ON SUMERIAN COPPER. 



437 



Sumerian Copper. — Report of Committee (Mr. H. J. E. Peake, Chairman ; 

 Mr. G. A. Garfitt, Secretary ; Mr. H. Balfour, Mr. L. H. Dudley 

 Buxton, Prof. Gordon Childe, Prof. C. H. Desch, Prof. H. J. 

 Fleure, Prof. S. Langdon, Mr. E. Mackay, Sir Flinders Petrie, 

 Mr. C. Leonard Woolley) appointed to report on the probable source 

 of the supply of copper used by the Sumcrians. 



The Secretary has procured a large number of samples of ore from Anatolia. Persia, 

 Arabia and Egypt, and many specimens of early metal found in Mesopotamia, Persia, 

 Egypt and India. These have been submitted for analysis to Prof. C. H. Desch and 

 Prof. C. O. Bannister. A report on some of these from Prof. Desch is appended. 



Report on the Metallurgical Examination of Specimens for the Sumerian 

 Committee of the British Association. By Prof. C. H. Desch, F.R.S. 



A PRINCIPAL object of the work of the committee has been to determine the source 

 of the copper used by the Sumerians. The most promising method of attaining that 

 object was to determine the nature of the impurities usually contained in the early 

 copper and bronze, with the possibility that some impurity might prove to be 

 sufiBciently characteristic to indicate the ore from which the copper had been obtained. 

 After examining a large amount of material it was found that nickel was frequently 

 present in the earUest specimens of copper and also of bronze. Most of the other 

 impurities are common to many ores, but nickel is by no means an invariable con- 

 stituent of copper ores, and it is very suitable for the purpose. The modern method 

 of estimating nickel in a chemical analysis is by precipitation with dimethylglyosime, 

 which gives a perfect quantitative separation from other metals, whilst the colour of 

 the precipitate is so characteristic that there is no possibility of confusion with other 

 impurities. In the course of the work it became advisable to examine the older 

 published analyses of ancient copper and bronze objects. The most important work 

 on this subject is ' Die Bronzen und Kupferlegirungen der alten und altesten Volker,' 

 by Ernst Freiherr von Bibra, published by Ferdinand Enke in Erlangen in 1869. 

 This work contains a critical examination of the composition of ancient copper and 

 bronze, with a very large number of analyses. The analyses of such objects found in 

 more recent books are very frequently derived from the work of von Bibra, althougli 

 they may be attributed to quite other authorities, having been repeatedly copied by 

 other writers at second or third hand. As many of the analyses show the presence 

 of nickel, and the modern method of estimating that element was not devised until 

 much later, it became necessary to examine the chemical methods used by von Bibra, 

 with a view to determining how far they may be relied on. This work was kindly 

 undertaken by Dr. F. Ibbotson, who carried through a number of analyses, proving 

 that von Bibra's method for the estimation of nickel, depending on the precipitation 

 of the ferrocyanide and its separation from other ferrocyanides by means of alkali, 

 is fairly trustworthy. It is liable under certain conditions to give rather high results, 

 but it will not indicate the presence of nickel in an alloy which does not contain that 

 metal. This is satisfactory, as it enables us to make use of a number of old analyses. 

 Some of the early copper specimens are of remarkable purity. It has been 

 suggested that this is due to native copper having been used, but such metal is not 

 invariably pure, and it is very likely that the pure metal has been obtained by 

 smelting malachite, a mineral of such characteristic appearance that it would be 

 easily recognised by the early metallurgists, and often of high purity. Two specimens 

 of native copper have been examined in the course of this investigation, the analj'ses, 

 after deducting sand and other mechanically mixed impurities, being as follows : — 



Native copper Native copper 



