After years of burial, archeological iron is often found deteriorated, fragile and covered in corrosion products and soils. Its shape and function may not be the same as when the object was first manufactured, used or thrown away. Iron is one of the most unstable archaeological materials, and corrodes very rapidly once it is buried [iron page]. Objects that were once functional with moving parts may survive after years in the ground, but if they do, it is unlikely that the parts of the object will still be able to be moved in the same way they did before. Imagine leaving a bicycle outside unprotected for years, with the gears, brakes and bolts left in one position. After time and exposure to rain, pollutants in the air and the other elements of nature, it is more than likely that the metal components will have rusted and parts such as the gears will not slide smoothly on their track any longer. If caught soon enough it may be possible to reverse some of this process but the bike will not ever be like new again.
This iron hook has suffered the same type of deterioration as the bicycle mentioned above. After being buried in the ground for over three hundred years, the links of the hook are no longer able to be moved and they remain frozen in one position. Iron is very fragile when it is discovered upon excavation, and it is important not to move parts of an object such as this. Iron becomes very fragile, brittle and stressed during burial and most of the original strength of the iron is reduced, as the metal core is turned to corrosion products in the ground. Internal stress and micro-cracks can sometimes be a factor with corroded iron, causing it to crack and fall apart if pressure or movement is applied by force. It takes careful cleaning of the corrosion products to determine whether or not the iron links would be able to be moved again.
When an object such as this is chosen for conservation, it is important to remember that the reason for doing conservation is not to try to make the object “work” or “move” the way it was originally intended during manufacturing. Years of use before it was buried may have added to its immobility and that is part of its history. If the object is able to regain function during conservation treatment, then that is an added benefit to the treatment — but not the intended goal. The goal is to stabilize the object for future generations to enjoy it, whether it moves or not. And whether it is able to regain movement or not is part of the archaeological history of the object which should be preserved as well.
In the case of this iron hook, not only were the links immovable, but the original shape of the hook was misshapen, as the extended link lay back onto the metal of the hook. Conservation treatment of the object involved mechanical cleaning of the obscuring corrosion, which was acting like glue—holding the metal fragments together frozen in one spot. As more and more of the corrosion was removed through careful cleaning, the link loosened from its position during burial and returned to its original position. The two links were still intact with no cracks or breaks in the loops. After the object was fully cleaned of corrosion products, the surfaces were coated and treated to ensure the long-term stability of the pieces. Future movement will be kept to a minimum to ensure that the iron remains stable and no further stress is applied to the object.
It is difficult to determine the function of this chain link and hook. It was probably part of a more complex object which was broken in use and this part is the only representative of the object recovered. It could also simply be part of a chain which could be used for a wide variety of functions and activities.