Tide and Time – a history of tidal science in Liverpool

This short film, by Andy Lane, Andy Heath and Craig Corbett, is part of the Tide and Time exhibition at the National Oceanography Centre, Liverpool. The exhibition showcases two tidal prediction machines – the Roberts-Légé and the Doodson-Légé. The film also explores the history of tidal science in Liverpool and its development as a port.


Tide & Time Exhibition opens

The Tide & Time Exhibition  is now open to the public.

The exhibition – at the National Oceanography Centre in Liverpool – showcases some of the fascinating achievements made in the Liverpool area in understanding and predicting the tides. The highlights of the exhibition are the rare Roberts-Légé and Doodson-Légé tide prediction machines, extraordinary analogue computers that calculate the rise and fall of the ocean tide. See these beautifully intricate machines up and running at the only place in the world where you can see two of them together.

Bidston Observatory was the home of the Roberts-Légé and Doodson-Légé tide prediction machines while they were still in use. The machines are now owned by National Museums Liverpool, who have carefully restored them to working condition.

Tide & Time is open to the public once a month (usually the first Tuesday of each month from 15:00 to 16:00) or by special arrangement for group visits and events. See this page for information on planning your visit and how to book.

The exhibition will also be open to the public during LightNight Liverpool on Friday 19th May 2017 from 17:00 to 22:00.

The Doodson-Légé machine in the 1990s in the reception area of the Proudman Oceanographic Laboratory. The machine is now on display at the National Oceanography Centre in Liverpool.


Reflections on Time

Kevin F. Taylor

I was recently invited to attend a garden party to celebrate 150 years of the Bidston Observatory, hosted by Stephen and Mandy Pickles on Saturday 17 September 2016 in the grounds of Bidston Lighthouse. This gave me a deep sense of déjà vu, as it reminded me so much of my first day as a member of Bidston staff at the start of 1972.

On that day, I drove up the same well-worn drive, past the sandstone wall entrance, and into the grounds. On my right hand side was a lawn that was shortly to be occupied by the new Proudman Building. But in early 1972 that area looked almost the same as it does now, except for a small vegetable patch that was attended to by a Mr. Connell. He and his family occupied the cottages that belonged to the lighthouse and had been built by the Mersey Docks and Harbour Board. On that balmy Saturday evening in September, I thought it quite strange that, here I was celebrating 150 years of the Observatory, and yet the ‘new’ Proudman Building had been built and demolished (in early 2013) within little more than 40 years, a fraction of the Observatory’s lifetime.

The nostalgia continued as I parked my car behind the rear of the Observatory in almost the same spot as I had on that first day at work. I remembered thinking back; my father would quite often force me to join him on one of his marathon walks. One of his favorite treks was from Moreton to Bidston, then over the Vyner Road footbridge, past the windmill, around the Observatory boundary wall down to the village, then home. In the 1950s and early 60s, I was infatuated by science fiction and men-from-outer-space movies, and TV dramas like Quatermass and Doomwatch. For me, looking over the walls surrounding the Observatory presented all kinds of mysteries: What secrets were hidden inside the huge white domes? My youthful and vivid imagination had no bounds in ‘them days’.

On my first day in 1972, I now had the chance to look at the Observatory from the inside out, as opposed to the outside in. How exciting! As I got out of my car and approached the entrance, a gentleman in front of me held the door open and greeted me with the words “Hello Kevin, glad to see you are joining us”. We then passed through the vestibule door and continued to chat in the hallway for a good ten minutes. He then finished by saying “you will be with Dr. Skinner’s group. I will take you to his office”. He gave a quick knock on the door, popped his head around, and said “Sorry Len, Kevin is not late, my fault I kept him chatting”. I was later taken through to the rear of the building for the mid-morning tea break when the same gentleman entered. I turned to one of the staff and asked “who the nice man was”. “That is Dr. Rossiter our director” was the reply. I was then informed that he was the brother of that brilliant actor Leonard Rossiter from the Rising Damp and Reginald Perrin television shows (come to think of it, they did look alike). [Editor’s Note: see mention of Rossiter and other Bidston Directors in an article by Graham Alcock].

So, allow me to digress about a couple of things that have struck me about time, and why I have given the title of this article as ‘Reflections on Time.’ It seems to me that we have different perceptions of time depending on the situation. For example, my first day at the Observatory was over forty years ago, and yet on that recent Saturday in September, it felt like only yesterday. Another example concerns my grandmother, who was 104 years of age when she passed away. When she was born in 1889, the Observatory building had been completed (in 1866) only 23 years before. So, why were we so concerned with celebrating the Observatory as an ‘historic building’, when my memories of my grandmother do not feel ‘historic’? She was just my Nan. So, time is a funny business.

One of the main reasons for the Observatory was to provide accurate time. This gives me a chance to refer to a hero of mine called John Harrison, who had nothing to do directly with the Observatory but, of course, also had an important role in our maritime history. When a fleet of warships ran aground with the loss of many lives and ships due to bad navigation, a vast reward was offered by the King to anybody who could come up with a good way to improve navigation at sea. The main problem was how to calculate longitude, and many ideas were offered: for example, a crazy scheme for anchoring old redundant ships at fixed positions apart, distributed across the whole ocean. The establishment was convinced that the only way that longitude could be calculated, was by using the stars and planets. Harrison in the meantime concentrated on trying to develop a precision marine chronometer. His theory, that longitude could be calculated by the use of time to good precision, was treated with great disdain.

To prove his theory, he would be entirely dependent on producing an accurate timepiece. This proved to be a formidable task. Not only had it to overcome a ship’s movement, but temperature played a significant part in the reliability of the timepieces he produced. Originally, clocks used a pendulum and weight with an escapement movement, but temperature would increase and decrease the length of the pendulum, making the precision he was looking for unsatisfactory. He spent many years trying to overcome this, by making the pendulum out of metal rods with different thermal coefficients of expansion, but alas to no avail. It was not until the latter part of his life that he produced the famous Harrison timepiece. The connection to the Observatory in this story is, of course, that the calibration of marine chronometers was subsequently to form an important part of activities at Bidston, in addition to the astronomical work in establishing the longitude of the port of Liverpool.

Accurate time has historically not been very important for most ordinary people – the sun came up, the sun went down, and what happened in between was neither here nor there. However, for those people who did need accurate timing (on land), the development of affordable watches and clocks, supplemented by sundials, was enabling decent and routine measurements of time by the end of the 18th century. One way of providing accurate timing information to the general population was by the use of time balls controlled by nearby observatories such as Bidston. A time ball was a large sphere (a ball) on top of a shaft positioned on the roof of a prominent building. At precisely midday (or another time such as 1 pm), the sphere would be dropped and people (including ships’ captains) would set their watches. This was a satisfactory situation only when visibility due to the weather allowed the time ball to be seen. Instead, the time balls were eventually complemented by an audible signal such as made by a canon. Hence, the famous Liverpool “One O’clock Gun” came into being. Originally the Liverpool Observatory was located at Waterloo Dock, and the gun (a remnant of the Crimean War) was fired from the Liverpool side of the Mersey. An improvement was made by moving the Observatory from Liverpool to the highest point on the Wirral side of the river, but close to the Dock Estate, this being Bidston Hill. The gun was relocated to Morpeth Dock in Birkenhead, and was now fired directly by an electrical signal from the Observatory.

Time eventually became a significant factor in everyone’s life, and now controls our lives more and more. Everyone knows about the advent of the industrial revolution, and the development of the railway, and the national adoption of Greenwich Mean Time. Now we are controlled by our smart-phones by time that comes from space via GPS satellites. Everyone is in a hurry or we’ll be ‘late’.

So I have been thinking back to that first day at work. At that time, I had many questions, such as “Why is the Observatory called The Institute of Coastal Oceanography and Tides, or ICOT for short?” Or, “What has oceanography got to do with astronomical observations?” These questions were answered for me over the years as I got to understand the relationships between the heavens and earth, and in particular the relationships between time and the tides, and so the ocean, and how these topics have evolved to become a crucial part of everyday life.

This has been a very brief look, from my perspective, at ‘time’ and at some small aspects of life at Bidston Observatory. It would take many volumes to do it justice to it regarding topics such as the development of tide tables, the use of precise instruments (e.g. for earth tides), the collection of oceanographic data from around the world, the fieldwork at many locations etc. Perhaps other people can cover these topics on this web site. Some of the world’s most famous oceanographic scientists have worked at or passed through the Observatory during its history. I feel very fortunate to have experienced a small part of the wealth of that Bidston history. And I hope that its historical significance is appreciated by future generations.


A brief history of Bidston Observatory

Bidston Observatory was built in 1866, when the expansion of Waterloo Dock forced Liverpool Observatory to re-locate to Bidston Hill. It was built alongside Bidston Lighthouse and Signals Station, on land owned by the Mersey Docks and Harbour Board. George Fosbery Lyster was the architect.

George Fosbery Lyster
George Fosbery Lyster

John Hartnup, astronomer and Assistant Secretary to the Royal Astronomical Society, had been the Director of Liverpool Observatory since it was built in 1843. Amongst his achievements was the calculation of the longitude of Liverpool, which was important for navigation and the development of the port. He presided over the move to Bidston Hill, and continued as director of Bidston Observatory until his retirement in 1885, when he was succeeded by his son. The second director, John Hartnup Jr  died on 21 April 1892, when he fell from the roof of the Observatory while making meteorological observations.

Bidston Observatory and Lighthouse, postmarked 1907
Bidston Observatory and Lighthouse, postmarked 1907

Over the years, the emphasis of the Observatory’s work shifted from astronomy to other things, but always in the tradition of Time and Tide, so important to the port of Liverpool.

Of Time. The progression from observations of the stars, to the determination of longitude, to the calibration of chronometers was a natural one. The Observatory’s two levels of cellars and other features made it especially suited for calibrating chronometers under controlled conditions of temperature and seismic vibrations. Mariners sent their chronometers from all over the empire for calibration at Bidston. The One-O-Clock gun at Morpeth Dock was signalled from Bidston Observatory.

Of Tide. Ever since Liverpool’s harbour-master William Hutchinson (the same fellow who pioneered the use of parabolic reflectors in lighthouses on Bidston Hill) took the first extended series of tidal measurements over a period of nearly thirty years, Liverpool had led the world in tidal studies. This work became centred at Bidston Observatory when the Liverpool Tidal Institute was set up there under Joseph Proudman’s direction after World War I. Arthur Doodson’s work with mechanical computers for tide prediction happened here. One of his machines was used to predict the tides for the D-Day landings.

Observatory staff by the original one-o-clock gun, after its removal to Bidston Hill from Morpeth Dock.
Observatory staff by the original one-o-clock gun, after its removal to Bidston Hill from Morpeth Dock.

In 1969, the Natural Environment Research Council (NERC) took over responsibility for the Observatory. Oceanographic research continued to expand under their auspices. During the 1970’s, the Joseph Proudman Building was constructed in the former kitchen gardens of Bidston Lighthouse.

In 1989, the Observatory, Lighthouse and the perimeter wall enclosing them became Grade-II listed buildings.

In 2004, the Proudman Oceanographic Laboratory moved from Bidston Hill to a new building at the University of Liverpool. Their oceanographic research is still continuing today, but now in the guise of the National Oceanography Centre.

The departure of the Proudman Oceanographic Laboratory from Bidston Hill began a 12-year limbo. NERC’s original plan to sell the site to a developer aroused opposition from local pressure groups, and the spectre of an eleven-story high-rise residential development was averted. In 2012, NERC applied for and obtained planning permission and listed buildings consent (now lapsed) to convert the Observatory into four residential apartments. Later that year, the Joseph Proudman Building was demolished. Having put the Observatory to the market on several occasions, NERC finally sold it in 2015 to a developer (Bidston Observatory Developments Limited), who had outbid a community-led consortium. This was the lowest point in the Observatory’s history. A period of systematic neglect saw a rapid deterioration of the fabric of the building and the appearance of the grounds, exacerbated by water ingress, unpaid bills and a winter with no heating, and the Observatory was nominated to the Victorian Society’s list of the top ten endangered buildings of 2016.

Fortunately, the Observatory was sold again in September of 2016. The new owners have announced their intentions to operate the Observatory as a not-for-profit artists’ research centre and to incorporate an exhibition celebrating the Observatory’s scientific heritage.




Hartnup moves in

This article appeared in the Liverpool Mercury on 20th December 1866, two days before Liverpool’s astronomer, John Hartnup, took possession of Liverpool’s shiny new observatory on Bidston Hill. It makes fascinating reading 150 years later.

The New Liverpool Observatory

Bidston-hill has hitherto been chiefly noted for its picnic parties, and for entertainments in which ham and eggs were the principal ingredients. It will now acquire a wider celebrity as the site of one of the most complete observatories at present in existence – one which is certain to make the Dock Board spoken of with respect by men of science, and to render Mr. Hartnup’s position, as astronomer of Liverpool, an object of something like envy to his professional brethren. For the interests both of the port and of science, it was certainly a good thing that the space which the old observatory has occupied during the last 22 years, on the Prince’s Pierhead, was required for docks. Close to the river on one side, and the murkiest part of the town on the other, Mr. Hartnup was often in a fog, not by any means intellectually, but materially, and still more frequently had his nicest observations interfered with by the smoky canopy which overhung his post of observation. Obliged to cast about for a new site, the dock board selected Bidston-hill as the most eligible situation to be found in the neighbourhood for an observatory. The design and erection of the building were left to Mr. Lyster, the dock engineer, and he and his staff have produced a work of which they have no reason to be ashamed. Commenced in 1864, it has been gradually growing up by the side of the old lighthouse, which formerly was the sole occupant of the height, and now with its two domes and picturesque outline, stands out as a prominent feature in the landscape. The transfer of instruments from the old observatory has been for some time in progress, and at the beginning of next year Mr. Hartnup will probably be able to resume his labours – made still more important by this change – under conditions more favourable than he has yet enjoyed.

Externally, the new observatory has a bold and massive appearance, which accords with the position in which it is placed. A building perched alone at the summit of a hill is in danger of looking insignificant from one or other points of view, but Mr. Lyster has so well arranged the different fronts that from all aspects an effective grouping is presented. Two domes, springing from octagonal towers at the east and west extremities of the south front, are prominent features of the building. Beneath one is the “equatorial”, for making astronomical observations, and beneath the other an instrument called the transit. The domes enclosing these instruments have apertures at several points, and are made to revolve, so that observations can be taken in any part of the heavens. The substantial character of the whole building strikes the observer at once. It is founded upon a rock, and if the waves as well as the winds could come to Bidston-hill, Mr. Hartnup’s castle would not be likely to fall. Strength and solidity are characteristics of Dock Board work, but there are special reasons for making an observatory, from foundation to summit, firm and secure as builders’ skill can contrive. Some of the operations carried on are so delicate that the variation of almost a hair’s breadth would seriously affect the results, and hence the utmost precautions have been taken to avoid the vibration to which all but the most substantial buildings are liable. A deep foundation excavated out of the solid rock and thick stone walls to form the superstructure were not considered sufficient to secure perfect immovability, and to prevent all possibility of vibration from anything short of an earthquake the building has been insulated from the surrounding rock to the depth of 12 or 14 feet by a trench about 18 inches wide. Even this has not been deemed a sufficently stable basis for the transit. That instrument is located immediately beneath the dome at the south-east angle of the building. It is used for taking the time, fixing the latitude, and determining the declination of the stars. These operations require the utmost accuracy of observation, and consequently the most perfect steadiness of position. To support the instrument a huge pillar, nine feet in diameter, has been carried up from the solid rock to the floor immediately beneath the dome, and this pillar, though passing through several floors, and apparently in contact with them, actually touches the building at no part. In other respects, the thorough adaptability of the building to the purpose for which it is intended has been studied. In many of the processes uniformity of temperature is very necessary, and towards securing this lofty cellars have been excavated in the basement, where an efficient heating apparatus, communicating with all the apartments in the building, is situated. The other internal arrangements are in a corresponding style of completeness. There is a fine chronometer room 36 feet long by 21 feet abroad; an anemometer room and a library, each 18 feet by 21 feet; a computation room; and, in short, every provision for carrying on efficiently the work belonging to an observatory. The northern portion of the building forms the private residence of Mr. Hartnup, and in reference to the arrangements of which it need only be said that the comfort and convenience of its occupant have been consulted in every particular.

There are a good many people in Liverpool, we dare say, who have a very shadowy notion of the objects of an observatory, and the labours which Mr. Hartnup has to perform. Quoting from his last report, we will let the astronomer tell in his own words what are the merely routine duties of the observatory :-

Observations are regularly taken with the transit instrument, for the purpose of ascertaining the local time. From the local time so obtained, the Greenwich mean time is deduced and communicated to the port daily by the dropping of the time-balls at the Observatory and at the Victoria Tower. The clocks at the Victoria Tower and Town Hall, and also the seconds clock seen from the Exchange flags, are controlled from the Observatory. The other public clocks on the dock estate are regulated twice each week, and a record is preserved showing their errors at the time they were regulated. The velocity and direction of the wind, and the fall of rain, as derived from the self-registering anemometer and rain-gauge, are tabulated for each hour of the day, and hourly readings are taken from the tracing produced by the self-registering barometer. The results thus obtained are tabulated, and the mean reading at each hour of the day is taken at the end of every month. The ordinary meteorological observations obtained by means of the standard barometer, thermometers, hygrometers, &c., are taken at eight and nine a.m., and at one, three, and nine p.m. daily. A telegram containing the corrected readings of the barometer, wet and dry thermometers, strength and direction of the wind, and general state of the weather for the proceeding 24 hours, is forwarded daily at eight a.m. to the Meteorological Department of the Board of Trade. Weekly meteorological observations are forwarded to the Mersey Docks and Harbour Board, and to the medical officers of health for Liverpool and Birkenhead. Monthly and weekly meteorological observations are forwarded to the Registrar-General of Births, Deaths and Marriages; and a tracing of the record produced by the self-registering barometer, together with an account of the hourly strength of the wind, &c., are supplied daily to the Liverpool Underwriters’ Association.

The value of the observatory in keeping an exact record of time is shown by the fact that in Liverpool there are, on an average, upwards of 2000 chronometers dependent on the time disseminated from the observatory for their errors on Greenwich mean time, and of their daily rates obtained while the ships to which they belong remain in port. Now that the observatory has been removed to Bidston, it is possible that the time-balls will give place to a time-gun, which is found to possess several advantages over the ball. With regard to meteorological observations, their importance is every year becoming more largely recognised, and during the last 20 years Mr. Hartnup has contributed not a little to the advance which this department of science has made by his carefully compiled tables of results.

In a more direct and immediate manner, the observatory at Bidston will be of immeasurable value to Liverpool by reason of the facilities it affords for testing nautical instruments. The seaman is chiefly dependent for a knowledge of his chronomoter, compass, sextant, &c. Errors in these have, times out of number, led to the destruction of noble ships, and the loss of many lives and the importance of efficiently testing nautical instruments has long been present to the mind of the astronomer. At the old observatory, chronometers only could be tested. Its nearness to the docks, the possible proximity of iron ships, and other disturbing influences, rendered the testing of compasses out of the question. At Bidston, all these difficulties will be removed, and it is proposed to erect a wooden house specially for the testing of compasses. If this be done, it is to be hoped nautical men will take advantage of the opportunity afforded them of ascertaining that their compasses act properly. It will also be possible at Bidston to test sextants; and if arrangements are made for that purpose, the Liverpool Observatory will be, with the single exception of Kew, the only place in the kingdom at which these instruments are tested. The practical advantage of subjecting instruments to a systematic test has already been exemplified in the case of chronometers. It is often that three or four voyages elapse before a captain ascertains the exact rate of his chronometer, whereas the testing process at the observatory puts him in possession of the information at once. This is the mode of testing chronometers –

All chronometers received at the Observatory are compared daily with the normal clock, which is kept as nearly as possible to Greenwich mean time. From subsequent astronomical observations, the daily errors of this clock, at the times of its comparison with the chronometer, are deduced, and the correction for each day, thus obtained, is applied to the daily comparisons of all the chronometers. In this way the error of each timekeeper is found daily, with as much accuracy as it is well possible to attain. The temperature in a glazed chamber is kept, by artifical means, between 50′ and 85′, and changed weekly 10′ or 15′, in order to show the change of rate that may be expected on going from a temperate to a tropical climate. The record supplied to the captain or owner of each chronometer, contains its error on Greenwich mean time for each of the first few days; and subsequently it is given at the end of each week, together with the mean daily rate, the temperature to which the instrument has been exposed, and the greatest variation of rate between any two days in each week. The corrections for imperfect adjustment are sometimes found to be so large or so irregular as to render it troublesome or difficult to apply them all efficiently, and in such cases the record becomes a serviceable guide to the maker, as it directs his attention to the peculiar fault, and often enables him to make the necessary adjustment at once.

It is rather puzzling to be told that the wind is made to register its own velocity, force, and direction; that the quantity of rain which falls is measured and recorded without human interference; and that the atmosphere marks its own variations on a sheet of paper. Yet all this is done by means of the anemometer, rain-gauge, and barograph – contrivances as ingenious as they are effective. Any one who has been in the neighbourhood of the observatory must have observed on the roof a sort of horizontal windmill, consisting of four hemispherical cups. These serve the double purpose of keeping a four-feet pressure plate facing the wind and turning the shaft which runs through into the room where the anemometer is situated. This shaft, by an ingenious contrivance, regulates the motions of a pencil placed in contact with a sheet of paper stretched round a slowly revolving cylinder. The sheets of paper which receive the record made by the pencil are divided by vertical lines into spaces equal to the hourly motion of the cylinder, and by horizontal lines into other spaces, representing the pressure of wind per square foot. The barograph, or self-registering barometer, has been in use about three years, and the Liverpool Observatory is the only institution which possesses an instrument of this character. It was invented by Mr. Alfred King, of this town, and shows great ingenuity of construction. In the ordinary barometer the variations in the atmospheric pressure are indicated by the varying height of a column of mercury within a tube; in the floating barometer these variations are made evident by the movements of the tube itself, and its changes of position are recorded in a somewhat similar manner to that adopted in connection with the anemometer. There are various other interesting features connected with the observatory, but we must bring this notice to a close. In many respects, the establishment of the new observatory is an important event, and there can be no question that Mr. Hartnup will turn to good account the increased advantages he will possess for carrying on his useful labours in the fine institution placed under his charge.