea, because of a unifying demand for each of the three interests to find a zero point. This zero point, or datum level, had yet to be decided on; from land surveying interests it seemed natural to take the sea as its base level, the question then lay as to at what level was the sea mean? At first, between the RS and Admiralty in the personages of J.A. Lloyd and Lubbock, the question centered on a choice between mean sea-level and low-water, each of which was not without its problems. As self-registering tide-gauges were introduced they provided new sets of data of a new scientific accuracy and these became an essential part of the Humboldtian element of tidal study. By 1831, with an influx of good quality data, Lubbock began to ask for – and hence seek the support and funding for more data – for longer periods at more widely separated places. As the observational operation did expand it was then strikingly obvious how consistency had to be introduced. Through the RS, Lubbock persuaded the Admiralty not only to observe but to have the results published so that other intellectuals might then ‘discuss’ them. Within its unique approach the BAAS then proposed a United Kingdom wide study for a full twenty four hours and at the same time brought light to bear upon the existence of another long term record held in Liverpool.

 

Study of Whewell the polymath, rather than a dissection of earlier studies, is added to in this dissertation. His entry into science was via writing textbooks, crystallography, and mineralogy; as he searched for a subject he introduced French analytical methods into physical science impressing J.D. Forbes, then after meteorology came his student Lubbock, with interests overlapping Whewell’s own. They first corresponded on tides in the Autumn of 1829. By the time Whewell presented Lubbock ’s paper to the BAAS meeting at Oxford in 1832, Whewell had not only found his subject but was well into it. It was his work on tides that taught him ‘the real difficulties in doing science’. With tides, Whewell became an active researcher. Devoted to his subject, tidology, for over twenty years, he published fifteen papers in the Philosophical Transactions and gained the Royal Society gold medal. Whewell saw in this branch of physical astronomy a need for advancement, which he significantly accomplished in both analysis and methodology. A contribution of Whewell’s was to organise sources of data, which is induction as opposed to Lubbock ’s deduction; through tidal work Whewell was developing his philosophy of the advancement of science, through an antithesis of fact and theory. Within the next five years the BAAS settled several hundred pounds on tidal study and during this time Whewell moved away from Lubbock and his empirical solutions of prediction and simultaneously moved to a philosophical search of theory, aided by field workers. He sought to connect the actual tides in different parts of the world, determining cotidal lines or maps of contemporaneous High-Water and deduced what the cotidal lines should be. At the specific level he highlighted observational error and determined the important qualities for finding the ‘establishment of the port’, semi-menstrual inequality and age of the tide. Whilst Lubbock had made an empirical calculation of the corrected establishment Whewell took this directly from the vulgar establishment, from his cotidal maps; from these maps he could then compile tables to test his theory, the graphical representation being new to science. Whewell went to the roots of the field, studying its nomenclature, history and validity, leading eventually in 1840 to his philosophy work; he was enabled to develop a heuristic with which to practice science. Whewell had two approaches; one long term for finding the laws of phenomenon the other, new, a short term observation of tides to note the waves’ progress.

 

Throughout the middle of this dissertation Reidy shows how Whewell was a successful critic and evaluator of science. Whewell’s pursuit of two lines of enquiry, long and short term, made him the perfect Humboldtian. He viewed science geographically and from within a network of people established a methodology of research based on his study of the philosophy of science. In Chapter 5 Reidy particularly turns to this aspect of Whewellian study – his philosophy and how it closely interacts with his tidal research. In addition Whewell lead in defining some of the hierarchical nature of Victorian science. In the same year, 1834, that Whewell published his most important paper on tidology he also begun his History of the Inductive Sciences, both works were based on the ascension of knowledge from facts, to laws of the phenomenon to laws of the cause. Reidy explicitly attempts to examine the connection between the History and his tidal work. As Whewell actually stated his History was both a precursor and a material source for his later Philosophy. Through the History he found informative instruction of how learning was achieved after error, this he considered to be the ‘inductive epoch’, important and essential in the history of each advanced science. The inductive epoch being the accumulation of facts and their ordering through the use of hypotheses. He saw in the example of Kepler the inductive method at work and the necessary slow march for the creation of a perfect theory to advance from phenomological laws to the causal laws of Newton and the all important verification. The pivotal and unexplained - verification of the general law of gravity – was the whole of tides. Tides as a subject of analysis were needed to close the induction on Newtonian theory, yet they had their own inherent process of induction. Subsequently Bernoulli had been able to advance theory enough to the point of testing with tables of prediction and then to compare these with observation of reality. From a long series of observations, Lubbock had produced tide tables which included the effects of transit time, declination & parallax, Whewell saw that his next step was to seek law of the phenomenon before looking at the cause. When Whewell was able to compare formulae derived from long-term observations of two places and find them to fit so well together he felt he had advanced the research; his first approach was as an extension of Lubbock’s work of finding laws of the data, his second was novel and prototypical Humboldtian covering first the British Isles and then nine countries world-wide. In this Whewell came to declare how tidal research was available to all - to the most humble of practitioners. His appreciation of the calculators might be considered an extreme example of Whewell’s compass, these field workers were nothing less than human computers; Lubbock worked with one, Dessiou, Whewell worked with two, Thomas Gamlen Bunt and Daniel Ross. Neither Bunt nor Ross was admissible to Royal Society soirees as they were not ‘gentlemen’. The dissertation is lyrical of Bunt and Whewell himself was so impressed by both Bunts’ mathematical and intellectual capacity that he quoted him in his report to the RS. Bunt’s work was in confirmation of sea-level being the mean tide. Bunt and Ross were powerfully able to further the main study, Bunt suggesting a look at Barometric effect and Ross that Australian tides could informatively be discussed; each of which resulted in papers by Whewell. Ross’s significant contribution was to considerably expand the number of places in the Admiralty Tide-Tables by more than a hundred. Bunt specialized in analysis and Ross in mathematical organisation.

 

In pursuit of his cotidal maps Whewell conducted research throughout the 1830’s until the ‘Fairy’ experiment of 1840 and thus the study becomes genuinely Victorian. Whewell had discovered a method of gaining knowledge, his heuristic, a knowledge of the history of a subject when his philosophy would then enable further advance. The middle to later chapters includes much specific detail, the result of overseas research and considerably extends Whewellian study. Chapter 5 in particular gives a good view of Whewell’s philosophical concept from a tidal aspect. Whewell elaborated the distinctions that science first discerns what takes place, before discerning why it happened.

 

The final work chapter serves much in the same office as some of the appendices, explaining the effect which Whewell had upon the philosophical, academic and scientific worlds. The chapter focuses on the multi-national tidal experiment of 1835 and extends into the relationship between Whewell and Beaufort. Whewell had turned to tides because of their potential and his philosophy had been developed therein, but his experiments of both 1834 & 1835 were spectacular. In this respect Beaufort was lynchpin to the advances under the Admiralty and its network. Whewell had been most able in securing funds for his early work yet for his experiments to succeed he needed not only the cooperation of his own government but that of those in countries overseas as well. The expansion of data gathering became one under Beaufort’s control. The Hydrographic Office replaced the Board of Longitude as the Admiralty’s research and development branch, and in the effort to build up the branch Beaufort deliberately set out to help Lubbock with observations gathered from all over the world. It had been through Beaufort that Whewell had been given his introductions to the more mundane workers, and then by extending his network through the Coast Guard Service Whewell began, as early as Autumn 1832, to formulate a much more elaborate set of observation and experiment. It was got under way in the Summer of 1834 with a network around just the British Isles and had brought Dessiou under Whewell’s influence. The experiments were such a success Whewell was in a position to convince that the arrangement and reduction of the massive quantity of data was beyond his singular power. The data so labored on by Dessiou, Bunt and Ross was used by the gentlemen for their own personal advances: Lubbock desired to derive establishments from the collected data, Whewell to determine any progression of the semimenstrual inequality along the coast. From the Home Waters experiment Beaufort agreed to Whewell expanding the same the following Summer.

 

The very medium of the British Empire allowed scientists to ask questions demanding observations on a world wide scale, an essential Humboldtian characteristic. This expanding science and the growing Empire each gained from the exertions of the other. There is some analysis of Humboldtian science; how it was organized and why it became an integral feature of the early Victorian era. Until Whewell, the study of tides and their observation lacked focus. His first phase of work had been one of time scale; this emerging second phase was a geographic consideration, making Whewell a particularly Humboldtian scientist. It was a crucial move of Whewell’s to go from viewing the tides through time to viewing them geographically. The first experiment proved propitious because use of a single service enabled observations to be made more regularly, with consistency and in the same manner; an inadvertent spin off was the accuracy introduced by virtue of the officers possession of watches, as a tool of their trade. Chronometers had also been used in Holland , augmenting the absolute mass of data from what were essentially the Empire and the United States . A function of repeating the experiment was to test the accuracy of earlier work – purely Humboldtian. His principal object, in the second experiment, was to determine exact cotidal lines over the ocean – this was his ‘second approximation’. From which he was firstly, able to theorize that an amphidrome must exist and secondly, to see, probably for the first time, that the inequality in the two tides of a day were commensurately in existence throughout the whole of Home Waters, and that it should be analyzed.

 

In this magnificent dissertation Doctor Reidy has demonstrated that early predictions were craft science. J.W. Lubbock assisted by J.F. Dessiou determined the corrected tidal establishments for London and Liverpool . W. Whewell assisted by D. Ross and T.G. Bunt determined the laws which make tidal springs and neaps, and the differences between the two tides of one day; they also determined the effects of lunar and solar parallax and declination. Through the complex help of computers, theoreticians, data gatherers, institutions and patronage methods of prediction were published and their analysis subsequently adopted. The intense detail of this work sets out the systematic development of quantifying the astronomical elements of a tidal wave and this theory was then tested in the utility of tidal prediction. This is the primary study of fundamental work in both astronomy and oceanography and is a gripping read.

 

Paul Hughes, Airmyn, 2001. Back

 

 

David E. Cartwright, 

“On the origins of knowledge of the sea tides from antiquity to the thirteenth century,” Earth Sciences History v.20, no. 2, (2001): 105-126.

 

This scientific review of tidal history contrasts well with Thomas Eckenrode’s historical review of tidal science. Divided into nine parts it considers seven epochs, with some emphasis on causal theories, astrology, lunar and non-lunar theories and the world’s oldest tide-table. The bibliography is exhaustive using the best sources in both humanities and science, with modern writings and acknowledgement of which texts are difficult to obtain.

 

Dr Cartwright introduces the epistemological peculiarity of tides, in that every advance in understanding raised questions leading to more research. The literature review sets the scene well, then delves into tidal word forms and the best consideration of early Indian tides so far written. It is particularly gratifying to see the late Alexander Thom’s often neglected work brought within the scope. Of particular use is the extraction, via German translation, from the ninth century Arab philosopher, Jaqub al Kindi. Al Kindi is an early writer to distinguish between tidal flow and rain water.

 

Consideration of the Ch’hien Thang river bore is taken back to the first century. This informed exposition gives them a scientific context, exploring the relation between loose qualitative terms with modern precision. The article is a good survey of tidal science before the Scientific Review from where Cartwright’s Tides – a scientific history takes off.