Harrison’s second timekeeper, H2, has been in the horology conservation workshop at the Royal Observatory undergoing research for quite a few weeks now and its study is proving most interesting. The complete measurement of all the parts has now been completed and photography is well under way.
West Dean College have been extremely helpful in making their XRF metals analysis equipment available to us, and the Clock Course Tutor, my old colleague Matthew Read, came up to Greenwich for the day to help with tests on a number of parts of H2 which appear to employ unusual alloys.
Some years ago the V&A kindly carried out XRF analysis on some of the parts of H3 and we discovered that Harrison employed various types of tin-bronze, principally in place of steel, which naturally would have been inclined to rust in a marine environment. It is reassuring to find after this recent analysis that those results were confirmed by the same alloys, chiefly a low tin-bronze where good tensile strength is required, and a very high tin-bronze where high compression strength is needed (such as in the anti-friction segments supporting the balances).
As is now well known, these timekeepers run without lubrication, and I was most interested to see if H2, like H1, has survived in good order after 50 years of constant running. I calculated, for example, that the balances, which each weigh over 8lbs, will have rolled on their bronze segments over one and a half billion times! Well, I was astonished to find that, after all those years, the bearings are simply unmarked. I am sure the balances could continue for several more billion oscillations without harm coming to them.
Delays over the photography have meant that the timekeeper’s return to the gallery has also been delayed, but reassembly is now about to start. Further updates will follow before the timekeeper returns to exhibition in the Longitude Gallery, now estimated to be sometime in early August.
The Eddystone Lighthouse is on the treacherous Eddystone Rock off the south coast of Devon, about 18 miles from Plymouth. There has been a lighthouse on this reef since 1698. The first was built by Henry Winstanley and was an octagonal structure made of wood. It lasted until 1703, when it was destroyed in that year’s Great Storm: Winstanley himself was among those swept away in it.
John Rudyerd was then commissioned by Captain (later Colonel) John Lovett – who held the lease – to design a new lighthouse, which was built as a conical wooden structure around a core of brick and concrete. It was first lit in 1709 and lasted until burnt down in 1755, after a spark from one of the candles used to illuminate it set fire to the top of the lantern.
Rudyerd’s Eddystone Lighthouse became the first successful offshore-rock lighthouse in the world. Sailmaker’s view includes four war ships identified by Lovett in 1708 as the Roebuck 42 guns, on the left, together with the Charles Galley, 36 guns, the Swallow, 32 guns and the ketch Aldborough, 24 guns, on the right. All these attended on the construction of the lighthouse, while those beyond bear the flags of the countries who contributed financially to the project. Plymouth harbour is visible in the background.
The National Maritime Museum acquired the oil painting of Rudyerd’s Eddystone Lighthouse by Isaac Sailmaker (1633-1721) in 2000, with major grants from the Macpherson Fund of the Society for Nautical Research, the Art Fund and its own Friends organization. The painting is important for its subject and for the artist. Sailmaker was a contemporary of William van de Velde the Younger and, like him, a Dutch immigrant who came to work in England before 1710. He is now known to have done four versions of this painting for Lovett but this one proved important in identifying his artistic hand, when it was first lent to the Museum in 1971. Until then there was no clearly documented painting by Sailmaker, who did not generally sign his work. An engraving of one of his Eddystone versions, naming him as artist, was published in 1733, proving the subject was by him and allowing firmer identification of other compositions hitherto only thought to be. In 1991 the owner took back the one lent to the Museum, however, and it was only after his death that we were able to acquire it permanently.
The painting is in oil medium on a linen canvas support measuring 1240mm x 1006mm. Overall it is in good condition, the original paint having been quite smoothly applied with a little impasto in the clouds and waves. The craqueleure is fine and even.
This photo shows it before conservation treatment. Paintings are always photographed and their condition documented before any work is undertaken.
The natural resin varnish layers, which were originally clear, had become very discoloured over time. The surface was also dirty, probably with soot from candles or an open fire, which obscured the colours and detail. In addition, the paint layers were loose and flaking in some areas, which can be caused by changes in the environment as high humidity or dry conditions make the canvas relax or tighten. This movement can eventually weaken the adhesion of the paint to the canvas, making it loose and, at worst, starting to fall off.
It is important that these weak areas are consolidated before any further treatment is undertaken. This photograph shows small pieces of tissue which have been impregnated with a suitable adhesive and laid over the loose areas of paint. A temperature-controlled heated spatula is used to gently warm the adhesive and reattach the flaking paint. The areas of tissue are then removed.
When the paint layers are stable the surface dirt can be removed. This is the layer of pollutants that lie on top of the varnish layer. The dirt can be nicotine, soot or straightforward environmental grime.
The natural resin varnish layers themselves can also be removed without damaging the original paint layer below. This photo shows a detail of the lighthouse during cleaning. Since most pictures of this age have been cleaned in previous centuries, by harsher methods than used today, the paint layers here show slight wear but the ships’ rigging is in good condition.
After the painting has been cleaned a synthetic varnish is applied with a brush, before final retouching, to protect the original paint. This is a specially made conservation varnish, which will not discolour and will remain easy to remove with a mild solvent.. Small areas of damage are then retouched with the same resin and dry pigment.
The final photograph shows the painting after conservation treatment has been completed.
The painting has now been reframed, glazed with low-reflect glass and the back of the frame fitted with a sealed backboard. This will protect the painting from climate changes and from dirt in the atmosphere, and will ensure that it looks as fresh in 100 years as it does today
The picture has been requested for loan to Chatham Historic Dockyard for display, in their new exhibition gallery in the No 1 Smithery, where most of the Museum’s ship models will also be rehoused later this year in a joint project with the Dockyard and the Imperial War Museum. The gallery will open to the public on 20 July 2010.
For the last few weeks, H2 has been in the horology conservation workshop at the Royal Observatory undergoing research. The work, which is part of the continuing research for a full published catalogue of the NMM’s collection of marine chronometers, involves the complete dismantling of the timekeeper. Every part is being studied, measured and photographed, the intention being to take a fresh look at Harrison’s work on his longitude machines.
Last year H1 was dismantled and studied, and some interesting comparisons can now be made about Harrison’s early work. It has always been believed that the simple portrayal of Harrison as a lone craftsman, was too simplistic, and we know that H1 was constructed with the help of Harrison’s brother James, and almost certainly with advice and supplies from George Graham’s contacts in London.
Harrison is known to have had help in his construction of H2, which was made in London, and the current study confirms this, with a much more professional feel to the materials and the finishing of this timekeeper; if H1 is a reminiscent of a fascinating ‘country clock’, then H2 has all the trappings of a ‘scientific instrument’.
There is no doubt Harrison had help in construction, but this doesn’t diminish the status of this extraordinary timekeeper, which teems with interesting ‘Harrisonian’ designs and construction features.
The timekeeper is now completely dismantled and before reassembly can begin there is full photography and measurement for CAD drawings to be done. Analysis is also planned on both the special alloys and the wood used in the timekeeper. It has always been said that the latter is lignum vitae, but as far as is known this has never been positively proved before.
Further updates will follow before the timekeeper returns to exhibition in the Longitude Gallery, now estimated to be sometime in late July.
The NMM is continually working to increase online access to its collections and, thanks to a grant to aid photography from the Gladys Krieble Delmas Foundation, over 400 drawings have just been added with often detailed commentary on what they show.
These drawings are from sketchbooks, mainly by Royal Navy officers as they sailed around the world, giving us views of tropical islands, exotic cities and native peoples. The works give a valuable and often humorous insight into life aboard ship during the 18th and 19th centuries and how the ability to draw a landscape was not just a pastime but also a means of intelligence gathering.
I hope you enjoy these drawings and that you are as intrigued by the content as I have been.
Lt James Henry Butt, Tombs of the 47 Ronins, Yedo (PAJ2063)