268 REPORTS ON THE STATE OP SCIENCE, ETC. 



Specimens 1 to 4 are therefore coppier, whilst 5 is bronze, apparently produced 

 from copper from a different source. 



The iinds at Ur during the excavations of the last season include a spear head 

 from the stratum just above the flood deposit, described as the earliest metal object 

 80 far found in the work. This has proved on analysis to be of copper, with no more 

 than traces of foreign elements. In the later deposits objects of both bronze and 

 copper have been found, but have not yet been analysed. Mr. Woolley is of opinion 

 that the finding of hammered copper axes of later date than the cast axes of bronze, 

 and to some extent imitating them in design, is evidence of a failure of the supply 

 of tin between 3200 and 2700 B.C. This clue appears to be worth following up. 

 So far, the source of the tin used in the making of these bronzes remains unknown. 



In view of the suggested connection between Sumerian and South African metals, 

 a series of specimens was obtained from Mr. H. B. Maufe, of the Geological Survey of 

 Rhodesia. Three metallic objects were examined : — 



Copper. Iron. Nickel. Tin. Lead. 

 1. Native copper. Falcon mine, ChiUmanzi 



district 97-50 0-35 tr. 



4. Partly smelted furnace product ; same 



source 6-45 25-79 0-37 tr. 



8. Native copper. Silverside mine, Lomagundi 



district 98-01 tr. tr. 



Specimens 2, 3, 5, 6 and 7 were ores, both pyritic and carbonate. None of these 

 proved to contain more than minute quantities of nickel. They do not, therefore, 

 enter into consideration as possible sources of Sumerian copper. The furnace product 

 4 is interesting, the ratio of nickel to copper being very high. In this respect it 

 resembles some of the South African alloys which have been described previously, 

 apparently made by the mixing of ores of copper and nickel. No information as to 

 its probable date is available. 



Mr. W. E. Collins also supplied a fragment of an ingot of copper found on Athlone 

 Farm, near Buiduva, S. Rhodesia, together with remains of crucibles. This proved 

 to be copper containing only traces of tin, iron and nickel. The date of these workings 

 is unknown. 



A large spear head from Zimbabwe, lent by the South African Museum, was 

 composed of bronze with 12-26 per cent, of tin, with only traces of iron and lead, and 

 no nickel. Many analyses of South African objects, bearing on this question, have 

 been published by Prof. G. H. Stanley (S. African Journal of Science, 1929, 26, 732). 



On account of the connection between Indian and Sumerian metals alreadj' recorded 

 it has been thought worth while to analyse two fragments of ancient celts from Burma 

 sent by Mr. T. 0. Morris. Both of these are cast material. No. 1, from Gyogya 

 Village, Thayetmyo district, contained 1-02 per cent, tin and a trace of iron, with 

 no lead or nickel. The other, from Thaminthal Village, Lower Chindwin district, 

 contained 2-77 per cent, tin, a trace of lead and no nickel. 



The opportunity has been taken to analyse a number of Chinese bronzes of dates 

 varying from the Chow to the T'ang periods. These are tin bronzes, most of which 

 contain relatively high percentages of lead. They are mostly free from nickel, and 

 appear to be derived from entirely different sources from the Sumerian material. 



Although there have been several recent papers on the subject, the cause of the 

 passage from copper to bronze remains completely obscure. The analysis of the 

 early bronzes offers no support for the suggestion that they were obtained accidentally 

 by smelting minerals which contain both copper and tin. Such minerals are always 

 of a complex character, and would not give rise to such pure alloys as the early bronzes 

 are found to be. It would appear, therefore, that these bronzes have been made 

 by mixing oxide ores of copper and tin, which must have been done deliberately. It 

 would be desirable to obtain further specimens of ores from various parts of Asia 

 within the possible range of Sumerian trade, in order to throw some light on this 

 question. 



