74 A. LIVERSIDGE. 
minerals and rocks. No explosions, however, occurred and no 
blebs were formed. 
The section of a nugget from Orange, New South Wales, repro- 
duced in Plate 5, on heating to incipient redness in a bunsen, gave 
perhaps, the sharpest explosions and the largest blebs of any. 
The weight of this nugget was 1:08 oz. Troy, and the Mint assay 
of the parcel from which it was obtained gave gold ‘9345, silver 
0600. No foreign matter was visible in the section until it had 
been etched, when it was found to be studded with minute grains 
of quartz and a little oxide of iron; the crystalline structure is on 
a much smaller scale than that of the West Australian nuggets. 
The blebs and the cavities left by them are well shown, and Plate 6 
shows the cavities left after the bleb-walls had been dissolved away. 
As already stated, no gas was observed to escape from the blebs 
when the walls were dissolved away by chlorine water, hence the 
blisters were not due to imprisoned liquid carbon dioxide or other 
similar substance, but apparently to water or to a hydrated sub- 
stance such as iron oxide. 
Although the process block shows the structure of this section 
fairly well, yet some of the detail is lost, and nothing is seen of 
certain long and straight well defined lines meeting at angles of 
about 70°; these lines are clearly visible in the section itself, they 
reflect light very brilliantly and appear to be the edges of crystals. 
A nugget from Nerrigundah, New South Wales, also showed 
these long straight brilliant and sharply defined edges; in both 
cases they were seen on the exterior of the nugget as well as in 
the section. Assay = ‘9805 gold and ‘010 silver. 
On Plate 5 there is also the etched section of a nugget from 
Adelong, New South Wales, weighing -4 oz. Troy, Mint assay of 
parcel = °9275 gold and 0650 silver. This section showed the 
presence of much iron oxide and a minutely crystalline structure. 
On heating only minute blebs were formed. 
On Plate 6 there is also the section of a nugget from Queensland 
which shows the gold in the form of veins enclosing much ferru- 
