W.L. UGLOW AND JW. A. JOHNSTON.

55°

cavities and inclusions. Two of the nuggets (Nos. 3 and 4)
apparently contain gold of different fineness, one part being higher
in silver than the other part. This is shown by the fact that when

i

Fic. 73. Polished and etched gold nuggets from Cariboo, B. C.; magni-
fied two diameters.

the surface is etched with aqua regia one part turns a persistent
gray whereas other parts remain bright. The contact between the
two kinds of gold is an irregular but sharply defined line (see
Fig. 74). The bright gold is not due to leaching of the silver

Fic. 74. Polished and etched surface of a gold nugget from Cariboo

B. C., showing the irregular contact of gold crystals of different fineness
magnified 128 diameters.

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