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To better understand the interest of these clocks, we should briefly recall the history of the appliances and machines used to divide the time until the appearance of the mechanical clock around the year 1300. To do so, we are going to refer to Echeverría's [7] clear and concise book.

The first clock of humankind was obviously the sundial which is as old as our civilization. The egiptian's obelisk, our menhirs and cromlechs were no more than sundials and astronomic observatories.

The sundials made with an iron stick fixed in a semi-spheric hole seem to be Chaldaic inventions and already in Greece they became very popular adopting later several shapes. Until the eighteenth century, this kind of clocks was still used to verify and set the mechanical clocks.

Another kind of clock was the astrolabe the invention of which by Hipparchos took place in 150 before Christ, and of which the evolution gave rise to the octant and later in the eighteenth century to the sextant which is still used by sailors today.
But even if our father sun is honest and precise, he has some inconveniences: what happens at night or if it is cloudy?

The medieval astronomers used a sort of astrolabe called "nocturnal" but with cloudy weather the problem persisted. Some devices were used with more or less success to solve this problem, even though they measured short periods of time, such as hourglasses or "fire clocks" of a very primitive origin which consist in measuring the time taken by a substance like oil or wax to burn out.

But the most widely spread was the water clock or clepsydra, of an unknown origin and already existing in Ancient Egypt. The idea is very simple: the water slowly leaks from a first container filling a second one, properly calibrated, whose marks permited to control the elapsed time. But this invention continued its evolution until its higher scientific expression in China, where a buddhist monk called L'HSING invents – in 725 A.D.- the first clepsydra with "escapement" like a watermill..

This date is memorable because the escapement is the fundamental piece of any hydraulic or mechanical clock as it is in charge of regularising the movement as we will see later.

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drawing dondi structure

Let's focus now on the gothic mechanical clock, the first real clock protagonist of this exhibition. The mechanical clock is the machine par excellence, the original mechanism. This rough assembly of cogwheels and iron sticks which constitutes a gothic clock gave rise not only to our modern chronometres but also to all our present and future mechanisation.

No one remembers nowadays that the locks of the firearms, all the devices moved by springs and all the inventions who made automation possible come from these first mechanisms. All the industrial nucleus of the Renaissance was developed from a trade still gothic : the mechanical clockmaker.

We will try to explain in a simple way the basic principles of what we call a mechanical clock, which has remained the same in its main parts till our days.

First of all we need a motor able to move the mechanism. This motor will first be gravity using weights and later a spring in table clocks. The stress of these motors is transmitted to a great toothed wheel which transmits it to other ones (Catherine wheel, etc...) in such a way that the last wheel will turn very quickly, while the one near to the motor's stress, will do it very slowly.


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The slow and regular working of the clock is imposed by a regulator which represents the speed of time. This main mechanism, which consists of the escapement and the regulator, deserves a detailed description:
the escapement with pallets is the first that we know and in spite of further very sophisticated inventions, it still existed in some clocks until the middle of the nineteenth century. This escapement is composed of an axle with two small pallets fixed to it, forming a right angle between
them.

These pallets mesh alternatively with the teeth of a wheel called crown or meeting wheel. The motive force makes the meeting wheel turn but the swinging of the pallets reduces the speed of the movement making the wheel turn with little jumps; this sincopated turning produces the characteristic "tick-tock" sound of the clock and is the basis of the escapement system. But this system is not a guarantee of the slow and regular working of the clock, we have to add a "regulator" or a "time controler".

The most primitive of these are constituted just by a swinging balance wheel, or by the "foliot" which is a stick with small weights on its sides that can be regulated.

These pallets mesh alternatively with the teeth of a wheel called crown or meeting wheel. The motive force makes the meeting wheel turn but the swinging of the pallets reduces the speed of the movement making the wheel turn with little jumps; this sincopated turning produces the characteristic "tick-tock" sound of the clock and is the basis of the escapement system. But this system is not a guarantee of the slow and regular working of the clock, we have to add a "regulator" or a "time controler".

This system is strongly fixed to the axle of the escapement and with it we can make the clock go faster or slower.Naturally, the face of these clocks has only one hand; the minute hand will appear with the pendulum, in the eighteenth century.

All the mechanism of a gothic clock is made of iron and "contained" in an iron cage. This is so usual in this period that they are also called iron clocks or skeleton clocks, without a box .Every part is fixed with cotter pins and not a single screw can be found until 1550.

Nowadays these mechanical systems that we have just described can be seen in perfect working in the clocks made by Ardavín.

Thanks to the great care with which they are made, these clocks have a real medieval look: the wheels' teeth are very long trying to imitate the shape of the original ones which were engraved one by one with a file. We have used wedges or cotter pins to fix the iron framework and there are no screws.

The appearance of these clocks has been obtained thanks to a complicated ageing process of every part, in both the iron and the wooden ones.

Bibliography

[1] Abeler, Jürgen: 5000 Jahre Zeitmessung. Wuppertal: Wuppertaler Uhrenmuseum, 1978
[2] Bourdais, Marcel & Gras, G.: ABC de l'apprenti horloger. Paris: Henry Renaud, 1917
[3] Bruton, Eric: Histoire des horloges, montres et pendules. Paris: Atlas, 1980
[4] Collard, F. Bernard Royer: Skeleton Clocks. London: N.A.G. Press, 1969
[5] De Carle, Donald: Horology. London: English Universities Press, 1965
[6] Curtis, Tony: Clocks & watches. Galashiels: Lyle Publications. 1977
[7] Echeverría, J.M.: Coleccionismo de relojes antiguos. León: Everest, 1975
[8] Echeverría, J.M.: Coleccionismo de relojes de bolsillo. Madrid: Editorial Everest, 1982
[9] Hana, W.F.J.: English lantern clocks. Poole: Blandford Press, 1979
[10] L'Heure devient décimale: décret de la Convention Nationale qui établit un concours sur les moyens d'organiser les montres et pendules en divisions décimales. Paris : A.N.C.A.H.A. 1989.
[11] Horloges rustiques de la Collection Meister, Zurich. La Chaux-de-Fonds: Musée international d'horlogerie, 1982
[12] Horloges gothiques, premières horloges mécaniques à poids, Fasc. 1. Le Locle: Musée d'Horlogerie, Château des Monts, 1969
[13] Hutchinson, Beresford: Guía de relojes antiguos. Barcelona: Grijalbo, 1986
[14] Jagger, Cedric: The World's great clocks & watches. London: Hamlyn, 1977
[15] Maitzner, Francis et Moreau, Jean: La Comtoise, La Morbier, La Morez. Vittel: F. Maitzner, 1976
[16] Mannoni, Edith: Montres anciennes. Paris: C. Massin, 1982
[17] Montañés, Luis: El Escape y el péndulo. Madrid: Antiqvaria, 1991
[18] Montañés, Luis: La máquina de las horas. Madrid: Isla, 1975
[19] Montañés, Luis: Relojes. Madrid: Cipsa, 1986
[20] Montañés, Luis: Relojes españoles. Madrid: Prensa Española, 1968
[21] Simoni, Antonio: Orologi italiani dal Cinquecento all'Ottocento. Milano: Antonio Vallardi, 1965
[22] Smith, Alan (ed.): The "Country life" international dictionary of clocks. London: Country Life Books, 1979
[23] Tardy: La Pendule française. Paris: Tardy, 1987
[19] Montañés, Luis: Relojes. Madrid: Cipsa, 1986
[20] Montañés, Luis: Relojes españoles. Madrid: Prensa Española, 1968
[21] Simoni, Antonio: Orologi italiani dal Cinquecento all'Ottocento. Milano: Antonio Vallardi, 1965
[22] Smith, Alan (ed.): The "Country life" international dictionary of clocks. London: Country Life Books, 1979
[23] Tardy: La Pendule française. Paris: Tardy, 1987


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