530 0. H. Matheivson — Metallographic Description 



structurally less homogeneous than worked structures and 

 oxidize more rapidly (cf. descriptions of Objects No. 2 and 

 ]STo. 5). Certain structure elements are attacked selectively on 

 long exposure to atmospheric influences. 



Garland (2) concludes from examination of some ancient 

 Egyptian bronzes that some recrystallization of worked por- 

 tions has very likely been effected by ageing. Rose (3) points 

 to possible recrystallization of an old trial plate of gold used 

 as an assay standard in the Royal (British) Mint. Such 

 conclusions are interesting but they are based wholly upon 

 circumstantial evidence. I have observed cases of incipient 

 recrystallization of vigorously worked metal in the present 

 collection of bronzes, but precisely the same effect may be pro- 

 duced by a form of annealing which is clearly indicated from 

 other considerations. Cf. description of Object Ko. 3 ; in 

 particular, photo-micrograph ISTo. 48. In other cases, the very 

 fine recrystallized grains show deformational characteristics 

 which proves that they were produced by the original craftsmen, 

 e. g., Object JSTo. 16. Numerous mechanically hardened and 

 subsequently unaltered (by perceptible recrystallization) struc- 

 tures were observed. In no case does it seem necessary to 

 resort to ageing for an explanation of the structures observed 

 in these bronzes. Whatever the actual facts involved, any 

 eventual reversion of unstable, mechanically hardened, struc- 

 tures to more stable (recrystallized) form cannot be defined as 

 a determinate function of the time involved in the transfor- 

 mation. 



It must likewise be conceded that metallographic examination 

 of the finished object cannot be expected to furnish any clue 

 to the smelting process used in preparing the metal or, indeed, 

 to indicate whether the alloy was produced directly by smelting 

 a mixed ore, or by alloying tin and copper. 



Summary of Analyses and Structural Examination. 



The present collection embraces about one hundred articles 

 which may be classed as tools, including axes, hatchets, knives, 

 chisels, bars and pointed instruments; domestic implements, 

 including mirrors, tweezers, small knives, pins or needles, 

 spatulas or spoons and various small articles ornamentally cast ; 

 articles of adornment, such as rings, bracelets, spangles, bells, 

 etc. ; and crude, or irregular pieces. A number of specimens 

 (thirty-three in all) intended to approximately represent the 

 diversity of the collection were analyzed. Twenty-one of these 



