76 A. LIVERSIDGE. 
aqua regia, Plate 9. The structure was found to be much more 
granular than that of the gold nuggets, and the mass readily 
disintegrated into particles of from 1 to 2 mm. in diameter and 
possessing a crystallised appearance with octahedral markings. 
Between many of the granules there were films of a pale buff 
coloured non-metallic mineral, which requires further examination. 
The nugget was evidently impure and requires to be analysed. 
Copper NvuGGETs. 
Some nuggets of native copper were sliced and etched, although 
they presented a crystaline structure it was not well marked. I 
hope to shortly procure some silver nuggets for examination. 
ARTIFICIAL NuGGets AND INGoTs. 
Next attempts were made to prepare artificial nuggets by 
electrolytic deposition; around wires, fairly thick masses were 
obtained, the sections of these showed well defined rings and 
traces of crystalline structure ; the rings or successive coats were 
clearly due to changes in the strength of the current and of the 
solution. Masses of fused gold were also cut, polished and etched, 
and in all cases a strongly marked crystalline structure was visible. 
In Plate 10 is shown the cross section through the centre of an 
ingot of gold weighing 1,400 oz. and assaying 1,000, i.e., it was 
nominally pure gold. The crystals are seen to be very large and 
well defined and radiating out from the sides, which were in 
contact with the ingot mould, in well-defined curves. ‘The hori- 
zontal lines may be due to the action of the planing tool by which 
the ingot was cut, the tool marks were filed and polished away 
completely, but doubtless the pressure of the tool set up stresses 
and molecular changes, and the effects of these become apparent 
in the process of etching; the shearing strain must have been 
considerable, for it required a nominal four-horse power engine to 
work the tool when making the vertical groove or cut, although 
the cutting edge was quite narrow. 
The next, Plate 11, shows the base of the ingot after etching; 
before etching no crystalline structure was apparent. 
ae te ye tae ey 
