CONSERVATION OF ANTIQUITIES — ^WERNER 599 



ing new material include the consolidation of friable paint in illumi- 

 nated manuscripts and powdery patina on bronzes. These examples 

 will suffice to show that the scientific evaluation of synthetic materials 

 of potential value in conservation has led to considerable advances in 

 this field. 



SCIENTIFIC AIDS IN CONSERVATION 



Another direction in which scientific methods are utilized in con- 

 servation is in the use of scientific aids such as metallographic and 

 microchemical analysis and radiography to provide information 

 necessary for the correct assessment of the factors involved in the 

 conservation. Radiography is, for example, frequently used in order 

 to find out if there is any decorative inlay lying hidden under layers 

 of corrosion products. Thus, when a fragment of an iron sword was 

 X-rayed (pi. 2, figs. 1 and 2), it was possible to obtain evidence of an 

 inlay which was present on both sides of the sword. By careful re- 

 moval of the overlaying layers of rust, it was subsequently possible to 

 reveal the inlay which had been carried out in a material similar to 

 brass, known as orichalcum (pi. 3). Another example which strik- 

 ingly illustrates the value of radiography in the exammation of an- 

 tiquities was a silver cup which was excavated at Enkomi in Cyprus 

 in the condition shown in plate 4, figure 1, covered with green cor- 

 rosion products derived from the copper which had been leached out 

 from the alloy. Preliminary examination showed that thin frag- 

 ments of gold, and also a black powdery material lay embedded in the 

 corrosion layers. Spectographic analysis of the black material 

 showed the major constituents to be silver and copper, thus indicating 

 a material similar to niello [11]. These findings indicated the prob- 

 able presence of a decorative inlay, and this was confirmed by X-ray. 

 This was important because it meant that special precautions had to 

 be taken in the choice of chemical reagent for removing the unsightly 

 incrustation without damaging the materials of the inlay. This was 

 achieved using hot formic acid to dissolve the copper corrosion prod- 

 ucts, when the original decoration round the cup was revealed in 

 surprising freslmess (pi. 4, fig. 2) . 



Another example which illustrates the need for scientific tests be- 

 fore commencing conservation of an antiquity was provided by a 

 silver libation vessel which was excavated at Nuri in the Sudan in a 

 fragmentary condition. Ancient silver is always very brittle, and 

 annealing of the silver to make it ductile is always the first stage in 

 the restoration of ancient silver objects. Normally, this does not pre- 

 sent any difficulties, but when tests were carried out on fragments 

 from this Nuri vessel it was found that for this case a special pro- 

 cedure would be necessary. In fact, metallographic examination of a 

 fragment as it was subjected to successively higher temperatures 



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