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A Steelyard Scale

Ashlar

Ground penetrating radar

A courtyard house

Rectified Photography

An Object Conservator

A Quern Stone

 

What is ?

Ashlar

Wall with tethering holes in the ashlar

Ashlar is the architectural term for a large dressed stone. At Zeugma, ashlars are often used as uprights, forming a framework which is then infilled with panels of lighter masonry such as mud brick or faced rubblework.

The results of the GPR survey in Mayenne

GPR in action at Mayenne France, which also involved the OAU and Stratascan.

What is ?

Ground Penetrating Radar

Ground Penetrating Radar (GPR) is a non-intrusive geophysical survey technique which can, under the right conditions, provide a detailed 3-dimensional profile of below ground deposits and structures up to and beyond depths of 3 metres. The radar sends a short pulse of energy into the ground which rebounds off different materials, for example walls and surfaces, and creates an image of the below ground archaeology. The amplitude of the echoes are recorded on radargrams and an approximate conversion is made to calculate the depth of features. The penetration of the radar varies depending on the local geological and topographical conditions: drier material such as sand, gravel and rock will permit the survey of deeper sections than materials that retain moisture such as clay. The penetration of the pulse can be increased by using longer wavelengths but at the expenseof resolution.

What is ?

A Courtyard House

The courtyard house is centred on a courtyard. This courtyard is open to the elements and is surrounded by colonnades on all four sides. The columns making up the colonnades sit on a plinth and support a roof over the passageway surrounding the courtyard. The rooms of the house opened off this walkway. At Zeugma the courtyards exposed so far have mosaic floors and below ground cisterns located to the side of the courtyard storing water. Usually the entrance from the main door of the house would lead to a vestibule with flanking rooms either side. From this vestibule you could access the courtyard, with the door normally positioned in the middle of one range. The main reception room was the triclinium or dining room. This was normally directly opposite the entrance. The triclinium could be the most lavishly decorated room of the building with as much money as possible spent on mosaic flooring and wall painting. Other rooms would include bedrooms, secondary dining rooms, kitchen and storerooms.

(Click here for large image of courtyard house plan)

What is ?

Rectified Photography

Rectified photography is a technique where, by the use of a large format camera in conjunction with theodolite survey, an accurate scaled image of an object or wall elevation can be made. It allows for a rapid but accurate record to be generated without the need for labour intensive, time consuming hand measured survey, a luxury not always available under archaeological 'rescue' conditions.

First, a series of surveyors targets are affixed to the architectural elevation or feature to be recorded. These targets are surveyed in using an EDM theodolite so that their precise locations are known relative to one another and to the overall site grid. Once the location of the targets has been recorded, the photograph can be taken. Each photograph will include a minimum of four surveying targets to allow for the image to be 'rectified' at the processing stage. Specialist medium or large format cameras are used as their large, flat photographic plates minimise the amount of distortion to the image.

Large format camera with flat, etched plate used for rectified photographic survey.

David Stevens undertaking rectified photographic survey of medieval masonry at the Château de Mayenne in Normandy, France.

In the photographic darkroom, the measurements between the surveying targets on the image are verified against the values from the theodolite survey before printing - this allows for the image to be minutely corrected ('rectified') to remove any minor distortions so that it presents a fully accurate, scaled image. Once the image has been accurately rectified, the photograph can be printed.

 

By scanning the scaled photographic image into the computer, the elevation can be traced 'on-screen' using computer aided design software and a scaled drawing produced. The technique of rectified photography is particularly useful for architectural elevations with a large amount of stonework detail and can significantly speed up the process of architectural recording without loss of accuracy

What is?

An Object Conservator

The finds recovered to date have been of an exceptional quality and quantity, providing non-stop work for the object conservators. On site these specialists provide emergency 'first aid' and lifting procedures for especially fragile finds. Back at the laboratory they undertake investigative cleaning treatments and recording of decorative and technical details on objects, as well as advising on storage and safe packaging. On site they carry a walkie/talkie so that they can be on call if needed in any trench.

Temporary packing for objects awaiting further treatment/radiography. Scales bottom shelf, lock top shelf

Dana Goodburn-Brown from AMTeC Recording the micro details - mineral preserved wood on a knife blade

A wide variety of artefacts have been found. Some are made from organic materials such as textiles, leather and timber that do not usually survive unless in waterlogged, oxygen free conditions . Interestingly, large quantities of charcoal have invariably been associated with these materials when found on site, suggesting that the charcoal in destruction layers may have provided a buffering microenvironment against agents of decay (much in the same way that activated charcoal and charcoal cloth are often used as protective measures to mop up organic acids in modern museum cases).

The conservation lab has a microscope with a video attachment. This helps record materials found in fine detail. We have been able to identify the scant remains of textile attached to a broach and the material a weaving kit was wrapped in.

All treatments undertaken on artefacts, both on and off site are documented and will form part of the site archive. The relationship between the nature of preservation of the materials excavated and the type of burial environment they lay in are of particular interest. A better understanding of these processes leads to more accurate predictions and management decisions for the site as a whole.

What is ?

A quern stone

Some of the largest artefacts found during the excavation are the quern stones made of the hard local stone, black basalt. Quern stones are tools used for grinding and include both hand querns and donkey mills.

Rotary hand querns are of a simple design and are easy to operate. The substance to be ground, for example flour or lentils, is placed between two rounded flat stones. The upper stone is rotated, either by hand, or more often with the aid of a short stick that is slotted into a hollow cut into the side of the top. The two stones are held together by a variety of ingenious methods. While the upper stone always has a central perforation, the lower stone can have a perforation, a low hump, or an iron spike in the centre. The upper stone either slots over the lower one, or a strong wooden stick with padding around the lower half is jammed into the two perforations.

 

These querns would have been a standard utensil in any Roman kitchen. Although they can be very large and heavy, they were carried by the Roman army on the march, with maybe one quern for every ten men. Rotary hand querns are not just an ancient tool, but were used extensively into the last century and are still used today in more rural areas, for example by Bedouins in south Jordan.

Rotary hand quern

Donkey mill

Donkey mills represent the industrial revolution in the world of quern stones. The upper stone is hourglass shaped with two handle blocks on the outside. These blocks are hollow squares with perforations in two sides. The perforated end of a large wooden beam would be slotted into the block and held in place by a peg running through from the holes in the sides. The lower stone is cone shaped. The upper stone sits on the cone and is turned by two donkeys tied to the beams or by two strong people. The top half of the hourglass provides a trough for feeding the grain into, whilst the grinding surface is the friction between the lower half and the cone.
Simple in design, donkey mills provided the means for grinding greater quantities of grain and their presence is indicative of larger-scale production and hence a bigger population. They are also thought to have been used for industrial purposes, for example in mines where they may have been used for grinding ore.

What is ?

A steelyard scale

The scales

A steelyard scale has been found in trench 9, the excavation area that revealed the remains of what are thought to be shops or workshops. This type of scale has three main parts, a horizontal bar with two suspension hooks, a weighing pan and a weight. The two hooks are situated at one end of the bar, on opposite sides. One is for suspending the complete scale and one is for the pan, which hangs down from the bar on chains. The remainder of the bar is marked out with notches indicating the different weights. The weight itself is suspended from the bar on a hook and chain. The scales operate by placing the object in the pan and then sliding the weight along the bar until it hangs level, the notch where the weight rests is thus the weight of the object.

Scales in temporary packaging awaiting further investigation/conservation treatment.

Modern scales.

Our steelyard scale is almost complete; the pan, weight and the bar with the two suspension hooks have all been found. The bar is hollow and it is likely that the long notched part upon which the weight would slide was a separate piece of metal to be inserted in the open end of the bar. This would allow the steelyard to be packed up and stored and transported easily. The weight is made of lead covered with copper plating. It is shaped like an acorn.The steelyard is one of the simplest types of scales, and the design has changed little over time; an hour's drive from the Zeugma site is the town of Sanliurfa where, in the copper market, similar scales are still being produced today.