Horological Butchery in the Piazza San Marco

Martin Burgess writes:
FULL MARKS to Renato and Franco Zamberlan for their superbly written and illustrated articles on the great clock. Full marks also to our editor and his team for presenting them so well. The story is not a happy one.
To those who know the wonders of the Piazza no word is needed. To those who have not experienced the artistic wonders of Venice there are no words in any language of man which can give any idea of those wonders. Unfortunately for the world, Messrs Brusa and Gorla have stuck their clumsy boots right in it.
I write as a Fellow of the International Institute for the Conservation of Historic and Artistic Works. Election is by international ballot and I have been one since 1955. The IIC has representatives all over the world. There are about 130 members in Italy alone. It has a very strict code of ethics concerning what you may or may not do to an antiquity. Our own BHI code of ethics is based on it. No one should ever change an antiquity except to preserve it for future generations. If, like a clock, it has to work, then the only work done should be that required to keep it working. The fact that things were done to this clock in 1858 should be of no consequence at all to the conservator — it is part of the history of the clock and must remain, in as far as this can be done.
The Zamberlans do not have to argue their case. Their photographic evidence is there for all to see. I am very familiar with the attitude typified by Gorla’s work. IIC spent the 50s and much of the 60s overcoming such approaches in UK museums. Some people were persuaded to change, some were moved sideways where they could do less harm, some retired and some died.
There is always a risk, especially where the ‘restorer’ is self employed, that corners will be cut and as little work as can be got away with, will be done in the shortest possible time. If such a man is to be employed then the materials and the craft methods used must be specified precisely.
Brusa is of course a renowned and very senior horological historian. If he had the authority to say exactly what should be done, it is to my mind absolutely inconceivable that he should advocate the basic changes in the digital display release mechanism and the escapement. Both of these were unnecessary, both cost a lot of money and both make the machine a worse clock.
It is axiomatic that if you want to let off an intermittent movement from a constantly moving machine, you trigger that movement from the fastest moving part. The clockmakers of 1857 were quite right to unlock the 5 minute drum from the escape wheel arbor. Properly done the energy consumption would be very small and would hardly fluctuate at all. Why change it if it was working? Or did the changed escape wheel and the lengthening of the crutch arbor preclude this? There will be irregular motion lower down the train so however well the new work has been done the let off of the drums will be less accurate than before. That is what the citizens; of Venice are going to see, a large sum of money spent to produce a worse result.
The clockmakers who made the long pendulum were absolutely right on three counts. First they supported it on a wall bracket. It is a bad plan to suspend a heavy pendulum from the clock frame, however robust it is. Second, the influence of the escapement on a pendulum depends on the length of the moment arm of torque on the pallet arbor in relation to the length of the pendulum. A turret clock must have surplus energy to get it through bad conditions like thick oil in winter. Small, light, delicate escapements can not be used. The only solution was to use a long pendulum. Third they used a wooden pendulum rod.
If the pendulum is not temperature compensated, wood, if it has been properly treated first to keep the damp out, is a good material. For the change of length of rod between a hot day in summer and a cold day in winter I would expect a time difference of about 5 seconds a day. Now the rod is steel I would expect an error of about 13 seconds a day. Is this an improvement? It is a public clock and, unlike any other great city I know, Venice is not pestered by the noise of traffic. The strike can be heard at a Great distance, I have often checked it with my watch, right over on the Zattere. Do the city fathers want to be laughed at, or more probably hated, after £150,000 has been spent to make this clock a worse timekeeper? The Temperatore is going to have to check and correct the clock at least once a day. Surely that was not the aim.
There is another problem which has been introduced which is, to my mind, far more serious. It is a feature of the dead beat escapement that the escape wheel must move suddenly from rest when the pendulum, and with it the pallets, are already moving. Nothing of any mass moves instantly from rest so to get the teeth or pins to impart the maximum energy to the pallets the escape wheel should be light and the pendulum should be slow. Gorla and Brusa have produced a worse mechanical system by making the pendulum faster and escape wheel heavier. With greater inertia much of the impulse may be lost, to be absorbed with a bang on locking after the considerable drop. Not content with that Gorla has made the pins from cap screws, which are not only a soft material but the considerable mass of their heads adds weight at the rim, the worst possible place. On top of all this, automatic winding can lead to neglect.
There was a lot of drop in the 1857 wheel, at least half a pin diameter, but then, and in 1755 the clockmakers could have used a Lepaute wheel. In this the original diameter of the ping is thicker, the upper half is cut away and part of the lower half also. This allows maximum impulse and a drop of only 0.5°. The pins of course would be individually made from good steel, hardened, tempered and polished. It would be a lot of careful work but the load on the whole going train could be reduced and the wear would be less.
Gorla and Brusa will get the clock to work by increasing the energy throughput, which will wear the train more quickly. Do these men not know anything about the mechanics of horology?
The man I am really sorry for is the last Temperatore, Alberto Peratoner. He grew up with the clock just as his father did and, I suppose, his grandfather. That great clock is in his blood. He knows all of it, its lubrication points, its ways. Yet this one man who knows it all was, we are told, pushed off the Committee. Of course, every time he went home he was entering a gold mine. I tremble to think what that flat in the clock tower must be worth in rent at the height of the season. Is that the reason for it all? It certainly looks like it to me.
That great clock which we all love, needs watching on a daily basis, like ‘Big Ben’. It is up to every one to see that things are put back the way they were.

Martin Burgess FIIC, FSA, FBHI
Boreham, Essex.