Before Big Ben

Pre-Victorian Turret Clocks and Their Preservation

Jonathan Betts

The wrought iron, turret clock in the chapel at Cotehele (National Trust) in Cornwall, c1485. The frame is of 'door frame' construction.
Figure 1: the wrought iron, turret clock in the chapel at Cotehele (National Trust) in Cornwall, c1485. The frame is of 'door frame' construction.

According to all the best sources, the very first mechanical clocks of all were turret clocks, in the form of large, wrought-iron movements, built in the great monasteries and abbeys of central Europe in the late 13th century. As such, these early turret clocks, together with millwork, represent one of the very first engineering technologies, the very basis upon which geared machinery of all kinds developed in the centuries which followed, and they should not be seen as crude concepts but, in the context of their time, highly sophisticated creations.

Intended only to sound the hours for prayer during the night and during cloudy days when a sundial could not be used, the primary function for the majority of these early clocks was to provide an audible indication of the time. The term 'clock' derives from the Latin 'clocca', for bell - most of these early timekeepers had no dial at all - and for many centuries after, the term clock specifically referred to a machine which sounded the hours on a bell. Few early clocks survive as intact as the hour-striking movement dating from c1485 in the chapel at Cotehele in Cornwall (Figure 1). Typically, it is weight-driven, although the mainspring as a driving source for smaller clocks, for domestic use, had been invented in the mid 15th century. The weights hang on ropes wrapped around wooden barrels to drive the clock, and are controlled by a verge escapement, with a folio as a controller. The escapement and controller form the 'beating heart' of a clock and it was improvements in these parts which would contribute the most to improving accuracy in mechanical clocks and watches in the following centuries.

The verge escapement controlled by a foliot however (Figure 2), as in Cotehele's movement, was a poor timekeeper. The foliot, a horizontal bar with weights suspended at either end, oscillated to and fro at a rate entirely dependent on the driving force delivered from the train (the series of wheels in the movement) to the escapement. As an oscillator, it had no 'natural frequency' of its own and, at the end of a day's running, these clocks might easily be out by as much as half an hour.

The parts of the Cotehele clock. All striking turret clocks are made up of these basic parts. The oscillating foliot, slung beneath the frame of the clock, is shown here as part of the escapement.
Figure 2: the parts of the Cotehele clock. All striking turret clocks are made up of these basic parts. The oscillating foliot, slung beneath the frame of the clock, is shown here as part of the escapement. (David Penney)

The important breakthrough came with the invention of the pendulum as a controlling device, which was just one of many scientific strides forward made during that fascinating and exciting period in mid-17th century Europe, often called the 'Scientific Golden Age'. The pendulum was a very good timekeeper because, influenced by gravity, it had a natural frequency. Although the great Italian astronomer Galileo Galilei had conceived a design for a pendulum clock in 1641, it was the famous Dutch scientist Christiaan Huygens who created the first practical pendulum clock design in 1656.

The Dover Castle clock, c1635, now on display in the Science Museum, London. It is of the 'end-to-end' layout, with its original foliot mounted on the top of the movement.
Figure 3: the Dover Castle clock, c1635, now on display in the Science Museum, London. It is of the 'end-to-end' layout, with its original foliot mounted on the top of the movement.
Turret clock movement by Christopher Gould of London, dated 1695. This movement has the trains next to each other in the 'side-by-side' formation, most common from 1670. (Belmont)
Figure 4: turret clock movement by Christopher Gould of London, dated 1695. This movement has the trains next to each other in the 'side-by-side' formation, most common from 1670. (Belmont)

Suddenly clocks were capable of timekeeping to within a few seconds a day! Needless to say, most new clocks were now designed to incorporate the pendulum and virtually all the older clocks, including turret clocks, had the foliot replaced with a pendulum to improve the timekeeping. Such alterations are today considered very much part of the clock's history, to be preserved along with the original parts.

DEVELOPMENTS

After the introduction of the pendulum, many of the major developments in turret clock design occurred in the Victorian era, outside the scope of this article. Mainstream pre-Victorian improvements chiefly concerned the layout of the frame of the movement. From the medieval arrangement where the striking train was usually behind the going train (the end to end frame, Figure 3) or one above the other (the door-frame construction, Figure 1), the incorporation of the pendulum and the anchor escapement (which used a longer pendulum) in about 1670, led to a new layout where the trains are side-by-side (Figure 4). A variation on this arrangement dating from the 1720s and originating in the north of England, saw the barrels extended out at the front of the movement to form a double frame (Figure 5), sometimes incorrectly called a 'chair-frame'.

Around the middle of the century another form of frame appeared, mirroring smaller domestic clock movements, known as a plate and spacer construction (Figure 6), and at the same time there appeared a form which became common place - the posted-frame (Figure 8). At the very end of our period the final form of frame, the flat bed, appears in British-made turret clocks, nominally from the 1820s (but from the 1730s in France and with isolated examples in Britain in the 18th century too).

Movement of the turret clock, by Whitehurst of Derby, c1765, at Shugborough Hall in Staffordshire (National Trust). This is of the 'double frame' construction where the barrels are extended at the front to allow more turns of line.
Figure 5: movement of the turret clock, by Whitehurst of Derby, c1765, at Shugborough Hall in Staffordshire (National Trust). This is of the 'double frame' construction where the barrels are extended at the front to allow more turns of line.
This movement is of the 'plate and spacer' form, in this example, at Waddesdon Manor in Buckinghamshire (National Trust), made by Moore of Clerkenwell in 1883, but the type was made from the middle of the 18th century.
Figure 6: this movement is of the 'plate and spacer' form, in this example, at Waddesdon Manor in Buckinghamshire (National Trust), made by Moore of Clerkenwell in 1883, but the type was made from the middle of the 18th century.

The materials and fixings used for the frame changed too. Once the side-by-side frame was established there was a gradual move from the frame parts being held together with wedges in holes, over to frames completely fixed together with square nuts on threads. Some clockmakers in particular regions of the country had always used frames of wooden construction but the most common material, wrought iron, also changed during the 18th century to cast iron. An intermediate form, often seen in movements made during the middle of the century, employs cast iron members for the frame, but with wrought iron inserts for the threads holding the frame together, as this form of iron is stronger in tension and shear.

By the 18th century and probably long before, most clock frames were painted for their protection, and the preservation of historic paint layers is very much an issue for today's turret clock conservator.

THE IMPORTANCE OF THE TURRET CLOCK

Unlike domestic clocks and watches, turret clocks were distinctly public in their role, with many more people depending on their good timekeeping, yet they were often expected to perform under conditions no other form of clock would tolerate. The very size of the dials and hands and their exposed situation puts additional burdens on turret clocks and the remoteness of their placing, often high up in a tower or roof space means they have to tolerate poor environments, atmospheric pollution, wide variations in temperature and humidity and often considerable neglect. To produce a good turret clock was therefore quite a technical achievement and over the years many very interesting and historically important designs have been created.

The turret clock at Dudmaston, Shropshire. Successful preservation of turret clocks by the National Trust provide hope and inspiration for thousands of parishes with ancient turret clocks, some of whom have to be persuaded that they should be preserved at all.
Figure 7: the turret clock at Dudmaston, Shropshire. Successful preservation of turret clocks by the National Trust provide hope and inspiration for thousands of parishes with ancient turret clocks, some of whom have to be persuaded that they should be preserved at all. (National Trust Photographic Library/Michael Caldwell)

Even when rapid developments were taking place in smaller clockwork, many of the good and great in the clock-making world exerted their finest efforts in designing and building turret clocks, and indeed some of our most important surviving horological artefacts are turret clocks. In short, there's a wealth of fascinating and historically important turret clocks in this country; a heritage to be enthusiastic and proud of and which we clearly should be preserving. As for pre-Victorian examples, it is very difficult to be certain about how many have survived, but according to figures kindly provided by Chris McKay of the Antiquarian Horological Society's Turret Clock Group, an informed 'guestimate' would suggest somewhere between 4,000 and 8,000 examples remain in the UK of which about half could be in churches across the land.

PRESERVATION

Posted frame movement from the stables at Hatchlands Park (National Trust) in Surrey. The main elements of the frame spring from four vertical columns at the corners.
Figure 8: posted frame movement from the stables at Hatchlands Park (National Trust) in Surrey. The main elements of the frame spring from four vertical columns at the corners.

As for the preservation of these fascinating machines, the reality is that even today we are still struggling to persuade some parishes and owners that these clocks should be preserved at all. But things are changing, and if we are in the fortunate position of giving advice on such a clock's future we should only give one kind of advice, that which will ensure its most complete preservation. It is sometimes argued that if the clock is of a known, 'standard' type, it need not be preserved so strictly, as such clocks are all basically much the same, but if there is one thing we learn in horology it is that there are exceptions to every rule. If these standard clocks really are standard then let them tell us so with their own information. Just as in a political democracy, only if the majority can be included can a meaningful consensus be found.

These days, in studies of watch and clockmaking, researchers are becoming more and more demanding in the data they hope to find, and we are starting to see this in turret clocks too. There is so much we still do not know about how turret clocks were designed, ordered, constructed and supplied, and the clocks themselves can help with that research. Nevertheless, conservation needs to be practical, otherwise it isn't good conservation, and those responsible for the preservation of turret clocks must recognise that most of them really are expected to work and keep reasonable time. It is true that, all other things being equal, turret clocks will always last longer if not working, and in some exceptional cases, this might be considered as an option, with the movement preserved in situ, with an alternative means of driving the dial. With pre-Victorian clocks, especially the early ones with wrought iron wheels, the wear caused by use can be considerable. In this latter category, the conservator may decide that, as well as oiling the pivots running in the frame, it is necessary to lubricate the teeth of the wheels, something horologists would never normally contemplate in ordinary clockwork.

tTe turret clock at Osterley Park in West London
Figure 9: the turret clock at Osterley Park in West London (National Trust Photographic Library/Rupert Truman)

The interesting large brass movement (Figures 9 & 11) by Richard Street of London at Osterley Park, the National Trust property in West London, is an example of an important clock movement which is now badly worn and which would have required such extensive repair that the decision was taken not to run it. A synchronous electric movement was installed to drive the dial and the original movement is preserved in situ. The only conditions in this decision were that no irreversible alterations whatever were to be made to the existing arrangement, and that the apparent movement of the hands on the dial must be as the original movement, precluding the use of a radio-controlled half minute or minute impulsed hand. The movement has been cleaned and is made available for study, but will not be run regularly for the foreseeable future. It would be absurd for us to demand that all worn turret clocks are preserved in this way, so it is all the more important that we ensure they are conserved as well as possible in use. Here, it might be useful to describe how the National Trust aims to achieve the best preservation of its turret clocks.

PRACTICAL CONSERVATION - THE NATIONAL TRUST'S APPROACH

In the Trust, sensible maintenance is balanced with the old, but still very true, clichés of 'less is more' and 'if it ain't broke, don't fix it'. This approach means the simple surface cleaning of movements to remove active corrosion, old dirt and accretions and to thoroughly clean the acting surfaces and bearings of old oil. Minimal and narrow bushing (the lining of a worn hole with new metal) of worn bearings and essential repairs are the order of the day. Where parts are badly worn or broken, every effort is made to keep as many of the old parts in the clock as possible. Where parts have been obviously but not ridiculously badly repaired, these too would be left. One restorer recently rang asking about an 18th century turret clock movement which had hexagonal nuts holding the frame together. The nuts were not original but were perfectly sound and he was recommended to leave them alone. "What will later people think about my work?" he complained. Here is where documentation is important and the Trust insists on a complete report of work carried out, including complete train counts, and all relevant observations on the condition and originality of the clock should be made then. Obviously there are limits to this preservation policy. Where there has been very poor work, which either endangers the safety or reliability of the clock, or the work is blatantly botched, then, with the agreement of the National Trust, things are put right. However, it has to be said that this situation arises very rarely.

Painted frames and alterations
Similarly, the repainting of frames is very rarely now undertaken. Paint samples taken from existing paint layers on clock frames can provide useful information about possible original paints and later repaints, and all of these should be kept if possible. Where the environmental conditions around the clock are a problem, the Trust is now researching practical ways of protecting the movement by controlling relative humidity and temperature, and by improving the physical protection of the movement from dust and grit, and from pests, with casing, conservation heating and insulation, and by careful pest control. If it is decided that repainting is the only course, it would be much better simply to clean down the existing paint and paint over it rather than to strip everything off beforehand. As for later alterations in turret clock movements, the Trust sees these as very much part of a clock's history, something it is interesting to distinguish from original parts by study, but not something one should ever attempt to remove and restore. After all, as Shakespeare has it: "what's done is done and cannot be undone", and all we would be doing is to just make yet another change to the clock in the 21st century.

THE CLOCK AS A PART OF THE BUILDING

When considering the preservation of a turret clock, remember that the movement itself is only one part of the mechanism as a whole. The movement is driven by weights which in turn usually run down shafts in the building known as weight chutes; the movement connects to the dial or dials via connecting rods known generically as lead-off work (which itself often includes right-angle drives known as bevel-work), and behind the dial or dials will be found the gears known as the motion work, which convert the one-revolution-per-hour drive for the minute hand into the one-revolution in 12 hours for the hour hand. With striking and chiming clocks, there are the additional connections to the hammers which strike the bells, and then there are the bells themselves which form part of the clock as a whole. All of these parts need the same careful maintenance and protection as the main movement but, being less accessible, are often more neglected and are more often than not one of the main components which break-down in the clock.

The 'flat bed' construction movement by Smiths of Derby at Dudmaston (National Trust) in Shropshire. The whole frame has unfortunately recently been stripped and repainted.
Figure 10: the 'flat bed' construction movement by Smiths of Derby at Dudmaston (National Trust) in Shropshire. The whole frame has unfortunately recently been stripped and repainted.

Historic buildings are increasingly having new uses found for them and with those containing turret clocks it is important to get in early to protect the clock's interests. In the past, turret clocks have often simply been removed, but after a case heard at a public enquiry in 1994, a precedent was set whereby the turret clock was determined to be a fixture in a listed building, and removal should not these days be an option. However, buildings with clocks are still being converted, and weight chutes have disappeared, turret clock movements and lead off works have been almost completely boxed in and so on. Beware of architects bearing plans!

ELECTRIC AUTOMATIC WINDING

The unusual brass turret clock movement by Richard Street of London, 1714, at Osterley Park in West London (National Trust). The movement is now being preserved without functioning.
Figure 11: the unusual brass turret clock movement by Richard Street of London, 1714, at Osterley Park in West London (National Trust). The movement is now being preserved without functioning.

The weekly winding of turret clocks is often seen as a chore and the issue of electric winding usually arises sooner or later. In the National Trust the first course of action is to resist auto-winding and to try and persuade local staff to perform that duty. If this is impractical, auto-winding is an acceptable option as long as the work is to an acceptable specification and is fitted entirely reversibly, without so much as a single new hole drilled in the clock. The specification the Trust prefers is usually either the Huygens endless system, if there is space, or the epicyclic auto-winding unit, as long as the latter is applied low down in the train and has sufficient fall on the striking side to ensure it does not operate during striking which will result in the rate of striking changing. Another way around this problem is to arrange the auto-winding switch always to activate as striking commences.

All forms of electric driving mechanism applied to the movement, and all forms of auto-winding which cause the wheel train to drive in the opposite sense from its intended one, are totally unacceptable, even in the case of heavily weighted carillon machines. This is because a wholly different wear pattern will result on surfaces not normally in action and, with striking and chiming trains, because a very jerky and uneven striking of the bell will result, with extra stress on acting parts. Similarly, the use of winding pinions as part of the driving train is unacceptable. Driving from the lowest part of the train is always the ideal solution, and does not necessarily mean the use of very heavy driving weights, as reduction gear can be fitted on the unit to increase the mechanical advantage of the driving weight.

Advisers on turret clock maintenance do have this significant difference from other clock advisers. Turret clocks are usually themselves very heavy, are usually in high places, and often have high stored energy in weights and pendulum. Health and safety plays a very important part in advice and naturally must always come top of the priorities. If there is any doubt about the physical security of a pendulum suspension spring or weight lines it goes without saying that they should be replaced. Like all parts replaced on antique clock movements, the new parts should be marked to identify when they were fitted, and the replaced parts must be returned to stay with the clock. The National Trust requires that the conservator's initials and the year are punch-marked on parts, where practicable.

CONSERVATORS AND CRAFTSMEN

Choosing the right kind of craftsman to work on turret clocks is another important issue. The experience of the National Trust over many years is that it is much safer to use clockmakers who specialise in turret clockwork exclusively. There are always going to be exceptions to this rule, but the Trust feels it is much safer to use those who work with these special clocks professionally every day. Secondly, experience has shown that it is better to use nominated individuals as turret clock conservators. This doesn't mean avoiding the larger companies, but it is always preferable to know the person doing the work. With turret clockwork, there is a greater need than in ordinary clockwork for workmen or women who can be relied on to use their discretion and make decisions independently, on site. How the work is done is often a rather personal thing and knowing you can trust the individual's judgement plays a large part in it. In summary then, pre-Victorian turret clocks may be large and may look more like agricultural machines than precision instruments, but all of them have a significant place in our horological heritage and adopting a conservative approach to their preservation today leaves the historical evidence for us to study and leaves the options open for future generations of clockmakers and historians to interpret.

FURTHER READING

Beeson, C F C, English Church Clocks 1280-1850 Antiquarian Horological Society, 1971

Grimthorpe, Edmund Beckett, Lord, A Rudimentary Treatise on Clocks and Watches, and Bells for Public Purposes, Crosby Lockwood, 1903

McKay, Christopher, The Turret Clock Keeper's Handbook AHS, 1998

McKay, Christopher, Stands the Church Clock, Bury St Edmunds Museum

McKay, Christopher (Editor), A Guide to Turret Clock Research, AHS

This article is reproduced from Historic Churches 2002

Author

JONATHAN BETTS is Curator of Horology at the National Maritime Museum. He is also horological consultant to the National Trust, Wallace Collection, the Harris Collection at Belmont in Kent and the Worshipful Company of Clockmakers. He is a member of the Clocks Committee at the Council for the Care of Churches and a Huntington Fellow at the Mariners' Museum at Newport News Virginia. He has lectured widely on the subject and written many articles, letters and reviews in the horological and antiquarian press.

Further information

RELATED ARTICLES

Rebuilding a Church Spire

Funding Cathedrals

Historic Methodist Architecture and Its Protection

RELATED PRODUCTS AND SERVICES

Clockmakers

BuildingConservation.com
Site Map